/* pngvalid.c - validate libpng by constructing then reading png files. | |
* | |
* Last changed in libpng 1.5.4 [July 7, 2011] | |
* Copyright (c) 2011 Glenn Randers-Pehrson | |
* Written by John Cunningham Bowler | |
* | |
* This code is released under the libpng license. | |
* For conditions of distribution and use, see the disclaimer | |
* and license in png.h | |
* | |
* NOTES: | |
* This is a C program that is intended to be linked against libpng. It | |
* generates bitmaps internally, stores them as PNG files (using the | |
* sequential write code) then reads them back (using the sequential | |
* read code) and validates that the result has the correct data. | |
* | |
* The program can be modified and extended to test the correctness of | |
* transformations performed by libpng. | |
*/ | |
#define _POSIX_SOURCE 1 | |
#include "png.h" | |
#if PNG_LIBPNG_VER < 10500 | |
/* This delibarately lacks the PNG_CONST. */ | |
typedef png_byte *png_const_bytep; | |
/* This is copied from 1.5.1 png.h: */ | |
#define PNG_INTERLACE_ADAM7_PASSES 7 | |
#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7) | |
#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7) | |
#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3) | |
#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3) | |
#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\ | |
-1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass)) | |
#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\ | |
-1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass)) | |
#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \ | |
(((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass)) | |
#define PNG_COL_FROM_PASS_COL(xIn, pass) \ | |
(((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass)) | |
#define PNG_PASS_MASK(pass,off) ( \ | |
((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \ | |
((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U)) | |
#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \ | |
((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1) | |
#define PNG_COL_IN_INTERLACE_PASS(x, pass) \ | |
((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1) | |
/* These are needed too for the default build: */ | |
#define PNG_WRITE_16BIT_SUPPORTED | |
#define PNG_READ_16BIT_SUPPORTED | |
/* This comes from pnglibconf.h afer 1.5: */ | |
#define PNG_GAMMA_THRESHOLD_FIXED\ | |
((png_fixed_point)(PNG_GAMMA_THRESHOLD * 100000)) | |
#endif | |
#include "zlib.h" /* For crc32 */ | |
#include <float.h> /* For floating point constants */ | |
#include <stdlib.h> /* For malloc */ | |
#include <string.h> /* For memcpy, memset */ | |
#include <math.h> /* For floor */ | |
/* Unused formal parameter errors are removed using the following macro which is | |
* expected to have no bad effects on performance. | |
*/ | |
#ifndef UNUSED | |
# if defined(__GNUC__) || defined(_MSC_VER) | |
# define UNUSED(param) (void)param; | |
# else | |
# define UNUSED(param) | |
# endif | |
#endif | |
/***************************** EXCEPTION HANDLING *****************************/ | |
#include "contrib/visupng/cexcept.h" | |
struct png_store; | |
define_exception_type(struct png_store*); | |
/* The following are macros to reduce typing everywhere where the well known | |
* name 'the_exception_context' must be defined. | |
*/ | |
#define anon_context(ps) struct exception_context *the_exception_context = \ | |
&(ps)->exception_context | |
#define context(ps,fault) anon_context(ps); png_store *fault | |
/******************************* UTILITIES ************************************/ | |
/* Error handling is particularly problematic in production code - error | |
* handlers often themselves have bugs which lead to programs that detect | |
* minor errors crashing. The following functions deal with one very | |
* common class of errors in error handlers - attempting to format error or | |
* warning messages into buffers that are too small. | |
*/ | |
static size_t safecat(char *buffer, size_t bufsize, size_t pos, | |
PNG_CONST char *cat) | |
{ | |
while (pos < bufsize && cat != NULL && *cat != 0) | |
buffer[pos++] = *cat++; | |
if (pos >= bufsize) | |
pos = bufsize-1; | |
buffer[pos] = 0; | |
return pos; | |
} | |
static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n) | |
{ | |
char number[64]; | |
sprintf(number, "%d", n); | |
return safecat(buffer, bufsize, pos, number); | |
} | |
#ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d, | |
int precision) | |
{ | |
char number[64]; | |
sprintf(number, "%.*f", precision, d); | |
return safecat(buffer, bufsize, pos, number); | |
} | |
#endif | |
static PNG_CONST char invalid[] = "invalid"; | |
static PNG_CONST char sep[] = ": "; | |
static PNG_CONST char *colour_types[8] = | |
{ | |
"greyscale", invalid, "truecolour", "indexed-colour", | |
"greyscale with alpha", invalid, "truecolour with alpha", invalid | |
}; | |
/* Generate random bytes. This uses a boring repeatable algorithm and it | |
* is implemented here so that it gives the same set of numbers on every | |
* architecture. It's a linear congruential generator (Knuth or Sedgewick | |
* "Algorithms") but it comes from the 'feedback taps' table in Horowitz and | |
* Hill, "The Art of Electronics". | |
*/ | |
static void | |
make_random_bytes(png_uint_32* seed, void* pv, size_t size) | |
{ | |
png_uint_32 u0 = seed[0], u1 = seed[1]; | |
png_bytep bytes = /*no cast required*/pv; | |
/* There are thirty three bits, the next bit in the sequence is bit-33 XOR | |
* bit-20. The top 1 bit is in u1, the bottom 32 are in u0. | |
*/ | |
size_t i; | |
for (i=0; i<size; ++i) | |
{ | |
/* First generate 8 new bits then shift them in at the end. */ | |
png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff; | |
u1 <<= 8; | |
u1 |= u0 >> 24; | |
u0 <<= 8; | |
u0 |= u; | |
*bytes++ = (png_byte)u; | |
} | |
seed[0] = u0; | |
seed[1] = u1; | |
} | |
static void | |
make_four_random_bytes(png_uint_32* seed, png_bytep bytes) | |
{ | |
make_random_bytes(seed, bytes, 4); | |
} | |
static void | |
randomize(void *pv, size_t size) | |
{ | |
static png_uint_32 random_seed[2] = {0x56789abc, 0xd}; | |
make_random_bytes(random_seed, pv, size); | |
} | |
#define RANDOMIZE(this) randomize(&(this), sizeof (this)) | |
/* A numeric ID based on PNG file characteristics. The 'do_interlace' field | |
* simply records whether pngvalid did the interlace itself or whether it | |
* was done by libpng. Width and height must be less than 256. 'palette' is an | |
* index of the palette to use for formats with a palette (0 otherwise.) | |
*/ | |
#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \ | |
((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \ | |
(((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24))) | |
#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U)) | |
#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU)) | |
#define PALETTE_FROM_ID(id) ((int)(((id) >> 8) & 0x1f)) | |
#define INTERLACE_FROM_ID(id) ((int)(((id) >> 13) & 0x3)) | |
#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1)) | |
#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff) | |
#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff) | |
/* Utility to construct a standard name for a standard image. */ | |
static size_t | |
standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type, | |
int bit_depth, int npalette, int interlace_type, | |
png_uint_32 w, png_uint_32 h, int do_interlace) | |
{ | |
pos = safecat(buffer, bufsize, pos, colour_types[colour_type]); | |
if (npalette > 0) | |
{ | |
pos = safecat(buffer, bufsize, pos, "["); | |
pos = safecatn(buffer, bufsize, pos, npalette); | |
pos = safecat(buffer, bufsize, pos, "]"); | |
} | |
pos = safecat(buffer, bufsize, pos, " "); | |
pos = safecatn(buffer, bufsize, pos, bit_depth); | |
pos = safecat(buffer, bufsize, pos, " bit"); | |
if (interlace_type != PNG_INTERLACE_NONE) | |
{ | |
pos = safecat(buffer, bufsize, pos, " interlaced"); | |
if (do_interlace) | |
pos = safecat(buffer, bufsize, pos, "(pngvalid)"); | |
else | |
pos = safecat(buffer, bufsize, pos, "(libpng)"); | |
} | |
if (w > 0 || h > 0) | |
{ | |
pos = safecat(buffer, bufsize, pos, " "); | |
pos = safecatn(buffer, bufsize, pos, w); | |
pos = safecat(buffer, bufsize, pos, "x"); | |
pos = safecatn(buffer, bufsize, pos, h); | |
} | |
return pos; | |
} | |
static size_t | |
standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id) | |
{ | |
return standard_name(buffer, bufsize, pos, COL_FROM_ID(id), | |
DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id), | |
WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id)); | |
} | |
/* Convenience API and defines to list valid formats. Note that 16 bit read and | |
* write support is required to do 16 bit read tests (we must be able to make a | |
* 16 bit image to test!) | |
*/ | |
#ifdef PNG_WRITE_16BIT_SUPPORTED | |
# define WRITE_BDHI 4 | |
# ifdef PNG_READ_16BIT_SUPPORTED | |
# define READ_BDHI 4 | |
# define DO_16BIT | |
# endif | |
#else | |
# define WRITE_BDHI 3 | |
#endif | |
#ifndef DO_16BIT | |
# define READ_BDHI 3 | |
#endif | |
/* The following defines the number of different palettes to generate for | |
* each log bit depth of a colour type 3 standard image. | |
*/ | |
#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1 : 16) | |
static int | |
next_format(png_bytep colour_type, png_bytep bit_depth, int* palette_number) | |
{ | |
if (*bit_depth == 0) | |
{ | |
*colour_type = 0, *bit_depth = 1, *palette_number = 0; | |
return 1; | |
} | |
if (*colour_type == 3) | |
{ | |
/* Add multiple palettes for colour type 3. */ | |
if (++*palette_number < PALETTE_COUNT(*bit_depth)) | |
return 1; | |
*palette_number = 0; | |
} | |
*bit_depth = (png_byte)(*bit_depth << 1); | |
/* Palette images are restricted to 8 bit depth */ | |
if (*bit_depth <= 8 | |
# ifdef DO_16BIT | |
|| (*colour_type != 3 && *bit_depth <= 16) | |
# endif | |
) | |
return 1; | |
/* Move to the next color type, or return 0 at the end. */ | |
switch (*colour_type) | |
{ | |
case 0: | |
*colour_type = 2; | |
*bit_depth = 8; | |
return 1; | |
case 2: | |
*colour_type = 3; | |
*bit_depth = 1; | |
return 1; | |
case 3: | |
*colour_type = 4; | |
*bit_depth = 8; | |
return 1; | |
case 4: | |
*colour_type = 6; | |
*bit_depth = 8; | |
return 1; | |
default: | |
return 0; | |
} | |
} | |
#ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
static unsigned int | |
sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth, | |
png_uint_32 x, unsigned int sample_index) | |
{ | |
png_uint_32 bit_index, result; | |
/* Find a sample index for the desired sample: */ | |
x *= bit_depth; | |
bit_index = x; | |
if ((colour_type & 1) == 0) /* !palette */ | |
{ | |
if (colour_type & 2) | |
bit_index *= 3; | |
if (colour_type & 4) | |
bit_index += x; /* Alpha channel */ | |
/* Multiple channels; select one: */ | |
if (colour_type & (2+4)) | |
bit_index += sample_index * bit_depth; | |
} | |
/* Return the sample from the row as an integer. */ | |
row += bit_index >> 3; | |
result = *row; | |
if (bit_depth == 8) | |
return result; | |
else if (bit_depth > 8) | |
return (result << 8) + *++row; | |
/* Less than 8 bits per sample. */ | |
bit_index &= 7; | |
return (result >> (8-bit_index-bit_depth)) & ((1U<<bit_depth)-1); | |
} | |
#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ | |
/* Copy a single pixel, of a given size, from one buffer to another - | |
* while this is basically bit addressed there is an implicit assumption | |
* that pixels 8 or more bits in size are byte aligned and that pixels | |
* do not otherwise cross byte boundaries. (This is, so far as I know, | |
* universally true in bitmap computer graphics. [JCB 20101212]) | |
* | |
* NOTE: The to and from buffers may be the same. | |
*/ | |
static void | |
pixel_copy(png_bytep toBuffer, png_uint_32 toIndex, | |
png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize) | |
{ | |
/* Assume we can multiply by 'size' without overflow because we are | |
* just working in a single buffer. | |
*/ | |
toIndex *= pixelSize; | |
fromIndex *= pixelSize; | |
if (pixelSize < 8) /* Sub-byte */ | |
{ | |
/* Mask to select the location of the copied pixel: */ | |
unsigned int destMask = ((1U<<pixelSize)-1) << (8-pixelSize-(toIndex&7)); | |
/* The following read the entire pixels and clears the extra: */ | |
unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask; | |
unsigned int sourceByte = fromBuffer[fromIndex >> 3]; | |
/* Don't rely on << or >> supporting '0' here, just in case: */ | |
fromIndex &= 7; | |
if (fromIndex > 0) sourceByte <<= fromIndex; | |
if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7; | |
toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask)); | |
} | |
else /* One or more bytes */ | |
memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3); | |
} | |
/* Compare pixels - they are assumed to start at the first byte in the | |
* given buffers. | |
*/ | |
static int | |
pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width) | |
{ | |
if (memcmp(pa, pb, bit_width>>3) == 0) | |
{ | |
png_uint_32 p; | |
if ((bit_width & 7) == 0) return 0; | |
/* Ok, any differences? */ | |
p = pa[bit_width >> 3]; | |
p ^= pb[bit_width >> 3]; | |
if (p == 0) return 0; | |
/* There are, but they may not be significant, remove the bits | |
* after the end (the low order bits in PNG.) | |
*/ | |
bit_width &= 7; | |
p >>= 8-bit_width; | |
if (p == 0) return 0; | |
} | |
return 1; /* Different */ | |
} | |
/*************************** BASIC PNG FILE WRITING ***************************/ | |
/* A png_store takes data from the sequential writer or provides data | |
* to the sequential reader. It can also store the result of a PNG | |
* write for later retrieval. | |
*/ | |
#define STORE_BUFFER_SIZE 500 /* arbitrary */ | |
typedef struct png_store_buffer | |
{ | |
struct png_store_buffer* prev; /* NOTE: stored in reverse order */ | |
png_byte buffer[STORE_BUFFER_SIZE]; | |
} png_store_buffer; | |
#define FILE_NAME_SIZE 64 | |
typedef struct store_palette_entry /* record of a single palette entry */ | |
{ | |
png_byte red; | |
png_byte green; | |
png_byte blue; | |
png_byte alpha; | |
} store_palette_entry, store_palette[256]; | |
typedef struct png_store_file | |
{ | |
struct png_store_file* next; /* as many as you like... */ | |
char name[FILE_NAME_SIZE]; | |
png_uint_32 id; /* must be correct (see FILEID) */ | |
png_size_t datacount; /* In this (the last) buffer */ | |
png_store_buffer data; /* Last buffer in file */ | |
int npalette; /* Number of entries in palette */ | |
store_palette_entry* palette; /* May be NULL */ | |
} png_store_file; | |
/* The following is a pool of memory allocated by a single libpng read or write | |
* operation. | |
*/ | |
typedef struct store_pool | |
{ | |
struct png_store *store; /* Back pointer */ | |
struct store_memory *list; /* List of allocated memory */ | |
png_byte mark[4]; /* Before and after data */ | |
/* Statistics for this run. */ | |
png_alloc_size_t max; /* Maximum single allocation */ | |
png_alloc_size_t current; /* Current allocation */ | |
png_alloc_size_t limit; /* Highest current allocation */ | |
png_alloc_size_t total; /* Total allocation */ | |
/* Overall statistics (retained across successive runs). */ | |
png_alloc_size_t max_max; | |
png_alloc_size_t max_limit; | |
png_alloc_size_t max_total; | |
} store_pool; | |
typedef struct png_store | |
{ | |
/* For cexcept.h exception handling - simply store one of these; | |
* the context is a self pointer but it may point to a different | |
* png_store (in fact it never does in this program.) | |
*/ | |
struct exception_context | |
exception_context; | |
unsigned int verbose :1; | |
unsigned int treat_warnings_as_errors :1; | |
unsigned int expect_error :1; | |
unsigned int expect_warning :1; | |
unsigned int saw_warning :1; | |
unsigned int speed :1; | |
unsigned int progressive :1; /* use progressive read */ | |
unsigned int validated :1; /* used as a temporary flag */ | |
int nerrors; | |
int nwarnings; | |
char test[128]; /* Name of test */ | |
char error[256]; | |
/* Read fields */ | |
png_structp pread; /* Used to read a saved file */ | |
png_infop piread; | |
png_store_file* current; /* Set when reading */ | |
png_store_buffer* next; /* Set when reading */ | |
png_size_t readpos; /* Position in *next */ | |
png_byte* image; /* Buffer for reading interlaced images */ | |
png_size_t cb_image; /* Size of this buffer */ | |
png_size_t cb_row; /* Row size of the image(s) */ | |
png_uint_32 image_h; /* Number of rows in a single image */ | |
store_pool read_memory_pool; | |
/* Write fields */ | |
png_store_file* saved; | |
png_structp pwrite; /* Used when writing a new file */ | |
png_infop piwrite; | |
png_size_t writepos; /* Position in .new */ | |
char wname[FILE_NAME_SIZE]; | |
png_store_buffer new; /* The end of the new PNG file being written. */ | |
store_pool write_memory_pool; | |
store_palette_entry* palette; | |
int npalette; | |
} png_store; | |
/* Initialization and cleanup */ | |
static void | |
store_pool_mark(png_bytep mark) | |
{ | |
static png_uint_32 store_seed[2] = { 0x12345678, 1}; | |
make_four_random_bytes(store_seed, mark); | |
} | |
/* Use this for random 32 bit values; this function makes sure the result is | |
* non-zero. | |
*/ | |
static png_uint_32 | |
random_32(void) | |
{ | |
for(;;) | |
{ | |
png_byte mark[4]; | |
png_uint_32 result; | |
store_pool_mark(mark); | |
result = png_get_uint_32(mark); | |
if (result != 0) | |
return result; | |
} | |
} | |
static void | |
store_pool_init(png_store *ps, store_pool *pool) | |
{ | |
memset(pool, 0, sizeof *pool); | |
pool->store = ps; | |
pool->list = NULL; | |
pool->max = pool->current = pool->limit = pool->total = 0; | |
pool->max_max = pool->max_limit = pool->max_total = 0; | |
store_pool_mark(pool->mark); | |
} | |
static void | |
store_init(png_store* ps) | |
{ | |
memset(ps, 0, sizeof *ps); | |
init_exception_context(&ps->exception_context); | |
store_pool_init(ps, &ps->read_memory_pool); | |
store_pool_init(ps, &ps->write_memory_pool); | |
ps->verbose = 0; | |
ps->treat_warnings_as_errors = 0; | |
ps->expect_error = 0; | |
ps->expect_warning = 0; | |
ps->saw_warning = 0; | |
ps->speed = 0; | |
ps->progressive = 0; | |
ps->validated = 0; | |
ps->nerrors = ps->nwarnings = 0; | |
ps->pread = NULL; | |
ps->piread = NULL; | |
ps->saved = ps->current = NULL; | |
ps->next = NULL; | |
ps->readpos = 0; | |
ps->image = NULL; | |
ps->cb_image = 0; | |
ps->cb_row = 0; | |
ps->image_h = 0; | |
ps->pwrite = NULL; | |
ps->piwrite = NULL; | |
ps->writepos = 0; | |
ps->new.prev = NULL; | |
ps->palette = NULL; | |
ps->npalette = 0; | |
} | |
static void | |
store_freebuffer(png_store_buffer* psb) | |
{ | |
if (psb->prev) | |
{ | |
store_freebuffer(psb->prev); | |
free(psb->prev); | |
psb->prev = NULL; | |
} | |
} | |
static void | |
store_freenew(png_store *ps) | |
{ | |
store_freebuffer(&ps->new); | |
ps->writepos = 0; | |
if (ps->palette != NULL) | |
{ | |
free(ps->palette); | |
ps->palette = NULL; | |
ps->npalette = 0; | |
} | |
} | |
static void | |
store_storenew(png_store *ps) | |
{ | |
png_store_buffer *pb; | |
if (ps->writepos != STORE_BUFFER_SIZE) | |
png_error(ps->pwrite, "invalid store call"); | |
pb = malloc(sizeof *pb); | |
if (pb == NULL) | |
png_error(ps->pwrite, "store new: OOM"); | |
*pb = ps->new; | |
ps->new.prev = pb; | |
ps->writepos = 0; | |
} | |
static void | |
store_freefile(png_store_file **ppf) | |
{ | |
if (*ppf != NULL) | |
{ | |
store_freefile(&(*ppf)->next); | |
store_freebuffer(&(*ppf)->data); | |
(*ppf)->datacount = 0; | |
if ((*ppf)->palette != NULL) | |
{ | |
free((*ppf)->palette); | |
(*ppf)->palette = NULL; | |
(*ppf)->npalette = 0; | |
} | |
free(*ppf); | |
*ppf = NULL; | |
} | |
} | |
/* Main interface to file storeage, after writing a new PNG file (see the API | |
* below) call store_storefile to store the result with the given name and id. | |
*/ | |
static void | |
store_storefile(png_store *ps, png_uint_32 id) | |
{ | |
png_store_file *pf = malloc(sizeof *pf); | |
if (pf == NULL) | |
png_error(ps->pwrite, "storefile: OOM"); | |
safecat(pf->name, sizeof pf->name, 0, ps->wname); | |
pf->id = id; | |
pf->data = ps->new; | |
pf->datacount = ps->writepos; | |
ps->new.prev = NULL; | |
ps->writepos = 0; | |
pf->palette = ps->palette; | |
pf->npalette = ps->npalette; | |
ps->palette = 0; | |
ps->npalette = 0; | |
/* And save it. */ | |
pf->next = ps->saved; | |
ps->saved = pf; | |
} | |
/* Generate an error message (in the given buffer) */ | |
static size_t | |
store_message(png_store *ps, png_structp pp, char *buffer, size_t bufsize, | |
size_t pos, PNG_CONST char *msg) | |
{ | |
if (pp != NULL && pp == ps->pread) | |
{ | |
/* Reading a file */ | |
pos = safecat(buffer, bufsize, pos, "read: "); | |
if (ps->current != NULL) | |
{ | |
pos = safecat(buffer, bufsize, pos, ps->current->name); | |
pos = safecat(buffer, bufsize, pos, sep); | |
} | |
} | |
else if (pp != NULL && pp == ps->pwrite) | |
{ | |
/* Writing a file */ | |
pos = safecat(buffer, bufsize, pos, "write: "); | |
pos = safecat(buffer, bufsize, pos, ps->wname); | |
pos = safecat(buffer, bufsize, pos, sep); | |
} | |
else | |
{ | |
/* Neither reading nor writing (or a memory error in struct delete) */ | |
pos = safecat(buffer, bufsize, pos, "pngvalid: "); | |
} | |
if (ps->test[0] != 0) | |
{ | |
pos = safecat(buffer, bufsize, pos, ps->test); | |
pos = safecat(buffer, bufsize, pos, sep); | |
} | |
pos = safecat(buffer, bufsize, pos, msg); | |
return pos; | |
} | |
/* Verbose output to the error stream: */ | |
static void | |
store_verbose(png_store *ps, png_structp pp, png_const_charp prefix, | |
png_const_charp message) | |
{ | |
char buffer[512]; | |
if (prefix) | |
fputs(prefix, stderr); | |
(void)store_message(ps, pp, buffer, sizeof buffer, 0, message); | |
fputs(buffer, stderr); | |
fputc('\n', stderr); | |
} | |
/* Log an error or warning - the relevant count is always incremented. */ | |
static void | |
store_log(png_store* ps, png_structp pp, png_const_charp message, int is_error) | |
{ | |
/* The warning is copied to the error buffer if there are no errors and it is | |
* the first warning. The error is copied to the error buffer if it is the | |
* first error (overwriting any prior warnings). | |
*/ | |
if (is_error ? (ps->nerrors)++ == 0 : | |
(ps->nwarnings)++ == 0 && ps->nerrors == 0) | |
store_message(ps, pp, ps->error, sizeof ps->error, 0, message); | |
if (ps->verbose) | |
store_verbose(ps, pp, is_error ? "error: " : "warning: ", message); | |
} | |
/* Functions to use as PNG callbacks. */ | |
static void | |
store_error(png_structp pp, png_const_charp message) /* PNG_NORETURN */ | |
{ | |
png_store *ps = png_get_error_ptr(pp); | |
if (!ps->expect_error) | |
store_log(ps, pp, message, 1 /* error */); | |
/* And finally throw an exception. */ | |
{ | |
struct exception_context *the_exception_context = &ps->exception_context; | |
Throw ps; | |
} | |
} | |
static void | |
store_warning(png_structp pp, png_const_charp message) | |
{ | |
png_store *ps = png_get_error_ptr(pp); | |
if (!ps->expect_warning) | |
store_log(ps, pp, message, 0 /* warning */); | |
else | |
ps->saw_warning = 1; | |
} | |
/* These somewhat odd functions are used when reading an image to ensure that | |
* the buffer is big enough, the png_structp is for errors. | |
*/ | |
/* Return a single row from the correct image. */ | |
static png_bytep | |
store_image_row(PNG_CONST png_store* ps, png_structp pp, int nImage, | |
png_uint_32 y) | |
{ | |
png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2; | |
if (ps->image == NULL) | |
png_error(pp, "no allocated image"); | |
if (coffset + ps->cb_row + 3 > ps->cb_image) | |
png_error(pp, "image too small"); | |
return ps->image + coffset; | |
} | |
static void | |
store_image_free(png_store *ps, png_structp pp) | |
{ | |
if (ps->image != NULL) | |
{ | |
png_bytep image = ps->image; | |
if (image[-1] != 0xed || image[ps->cb_image] != 0xfe) | |
{ | |
if (pp != NULL) | |
png_error(pp, "png_store image overwrite (1)"); | |
else | |
store_log(ps, NULL, "png_store image overwrite (2)", 1); | |
} | |
ps->image = NULL; | |
ps->cb_image = 0; | |
--image; | |
free(image); | |
} | |
} | |
static void | |
store_ensure_image(png_store *ps, png_structp pp, int nImages, png_size_t cbRow, | |
png_uint_32 cRows) | |
{ | |
png_size_t cb = nImages * cRows * (cbRow + 5); | |
if (ps->cb_image < cb) | |
{ | |
png_bytep image; | |
store_image_free(ps, pp); | |
/* The buffer is deliberately mis-aligned. */ | |
image = malloc(cb+2); | |
if (image == NULL) | |
{ | |
/* Called from the startup - ignore the error for the moment. */ | |
if (pp == NULL) | |
return; | |
png_error(pp, "OOM allocating image buffer"); | |
} | |
/* These magic tags are used to detect overwrites above. */ | |
++image; | |
image[-1] = 0xed; | |
image[cb] = 0xfe; | |
ps->image = image; | |
ps->cb_image = cb; | |
} | |
/* We have an adequate sized image; lay out the rows. There are 2 bytes at | |
* the start and three at the end of each (this ensures that the row | |
* alignment starts out odd - 2+1 and changes for larger images on each row.) | |
*/ | |
ps->cb_row = cbRow; | |
ps->image_h = cRows; | |
/* For error checking, the whole buffer is set to '1' - this matches what | |
* happens with the 'size' test images on write and also matches the unused | |
* bits in the test rows. | |
*/ | |
memset(ps->image, 0xff, cb); | |
/* Then put in the marks. */ | |
while (--nImages >= 0) | |
{ | |
png_uint_32 y; | |
for (y=0; y<cRows; ++y) | |
{ | |
png_bytep row = store_image_row(ps, pp, nImages, y); | |
/* The markers: */ | |
row[-2] = 190; | |
row[-1] = 239; | |
row[cbRow] = 222; | |
row[cbRow+1] = 173; | |
row[cbRow+2] = 17; | |
} | |
} | |
} | |
static void | |
store_image_check(PNG_CONST png_store* ps, png_structp pp, int iImage) | |
{ | |
png_const_bytep image = ps->image; | |
if (image[-1] != 0xed || image[ps->cb_image] != 0xfe) | |
png_error(pp, "image overwrite"); | |
else | |
{ | |
png_size_t cbRow = ps->cb_row; | |
png_uint_32 rows = ps->image_h; | |
image += iImage * (cbRow+5) * ps->image_h; | |
image += 2; /* skip image first row markers */ | |
while (rows-- > 0) | |
{ | |
if (image[-2] != 190 || image[-1] != 239) | |
png_error(pp, "row start overwritten"); | |
if (image[cbRow] != 222 || image[cbRow+1] != 173 || | |
image[cbRow+2] != 17) | |
png_error(pp, "row end overwritten"); | |
image += cbRow+5; | |
} | |
} | |
} | |
static void | |
store_write(png_structp pp, png_bytep pb, png_size_t st) | |
{ | |
png_store *ps = png_get_io_ptr(pp); | |
if (ps->pwrite != pp) | |
png_error(pp, "store state damaged"); | |
while (st > 0) | |
{ | |
size_t cb; | |
if (ps->writepos >= STORE_BUFFER_SIZE) | |
store_storenew(ps); | |
cb = st; | |
if (cb > STORE_BUFFER_SIZE - ps->writepos) | |
cb = STORE_BUFFER_SIZE - ps->writepos; | |
memcpy(ps->new.buffer + ps->writepos, pb, cb); | |
pb += cb; | |
st -= cb; | |
ps->writepos += cb; | |
} | |
} | |
static void | |
store_flush(png_structp pp) | |
{ | |
UNUSED(pp) /*DOES NOTHING*/ | |
} | |
static size_t | |
store_read_buffer_size(png_store *ps) | |
{ | |
/* Return the bytes available for read in the current buffer. */ | |
if (ps->next != &ps->current->data) | |
return STORE_BUFFER_SIZE; | |
return ps->current->datacount; | |
} | |
#ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
/* Return total bytes available for read. */ | |
static size_t | |
store_read_buffer_avail(png_store *ps) | |
{ | |
if (ps->current != NULL && ps->next != NULL) | |
{ | |
png_store_buffer *next = &ps->current->data; | |
size_t cbAvail = ps->current->datacount; | |
while (next != ps->next && next != NULL) | |
{ | |
next = next->prev; | |
cbAvail += STORE_BUFFER_SIZE; | |
} | |
if (next != ps->next) | |
png_error(ps->pread, "buffer read error"); | |
if (cbAvail > ps->readpos) | |
return cbAvail - ps->readpos; | |
} | |
return 0; | |
} | |
#endif | |
static int | |
store_read_buffer_next(png_store *ps) | |
{ | |
png_store_buffer *pbOld = ps->next; | |
png_store_buffer *pbNew = &ps->current->data; | |
if (pbOld != pbNew) | |
{ | |
while (pbNew != NULL && pbNew->prev != pbOld) | |
pbNew = pbNew->prev; | |
if (pbNew != NULL) | |
{ | |
ps->next = pbNew; | |
ps->readpos = 0; | |
return 1; | |
} | |
png_error(ps->pread, "buffer lost"); | |
} | |
return 0; /* EOF or error */ | |
} | |
/* Need separate implementation and callback to allow use of the same code | |
* during progressive read, where the io_ptr is set internally by libpng. | |
*/ | |
static void | |
store_read_imp(png_store *ps, png_bytep pb, png_size_t st) | |
{ | |
if (ps->current == NULL || ps->next == NULL) | |
png_error(ps->pread, "store state damaged"); | |
while (st > 0) | |
{ | |
size_t cbAvail = store_read_buffer_size(ps) - ps->readpos; | |
if (cbAvail > 0) | |
{ | |
if (cbAvail > st) cbAvail = st; | |
memcpy(pb, ps->next->buffer + ps->readpos, cbAvail); | |
st -= cbAvail; | |
pb += cbAvail; | |
ps->readpos += cbAvail; | |
} | |
else if (!store_read_buffer_next(ps)) | |
png_error(ps->pread, "read beyond end of file"); | |
} | |
} | |
static void | |
store_read(png_structp pp, png_bytep pb, png_size_t st) | |
{ | |
png_store *ps = png_get_io_ptr(pp); | |
if (ps == NULL || ps->pread != pp) | |
png_error(pp, "bad store read call"); | |
store_read_imp(ps, pb, st); | |
} | |
static void | |
store_progressive_read(png_store *ps, png_structp pp, png_infop pi) | |
{ | |
/* Notice that a call to store_read will cause this function to fail because | |
* readpos will be set. | |
*/ | |
if (ps->pread != pp || ps->current == NULL || ps->next == NULL) | |
png_error(pp, "store state damaged (progressive)"); | |
do | |
{ | |
if (ps->readpos != 0) | |
png_error(pp, "store_read called during progressive read"); | |
png_process_data(pp, pi, ps->next->buffer, store_read_buffer_size(ps)); | |
} | |
while (store_read_buffer_next(ps)); | |
} | |
/* The caller must fill this in: */ | |
static store_palette_entry * | |
store_write_palette(png_store *ps, int npalette) | |
{ | |
if (ps->pwrite == NULL) | |
store_log(ps, NULL, "attempt to write palette without write stream", 1); | |
if (ps->palette != NULL) | |
png_error(ps->pwrite, "multiple store_write_palette calls"); | |
/* This function can only return NULL if called with '0'! */ | |
if (npalette > 0) | |
{ | |
ps->palette = malloc(npalette * sizeof *ps->palette); | |
if (ps->palette == NULL) | |
png_error(ps->pwrite, "store new palette: OOM"); | |
ps->npalette = npalette; | |
} | |
return ps->palette; | |
} | |
static store_palette_entry * | |
store_current_palette(png_store *ps, int *npalette) | |
{ | |
/* This is an internal error (the call has been made outside a read | |
* operation.) | |
*/ | |
if (ps->current == NULL) | |
store_log(ps, ps->pread, "no current stream for palette", 1); | |
/* The result may be null if there is no palette. */ | |
*npalette = ps->current->npalette; | |
return ps->current->palette; | |
} | |
/***************************** MEMORY MANAGEMENT*** ***************************/ | |
/* A store_memory is simply the header for an allocated block of memory. The | |
* pointer returned to libpng is just after the end of the header block, the | |
* allocated memory is followed by a second copy of the 'mark'. | |
*/ | |
typedef struct store_memory | |
{ | |
store_pool *pool; /* Originating pool */ | |
struct store_memory *next; /* Singly linked list */ | |
png_alloc_size_t size; /* Size of memory allocated */ | |
png_byte mark[4]; /* ID marker */ | |
} store_memory; | |
/* Handle a fatal error in memory allocation. This calls png_error if the | |
* libpng struct is non-NULL, else it outputs a message and returns. This means | |
* that a memory problem while libpng is running will abort (png_error) the | |
* handling of particular file while one in cleanup (after the destroy of the | |
* struct has returned) will simply keep going and free (or attempt to free) | |
* all the memory. | |
*/ | |
static void | |
store_pool_error(png_store *ps, png_structp pp, PNG_CONST char *msg) | |
{ | |
if (pp != NULL) | |
png_error(pp, msg); | |
/* Else we have to do it ourselves. png_error eventually calls store_log, | |
* above. store_log accepts a NULL png_structp - it just changes what gets | |
* output by store_message. | |
*/ | |
store_log(ps, pp, msg, 1 /* error */); | |
} | |
static void | |
store_memory_free(png_structp pp, store_pool *pool, store_memory *memory) | |
{ | |
/* Note that pp may be NULL (see store_pool_delete below), the caller has | |
* found 'memory' in pool->list *and* unlinked this entry, so this is a valid | |
* pointer (for sure), but the contents may have been trashed. | |
*/ | |
if (memory->pool != pool) | |
store_pool_error(pool->store, pp, "memory corrupted (pool)"); | |
else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0) | |
store_pool_error(pool->store, pp, "memory corrupted (start)"); | |
/* It should be safe to read the size field now. */ | |
else | |
{ | |
png_alloc_size_t cb = memory->size; | |
if (cb > pool->max) | |
store_pool_error(pool->store, pp, "memory corrupted (size)"); | |
else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark) | |
!= 0) | |
store_pool_error(pool->store, pp, "memory corrupted (end)"); | |
/* Finally give the library a chance to find problems too: */ | |
else | |
{ | |
pool->current -= cb; | |
free(memory); | |
} | |
} | |
} | |
static void | |
store_pool_delete(png_store *ps, store_pool *pool) | |
{ | |
if (pool->list != NULL) | |
{ | |
fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test, | |
pool == &ps->read_memory_pool ? "read" : "write", | |
pool == &ps->read_memory_pool ? (ps->current != NULL ? | |
ps->current->name : "unknown file") : ps->wname); | |
++ps->nerrors; | |
do | |
{ | |
store_memory *next = pool->list; | |
pool->list = next->next; | |
next->next = NULL; | |
fprintf(stderr, "\t%lu bytes @ %p\n", | |
(unsigned long)next->size, (PNG_CONST void*)(next+1)); | |
/* The NULL means this will always return, even if the memory is | |
* corrupted. | |
*/ | |
store_memory_free(NULL, pool, next); | |
} | |
while (pool->list != NULL); | |
} | |
/* And reset the other fields too for the next time. */ | |
if (pool->max > pool->max_max) pool->max_max = pool->max; | |
pool->max = 0; | |
if (pool->current != 0) /* unexpected internal error */ | |
fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n", | |
ps->test, pool == &ps->read_memory_pool ? "read" : "write", | |
pool == &ps->read_memory_pool ? (ps->current != NULL ? | |
ps->current->name : "unknown file") : ps->wname); | |
pool->current = 0; | |
if (pool->limit > pool->max_limit) | |
pool->max_limit = pool->limit; | |
pool->limit = 0; | |
if (pool->total > pool->max_total) | |
pool->max_total = pool->total; | |
pool->total = 0; | |
/* Get a new mark too. */ | |
store_pool_mark(pool->mark); | |
} | |
/* The memory callbacks: */ | |
static png_voidp | |
store_malloc(png_structp pp, png_alloc_size_t cb) | |
{ | |
store_pool *pool = png_get_mem_ptr(pp); | |
store_memory *new = malloc(cb + (sizeof *new) + (sizeof pool->mark)); | |
if (new != NULL) | |
{ | |
if (cb > pool->max) | |
pool->max = cb; | |
pool->current += cb; | |
if (pool->current > pool->limit) | |
pool->limit = pool->current; | |
pool->total += cb; | |
new->size = cb; | |
memcpy(new->mark, pool->mark, sizeof new->mark); | |
memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark); | |
new->pool = pool; | |
new->next = pool->list; | |
pool->list = new; | |
++new; | |
} | |
else | |
store_pool_error(pool->store, pp, "out of memory"); | |
return new; | |
} | |
static void | |
store_free(png_structp pp, png_voidp memory) | |
{ | |
store_pool *pool = png_get_mem_ptr(pp); | |
store_memory *this = memory, **test; | |
/* First check that this 'memory' really is valid memory - it must be in the | |
* pool list. If it is, use the shared memory_free function to free it. | |
*/ | |
--this; | |
for (test = &pool->list; *test != this; test = &(*test)->next) | |
{ | |
if (*test == NULL) | |
{ | |
store_pool_error(pool->store, pp, "bad pointer to free"); | |
return; | |
} | |
} | |
/* Unlink this entry, *test == this. */ | |
*test = this->next; | |
this->next = NULL; | |
store_memory_free(pp, pool, this); | |
} | |
/* Setup functions. */ | |
/* Cleanup when aborting a write or after storing the new file. */ | |
static void | |
store_write_reset(png_store *ps) | |
{ | |
if (ps->pwrite != NULL) | |
{ | |
anon_context(ps); | |
Try | |
png_destroy_write_struct(&ps->pwrite, &ps->piwrite); | |
Catch_anonymous | |
{ | |
/* memory corruption: continue. */ | |
} | |
ps->pwrite = NULL; | |
ps->piwrite = NULL; | |
} | |
/* And make sure that all the memory has been freed - this will output | |
* spurious errors in the case of memory corruption above, but this is safe. | |
*/ | |
store_pool_delete(ps, &ps->write_memory_pool); | |
store_freenew(ps); | |
} | |
/* The following is the main write function, it returns a png_struct and, | |
* optionally, a png_info suitable for writiing a new PNG file. Use | |
* store_storefile above to record this file after it has been written. The | |
* returned libpng structures as destroyed by store_write_reset above. | |
*/ | |
static png_structp | |
set_store_for_write(png_store *ps, png_infopp ppi, | |
PNG_CONST char * volatile name) | |
{ | |
anon_context(ps); | |
Try | |
{ | |
if (ps->pwrite != NULL) | |
png_error(ps->pwrite, "write store already in use"); | |
store_write_reset(ps); | |
safecat(ps->wname, sizeof ps->wname, 0, name); | |
/* Don't do the slow memory checks if doing a speed test. */ | |
if (ps->speed) | |
ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING, | |
ps, store_error, store_warning); | |
else | |
ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING, | |
ps, store_error, store_warning, &ps->write_memory_pool, | |
store_malloc, store_free); | |
png_set_write_fn(ps->pwrite, ps, store_write, store_flush); | |
if (ppi != NULL) | |
*ppi = ps->piwrite = png_create_info_struct(ps->pwrite); | |
} | |
Catch_anonymous | |
return NULL; | |
return ps->pwrite; | |
} | |
/* Cleanup when finished reading (either due to error or in the success case). | |
*/ | |
static void | |
store_read_reset(png_store *ps) | |
{ | |
if (ps->pread != NULL) | |
{ | |
anon_context(ps); | |
Try | |
png_destroy_read_struct(&ps->pread, &ps->piread, NULL); | |
Catch_anonymous | |
{ | |
/* error already output: continue */ | |
} | |
ps->pread = NULL; | |
ps->piread = NULL; | |
} | |
/* Always do this to be safe. */ | |
store_pool_delete(ps, &ps->read_memory_pool); | |
ps->current = NULL; | |
ps->next = NULL; | |
ps->readpos = 0; | |
ps->validated = 0; | |
} | |
static void | |
store_read_set(png_store *ps, png_uint_32 id) | |
{ | |
png_store_file *pf = ps->saved; | |
while (pf != NULL) | |
{ | |
if (pf->id == id) | |
{ | |
ps->current = pf; | |
ps->next = NULL; | |
store_read_buffer_next(ps); | |
return; | |
} | |
pf = pf->next; | |
} | |
{ | |
size_t pos; | |
char msg[FILE_NAME_SIZE+64]; | |
pos = standard_name_from_id(msg, sizeof msg, 0, id); | |
pos = safecat(msg, sizeof msg, pos, ": file not found"); | |
png_error(ps->pread, msg); | |
} | |
} | |
/* The main interface for reading a saved file - pass the id number of the file | |
* to retrieve. Ids must be unique or the earlier file will be hidden. The API | |
* returns a png_struct and, optionally, a png_info. Both of these will be | |
* destroyed by store_read_reset above. | |
*/ | |
static png_structp | |
set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id, | |
PNG_CONST char *name) | |
{ | |
/* Set the name for png_error */ | |
safecat(ps->test, sizeof ps->test, 0, name); | |
if (ps->pread != NULL) | |
png_error(ps->pread, "read store already in use"); | |
store_read_reset(ps); | |
/* Both the create APIs can return NULL if used in their default mode | |
* (because there is no other way of handling an error because the jmp_buf | |
* by default is stored in png_struct and that has not been allocated!) | |
* However, given that store_error works correctly in these circumstances | |
* we don't ever expect NULL in this program. | |
*/ | |
if (ps->speed) | |
ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps, | |
store_error, store_warning); | |
else | |
ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps, | |
store_error, store_warning, &ps->read_memory_pool, store_malloc, | |
store_free); | |
if (ps->pread == NULL) | |
{ | |
struct exception_context *the_exception_context = &ps->exception_context; | |
store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)", | |
1 /*error*/); | |
Throw ps; | |
} | |
store_read_set(ps, id); | |
if (ppi != NULL) | |
*ppi = ps->piread = png_create_info_struct(ps->pread); | |
return ps->pread; | |
} | |
/* The overall cleanup of a store simply calls the above then removes all the | |
* saved files. This does not delete the store itself. | |
*/ | |
static void | |
store_delete(png_store *ps) | |
{ | |
store_write_reset(ps); | |
store_read_reset(ps); | |
store_freefile(&ps->saved); | |
store_image_free(ps, NULL); | |
} | |
/*********************** PNG FILE MODIFICATION ON READ ************************/ | |
/* Files may be modified on read. The following structure contains a complete | |
* png_store together with extra members to handle modification and a special | |
* read callback for libpng. To use this the 'modifications' field must be set | |
* to a list of png_modification structures that actually perform the | |
* modification, otherwise a png_modifier is functionally equivalent to a | |
* png_store. There is a special read function, set_modifier_for_read, which | |
* replaces set_store_for_read. | |
*/ | |
typedef struct png_modifier | |
{ | |
png_store this; /* I am a png_store */ | |
struct png_modification *modifications; /* Changes to make */ | |
enum modifier_state | |
{ | |
modifier_start, /* Initial value */ | |
modifier_signature, /* Have a signature */ | |
modifier_IHDR /* Have an IHDR */ | |
} state; /* My state */ | |
/* Information from IHDR: */ | |
png_byte bit_depth; /* From IHDR */ | |
png_byte colour_type; /* From IHDR */ | |
/* While handling PLTE, IDAT and IEND these chunks may be pended to allow | |
* other chunks to be inserted. | |
*/ | |
png_uint_32 pending_len; | |
png_uint_32 pending_chunk; | |
/* Test values */ | |
double *gammas; | |
unsigned int ngammas; | |
/* Lowest sbit to test (libpng fails for sbit < 8) */ | |
png_byte sbitlow; | |
/* Error control - these are the limits on errors accepted by the gamma tests | |
* below. | |
*/ | |
double maxout8; /* Maximum output value error */ | |
double maxabs8; /* Absolute sample error 0..1 */ | |
double maxcalc8; /* Absolute sample error 0..1 */ | |
double maxpc8; /* Percentage sample error 0..100% */ | |
double maxout16; /* Maximum output value error */ | |
double maxabs16; /* Absolute sample error 0..1 */ | |
double maxcalc16;/* Absolute sample error 0..1 */ | |
double maxpc16; /* Percentage sample error 0..100% */ | |
/* Log limits - values above this are logged, but not necessarily | |
* warned. | |
*/ | |
double log8; /* Absolute error in 8 bits to log */ | |
double log16; /* Absolute error in 16 bits to log */ | |
/* Logged 8 and 16 bit errors ('output' values): */ | |
double error_gray_2; | |
double error_gray_4; | |
double error_gray_8; | |
double error_gray_16; | |
double error_color_8; | |
double error_color_16; | |
double error_indexed; | |
/* Flags: */ | |
/* Whether or not to interlace. */ | |
int interlace_type :9; /* int, but must store '1' */ | |
/* Run the standard tests? */ | |
unsigned int test_standard :1; | |
/* Run the odd-sized image and interlace read/write tests? */ | |
unsigned int test_size :1; | |
/* Run tests on reading with a combiniation of transforms, */ | |
unsigned int test_transform :1; | |
/* When to use the use_input_precision option: */ | |
unsigned int use_input_precision :1; | |
unsigned int use_input_precision_sbit :1; | |
unsigned int use_input_precision_16to8 :1; | |
/* If set assume that the calculation bit depth is set by the input | |
* precision, not the output precision. | |
*/ | |
unsigned int calculations_use_input_precision :1; | |
/* If set assume that the calculations are done in 16 bits even if both input | |
* and output are 8 bit or less. | |
*/ | |
unsigned int assume_16_bit_calculations :1; | |
/* Which gamma tests to run: */ | |
unsigned int test_gamma_threshold :1; | |
unsigned int test_gamma_transform :1; /* main tests */ | |
unsigned int test_gamma_sbit :1; | |
unsigned int test_gamma_scale16 :1; | |
unsigned int test_gamma_background :1; | |
unsigned int test_gamma_alpha_mode :1; | |
unsigned int test_gamma_expand16 :1; | |
unsigned int log :1; /* Log max error */ | |
/* Buffer information, the buffer size limits the size of the chunks that can | |
* be modified - they must fit (including header and CRC) into the buffer! | |
*/ | |
size_t flush; /* Count of bytes to flush */ | |
size_t buffer_count; /* Bytes in buffer */ | |
size_t buffer_position; /* Position in buffer */ | |
png_byte buffer[1024]; | |
} png_modifier; | |
/* This returns true if the test should be stopped now because it has already | |
* failed and it is running silently. | |
*/ | |
static int fail(png_modifier *pm) | |
{ | |
return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 || | |
(pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0)); | |
} | |
static void | |
modifier_init(png_modifier *pm) | |
{ | |
memset(pm, 0, sizeof *pm); | |
store_init(&pm->this); | |
pm->modifications = NULL; | |
pm->state = modifier_start; | |
pm->sbitlow = 1U; | |
pm->ngammas = 0; | |
pm->gammas = 0; | |
pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0; | |
pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0; | |
pm->log8 = pm->log16 = 0; /* Means 'off' */ | |
pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0; | |
pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0; | |
pm->error_indexed = 0; | |
pm->interlace_type = PNG_INTERLACE_NONE; | |
pm->test_standard = 0; | |
pm->test_size = 0; | |
pm->test_transform = 0; | |
pm->use_input_precision = 0; | |
pm->use_input_precision_sbit = 0; | |
pm->use_input_precision_16to8 = 0; | |
pm->calculations_use_input_precision = 0; | |
pm->test_gamma_threshold = 0; | |
pm->test_gamma_transform = 0; | |
pm->test_gamma_sbit = 0; | |
pm->test_gamma_scale16 = 0; | |
pm->test_gamma_background = 0; | |
pm->test_gamma_alpha_mode = 0; | |
pm->test_gamma_expand16 = 0; | |
pm->log = 0; | |
/* Rely on the memset for all the other fields - there are no pointers */ | |
} | |
#ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
/* If pm->calculations_use_input_precision is set then operations will happen | |
* with only 8 bit precision unless both the input and output bit depth are 16. | |
* | |
* If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16 | |
* bit precision. This only affects those of the following limits that pertain | |
* to a calculation - not a digitization operation! | |
*/ | |
static double abserr(png_modifier *pm, int in_depth, int out_depth) | |
{ | |
/* Absolute error permitted in linear values - affected by the bit depth of | |
* the calculations. | |
*/ | |
if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 || | |
!pm->calculations_use_input_precision))) | |
return pm->maxabs16; | |
else | |
return pm->maxabs8; | |
} | |
static double calcerr(png_modifier *pm, int in_depth, int out_depth) | |
{ | |
/* Error in the linear composition arithmetic - only relevant when | |
* composition actually happens (0 < alpha < 1). | |
*/ | |
if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 || | |
!pm->calculations_use_input_precision))) | |
return pm->maxcalc16; | |
else | |
return pm->maxcalc8; | |
} | |
static double pcerr(png_modifier *pm, int in_depth, int out_depth) | |
{ | |
/* Percentage error permitted in the linear values. Note that the specified | |
* value is a percentage but this routine returns a simple number. | |
*/ | |
if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 || | |
!pm->calculations_use_input_precision))) | |
return pm->maxpc16 * .01; | |
else | |
return pm->maxpc8 * .01; | |
} | |
/* Output error - the error in the encoded value. This is determined by the | |
* digitization of the output so can be +/-0.5 in the actual output value. In | |
* the expand_16 case with the current code in libpng the expand happens after | |
* all the calculations are done in 8 bit arithmetic, so even though the output | |
* depth is 16 the output error is determined by the 8 bit calculation. | |
* | |
* This limit is not determined by the bit depth of internal calculations. | |
* | |
* The specified parameter does *not* include the base .5 digitization error but | |
* it is added here. | |
*/ | |
static double outerr(png_modifier *pm, int in_depth, int out_depth) | |
{ | |
/* There is a serious error in the 2 and 4 bit grayscale transform because | |
* the gamma table value (8 bits) is simply shifted, not rounded, so the | |
* error in 4 bit greyscale gamma is up to the value below. This is a hack | |
* to allow pngvalid to succeed: | |
* | |
* TODO: fix this in libpng | |
*/ | |
if (out_depth == 2) | |
return .73182-.5; | |
if (out_depth == 4) | |
return .90644-.5; | |
if (out_depth == 16 && (in_depth == 16 || | |
!pm->calculations_use_input_precision)) | |
return pm->maxout16; | |
/* This is the case where the value was calculated at 8-bit precision then | |
* scaled to 16 bits. | |
*/ | |
else if (out_depth == 16) | |
return pm->maxout8 * 257; | |
else | |
return pm->maxout8; | |
} | |
/* This does the same thing as the above however it returns the value to log, | |
* rather than raising a warning. This is useful for debugging to track down | |
* exactly what set of parameters cause high error values. | |
*/ | |
static double outlog(png_modifier *pm, int in_depth, int out_depth) | |
{ | |
/* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535) | |
* and so must be adjusted for low bit depth grayscale: | |
*/ | |
if (out_depth <= 8) | |
{ | |
if (pm->log8 == 0) /* switched off */ | |
return 256; | |
if (out_depth < 8) | |
return pm->log8 / 255 * ((1<<out_depth)-1); | |
return pm->log8; | |
} | |
if (out_depth == 16 && (in_depth == 16 || | |
!pm->calculations_use_input_precision)) | |
{ | |
if (pm->log16 == 0) | |
return 65536; | |
return pm->log16; | |
} | |
/* This is the case where the value was calculated at 8-bit precision then | |
* scaled to 16 bits. | |
*/ | |
if (pm->log8 == 0) | |
return 65536; | |
return pm->log8 * 257; | |
} | |
/* This complements the above by providing the appropriate quantization for the | |
* final value. Normally this would just be quantization to an integral value, | |
* but in the 8 bit calculation case it's actually quantization to a multiple of | |
* 257! | |
*/ | |
static int output_quantization_factor(png_modifier *pm, int in_depth, | |
int out_depth) | |
{ | |
if (out_depth == 16 && in_depth != 16 | |
&& pm->calculations_use_input_precision) | |
return 257; | |
else | |
return 1; | |
} | |
/* One modification structure must be provided for each chunk to be modified (in | |
* fact more than one can be provided if multiple separate changes are desired | |
* for a single chunk.) Modifications include adding a new chunk when a | |
* suitable chunk does not exist. | |
* | |
* The caller of modify_fn will reset the CRC of the chunk and record 'modified' | |
* or 'added' as appropriate if the modify_fn returns 1 (true). If the | |
* modify_fn is NULL the chunk is simply removed. | |
*/ | |
typedef struct png_modification | |
{ | |
struct png_modification *next; | |
png_uint_32 chunk; | |
/* If the following is NULL all matching chunks will be removed: */ | |
int (*modify_fn)(struct png_modifier *pm, | |
struct png_modification *me, int add); | |
/* If the following is set to PLTE, IDAT or IEND and the chunk has not been | |
* found and modified (and there is a modify_fn) the modify_fn will be called | |
* to add the chunk before the relevant chunk. | |
*/ | |
png_uint_32 add; | |
unsigned int modified :1; /* Chunk was modified */ | |
unsigned int added :1; /* Chunk was added */ | |
unsigned int removed :1; /* Chunk was removed */ | |
} png_modification; | |
static void modification_reset(png_modification *pmm) | |
{ | |
if (pmm != NULL) | |
{ | |
pmm->modified = 0; | |
pmm->added = 0; | |
pmm->removed = 0; | |
modification_reset(pmm->next); | |
} | |
} | |
static void | |
modification_init(png_modification *pmm) | |
{ | |
memset(pmm, 0, sizeof *pmm); | |
pmm->next = NULL; | |
pmm->chunk = 0; | |
pmm->modify_fn = NULL; | |
pmm->add = 0; | |
modification_reset(pmm); | |
} | |
static void | |
modifier_reset(png_modifier *pm) | |
{ | |
store_read_reset(&pm->this); | |
pm->modifications = NULL; | |
pm->state = modifier_start; | |
pm->bit_depth = pm->colour_type = 0; | |
pm->pending_len = pm->pending_chunk = 0; | |
pm->flush = pm->buffer_count = pm->buffer_position = 0; | |
} | |
/* Convenience macros. */ | |
#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d)) | |
#define CHUNK_IHDR CHUNK(73,72,68,82) | |
#define CHUNK_PLTE CHUNK(80,76,84,69) | |
#define CHUNK_IDAT CHUNK(73,68,65,84) | |
#define CHUNK_IEND CHUNK(73,69,78,68) | |
#define CHUNK_cHRM CHUNK(99,72,82,77) | |
#define CHUNK_gAMA CHUNK(103,65,77,65) | |
#define CHUNK_sBIT CHUNK(115,66,73,84) | |
#define CHUNK_sRGB CHUNK(115,82,71,66) | |
/* The guts of modification are performed during a read. */ | |
static void | |
modifier_crc(png_bytep buffer) | |
{ | |
/* Recalculate the chunk CRC - a complete chunk must be in | |
* the buffer, at the start. | |
*/ | |
uInt datalen = png_get_uint_32(buffer); | |
png_save_uint_32(buffer+datalen+8, crc32(0L, buffer+4, datalen+4)); | |
} | |
static void | |
modifier_setbuffer(png_modifier *pm) | |
{ | |
modifier_crc(pm->buffer); | |
pm->buffer_count = png_get_uint_32(pm->buffer)+12; | |
pm->buffer_position = 0; | |
} | |
/* Separate the callback into the actual implementation (which is passed the | |
* png_modifier explicitly) and the callback, which gets the modifier from the | |
* png_struct. | |
*/ | |
static void | |
modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st) | |
{ | |
while (st > 0) | |
{ | |
size_t cb; | |
png_uint_32 len, chunk; | |
png_modification *mod; | |
if (pm->buffer_position >= pm->buffer_count) switch (pm->state) | |
{ | |
static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 }; | |
case modifier_start: | |
store_read_imp(&pm->this, pm->buffer, 8); /* size of signature. */ | |
pm->buffer_count = 8; | |
pm->buffer_position = 0; | |
if (memcmp(pm->buffer, sign, 8) != 0) | |
png_error(pm->this.pread, "invalid PNG file signature"); | |
pm->state = modifier_signature; | |
break; | |
case modifier_signature: | |
store_read_imp(&pm->this, pm->buffer, 13+12); /* size of IHDR */ | |
pm->buffer_count = 13+12; | |
pm->buffer_position = 0; | |
if (png_get_uint_32(pm->buffer) != 13 || | |
png_get_uint_32(pm->buffer+4) != CHUNK_IHDR) | |
png_error(pm->this.pread, "invalid IHDR"); | |
/* Check the list of modifiers for modifications to the IHDR. */ | |
mod = pm->modifications; | |
while (mod != NULL) | |
{ | |
if (mod->chunk == CHUNK_IHDR && mod->modify_fn && | |
(*mod->modify_fn)(pm, mod, 0)) | |
{ | |
mod->modified = 1; | |
modifier_setbuffer(pm); | |
} | |
/* Ignore removal or add if IHDR! */ | |
mod = mod->next; | |
} | |
/* Cache information from the IHDR (the modified one.) */ | |
pm->bit_depth = pm->buffer[8+8]; | |
pm->colour_type = pm->buffer[8+8+1]; | |
pm->state = modifier_IHDR; | |
pm->flush = 0; | |
break; | |
case modifier_IHDR: | |
default: | |
/* Read a new chunk and process it until we see PLTE, IDAT or | |
* IEND. 'flush' indicates that there is still some data to | |
* output from the preceding chunk. | |
*/ | |
if ((cb = pm->flush) > 0) | |
{ | |
if (cb > st) cb = st; | |
pm->flush -= cb; | |
store_read_imp(&pm->this, pb, cb); | |
pb += cb; | |
st -= cb; | |
if (st == 0) return; | |
} | |
/* No more bytes to flush, read a header, or handle a pending | |
* chunk. | |
*/ | |
if (pm->pending_chunk != 0) | |
{ | |
png_save_uint_32(pm->buffer, pm->pending_len); | |
png_save_uint_32(pm->buffer+4, pm->pending_chunk); | |
pm->pending_len = 0; | |
pm->pending_chunk = 0; | |
} | |
else | |
store_read_imp(&pm->this, pm->buffer, 8); | |
pm->buffer_count = 8; | |
pm->buffer_position = 0; | |
/* Check for something to modify or a terminator chunk. */ | |
len = png_get_uint_32(pm->buffer); | |
chunk = png_get_uint_32(pm->buffer+4); | |
/* Terminators first, they may have to be delayed for added | |
* chunks | |
*/ | |
if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT || | |
chunk == CHUNK_IEND) | |
{ | |
mod = pm->modifications; | |
while (mod != NULL) | |
{ | |
if ((mod->add == chunk || | |
(mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) && | |
mod->modify_fn != NULL && !mod->modified && !mod->added) | |
{ | |
/* Regardless of what the modify function does do not run | |
* this again. | |
*/ | |
mod->added = 1; | |
if ((*mod->modify_fn)(pm, mod, 1 /*add*/)) | |
{ | |
/* Reset the CRC on a new chunk */ | |
if (pm->buffer_count > 0) | |
modifier_setbuffer(pm); | |
else | |
{ | |
pm->buffer_position = 0; | |
mod->removed = 1; | |
} | |
/* The buffer has been filled with something (we assume) | |
* so output this. Pend the current chunk. | |
*/ | |
pm->pending_len = len; | |
pm->pending_chunk = chunk; | |
break; /* out of while */ | |
} | |
} | |
mod = mod->next; | |
} | |
/* Don't do any further processing if the buffer was modified - | |
* otherwise the code will end up modifying a chunk that was | |
* just added. | |
*/ | |
if (mod != NULL) | |
break; /* out of switch */ | |
} | |
/* If we get to here then this chunk may need to be modified. To | |
* do this it must be less than 1024 bytes in total size, otherwise | |
* it just gets flushed. | |
*/ | |
if (len+12 <= sizeof pm->buffer) | |
{ | |
store_read_imp(&pm->this, pm->buffer+pm->buffer_count, | |
len+12-pm->buffer_count); | |
pm->buffer_count = len+12; | |
/* Check for a modification, else leave it be. */ | |
mod = pm->modifications; | |
while (mod != NULL) | |
{ | |
if (mod->chunk == chunk) | |
{ | |
if (mod->modify_fn == NULL) | |
{ | |
/* Remove this chunk */ | |
pm->buffer_count = pm->buffer_position = 0; | |
mod->removed = 1; | |
break; /* Terminate the while loop */ | |
} | |
else if ((*mod->modify_fn)(pm, mod, 0)) | |
{ | |
mod->modified = 1; | |
/* The chunk may have been removed: */ | |
if (pm->buffer_count == 0) | |
{ | |
pm->buffer_position = 0; | |
break; | |
} | |
modifier_setbuffer(pm); | |
} | |
} | |
mod = mod->next; | |
} | |
} | |
else | |
pm->flush = len+12 - pm->buffer_count; /* data + crc */ | |
/* Take the data from the buffer (if there is any). */ | |
break; | |
} | |
/* Here to read from the modifier buffer (not directly from | |
* the store, as in the flush case above.) | |
*/ | |
cb = pm->buffer_count - pm->buffer_position; | |
if (cb > st) | |
cb = st; | |
memcpy(pb, pm->buffer + pm->buffer_position, cb); | |
st -= cb; | |
pb += cb; | |
pm->buffer_position += cb; | |
} | |
} | |
/* The callback: */ | |
static void | |
modifier_read(png_structp pp, png_bytep pb, png_size_t st) | |
{ | |
png_modifier *pm = png_get_io_ptr(pp); | |
if (pm == NULL || pm->this.pread != pp) | |
png_error(pp, "bad modifier_read call"); | |
modifier_read_imp(pm, pb, st); | |
} | |
/* Like store_progressive_read but the data is getting changed as we go so we | |
* need a local buffer. | |
*/ | |
static void | |
modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi) | |
{ | |
if (pm->this.pread != pp || pm->this.current == NULL || | |
pm->this.next == NULL) | |
png_error(pp, "store state damaged (progressive)"); | |
/* This is another Horowitz and Hill random noise generator. In this case | |
* the aim is to stress the progressive reader with truely horrible variable | |
* buffer sizes in the range 1..500, so a sequence of 9 bit random numbers | |
* is generated. We could probably just count from 1 to 32767 and get as | |
* good a result. | |
*/ | |
for (;;) | |
{ | |
static png_uint_32 noise = 1; | |
png_size_t cb, cbAvail; | |
png_byte buffer[512]; | |
/* Generate 15 more bits of stuff: */ | |
noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff); | |
cb = noise & 0x1ff; | |
/* Check that this number of bytes are available (in the current buffer.) | |
* (This doesn't quite work - the modifier might delete a chunk; unlikely | |
* but possible, it doesn't happen at present because the modifier only | |
* adds chunks to standard images.) | |
*/ | |
cbAvail = store_read_buffer_avail(&pm->this); | |
if (pm->buffer_count > pm->buffer_position) | |
cbAvail += pm->buffer_count - pm->buffer_position; | |
if (cb > cbAvail) | |
{ | |
/* Check for EOF: */ | |
if (cbAvail == 0) | |
break; | |
cb = cbAvail; | |
} | |
modifier_read_imp(pm, buffer, cb); | |
png_process_data(pp, pi, buffer, cb); | |
} | |
/* Check the invariants at the end (if this fails it's a problem in this | |
* file!) | |
*/ | |
if (pm->buffer_count > pm->buffer_position || | |
pm->this.next != &pm->this.current->data || | |
pm->this.readpos < pm->this.current->datacount) | |
png_error(pp, "progressive read implementation error"); | |
} | |
/* Set up a modifier. */ | |
static png_structp | |
set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id, | |
PNG_CONST char *name) | |
{ | |
/* Do this first so that the modifier fields are cleared even if an error | |
* happens allocating the png_struct. No allocation is done here so no | |
* cleanup is required. | |
*/ | |
pm->state = modifier_start; | |
pm->bit_depth = 0; | |
pm->colour_type = 255; | |
pm->pending_len = 0; | |
pm->pending_chunk = 0; | |
pm->flush = 0; | |
pm->buffer_count = 0; | |
pm->buffer_position = 0; | |
return set_store_for_read(&pm->this, ppi, id, name); | |
} | |
#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ | |
/***************************** STANDARD PNG FILES *****************************/ | |
/* Standard files - write and save standard files. */ | |
/* There are two basic forms of standard images. Those which attempt to have | |
* all the possible pixel values (not possible for 16bpp images, but a range of | |
* values are produced) and those which have a range of image sizes. The former | |
* are used for testing transforms, in particular gamma correction and bit | |
* reduction and increase. The latter are reserved for testing the behavior of | |
* libpng with respect to 'odd' image sizes - particularly small images where | |
* rows become 1 byte and interlace passes disappear. | |
* | |
* The first, most useful, set are the 'transform' images, the second set of | |
* small images are the 'size' images. | |
* | |
* The transform files are constructed with rows which fit into a 1024 byte row | |
* buffer. This makes allocation easier below. Further regardless of the file | |
* format every row has 128 pixels (giving 1024 bytes for 64bpp formats). | |
* | |
* Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed | |
* and with an ID derived from the colour type, bit depth and interlace type | |
* as above (FILEID). The width (128) and height (variable) are not stored in | |
* the FILEID - instead the fields are set to 0, indicating a transform file. | |
* | |
* The size files ar constructed with rows a maximum of 128 bytes wide, allowing | |
* a maximum width of 16 pixels (for the 64bpp case.) They also have a maximum | |
* height of 16 rows. The width and height are stored in the FILEID and, being | |
* non-zero, indicate a size file. | |
* | |
* For palette image (colour type 3) multiple transform images are stored with | |
* the same bit depth to allow testing of more colour combinations - | |
* particularly important for testing the gamma code because libpng uses a | |
* different code path for palette images. For size images a single palette is | |
* used. | |
*/ | |
/* Make a 'standard' palette. Because there are only 256 entries in a palette | |
* (maximum) this actually makes a random palette in the hope that enough tests | |
* will catch enough errors. (Note that the same palette isn't produced every | |
* time for the same test - it depends on what previous tests have been run - | |
* but a given set of arguments to pngvalid will always produce the same palette | |
* at the same test! This is why pseudo-random number generators are useful for | |
* testing.) | |
* | |
* The store must be open for write when this is called, otherwise an internal | |
* error will occur. This routine contains its own magic number seed, so the | |
* palettes generated don't change if there are intervening errors (changing the | |
* calls to the store_mark seed.) | |
*/ | |
static store_palette_entry * | |
make_standard_palette(png_store* ps, int npalette, int do_tRNS) | |
{ | |
static png_uint_32 palette_seed[2] = { 0x87654321, 9 }; | |
int i = 0; | |
png_byte values[256][4]; | |
/* Always put in black and white plus the six primary and secondary colors. | |
*/ | |
for (; i<8; ++i) | |
{ | |
values[i][1] = (i&1) ? 255 : 0; | |
values[i][2] = (i&2) ? 255 : 0; | |
values[i][3] = (i&4) ? 255 : 0; | |
} | |
/* Then add 62 greys (one quarter of the remaining 256 slots). */ | |
{ | |
int j = 0; | |
png_byte random_bytes[4]; | |
png_byte need[256]; | |
need[0] = 0; /*got black*/ | |
memset(need+1, 1, (sizeof need)-2); /*need these*/ | |
need[255] = 0; /*but not white*/ | |
while (i<70) | |
{ | |
png_byte b; | |
if (j==0) | |
{ | |
make_four_random_bytes(palette_seed, random_bytes); | |
j = 4; | |
} | |
b = random_bytes[--j]; | |
if (need[b]) | |
{ | |
values[i][1] = b; | |
values[i][2] = b; | |
values[i++][3] = b; | |
} | |
} | |
} | |
/* Finally add 192 colors at random - don't worry about matches to things we | |
* already have, chance is less than 1/65536. Don't worry about greys, | |
* chance is the same, so we get a duplicate or extra gray less than 1 time | |
* in 170. | |
*/ | |
for (; i<256; ++i) | |
make_four_random_bytes(palette_seed, values[i]); | |
/* Fill in the alpha values in the first byte. Just use all possible values | |
* (0..255) in an apparently random order: | |
*/ | |
{ | |
store_palette_entry *palette; | |
png_byte selector[4]; | |
make_four_random_bytes(palette_seed, selector); | |
if (do_tRNS) | |
for (i=0; i<256; ++i) | |
values[i][0] = (png_byte)(i ^ selector[0]); | |
else | |
for (i=0; i<256; ++i) | |
values[i][0] = 255; /* no transparency/tRNS chunk */ | |
/* 'values' contains 256 ARGB values, but we only need 'npalette'. | |
* 'npalette' will always be a power of 2: 2, 4, 16 or 256. In the low | |
* bit depth cases select colors at random, else it is difficult to have | |
* a set of low bit depth palette test with any chance of a reasonable | |
* range of colors. Do this by randomly permuting values into the low | |
* 'npalette' entries using an XOR mask generated here. This also | |
* permutes the npalette == 256 case in a potentially useful way (there is | |
* no relationship between palette index and the color value therein!) | |
*/ | |
palette = store_write_palette(ps, npalette); | |
for (i=0; i<npalette; ++i) | |
{ | |
palette[i].alpha = values[i ^ selector[1]][0]; | |
palette[i].red = values[i ^ selector[1]][1]; | |
palette[i].green = values[i ^ selector[1]][2]; | |
palette[i].blue = values[i ^ selector[1]][3]; | |
} | |
return palette; | |
} | |
} | |
/* Initialize a standard palette on a write stream. The 'do_tRNS' argument | |
* indicates whether or not to also set the tRNS chunk. | |
*/ | |
static void | |
init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette, | |
int do_tRNS) | |
{ | |
store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS); | |
{ | |
int i; | |
png_color palette[256]; | |
/* Set all entries to detect overread errors. */ | |
for (i=0; i<npalette; ++i) | |
{ | |
palette[i].red = ppal[i].red; | |
palette[i].green = ppal[i].green; | |
palette[i].blue = ppal[i].blue; | |
} | |
/* Just in case fill in the rest with detectable values: */ | |
for (; i<256; ++i) | |
palette[i].red = palette[i].green = palette[i].blue = 42; | |
png_set_PLTE(pp, pi, palette, npalette); | |
} | |
if (do_tRNS) | |
{ | |
int i, j; | |
png_byte tRNS[256]; | |
/* Set all the entries, but skip trailing opaque entries */ | |
for (i=j=0; i<npalette; ++i) | |
if ((tRNS[i] = ppal[i].alpha) < 255) | |
j = i+1; | |
/* Fill in the remainder with a detectable value: */ | |
for (; i<256; ++i) | |
tRNS[i] = 24; | |
if (j > 0) | |
png_set_tRNS(pp, pi, tRNS, j, 0/*color*/); | |
} | |
} | |
/* The number of passes is related to the interlace type. There was no libpng | |
* API to determine this prior to 1.5, so we need an inquiry function: | |
*/ | |
static int | |
npasses_from_interlace_type(png_structp pp, int interlace_type) | |
{ | |
switch (interlace_type) | |
{ | |
default: | |
png_error(pp, "invalid interlace type"); | |
case PNG_INTERLACE_NONE: | |
return 1; | |
case PNG_INTERLACE_ADAM7: | |
return PNG_INTERLACE_ADAM7_PASSES; | |
} | |
} | |
static unsigned int | |
bit_size(png_structp pp, png_byte colour_type, png_byte bit_depth) | |
{ | |
switch (colour_type) | |
{ | |
default: png_error(pp, "invalid color type"); | |
case 0: return bit_depth; | |
case 2: return 3*bit_depth; | |
case 3: return bit_depth; | |
case 4: return 2*bit_depth; | |
case 6: return 4*bit_depth; | |
} | |
} | |
#define TRANSFORM_WIDTH 128U | |
#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U) | |
#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */ | |
#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */ | |
#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */ | |
static size_t | |
transform_rowsize(png_structp pp, png_byte colour_type, png_byte bit_depth) | |
{ | |
return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8; | |
} | |
/* transform_width(pp, colour_type, bit_depth) current returns the same number | |
* every time, so just use a macro: | |
*/ | |
#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH | |
static png_uint_32 | |
transform_height(png_structp pp, png_byte colour_type, png_byte bit_depth) | |
{ | |
switch (bit_size(pp, colour_type, bit_depth)) | |
{ | |
case 1: | |
case 2: | |
case 4: | |
return 1; /* Total of 128 pixels */ | |
case 8: | |
return 2; /* Total of 256 pixels/bytes */ | |
case 16: | |
return 512; /* Total of 65536 pixels */ | |
case 24: | |
case 32: | |
return 512; /* 65536 pixels */ | |
case 48: | |
case 64: | |
return 2048;/* 4 x 65536 pixels. */ | |
# define TRANSFORM_HEIGHTMAX 2048 | |
default: | |
return 0; /* Error, will be caught later */ | |
} | |
} | |
/* The following can only be defined here, now we have the definitions | |
* of the transform image sizes. | |
*/ | |
static png_uint_32 | |
standard_width(png_structp pp, png_uint_32 id) | |
{ | |
png_uint_32 width = WIDTH_FROM_ID(id); | |
UNUSED(pp) | |
if (width == 0) | |
width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id)); | |
return width; | |
} | |
static png_uint_32 | |
standard_height(png_structp pp, png_uint_32 id) | |
{ | |
png_uint_32 height = HEIGHT_FROM_ID(id); | |
if (height == 0) | |
height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id)); | |
return height; | |
} | |
static png_uint_32 | |
standard_rowsize(png_structp pp, png_uint_32 id) | |
{ | |
png_uint_32 width = standard_width(pp, id); | |
/* This won't overflow: */ | |
width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id)); | |
return (width + 7) / 8; | |
} | |
static void | |
transform_row(png_structp pp, png_byte buffer[TRANSFORM_ROWMAX], | |
png_byte colour_type, png_byte bit_depth, png_uint_32 y) | |
{ | |
png_uint_32 v = y << 7; | |
png_uint_32 i = 0; | |
switch (bit_size(pp, colour_type, bit_depth)) | |
{ | |
case 1: | |
while (i<128/8) buffer[i] = v & 0xff, v += 17, ++i; | |
return; | |
case 2: | |
while (i<128/4) buffer[i] = v & 0xff, v += 33, ++i; | |
return; | |
case 4: | |
while (i<128/2) buffer[i] = v & 0xff, v += 65, ++i; | |
return; | |
case 8: | |
/* 256 bytes total, 128 bytes in each row set as follows: */ | |
while (i<128) buffer[i] = v & 0xff, ++v, ++i; | |
return; | |
case 16: | |
/* Generate all 65536 pixel values in order, which includes the 8 bit | |
* GA case as well as the 16 bit G case. | |
*/ | |
while (i<128) | |
buffer[2*i] = (v>>8) & 0xff, buffer[2*i+1] = v & 0xff, ++v, ++i; | |
return; | |
case 24: | |
/* 65535 pixels, but rotate the values. */ | |
while (i<128) | |
{ | |
/* Three bytes per pixel, r, g, b, make b by r^g */ | |
buffer[3*i+0] = (v >> 8) & 0xff; | |
buffer[3*i+1] = v & 0xff; | |
buffer[3*i+2] = ((v >> 8) ^ v) & 0xff; | |
++v; | |
++i; | |
} | |
return; | |
case 32: | |
/* 65535 pixels, r, g, b, a; just replicate */ | |
while (i<128) | |
{ | |
buffer[4*i+0] = (v >> 8) & 0xff; | |
buffer[4*i+1] = v & 0xff; | |
buffer[4*i+2] = (v >> 8) & 0xff; | |
buffer[4*i+3] = v & 0xff; | |
++v; | |
++i; | |
} | |
return; | |
case 48: | |
/* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at | |
* each pixel, g increase by 257 (0x101) and 'b' by 0x1111: | |
*/ | |
while (i<128) | |
{ | |
png_uint_32 t = v++; | |
buffer[6*i+0] = (t >> 8) & 0xff; | |
buffer[6*i+1] = t & 0xff; | |
t *= 257; | |
buffer[6*i+2] = (t >> 8) & 0xff; | |
buffer[6*i+3] = t & 0xff; | |
t *= 17; | |
buffer[6*i+4] = (t >> 8) & 0xff; | |
buffer[6*i+5] = t & 0xff; | |
++i; | |
} | |
return; | |
case 64: | |
/* As above in the 32 bit case. */ | |
while (i<128) | |
{ | |
png_uint_32 t = v++; | |
buffer[8*i+0] = (t >> 8) & 0xff; | |
buffer[8*i+1] = t & 0xff; | |
buffer[8*i+4] = (t >> 8) & 0xff; | |
buffer[8*i+5] = t & 0xff; | |
t *= 257; | |
buffer[8*i+2] = (t >> 8) & 0xff; | |
buffer[8*i+3] = t & 0xff; | |
buffer[8*i+6] = (t >> 8) & 0xff; | |
buffer[8*i+7] = t & 0xff; | |
++i; | |
} | |
return; | |
default: | |
break; | |
} | |
png_error(pp, "internal error"); | |
} | |
/* This is just to do the right cast - could be changed to a function to check | |
* 'bd' but there isn't much point. | |
*/ | |
#define DEPTH(bd) ((png_byte)(1U << (bd))) | |
/* Make a standardized image given a an image colour type, bit depth and | |
* interlace type. The standard images have a very restricted range of | |
* rows and heights and are used for testing transforms rather than image | |
* layout details. See make_size_images below for a way to make images | |
* that test odd sizes along with the libpng interlace handling. | |
*/ | |
static void | |
make_transform_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, | |
png_byte PNG_CONST bit_depth, int palette_number, int interlace_type, | |
png_const_charp name) | |
{ | |
context(ps, fault); | |
Try | |
{ | |
png_infop pi; | |
png_structp pp = set_store_for_write(ps, &pi, name); | |
png_uint_32 h; | |
/* In the event of a problem return control to the Catch statement below | |
* to do the clean up - it is not possible to 'return' directly from a Try | |
* block. | |
*/ | |
if (pp == NULL) | |
Throw ps; | |
h = transform_height(pp, colour_type, bit_depth); | |
png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth), h, | |
bit_depth, colour_type, interlace_type, | |
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); | |
#ifdef PNG_TEXT_SUPPORTED | |
{ | |
static char key[] = "image name"; /* must be writeable */ | |
size_t pos; | |
png_text text; | |
char copy[FILE_NAME_SIZE]; | |
/* Use a compressed text string to test the correct interaction of text | |
* compression and IDAT compression. | |
*/ | |
text.compression = PNG_TEXT_COMPRESSION_zTXt; | |
text.key = key; | |
/* Yuck: the text must be writable! */ | |
pos = safecat(copy, sizeof copy, 0, ps->wname); | |
text.text = copy; | |
text.text_length = pos; | |
text.itxt_length = 0; | |
text.lang = 0; | |
text.lang_key = 0; | |
png_set_text(pp, pi, &text, 1); | |
} | |
#endif | |
if (colour_type == 3) /* palette */ | |
init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/); | |
png_write_info(pp, pi); | |
if (png_get_rowbytes(pp, pi) != | |
transform_rowsize(pp, colour_type, bit_depth)) | |
png_error(pp, "row size incorrect"); | |
else | |
{ | |
/* Somewhat confusingly this must be called *after* png_write_info | |
* because if it is called before, the information in *pp has not been | |
* updated to reflect the interlaced image. | |
*/ | |
int npasses = png_set_interlace_handling(pp); | |
int pass; | |
if (npasses != npasses_from_interlace_type(pp, interlace_type)) | |
png_error(pp, "write: png_set_interlace_handling failed"); | |
for (pass=0; pass<npasses; ++pass) | |
{ | |
png_uint_32 y; | |
for (y=0; y<h; ++y) | |
{ | |
png_byte buffer[TRANSFORM_ROWMAX]; | |
transform_row(pp, buffer, colour_type, bit_depth, y); | |
png_write_row(pp, buffer); | |
} | |
} | |
} | |
#ifdef PNG_TEXT_SUPPORTED | |
{ | |
static char key[] = "end marker"; | |
static char comment[] = "end"; | |
png_text text; | |
/* Use a compressed text string to test the correct interaction of text | |
* compression and IDAT compression. | |
*/ | |
text.compression = PNG_TEXT_COMPRESSION_zTXt; | |
text.key = key; | |
text.text = comment; | |
text.text_length = (sizeof comment)-1; | |
text.itxt_length = 0; | |
text.lang = 0; | |
text.lang_key = 0; | |
png_set_text(pp, pi, &text, 1); | |
} | |
#endif | |
png_write_end(pp, pi); | |
/* And store this under the appropriate id, then clean up. */ | |
store_storefile(ps, FILEID(colour_type, bit_depth, palette_number, | |
interlace_type, 0, 0, 0)); | |
store_write_reset(ps); | |
} | |
Catch(fault) | |
{ | |
/* Use the png_store returned by the exception. This may help the compiler | |
* because 'ps' is not used in this branch of the setjmp. Note that fault | |
* and ps will always be the same value. | |
*/ | |
store_write_reset(fault); | |
} | |
} | |
static void | |
make_transform_images(png_store *ps) | |
{ | |
png_byte colour_type = 0; | |
png_byte bit_depth = 0; | |
int palette_number = 0; | |
/* This is in case of errors. */ | |
safecat(ps->test, sizeof ps->test, 0, "make standard images"); | |
/* Use next_format to enumerate all the combinations we test, including | |
* generating multiple low bit depth palette images. | |
*/ | |
while (next_format(&colour_type, &bit_depth, &palette_number)) | |
{ | |
int interlace_type; | |
for (interlace_type = PNG_INTERLACE_NONE; | |
interlace_type < PNG_INTERLACE_LAST; ++interlace_type) | |
{ | |
char name[FILE_NAME_SIZE]; | |
standard_name(name, sizeof name, 0, colour_type, bit_depth, | |
palette_number, interlace_type, 0, 0, 0); | |
make_transform_image(ps, colour_type, bit_depth, palette_number, | |
interlace_type, name); | |
} | |
} | |
} | |
/* The following two routines use the PNG interlace support macros from | |
* png.h to interlace or deinterlace rows. | |
*/ | |
static void | |
interlace_row(png_bytep buffer, png_const_bytep imageRow, | |
unsigned int pixel_size, png_uint_32 w, int pass) | |
{ | |
png_uint_32 xin, xout, xstep; | |
/* Note that this can, trivially, be optimized to a memcpy on pass 7, the | |
* code is presented this way to make it easier to understand. In practice | |
* consult the code in the libpng source to see other ways of doing this. | |
*/ | |
xin = PNG_PASS_START_COL(pass); | |
xstep = 1U<<PNG_PASS_COL_SHIFT(pass); | |
for (xout=0; xin<w; xin+=xstep) | |
{ | |
pixel_copy(buffer, xout, imageRow, xin, pixel_size); | |
++xout; | |
} | |
} | |
static void | |
deinterlace_row(png_bytep buffer, png_const_bytep row, | |
unsigned int pixel_size, png_uint_32 w, int pass) | |
{ | |
/* The inverse of the above, 'row' is part of row 'y' of the output image, | |
* in 'buffer'. The image is 'w' wide and this is pass 'pass', distribute | |
* the pixels of row into buffer and return the number written (to allow | |
* this to be checked). | |
*/ | |
png_uint_32 xin, xout, xstep; | |
xout = PNG_PASS_START_COL(pass); | |
xstep = 1U<<PNG_PASS_COL_SHIFT(pass); | |
for (xin=0; xout<w; xout+=xstep) | |
{ | |
pixel_copy(buffer, xout, row, xin, pixel_size); | |
++xin; | |
} | |
} | |
/* Build a single row for the 'size' test images; this fills in only the | |
* first bit_width bits of the sample row. | |
*/ | |
static void | |
size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y) | |
{ | |
/* height is in the range 1 to 16, so: */ | |
y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4); | |
/* the following ensures bits are set in small images: */ | |
y ^= 0xA5; | |
while (bit_width >= 8) | |
*buffer++ = (png_byte)y++, bit_width -= 8; | |
/* There may be up to 7 remaining bits, these go in the most significant | |
* bits of the byte. | |
*/ | |
if (bit_width > 0) | |
{ | |
png_uint_32 mask = (1U<<(8-bit_width))-1; | |
*buffer = (png_byte)((*buffer & mask) | (y & ~mask)); | |
} | |
} | |
static void | |
make_size_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, | |
png_byte PNG_CONST bit_depth, int PNG_CONST interlace_type, | |
png_uint_32 PNG_CONST w, png_uint_32 PNG_CONST h, | |
int PNG_CONST do_interlace) | |
{ | |
context(ps, fault); | |
Try | |
{ | |
png_infop pi; | |
png_structp pp; | |
unsigned int pixel_size; | |
/* Make a name and get an appropriate id for the store: */ | |
char name[FILE_NAME_SIZE]; | |
PNG_CONST png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/, | |
interlace_type, w, h, do_interlace); | |
standard_name_from_id(name, sizeof name, 0, id); | |
pp = set_store_for_write(ps, &pi, name); | |
/* In the event of a problem return control to the Catch statement below | |
* to do the clean up - it is not possible to 'return' directly from a Try | |
* block. | |
*/ | |
if (pp == NULL) | |
Throw ps; | |
png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type, | |
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); | |
if (colour_type == 3) /* palette */ | |
init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/); | |
png_write_info(pp, pi); | |
/* Calculate the bit size, divide by 8 to get the byte size - this won't | |
* overflow because we know the w values are all small enough even for | |
* a system where 'unsigned int' is only 16 bits. | |
*/ | |
pixel_size = bit_size(pp, colour_type, bit_depth); | |
if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8) | |
png_error(pp, "row size incorrect"); | |
else | |
{ | |
int npasses = npasses_from_interlace_type(pp, interlace_type); | |
png_uint_32 y; | |
int pass; | |
png_byte image[16][SIZE_ROWMAX]; | |
/* To help consistent error detection make the parts of this buffer | |
* that aren't set below all '1': | |
*/ | |
memset(image, 0xff, sizeof image); | |
if (!do_interlace && npasses != png_set_interlace_handling(pp)) | |
png_error(pp, "write: png_set_interlace_handling failed"); | |
/* Prepare the whole image first to avoid making it 7 times: */ | |
for (y=0; y<h; ++y) | |
size_row(image[y], w * pixel_size, y); | |
for (pass=0; pass<npasses; ++pass) | |
{ | |
/* The following two are for checking the macros: */ | |
PNG_CONST png_uint_32 wPass = PNG_PASS_COLS(w, pass); | |
/* If do_interlace is set we don't call png_write_row for every | |
* row because some of them are empty. In fact, for a 1x1 image, | |
* most of them are empty! | |
*/ | |
for (y=0; y<h; ++y) | |
{ | |
png_const_bytep row = image[y]; | |
png_byte tempRow[SIZE_ROWMAX]; | |
/* If do_interlace *and* the image is interlaced we | |
* need a reduced interlace row; this may be reduced | |
* to empty. | |
*/ | |
if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7) | |
{ | |
/* The row must not be written if it doesn't exist, notice | |
* that there are two conditions here, either the row isn't | |
* ever in the pass or the row would be but isn't wide | |
* enough to contribute any pixels. In fact the wPass test | |
* can be used to skip the whole y loop in this case. | |
*/ | |
if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0) | |
{ | |
/* Set to all 1's for error detection (libpng tends to | |
* set unset things to 0). | |
*/ | |
memset(tempRow, 0xff, sizeof tempRow); | |
interlace_row(tempRow, row, pixel_size, w, pass); | |
row = tempRow; | |
} | |
else | |
continue; | |
} | |
/* Only get to here if the row has some pixels in it. */ | |
png_write_row(pp, row); | |
} | |
} | |
} | |
png_write_end(pp, pi); | |
/* And store this under the appropriate id, then clean up. */ | |
store_storefile(ps, id); | |
store_write_reset(ps); | |
} | |
Catch(fault) | |
{ | |
/* Use the png_store returned by the exception. This may help the compiler | |
* because 'ps' is not used in this branch of the setjmp. Note that fault | |
* and ps will always be the same value. | |
*/ | |
store_write_reset(fault); | |
} | |
} | |
static void | |
make_size(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, int bdlo, | |
int PNG_CONST bdhi) | |
{ | |
for (; bdlo <= bdhi; ++bdlo) | |
{ | |
png_uint_32 width; | |
for (width = 1; width <= 16; ++width) | |
{ | |
png_uint_32 height; | |
for (height = 1; height <= 16; ++height) | |
{ | |
/* The four combinations of DIY interlace and interlace or not - | |
* no interlace + DIY should be identical to no interlace with | |
* libpng doing it. | |
*/ | |
make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE, | |
width, height, 0); | |
make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE, | |
width, height, 1); | |
make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7, | |
width, height, 0); | |
make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7, | |
width, height, 1); | |
} | |
} | |
} | |
} | |
static void | |
make_size_images(png_store *ps) | |
{ | |
/* This is in case of errors. */ | |
safecat(ps->test, sizeof ps->test, 0, "make size images"); | |
/* Arguments are colour_type, low bit depth, high bit depth | |
*/ | |
make_size(ps, 0, 0, WRITE_BDHI); | |
make_size(ps, 2, 3, WRITE_BDHI); | |
make_size(ps, 3, 0, 3 /*palette: max 8 bits*/); | |
make_size(ps, 4, 3, WRITE_BDHI); | |
make_size(ps, 6, 3, WRITE_BDHI); | |
} | |
/* Return a row based on image id and 'y' for checking: */ | |
static void | |
standard_row(png_structp pp, png_byte std[STANDARD_ROWMAX], png_uint_32 id, | |
png_uint_32 y) | |
{ | |
if (WIDTH_FROM_ID(id) == 0) | |
transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y); | |
else | |
size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id), | |
DEPTH_FROM_ID(id)), y); | |
} | |
/* Tests - individual test cases */ | |
/* Like 'make_standard' but errors are deliberately introduced into the calls | |
* to ensure that they get detected - it should not be possible to write an | |
* invalid image with libpng! | |
*/ | |
#ifdef PNG_WARNINGS_SUPPORTED | |
static void | |
sBIT0_error_fn(png_structp pp, png_infop pi) | |
{ | |
/* 0 is invalid... */ | |
png_color_8 bad; | |
bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0; | |
png_set_sBIT(pp, pi, &bad); | |
} | |
static void | |
sBIT_error_fn(png_structp pp, png_infop pi) | |
{ | |
png_byte bit_depth; | |
png_color_8 bad; | |
if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE) | |
bit_depth = 8; | |
else | |
bit_depth = png_get_bit_depth(pp, pi); | |
/* Now we know the bit depth we can easily generate an invalid sBIT entry */ | |
bad.red = bad.green = bad.blue = bad.gray = bad.alpha = | |
(png_byte)(bit_depth+1); | |
png_set_sBIT(pp, pi, &bad); | |
} | |
static PNG_CONST struct | |
{ | |
void (*fn)(png_structp, png_infop); | |
PNG_CONST char *msg; | |
unsigned int warning :1; /* the error is a warning... */ | |
} error_test[] = | |
{ | |
/* no warnings makes these errors undetectable. */ | |
{ sBIT0_error_fn, "sBIT(0): failed to detect error", 1 }, | |
{ sBIT_error_fn, "sBIT(too big): failed to detect error", 1 }, | |
}; | |
static void | |
make_error(png_store* volatile ps, png_byte PNG_CONST colour_type, | |
png_byte bit_depth, int interlace_type, int test, png_const_charp name) | |
{ | |
context(ps, fault); | |
Try | |
{ | |
png_structp pp; | |
png_infop pi; | |
pp = set_store_for_write(ps, &pi, name); | |
if (pp == NULL) | |
Throw ps; | |
png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth), | |
transform_height(pp, colour_type, bit_depth), bit_depth, colour_type, | |
interlace_type, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); | |
if (colour_type == 3) /* palette */ | |
init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/); | |
/* Time for a few errors; these are in various optional chunks, the | |
* standard tests test the standard chunks pretty well. | |
*/ | |
# define exception__prev exception_prev_1 | |
# define exception__env exception_env_1 | |
Try | |
{ | |
/* Expect this to throw: */ | |
ps->expect_error = !error_test[test].warning; | |
ps->expect_warning = error_test[test].warning; | |
ps->saw_warning = 0; | |
error_test[test].fn(pp, pi); | |
/* Normally the error is only detected here: */ | |
png_write_info(pp, pi); | |
/* And handle the case where it was only a warning: */ | |
if (ps->expect_warning && ps->saw_warning) | |
Throw ps; | |
/* If we get here there is a problem, we have success - no error or | |
* no warning - when we shouldn't have success. Log an error. | |
*/ | |
store_log(ps, pp, error_test[test].msg, 1 /*error*/); | |
} | |
Catch (fault) | |
ps = fault; /* expected exit, make sure ps is not clobbered */ | |
#undef exception__prev | |
#undef exception__env | |
/* And clear these flags */ | |
ps->expect_error = 0; | |
ps->expect_warning = 0; | |
/* Now write the whole image, just to make sure that the detected, or | |
* undetected, errro has not created problems inside libpng. | |
*/ | |
if (png_get_rowbytes(pp, pi) != | |
transform_rowsize(pp, colour_type, bit_depth)) | |
png_error(pp, "row size incorrect"); | |
else | |
{ | |
png_uint_32 h = transform_height(pp, colour_type, bit_depth); | |
int npasses = png_set_interlace_handling(pp); | |
int pass; | |
if (npasses != npasses_from_interlace_type(pp, interlace_type)) | |
png_error(pp, "write: png_set_interlace_handling failed"); | |
for (pass=0; pass<npasses; ++pass) | |
{ | |
png_uint_32 y; | |
for (y=0; y<h; ++y) | |
{ | |
png_byte buffer[TRANSFORM_ROWMAX]; | |
transform_row(pp, buffer, colour_type, bit_depth, y); | |
png_write_row(pp, buffer); | |
} | |
} | |
} | |
png_write_end(pp, pi); | |
/* The following deletes the file that was just written. */ | |
store_write_reset(ps); | |
} | |
Catch(fault) | |
{ | |
store_write_reset(fault); | |
} | |
} | |
static int | |
make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type, | |
int bdlo, int PNG_CONST bdhi) | |
{ | |
for (; bdlo <= bdhi; ++bdlo) | |
{ | |
int interlace_type; | |
for (interlace_type = PNG_INTERLACE_NONE; | |
interlace_type < PNG_INTERLACE_LAST; ++interlace_type) | |
{ | |
unsigned int test; | |
char name[FILE_NAME_SIZE]; | |
standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0, | |
interlace_type, 0, 0, 0); | |
for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test) | |
{ | |
make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type, | |
test, name); | |
if (fail(pm)) | |
return 0; | |
} | |
} | |
} | |
return 1; /* keep going */ | |
} | |
#endif | |
static void | |
perform_error_test(png_modifier *pm) | |
{ | |
#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */ | |
/* Need to do this here because we just write in this test. */ | |
safecat(pm->this.test, sizeof pm->this.test, 0, "error test"); | |
if (!make_errors(pm, 0, 0, WRITE_BDHI)) | |
return; | |
if (!make_errors(pm, 2, 3, WRITE_BDHI)) | |
return; | |
if (!make_errors(pm, 3, 0, 3)) | |
return; | |
if (!make_errors(pm, 4, 3, WRITE_BDHI)) | |
return; | |
if (!make_errors(pm, 6, 3, WRITE_BDHI)) | |
return; | |
#else | |
UNUSED(pm) | |
#endif | |
} | |
/* This is just to validate the internal PNG formatting code - if this fails | |
* then the warning messages the library outputs will probably be garbage. | |
*/ | |
static void | |
perform_formatting_test(png_store *volatile ps) | |
{ | |
#ifdef PNG_TIME_RFC1123_SUPPORTED | |
/* The handle into the formatting code is the RFC1123 support; this test does | |
* nothing if that is compiled out. | |
*/ | |
context(ps, fault); | |
Try | |
{ | |
png_const_charp correct = "29 Aug 2079 13:53:60 +0000"; | |
png_const_charp result; | |
png_structp pp; | |
png_time pt; | |
pp = set_store_for_write(ps, NULL, "libpng formatting test"); | |
if (pp == NULL) | |
Throw ps; | |
/* Arbitrary settings: */ | |
pt.year = 2079; | |
pt.month = 8; | |
pt.day = 29; | |
pt.hour = 13; | |
pt.minute = 53; | |
pt.second = 60; /* a leap second */ | |
result = png_convert_to_rfc1123(pp, &pt); | |
if (result == NULL) | |
png_error(pp, "png_convert_to_rfc1123 failed"); | |
if (strcmp(result, correct) != 0) | |
{ | |
size_t pos = 0; | |
char msg[128]; | |
pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123("); | |
pos = safecat(msg, sizeof msg, pos, correct); | |
pos = safecat(msg, sizeof msg, pos, ") returned: '"); | |
pos = safecat(msg, sizeof msg, pos, result); | |
pos = safecat(msg, sizeof msg, pos, "'"); | |
png_error(pp, msg); | |
} | |
store_write_reset(ps); | |
} | |
Catch(fault) | |
{ | |
store_write_reset(fault); | |
} | |
#else | |
UNUSED(ps) | |
#endif | |
} | |
/* Because we want to use the same code in both the progressive reader and the | |
* sequential reader it is necessary to deal with the fact that the progressive | |
* reader callbacks only have one parameter (png_get_progressive_ptr()), so this | |
* must contain all the test parameters and all the local variables directly | |
* accessible to the sequential reader implementation. | |
* | |
* The technique adopted is to reinvent part of what Dijkstra termed a | |
* 'display'; an array of pointers to the stack frames of enclosing functions so | |
* that a nested function definition can access the local (C auto) variables of | |
* the functions that contain its definition. In fact C provides the first | |
* pointer (the local variables - the stack frame pointer) and the last (the | |
* global variables - the BCPL global vector typically implemented as global | |
* addresses), this code requires one more pointer to make the display - the | |
* local variables (and function call parameters) of the function that actually | |
* invokes either the progressive or sequential reader. | |
* | |
* Perhaps confusingly this technique is confounded with classes - the | |
* 'standard_display' defined here is sub-classed as the 'gamma_display' below. | |
* A gamma_display is a standard_display, taking advantage of the ANSI-C | |
* requirement that the pointer to the first member of a structure must be the | |
* same as the pointer to the structure. This allows us to reuse standard_ | |
* functions in the gamma test code; something that could not be done with | |
* nested functions! | |
*/ | |
typedef struct standard_display | |
{ | |
png_store* ps; /* Test parameters (passed to the function) */ | |
png_byte colour_type; | |
png_byte bit_depth; | |
png_byte red_sBIT; /* Input data sBIT values. */ | |
png_byte green_sBIT; | |
png_byte blue_sBIT; | |
png_byte alpha_sBIT; | |
int interlace_type; | |
png_uint_32 id; /* Calculated file ID */ | |
png_uint_32 w; /* Width of image */ | |
png_uint_32 h; /* Height of image */ | |
int npasses; /* Number of interlaced passes */ | |
png_uint_32 pixel_size; /* Width of one pixel in bits */ | |
png_uint_32 bit_width; /* Width of output row in bits */ | |
size_t cbRow; /* Bytes in a row of the output image */ | |
int do_interlace; /* Do interlacing internally */ | |
int is_transparent; /* Transparency information was present. */ | |
int speed; /* Doing a speed test */ | |
struct | |
{ | |
png_uint_16 red; | |
png_uint_16 green; | |
png_uint_16 blue; | |
} transparent; /* The transparent color, if set. */ | |
int npalette; /* Number of entries in the palette. */ | |
store_palette | |
palette; | |
} standard_display; | |
static void | |
standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id, | |
int do_interlace) | |
{ | |
dp->ps = ps; | |
dp->colour_type = COL_FROM_ID(id); | |
dp->bit_depth = DEPTH_FROM_ID(id); | |
if (dp->colour_type == 3) | |
dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8; | |
else | |
dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = | |
dp->bit_depth; | |
dp->interlace_type = INTERLACE_FROM_ID(id); | |
dp->id = id; | |
/* All the rest are filled in after the read_info: */ | |
dp->w = 0; | |
dp->h = 0; | |
dp->npasses = 0; | |
dp->pixel_size = 0; | |
dp->bit_width = 0; | |
dp->cbRow = 0; | |
dp->do_interlace = do_interlace; | |
dp->is_transparent = 0; | |
dp->speed = ps->speed; | |
dp->npalette = 0; | |
/* Preset the transparent color to black: */ | |
memset(&dp->transparent, 0, sizeof dp->transparent); | |
/* Preset the palette to full intensity/opaque througout: */ | |
memset(dp->palette, 0xff, sizeof dp->palette); | |
} | |
/* Initialize the palette fields - this must be done later because the palette | |
* comes from the particular png_store_file that is selected. | |
*/ | |
static void | |
standard_palette_init(standard_display *dp) | |
{ | |
store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette); | |
/* The remaining entries remain white/opaque. */ | |
if (dp->npalette > 0) | |
{ | |
int i = dp->npalette; | |
memcpy(dp->palette, palette, i * sizeof *palette); | |
/* Check for a non-opaque palette entry: */ | |
while (--i >= 0) | |
if (palette[i].alpha < 255) | |
break; | |
# ifdef __GNUC__ | |
/* GCC can't handle the more obviously optimizable version. */ | |
if (i >= 0) | |
dp->is_transparent = 1; | |
else | |
dp->is_transparent = 0; | |
# else | |
dp->is_transparent = (i >= 0); | |
# endif | |
} | |
} | |
/* Utility to read the palette from the PNG file and convert it into | |
* store_palette format. This returns 1 if there is any transparency in the | |
* palette (it does not check for a transparent colour in the non-palette case.) | |
*/ | |
static int | |
read_palette(store_palette palette, int *npalette, png_structp pp, png_infop pi) | |
{ | |
png_colorp pal; | |
png_bytep trans_alpha; | |
int num; | |
pal = 0; | |
*npalette = -1; | |
if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE) | |
{ | |
int i = *npalette; | |
if (i <= 0 || i > 256) | |
png_error(pp, "validate: invalid PLTE count"); | |
while (--i >= 0) | |
{ | |
palette[i].red = pal[i].red; | |
palette[i].green = pal[i].green; | |
palette[i].blue = pal[i].blue; | |
} | |
/* Mark the remainder of the entries with a flag value (other than | |
* white/opaque which is the flag value stored above.) | |
*/ | |
memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette); | |
} | |
else /* !png_get_PLTE */ | |
{ | |
if (*npalette != (-1)) | |
png_error(pp, "validate: invalid PLTE result"); | |
/* But there is no palette, so record this: */ | |
*npalette = 0; | |
memset(palette, 113, sizeof palette); | |
} | |
trans_alpha = 0; | |
num = 2; /* force error below */ | |
if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 && | |
(trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) && | |
/* Oops, if a palette tRNS gets expanded png_read_update_info (at least so | |
* far as 1.5.4) does not zap the trans_alpha pointer, only num_trans, so | |
* in the above call we get a success, we get a pointer (who knows what | |
* to) and we get num_trans == 0: | |
*/ | |
!(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */ | |
{ | |
int i; | |
/* Any of these are crash-worthy - given the implementation of | |
* png_get_tRNS up to 1.5 an app won't crash if it just checks the | |
* result above and fails to check that the variables it passed have | |
* actually been filled in! Note that if the app were to pass the | |
* last, png_color_16p, variable too it couldn't rely on this. | |
*/ | |
if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette) | |
png_error(pp, "validate: unexpected png_get_tRNS (palette) result"); | |
for (i=0; i<num; ++i) | |
palette[i].alpha = trans_alpha[i]; | |
for (num=*npalette; i<num; ++i) | |
palette[i].alpha = 255; | |
for (; i<256; ++i) | |
palette[i].alpha = 33; /* flag value */ | |
return 1; /* transparency */ | |
} | |
else | |
{ | |
/* No palette transparency - just set the alpha channel to opaque. */ | |
int i; | |
for (i=0, num=*npalette; i<num; ++i) | |
palette[i].alpha = 255; | |
for (; i<256; ++i) | |
palette[i].alpha = 55; /* flag value */ | |
return 0; /* no transparency */ | |
} | |
} | |
/* Utility to validate the palette if it should not have changed (the | |
* non-transform case). | |
*/ | |
static void | |
standard_palette_validate(standard_display *dp, png_structp pp, png_infop pi) | |
{ | |
int npalette; | |
store_palette palette; | |
if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent) | |
png_error(pp, "validate: palette transparency changed"); | |
if (npalette != dp->npalette) | |
{ | |
size_t pos = 0; | |
char msg[64]; | |
pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: "); | |
pos = safecatn(msg, sizeof msg, pos, dp->npalette); | |
pos = safecat(msg, sizeof msg, pos, " -> "); | |
pos = safecatn(msg, sizeof msg, pos, npalette); | |
png_error(pp, msg); | |
} | |
{ | |
int i = npalette; /* npalette is aliased */ | |
while (--i >= 0) | |
if (palette[i].red != dp->palette[i].red || | |
palette[i].green != dp->palette[i].green || | |
palette[i].blue != dp->palette[i].blue || | |
palette[i].alpha != dp->palette[i].alpha) | |
png_error(pp, "validate: PLTE or tRNS chunk changed"); | |
} | |
} | |
/* By passing a 'standard_display' the progressive callbacks can be used | |
* directly by the sequential code, the functions suffixed "_imp" are the | |
* implementations, the functions without the suffix are the callbacks. | |
* | |
* The code for the info callback is split into two because this callback calls | |
* png_read_update_info or png_start_read_image and what gets called depends on | |
* whether the info needs updating (we want to test both calls in pngvalid.) | |
*/ | |
static void | |
standard_info_part1(standard_display *dp, png_structp pp, png_infop pi) | |
{ | |
if (png_get_bit_depth(pp, pi) != dp->bit_depth) | |
png_error(pp, "validate: bit depth changed"); | |
if (png_get_color_type(pp, pi) != dp->colour_type) | |
png_error(pp, "validate: color type changed"); | |
if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE) | |
png_error(pp, "validate: filter type changed"); | |
if (png_get_interlace_type(pp, pi) != dp->interlace_type) | |
png_error(pp, "validate: interlacing changed"); | |
if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE) | |
png_error(pp, "validate: compression type changed"); | |
dp->w = png_get_image_width(pp, pi); | |
if (dp->w != standard_width(pp, dp->id)) | |
png_error(pp, "validate: image width changed"); | |
dp->h = png_get_image_height(pp, pi); | |
if (dp->h != standard_height(pp, dp->id)) | |
png_error(pp, "validate: image height changed"); | |
/* Record (but don't check at present) the input sBIT according to the colour | |
* type information. | |
*/ | |
{ | |
png_color_8p sBIT = 0; | |
if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT) | |
{ | |
int sBIT_invalid = 0; | |
if (sBIT == 0) | |
png_error(pp, "validate: unexpected png_get_sBIT result"); | |
if (dp->colour_type & PNG_COLOR_MASK_COLOR) | |
{ | |
if (sBIT->red == 0 || sBIT->red > dp->bit_depth) | |
sBIT_invalid = 1; | |
else | |
dp->red_sBIT = sBIT->red; | |
if (sBIT->green == 0 || sBIT->green > dp->bit_depth) | |
sBIT_invalid = 1; | |
else | |
dp->green_sBIT = sBIT->green; | |
if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth) | |
sBIT_invalid = 1; | |
else | |
dp->blue_sBIT = sBIT->blue; | |
} | |
else /* !COLOR */ | |
{ | |
if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth) | |
sBIT_invalid = 1; | |
else | |
dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray; | |
} | |
/* All 8 bits in tRNS for a palette image are significant - see the | |
* spec. | |
*/ | |
if (dp->colour_type & PNG_COLOR_MASK_ALPHA) | |
{ | |
if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth) | |
sBIT_invalid = 1; | |
else | |
dp->alpha_sBIT = sBIT->alpha; | |
} | |
if (sBIT_invalid) | |
png_error(pp, "validate: sBIT value out of range"); | |
} | |
} | |
/* Important: this is validating the value *before* any transforms have been | |
* put in place. It doesn't matter for the standard tests, where there are | |
* no transforms, but it does for other tests where rowbytes may change after | |
* png_read_update_info. | |
*/ | |
if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id)) | |
png_error(pp, "validate: row size changed"); | |
/* Validate the colour type 3 palette (this can be present on other color | |
* types.) | |
*/ | |
standard_palette_validate(dp, pp, pi); | |
/* In any case always check for a tranparent color (notice that the | |
* colour type 3 case must not give a successful return on the get_tRNS call | |
* with these arguments!) | |
*/ | |
{ | |
png_color_16p trans_color = 0; | |
if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS) | |
{ | |
if (trans_color == 0) | |
png_error(pp, "validate: unexpected png_get_tRNS (color) result"); | |
switch (dp->colour_type) | |
{ | |
case 0: | |
dp->transparent.red = dp->transparent.green = dp->transparent.blue = | |
trans_color->gray; | |
dp->is_transparent = 1; | |
break; | |
case 2: | |
dp->transparent.red = trans_color->red; | |
dp->transparent.green = trans_color->green; | |
dp->transparent.blue = trans_color->blue; | |
dp->is_transparent = 1; | |
break; | |
case 3: | |
/* Not expected because it should result in the array case | |
* above. | |
*/ | |
png_error(pp, "validate: unexpected png_get_tRNS result"); | |
break; | |
default: | |
png_error(pp, "validate: invalid tRNS chunk with alpha image"); | |
} | |
} | |
} | |
/* Read the number of passes - expected to match the value used when | |
* creating the image (interlaced or not). This has the side effect of | |
* turning on interlace handling (if do_interlace is not set.) | |
*/ | |
dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type); | |
if (!dp->do_interlace && dp->npasses != png_set_interlace_handling(pp)) | |
png_error(pp, "validate: file changed interlace type"); | |
/* Caller calls png_read_update_info or png_start_read_image now, then calls | |
* part2. | |
*/ | |
} | |
/* This must be called *after* the png_read_update_info call to get the correct | |
* 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed | |
* image. | |
*/ | |
static void | |
standard_info_part2(standard_display *dp, png_structp pp, png_infop pi, | |
int nImages) | |
{ | |
/* Record cbRow now that it can be found. */ | |
dp->pixel_size = bit_size(pp, png_get_color_type(pp, pi), | |
png_get_bit_depth(pp, pi)); | |
dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size; | |
dp->cbRow = png_get_rowbytes(pp, pi); | |
/* Validate the rowbytes here again. */ | |
if (dp->cbRow != (dp->bit_width+7)/8) | |
png_error(pp, "bad png_get_rowbytes calculation"); | |
/* Then ensure there is enough space for the output image(s). */ | |
store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h); | |
} | |
static void | |
standard_info_imp(standard_display *dp, png_structp pp, png_infop pi, | |
int nImages) | |
{ | |
/* Note that the validation routine has the side effect of turning on | |
* interlace handling in the subsequent code. | |
*/ | |
standard_info_part1(dp, pp, pi); | |
/* And the info callback has to call this (or png_read_update_info - see | |
* below in the png_modifier code for that variant. | |
*/ | |
png_start_read_image(pp); | |
/* Validate the height, width and rowbytes plus ensure that sufficient buffer | |
* exists for decoding the image. | |
*/ | |
standard_info_part2(dp, pp, pi, nImages); | |
} | |
static void | |
standard_info(png_structp pp, png_infop pi) | |
{ | |
standard_display *dp = png_get_progressive_ptr(pp); | |
/* Call with nImages==1 because the progressive reader can only produce one | |
* image. | |
*/ | |
standard_info_imp(dp, pp, pi, 1 /*only one image*/); | |
} | |
static void | |
progressive_row(png_structp pp, png_bytep new_row, png_uint_32 y, int pass) | |
{ | |
PNG_CONST standard_display *dp = png_get_progressive_ptr(pp); | |
/* When handling interlacing some rows will be absent in each pass, the | |
* callback still gets called, but with a NULL pointer. This is checked | |
* in the 'else' clause below. We need our own 'cbRow', but we can't call | |
* png_get_rowbytes because we got no info structure. | |
*/ | |
if (new_row != NULL) | |
{ | |
png_bytep row; | |
/* In the case where the reader doesn't do the interlace it gives | |
* us the y in the sub-image: | |
*/ | |
if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7) | |
{ | |
#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED | |
/* Use this opportunity to validate the png 'current' APIs: */ | |
if (y != png_get_current_row_number(pp)) | |
png_error(pp, "png_get_current_row_number is broken"); | |
if (pass != png_get_current_pass_number(pp)) | |
png_error(pp, "png_get_current_pass_number is broken"); | |
#endif | |
y = PNG_ROW_FROM_PASS_ROW(y, pass); | |
} | |
/* Validate this just in case. */ | |
if (y >= dp->h) | |
png_error(pp, "invalid y to progressive row callback"); | |
row = store_image_row(dp->ps, pp, 0, y); | |
/* Combine the new row into the old: */ | |
if (dp->do_interlace) | |
{ | |
if (dp->interlace_type == PNG_INTERLACE_ADAM7) | |
deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass); | |
else | |
memcpy(row, new_row, dp->cbRow); | |
} | |
else | |
png_progressive_combine_row(pp, row, new_row); | |
} else if (dp->interlace_type == PNG_INTERLACE_ADAM7 && | |
PNG_ROW_IN_INTERLACE_PASS(y, pass) && | |
PNG_PASS_COLS(dp->w, pass) > 0) | |
png_error(pp, "missing row in progressive de-interlacing"); | |
} | |
static void | |
sequential_row(standard_display *dp, png_structp pp, png_infop pi, | |
PNG_CONST int iImage, PNG_CONST int iDisplay) | |
{ | |
PNG_CONST int npasses = dp->npasses; | |
PNG_CONST int do_interlace = dp->do_interlace && | |
dp->interlace_type == PNG_INTERLACE_ADAM7; | |
PNG_CONST png_uint_32 height = standard_height(pp, dp->id); | |
PNG_CONST png_uint_32 width = standard_width(pp, dp->id); | |
PNG_CONST png_store* ps = dp->ps; | |
int pass; | |
for (pass=0; pass<npasses; ++pass) | |
{ | |
png_uint_32 y; | |
png_uint_32 wPass = PNG_PASS_COLS(width, pass); | |
for (y=0; y<height; ++y) | |
{ | |
if (do_interlace) | |
{ | |
/* wPass may be zero or this row may not be in this pass. | |
* png_read_row must not be called in either case. | |
*/ | |
if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass)) | |
{ | |
/* Read the row into a pair of temporary buffers, then do the | |
* merge here into the output rows. | |
*/ | |
png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX]; | |
/* The following aids (to some extent) error detection - we can | |
* see where png_read_row wrote. Use opposite values in row and | |
* display to make this easier. | |
*/ | |
memset(row, 0xff, sizeof row); | |
memset(display, 0, sizeof display); | |
png_read_row(pp, row, display); | |
if (iImage >= 0) | |
deinterlace_row(store_image_row(ps, pp, iImage, y), row, | |
dp->pixel_size, dp->w, pass); | |
if (iDisplay >= 0) | |
deinterlace_row(store_image_row(ps, pp, iDisplay, y), display, | |
dp->pixel_size, dp->w, pass); | |
} | |
} | |
else | |
png_read_row(pp, | |
iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL, | |
iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL); | |
} | |
} | |
/* And finish the read operation (only really necessary if the caller wants | |
* to find additional data in png_info from chunks after the last IDAT.) | |
*/ | |
png_read_end(pp, pi); | |
} | |
static void | |
standard_row_validate(standard_display *dp, png_structp pp, | |
int iImage, int iDisplay, png_uint_32 y) | |
{ | |
png_byte std[STANDARD_ROWMAX]; | |
memset(std, 0xff, sizeof std); | |
standard_row(pp, std, dp->id, y); | |
/* At the end both the 'row' and 'display' arrays should end up identical. | |
* In earlier passes 'row' will be partially filled in, with only the pixels | |
* that have been read so far, but 'display' will have those pixels | |
* replicated to fill the unread pixels while reading an interlaced image. | |
* The side effect inside the libpng sequential reader is that the 'row' | |
* array retains the correct values for unwritten pixels within the row | |
* bytes, while the 'display' array gets bits off the end of the image (in | |
* the last byte) trashed. Unfortunately in the progressive reader the | |
* row bytes are always trashed, so we always do a pixel_cmp here even though | |
* a memcmp of all cbRow bytes will succeed for the sequential reader. | |
*/ | |
if (iImage >= 0 && pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y), | |
dp->bit_width) != 0) | |
{ | |
char msg[64]; | |
sprintf(msg, "PNG image row %d changed", y); | |
png_error(pp, msg); | |
} | |
/* In this case use pixel_cmp because we need to compare a partial | |
* byte at the end of the row if the row is not an exact multiple | |
* of 8 bits wide. | |
*/ | |
if (iDisplay >= 0 && pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y), | |
dp->bit_width) != 0) | |
{ | |
char msg[64]; | |
sprintf(msg, "display row %d changed", y); | |
png_error(pp, msg); | |
} | |
} | |
static void | |
standard_image_validate(standard_display *dp, png_structp pp, int iImage, | |
int iDisplay) | |
{ | |
png_uint_32 y; | |
if (iImage >= 0) | |
store_image_check(dp->ps, pp, iImage); | |
if (iDisplay >= 0) | |
store_image_check(dp->ps, pp, iDisplay); | |
for (y=0; y<dp->h; ++y) | |
standard_row_validate(dp, pp, iImage, iDisplay, y); | |
/* This avoids false positives if the validation code is never called! */ | |
dp->ps->validated = 1; | |
} | |
static void | |
standard_end(png_structp pp, png_infop pi) | |
{ | |
standard_display *dp = png_get_progressive_ptr(pp); | |
UNUSED(pi) | |
/* Validate the image - progressive reading only produces one variant for | |
* interlaced images. | |
*/ | |
standard_image_validate(dp, pp, 0, -1); | |
} | |
/* A single test run checking the standard image to ensure it is not damaged. */ | |
static void | |
standard_test(png_store* PNG_CONST psIn, png_uint_32 PNG_CONST id, | |
int do_interlace) | |
{ | |
standard_display d; | |
context(psIn, fault); | |
/* Set up the display (stack frame) variables from the arguments to the | |
* function and initialize the locals that are filled in later. | |
*/ | |
standard_display_init(&d, psIn, id, do_interlace); | |
/* Everything is protected by a Try/Catch. The functions called also | |
* typically have local Try/Catch blocks. | |
*/ | |
Try | |
{ | |
png_structp pp; | |
png_infop pi; | |
/* Get a png_struct for reading the image. This will throw an error if it | |
* fails, so we don't need to check the result. | |
*/ | |
pp = set_store_for_read(d.ps, &pi, d.id, | |
d.do_interlace ? (d.ps->progressive ? | |
"pngvalid progressive deinterlacer" : | |
"pngvalid sequential deinterlacer") : (d.ps->progressive ? | |
"progressive reader" : "sequential reader")); | |
/* Initialize the palette correctly from the png_store_file. */ | |
standard_palette_init(&d); | |
/* Introduce the correct read function. */ | |
if (d.ps->progressive) | |
{ | |
png_set_progressive_read_fn(pp, &d, standard_info, progressive_row, | |
standard_end); | |
/* Now feed data into the reader until we reach the end: */ | |
store_progressive_read(d.ps, pp, pi); | |
} | |
else | |
{ | |
/* Note that this takes the store, not the display. */ | |
png_set_read_fn(pp, d.ps, store_read); | |
/* Check the header values: */ | |
png_read_info(pp, pi); | |
/* The code tests both versions of the images that the sequential | |
* reader can produce. | |
*/ | |
standard_info_imp(&d, pp, pi, 2 /*images*/); | |
/* Need the total bytes in the image below; we can't get to this point | |
* unless the PNG file values have been checked against the expected | |
* values. | |
*/ | |
{ | |
sequential_row(&d, pp, pi, 0, 1); | |
/* After the last pass loop over the rows again to check that the | |
* image is correct. | |
*/ | |
if (!d.speed) | |
standard_image_validate(&d, pp, 0, 1); | |
} | |
} | |
/* Check for validation. */ | |
if (!d.ps->validated) | |
png_error(pp, "image read failed silently"); | |
/* Successful completion. */ | |
} | |
Catch(fault) | |
d.ps = fault; /* make sure this hasn't been clobbered. */ | |
/* In either case clean up the store. */ | |
store_read_reset(d.ps); | |
} | |
static int | |
test_standard(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type, | |
int bdlo, int PNG_CONST bdhi) | |
{ | |
for (; bdlo <= bdhi; ++bdlo) | |
{ | |
int interlace_type; | |
for (interlace_type = PNG_INTERLACE_NONE; | |
interlace_type < PNG_INTERLACE_LAST; ++interlace_type) | |
{ | |
standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, | |
interlace_type, 0, 0, 0), 0/*do_interlace*/); | |
if (fail(pm)) | |
return 0; | |
} | |
} | |
return 1; /* keep going */ | |
} | |
static void | |
perform_standard_test(png_modifier *pm) | |
{ | |
/* Test each colour type over the valid range of bit depths (expressed as | |
* log2(bit_depth) in turn, stop as soon as any error is detected. | |
*/ | |
if (!test_standard(pm, 0, 0, READ_BDHI)) | |
return; | |
if (!test_standard(pm, 2, 3, READ_BDHI)) | |
return; | |
if (!test_standard(pm, 3, 0, 3)) | |
return; | |
if (!test_standard(pm, 4, 3, READ_BDHI)) | |
return; | |
if (!test_standard(pm, 6, 3, READ_BDHI)) | |
return; | |
} | |
/********************************** SIZE TESTS ********************************/ | |
static int | |
test_size(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type, | |
int bdlo, int PNG_CONST bdhi) | |
{ | |
/* Run the tests on each combination. | |
* | |
* NOTE: on my 32 bit x86 each of the following blocks takes | |
* a total of 3.5 seconds if done across every combo of bit depth | |
* width and height. This is a waste of time in practice, hence the | |
* hinc and winc stuff: | |
*/ | |
static PNG_CONST png_byte hinc[] = {1, 3, 11, 1, 5}; | |
static PNG_CONST png_byte winc[] = {1, 9, 5, 7, 1}; | |
for (; bdlo <= bdhi; ++bdlo) | |
{ | |
png_uint_32 h, w; | |
for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo]) | |
{ | |
/* First test all the 'size' images against the sequential | |
* reader using libpng to deinterlace (where required.) This | |
* validates the write side of libpng. There are four possibilities | |
* to validate. | |
*/ | |
standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, | |
PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/); | |
if (fail(pm)) | |
return 0; | |
standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, | |
PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/); | |
if (fail(pm)) | |
return 0; | |
standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, | |
PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/); | |
if (fail(pm)) | |
return 0; | |
standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, | |
PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/); | |
if (fail(pm)) | |
return 0; | |
/* Now validate the interlaced read side - do_interlace true, | |
* in the progressive case this does actually make a difference | |
* to the code used in the non-interlaced case too. | |
*/ | |
standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, | |
PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/); | |
if (fail(pm)) | |
return 0; | |
standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, | |
PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/); | |
if (fail(pm)) | |
return 0; | |
} | |
} | |
return 1; /* keep going */ | |
} | |
static void | |
perform_size_test(png_modifier *pm) | |
{ | |
/* Test each colour type over the valid range of bit depths (expressed as | |
* log2(bit_depth) in turn, stop as soon as any error is detected. | |
*/ | |
if (!test_size(pm, 0, 0, READ_BDHI)) | |
return; | |
if (!test_size(pm, 2, 3, READ_BDHI)) | |
return; | |
/* For the moment don't do the palette test - it's a waste of time when | |
* compared to the greyscale test. | |
*/ | |
#if 0 | |
if (!test_size(pm, 3, 0, 3)) | |
return; | |
#endif | |
if (!test_size(pm, 4, 3, READ_BDHI)) | |
return; | |
if (!test_size(pm, 6, 3, READ_BDHI)) | |
return; | |
} | |
/******************************* TRANSFORM TESTS ******************************/ | |
#ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
/* A set of tests to validate libpng image transforms. The possibilities here | |
* are legion because the transforms can be combined in a combinatorial | |
* fashion. To deal with this some measure of restraint is required, otherwise | |
* the tests would take forever. | |
*/ | |
typedef struct image_pixel | |
{ | |
/* A local (pngvalid) representation of a PNG pixel, in all its | |
* various forms. | |
*/ | |
unsigned int red, green, blue, alpha; /* For non-palette images. */ | |
unsigned int palette_index; /* For a palette image. */ | |
png_byte colour_type; /* As in the spec. */ | |
png_byte bit_depth; /* Defines bit size in row */ | |
png_byte sample_depth; /* Scale of samples */ | |
int have_tRNS; /* tRNS chunk may need processing */ | |
/* For checking the code calculates double precision floating point values | |
* along with an error value, accumulated from the transforms. Because an | |
* sBIT setting allows larger error bounds (indeed, by the spec, apparently | |
* up to just less than +/-1 in the scaled value) the *lowest* sBIT for each | |
* channel is stored. This sBIT value is folded in to the stored error value | |
* at the end of the application of the transforms to the pixel. | |
*/ | |
double redf, greenf, bluef, alphaf; | |
double rede, greene, bluee, alphae; | |
png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT; | |
} image_pixel; | |
/* Shared utility function, see below. */ | |
static void | |
image_pixel_setf(image_pixel *this, unsigned int max) | |
{ | |
this->redf = this->red / (double)max; | |
this->greenf = this->green / (double)max; | |
this->bluef = this->blue / (double)max; | |
this->alphaf = this->alpha / (double)max; | |
if (this->red < max) | |
this->rede = this->redf * DBL_EPSILON; | |
else | |
this->rede = 0; | |
if (this->green < max) | |
this->greene = this->greenf * DBL_EPSILON; | |
else | |
this->greene = 0; | |
if (this->blue < max) | |
this->bluee = this->bluef * DBL_EPSILON; | |
else | |
this->bluee = 0; | |
if (this->alpha < max) | |
this->alphae = this->alphaf * DBL_EPSILON; | |
else | |
this->alphae = 0; | |
} | |
/* Initialize the structure for the next pixel - call this before doing any | |
* transforms and call it for each pixel since all the fields may need to be | |
* reset. | |
*/ | |
static void | |
image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type, | |
png_byte bit_depth, png_uint_32 x, store_palette palette) | |
{ | |
PNG_CONST png_byte sample_depth = (png_byte)(colour_type == | |
PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth); | |
PNG_CONST unsigned int max = (1U<<sample_depth)-1; | |
/* Initially just set everything to the same number and the alpha to opaque. | |
* Note that this currently assumes a simple palette where entry x has colour | |
* rgb(x,x,x)! | |
*/ | |
this->palette_index = this->red = this->green = this->blue = | |
sample(row, colour_type, bit_depth, x, 0); | |
this->alpha = max; | |
this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT = | |
sample_depth; | |
/* Then override as appropriate: */ | |
if (colour_type == 3) /* palette */ | |
{ | |
/* This permits the caller to default to the sample value. */ | |
if (palette != 0) | |
{ | |
PNG_CONST unsigned int i = this->palette_index; | |
this->red = palette[i].red; | |
this->green = palette[i].green; | |
this->blue = palette[i].blue; | |
this->alpha = palette[i].alpha; | |
} | |
} | |
else /* not palette */ | |
{ | |
unsigned int i = 0; | |
if (colour_type & 2) | |
{ | |
this->green = sample(row, colour_type, bit_depth, x, 1); | |
this->blue = sample(row, colour_type, bit_depth, x, 2); | |
i = 2; | |
} | |
if (colour_type & 4) | |
this->alpha = sample(row, colour_type, bit_depth, x, ++i); | |
} | |
/* Calculate the scaled values, these are simply the values divided by | |
* 'max' and the error is initialized to the double precision epsilon value | |
* from the header file. | |
*/ | |
image_pixel_setf(this, max); | |
/* Store the input information for use in the transforms - these will | |
* modify the information. | |
*/ | |
this->colour_type = colour_type; | |
this->bit_depth = bit_depth; | |
this->sample_depth = sample_depth; | |
this->have_tRNS = 0; | |
} | |
/* Convert a palette image to an rgb image. This necessarily converts the tRNS | |
* chunk at the same time, because the tRNS will be in palette form. The way | |
* palette validation works means that the original palette is never updated, | |
* instead the image_pixel value from the row contains the RGB of the | |
* corresponding palette entry and *this* is updated. Consequently this routine | |
* only needs to change the colour type information. | |
*/ | |
static void | |
image_pixel_convert_PLTE(image_pixel *this) | |
{ | |
if (this->colour_type == PNG_COLOR_TYPE_PALETTE) | |
{ | |
if (this->have_tRNS) | |
{ | |
this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA; | |
this->have_tRNS = 0; | |
} | |
else | |
this->colour_type = PNG_COLOR_TYPE_RGB; | |
/* The bit depth of the row changes at this point too (notice that this is | |
* the row format, not the sample depth, which is separate.) | |
*/ | |
this->bit_depth = 8; | |
} | |
} | |
/* Add an alpha channel; this will import the tRNS information because tRNS is | |
* not valid in an alpha image. The bit depth will invariably be set to at | |
* least 8. Palette images will be converted to alpha (using the above API). | |
*/ | |
static void | |
image_pixel_add_alpha(image_pixel *this, const standard_display *display) | |
{ | |
if (this->colour_type == PNG_COLOR_TYPE_PALETTE) | |
image_pixel_convert_PLTE(this); | |
if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0) | |
{ | |
if (this->colour_type == PNG_COLOR_TYPE_GRAY) | |
{ | |
if (this->bit_depth < 8) | |
this->bit_depth = 8; | |
if (this->have_tRNS) | |
{ | |
this->have_tRNS = 0; | |
/* Check the input, original, channel value here against the | |
* original tRNS gray chunk valie. | |
*/ | |
if (this->red == display->transparent.red) | |
this->alphaf = 0; | |
else | |
this->alphaf = 1; | |
} | |
else | |
this->alphaf = 1; | |
this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA; | |
} | |
else if (this->colour_type == PNG_COLOR_TYPE_RGB) | |
{ | |
if (this->have_tRNS) | |
{ | |
this->have_tRNS = 0; | |
/* Again, check the exact input values, not the current transformed | |
* value! | |
*/ | |
if (this->red == display->transparent.red && | |
this->green == display->transparent.green && | |
this->blue == display->transparent.blue) | |
this->alphaf = 0; | |
else | |
this->alphaf = 1; | |
this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA; | |
} | |
} | |
/* The error in the alpha is zero and the sBIT value comes from the | |
* original sBIT data (actually it will always be the original bit depth). | |
*/ | |
this->alphae = 0; | |
this->alpha_sBIT = display->alpha_sBIT; | |
} | |
} | |
struct transform_display; | |
typedef struct image_transform | |
{ | |
/* The name of this transform: a string. */ | |
PNG_CONST char *name; | |
/* Each transform can be disabled from the command line: */ | |
int enable; | |
/* The global list of transforms; read only. */ | |
struct image_transform *PNG_CONST list; | |
/* The global count of the number of times this transform has been set on an | |
* image. | |
*/ | |
unsigned int global_use; | |
/* The local count of the number of times this transform has been set. */ | |
unsigned int local_use; | |
/* The next transform in the list, each transform must call its own next | |
* transform after it has processed the pixel successfully. | |
*/ | |
PNG_CONST struct image_transform *next; | |
/* A single transform for the image, expressed as a series of function | |
* callbacks and some space for values. | |
* | |
* First a callback to set the transform on the current png_read_struct: | |
*/ | |
void (*set)(PNG_CONST struct image_transform *this, | |
struct transform_display *that, png_structp pp, png_infop pi); | |
/* Then a transform that takes an input pixel in one PNG format or another | |
* and modifies it by a pngvalid implementation of the transform (thus | |
* duplicating the libpng intent without, we hope, duplicating the bugs | |
* in the libpng implementation!) The png_structp is solely to allow error | |
* reporting via png_error and png_warning. | |
*/ | |
void (*mod)(PNG_CONST struct image_transform *this, image_pixel *that, | |
png_structp pp, PNG_CONST struct transform_display *display); | |
/* Add this transform to the list and return true if the transform is | |
* meaningful for this colour type and bit depth - if false then the | |
* transform should have no effect on the image so there's not a lot of | |
* point running it. | |
*/ | |
int (*add)(struct image_transform *this, | |
PNG_CONST struct image_transform **that, png_byte colour_type, | |
png_byte bit_depth); | |
} image_transform; | |
typedef struct transform_display | |
{ | |
standard_display this; | |
/* Parameters */ | |
png_modifier* pm; | |
PNG_CONST image_transform* transform_list; | |
/* Local variables */ | |
png_byte output_colour_type; | |
png_byte output_bit_depth; | |
/* Variables for the individual transforms. */ | |
/* png_set_background */ | |
image_pixel background_colour; | |
} transform_display; | |
/* Two functions to end the list: */ | |
static void | |
image_transform_set_end(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
UNUSED(this) | |
UNUSED(that) | |
UNUSED(pp) | |
UNUSED(pi) | |
} | |
/* At the end of the list recalculate the output image pixel value from the | |
* double precision values set up by the preceding 'mod' calls: | |
*/ | |
static unsigned int | |
sample_scale(double sample_value, unsigned int scale) | |
{ | |
sample_value = floor(sample_value * scale + .5); | |
/* Return NaN as 0: */ | |
if (!(sample_value > 0)) | |
sample_value = 0; | |
else if (sample_value > scale) | |
sample_value = scale; | |
return (unsigned int)sample_value; | |
} | |
static void | |
image_transform_mod_end(PNG_CONST image_transform *this, image_pixel *that, | |
png_structp pp, PNG_CONST transform_display *display) | |
{ | |
PNG_CONST unsigned int scale = (1U<<that->sample_depth)-1; | |
UNUSED(this) | |
UNUSED(pp) | |
UNUSED(display) | |
/* At the end recalculate the digitized red green and blue values according | |
* to the current sample_depth of the pixel. | |
* | |
* The sample value is simply scaled to the maximum, checking for over | |
* and underflow (which can both happen for some image transforms, | |
* including simple size scaling, though libpng doesn't do that at present. | |
*/ | |
that->red = sample_scale(that->redf, scale); | |
/* The error value is increased, at the end, according to the lowest sBIT | |
* value seen. Common sense tells us that the intermediate integer | |
* representations are no more accurate than +/- 0.5 in the integral values, | |
* the sBIT allows the implementation to be worse than this. In addition the | |
* PNG specification actually permits any error within the range (-1..+1), | |
* but that is ignored here. Instead the final digitized value is compared, | |
* below to the digitized value of the error limits - this has the net effect | |
* of allowing (almost) +/-1 in the output value. It's difficult to see how | |
* any algorithm that digitizes intermediate results can be more accurate. | |
*/ | |
that->rede += 1./(2*((1U<<that->red_sBIT)-1)); | |
if (that->colour_type & PNG_COLOR_MASK_COLOR) | |
{ | |
that->green = sample_scale(that->greenf, scale); | |
that->blue = sample_scale(that->bluef, scale); | |
that->greene += 1./(2*((1U<<that->green_sBIT)-1)); | |
that->bluee += 1./(2*((1U<<that->blue_sBIT)-1)); | |
} | |
else | |
{ | |
that->blue = that->green = that->red; | |
that->bluef = that->greenf = that->redf; | |
that->bluee = that->greene = that->rede; | |
} | |
if ((that->colour_type & PNG_COLOR_MASK_ALPHA) || | |
that->colour_type == PNG_COLOR_TYPE_PALETTE) | |
{ | |
that->alpha = sample_scale(that->alphaf, scale); | |
that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1)); | |
} | |
else | |
{ | |
that->alpha = scale; /* opaque */ | |
that->alpha = 1; /* Override this. */ | |
that->alphae = 0; /* It's exact ;-) */ | |
} | |
} | |
/* Static 'end' structure: */ | |
static image_transform image_transform_end = | |
{ | |
"(end)", /* name */ | |
1, /* enable */ | |
0, /* list */ | |
0, /* global_use */ | |
0, /* local_use */ | |
0, /* next */ | |
image_transform_set_end, | |
image_transform_mod_end, | |
0 /* never called, I want it to crash if it is! */ | |
}; | |
/* Reader callbacks and implementations, where they differ from the standard | |
* ones. | |
*/ | |
static void | |
transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id, | |
PNG_CONST image_transform *transform_list) | |
{ | |
/* Standard fields */ | |
standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/); | |
/* Parameter fields */ | |
dp->pm = pm; | |
dp->transform_list = transform_list; | |
/* Local variable fields */ | |
dp->output_colour_type = 255; /* invalid */ | |
dp->output_bit_depth = 255; /* invalid */ | |
} | |
static void | |
transform_info_imp(transform_display *dp, png_structp pp, png_infop pi) | |
{ | |
/* Reuse the standard stuff as appropriate. */ | |
standard_info_part1(&dp->this, pp, pi); | |
/* Now set the list of transforms. */ | |
dp->transform_list->set(dp->transform_list, dp, pp, pi); | |
/* Update the info structure for these transforms: */ | |
png_read_update_info(pp, pi); | |
/* And get the output information into the standard_display */ | |
standard_info_part2(&dp->this, pp, pi, 1/*images*/); | |
/* Plus the extra stuff we need for the transform tests: */ | |
dp->output_colour_type = png_get_color_type(pp, pi); | |
dp->output_bit_depth = png_get_bit_depth(pp, pi); | |
/* Validate the combination of colour type and bit depth that we are getting | |
* out of libpng; the semantics of something not in the PNG spec are, at | |
* best, unclear. | |
*/ | |
switch (dp->output_colour_type) | |
{ | |
case PNG_COLOR_TYPE_PALETTE: | |
if (dp->output_bit_depth > 8) goto error; | |
/*FALL THROUGH*/ | |
case PNG_COLOR_TYPE_GRAY: | |
if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 || | |
dp->output_bit_depth == 4) | |
break; | |
/*FALL THROUGH*/ | |
default: | |
if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16) | |
break; | |
/*FALL THROUGH*/ | |
error: | |
{ | |
char message[128]; | |
size_t pos; | |
pos = safecat(message, sizeof message, 0, | |
"invalid final bit depth: colour type("); | |
pos = safecatn(message, sizeof message, pos, dp->output_colour_type); | |
pos = safecat(message, sizeof message, pos, ") with bit depth: "); | |
pos = safecatn(message, sizeof message, pos, dp->output_bit_depth); | |
png_error(pp, message); | |
} | |
} | |
/* Use a test pixel to check that the output agrees with what we expect - | |
* this avoids running the whole test if the output is unexpected. | |
*/ | |
{ | |
image_pixel test_pixel; | |
memset(&test_pixel, 0, sizeof test_pixel); | |
test_pixel.colour_type = dp->this.colour_type; /* input */ | |
test_pixel.bit_depth = dp->this.bit_depth; | |
if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE) | |
test_pixel.sample_depth = 8; | |
else | |
test_pixel.sample_depth = test_pixel.bit_depth; | |
/* Don't need sBIT here */ | |
test_pixel.have_tRNS = dp->this.is_transparent; | |
dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp); | |
if (test_pixel.colour_type != dp->output_colour_type) | |
{ | |
char message[128]; | |
size_t pos = safecat(message, sizeof message, 0, "colour type "); | |
pos = safecatn(message, sizeof message, pos, dp->output_colour_type); | |
pos = safecat(message, sizeof message, pos, " expected "); | |
pos = safecatn(message, sizeof message, pos, test_pixel.colour_type); | |
png_error(pp, message); | |
} | |
if (test_pixel.bit_depth != dp->output_bit_depth) | |
{ | |
char message[128]; | |
size_t pos = safecat(message, sizeof message, 0, "bit depth "); | |
pos = safecatn(message, sizeof message, pos, dp->output_bit_depth); | |
pos = safecat(message, sizeof message, pos, " expected "); | |
pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth); | |
png_error(pp, message); | |
} | |
/* If both bit depth and colour type are correct check the sample depth. | |
* I believe these are both internal errors. | |
*/ | |
if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE) | |
{ | |
if (test_pixel.sample_depth != 8) /* oops - internal error! */ | |
png_error(pp, "pngvalid: internal: palette sample depth not 8"); | |
} | |
else if (test_pixel.sample_depth != dp->output_bit_depth) | |
{ | |
char message[128]; | |
size_t pos = safecat(message, sizeof message, 0, | |
"internal: sample depth "); | |
pos = safecatn(message, sizeof message, pos, dp->output_bit_depth); | |
pos = safecat(message, sizeof message, pos, " expected "); | |
pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth); | |
png_error(pp, message); | |
} | |
} | |
} | |
static void | |
transform_info(png_structp pp, png_infop pi) | |
{ | |
transform_info_imp(png_get_progressive_ptr(pp), pp, pi); | |
} | |
static void | |
transform_range_check(png_structp pp, unsigned int r, unsigned int g, | |
unsigned int b, unsigned int a, unsigned int in_digitized, double in, | |
unsigned int out, png_byte sample_depth, double err, PNG_CONST char *name, | |
double digitization_error) | |
{ | |
/* Compare the scaled, digitzed, values of our local calculation (in+-err) | |
* with the digitized values libpng produced; 'sample_depth' is the actual | |
* digitization depth of the libpng output colors (the bit depth except for | |
* palette images where it is always 8.) The check on 'err' is to detect | |
* internal errors in pngvalid itself (the threshold is about 1/255.) | |
*/ | |
unsigned int max = (1U<<sample_depth)-1; | |
double in_min = ceil((in-err)*max - digitization_error); | |
double in_max = floor((in+err)*max + digitization_error); | |
if (err > 4E-3 || !(out >= in_min && out <= in_max)) | |
{ | |
char message[256]; | |
size_t pos; | |
pos = safecat(message, sizeof message, 0, name); | |
pos = safecat(message, sizeof message, pos, " output value error: rgba("); | |
pos = safecatn(message, sizeof message, pos, r); | |
pos = safecat(message, sizeof message, pos, ","); | |
pos = safecatn(message, sizeof message, pos, g); | |
pos = safecat(message, sizeof message, pos, ","); | |
pos = safecatn(message, sizeof message, pos, b); | |
pos = safecat(message, sizeof message, pos, ","); | |
pos = safecatn(message, sizeof message, pos, a); | |
pos = safecat(message, sizeof message, pos, "): "); | |
pos = safecatn(message, sizeof message, pos, out); | |
pos = safecat(message, sizeof message, pos, " expected: "); | |
pos = safecatn(message, sizeof message, pos, in_digitized); | |
pos = safecat(message, sizeof message, pos, " ("); | |
pos = safecatd(message, sizeof message, pos, (in-err)*max, 3); | |
pos = safecat(message, sizeof message, pos, ".."); | |
pos = safecatd(message, sizeof message, pos, (in+err)*max, 3); | |
pos = safecat(message, sizeof message, pos, ")"); | |
png_error(pp, message); | |
} | |
} | |
static void | |
transform_image_validate(transform_display *dp, png_structp pp, png_infop pi) | |
{ | |
/* Constants for the loop below: */ | |
PNG_CONST png_store* PNG_CONST ps = dp->this.ps; | |
PNG_CONST png_byte in_ct = dp->this.colour_type; | |
PNG_CONST png_byte in_bd = dp->this.bit_depth; | |
PNG_CONST png_uint_32 w = dp->this.w; | |
PNG_CONST png_uint_32 h = dp->this.h; | |
PNG_CONST png_byte out_ct = dp->output_colour_type; | |
PNG_CONST png_byte out_bd = dp->output_bit_depth; | |
PNG_CONST png_byte sample_depth = (png_byte)(out_ct == | |
PNG_COLOR_TYPE_PALETTE ? 8 : out_bd); | |
PNG_CONST png_byte red_sBIT = dp->this.red_sBIT; | |
PNG_CONST png_byte green_sBIT = dp->this.green_sBIT; | |
PNG_CONST png_byte blue_sBIT = dp->this.blue_sBIT; | |
PNG_CONST png_byte alpha_sBIT = dp->this.alpha_sBIT; | |
PNG_CONST int have_tRNS = dp->this.is_transparent; | |
double digitization_error; | |
store_palette out_palette; | |
png_uint_32 y; | |
UNUSED(pi) | |
/* Check for row overwrite errors */ | |
store_image_check(dp->this.ps, pp, 0); | |
/* Read the palette corresponding to the output if the output colour type | |
* indicates a palette, othewise set out_palette to garbage. | |
*/ | |
if (out_ct == PNG_COLOR_TYPE_PALETTE) | |
{ | |
/* Validate that the palette count itself has not changed - this is not | |
* expected. | |
*/ | |
int npalette = (-1); | |
(void)read_palette(out_palette, &npalette, pp, pi); | |
if (npalette != dp->this.npalette) | |
png_error(pp, "unexpected change in palette size"); | |
digitization_error = .5; | |
} | |
else | |
{ | |
png_byte in_sample_depth; | |
memset(out_palette, 0x5e, sizeof out_palette); | |
/* assume-8-bit-calculations means assume that if the input has 8 bit | |
* (or less) samples and the output has 16 bit samples the calculations | |
* will be done with 8 bit precision, not 16. | |
* | |
* TODO: fix this in libpng; png_set_expand_16 should cause 16 bit | |
* calculations to be used throughout. | |
*/ | |
if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16) | |
in_sample_depth = 8; | |
else | |
in_sample_depth = in_bd; | |
if (sample_depth != 16 || in_sample_depth > 8 || | |
!dp->pm->calculations_use_input_precision) | |
digitization_error = .5; | |
/* Else errors are at 8 bit precision, scale .5 in 8 bits to the 16 bits: | |
*/ | |
else | |
digitization_error = .5 * 257; | |
} | |
for (y=0; y<h; ++y) | |
{ | |
png_const_bytep PNG_CONST pRow = store_image_row(ps, pp, 0, y); | |
png_uint_32 x; | |
/* The original, standard, row pre-transforms. */ | |
png_byte std[STANDARD_ROWMAX]; | |
transform_row(pp, std, in_ct, in_bd, y); | |
/* Go through each original pixel transforming it and comparing with what | |
* libpng did to the same pixel. | |
*/ | |
for (x=0; x<w; ++x) | |
{ | |
image_pixel in_pixel, out_pixel; | |
unsigned int r, g, b, a; | |
/* Find out what we think the pixel should be: */ | |
image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette); | |
in_pixel.red_sBIT = red_sBIT; | |
in_pixel.green_sBIT = green_sBIT; | |
in_pixel.blue_sBIT = blue_sBIT; | |
in_pixel.alpha_sBIT = alpha_sBIT; | |
in_pixel.have_tRNS = have_tRNS; | |
/* For error detection, below. */ | |
r = in_pixel.red; | |
g = in_pixel.green; | |
b = in_pixel.blue; | |
a = in_pixel.alpha; | |
dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp); | |
/* Read the output pixel and compare it to what we got, we don't | |
* use the error field here, so no need to update sBIT. | |
*/ | |
image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette); | |
/* We don't expect changes to the index here even if the bit depth is | |
* changed. | |
*/ | |
if (in_ct == PNG_COLOR_TYPE_PALETTE && | |
out_ct == PNG_COLOR_TYPE_PALETTE) | |
{ | |
if (in_pixel.palette_index != out_pixel.palette_index) | |
png_error(pp, "unexpected transformed palette index"); | |
} | |
/* Check the colours for palette images too - in fact the palette could | |
* be separately verified itself in most cases. | |
*/ | |
if (in_pixel.red != out_pixel.red) | |
transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf, | |
out_pixel.red, sample_depth, in_pixel.rede, "red/gray", | |
digitization_error); | |
if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 && | |
in_pixel.green != out_pixel.green) | |
transform_range_check(pp, r, g, b, a, in_pixel.green, | |
in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene, | |
"green", digitization_error); | |
if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 && | |
in_pixel.blue != out_pixel.blue) | |
transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef, | |
out_pixel.blue, sample_depth, in_pixel.bluee, "blue", | |
digitization_error); | |
if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 && | |
in_pixel.alpha != out_pixel.alpha) | |
transform_range_check(pp, r, g, b, a, in_pixel.alpha, | |
in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae, | |
"alpha", digitization_error); | |
} /* pixel (x) loop */ | |
} /* row (y) loop */ | |
/* Record that something was actually checked to avoid a false positive. */ | |
dp->this.ps->validated = 1; | |
} | |
static void | |
transform_end(png_structp pp, png_infop pi) | |
{ | |
transform_display *dp = png_get_progressive_ptr(pp); | |
transform_image_validate(dp, pp, pi); | |
} | |
/* A single test run. */ | |
static void | |
transform_test(png_modifier *pmIn, PNG_CONST png_uint_32 idIn, | |
PNG_CONST image_transform* transform_listIn, PNG_CONST char *name) | |
{ | |
transform_display d; | |
context(&pmIn->this, fault); | |
transform_display_init(&d, pmIn, idIn, transform_listIn); | |
Try | |
{ | |
png_structp pp; | |
png_infop pi; | |
/* Get a png_struct for reading the image. */ | |
pp = set_modifier_for_read(d.pm, &pi, d.this.id, name); | |
standard_palette_init(&d.this); | |
# if 0 | |
/* Logging (debugging only) */ | |
{ | |
char buffer[256]; | |
(void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0, | |
"running test"); | |
fprintf(stderr, "%s\n", buffer); | |
} | |
# endif | |
/* Introduce the correct read function. */ | |
if (d.pm->this.progressive) | |
{ | |
/* Share the row function with the standard implementation. */ | |
png_set_progressive_read_fn(pp, &d, transform_info, progressive_row, | |
transform_end); | |
/* Now feed data into the reader until we reach the end: */ | |
modifier_progressive_read(d.pm, pp, pi); | |
} | |
else | |
{ | |
/* modifier_read expects a png_modifier* */ | |
png_set_read_fn(pp, d.pm, modifier_read); | |
/* Check the header values: */ | |
png_read_info(pp, pi); | |
/* Process the 'info' requirements. Only one image is generated */ | |
transform_info_imp(&d, pp, pi); | |
sequential_row(&d.this, pp, pi, -1, 0); | |
if (!d.this.speed) | |
transform_image_validate(&d, pp, pi); | |
} | |
modifier_reset(d.pm); | |
} | |
Catch(fault) | |
modifier_reset((png_modifier*)fault); | |
} | |
/* The transforms: */ | |
#define ITSTRUCT(name) image_transform_##name | |
#define IT(name)\ | |
static image_transform ITSTRUCT(name) =\ | |
{\ | |
#name,\ | |
1, /*enable*/\ | |
&PT, /*list*/\ | |
0, /*global_use*/\ | |
0, /*local_use*/\ | |
0, /*next*/\ | |
image_transform_png_set_##name##_set,\ | |
image_transform_png_set_##name##_mod,\ | |
image_transform_png_set_##name##_add\ | |
} | |
#define PT ITSTRUCT(end) /* stores the previous transform */ | |
/* To save code: */ | |
static int | |
image_transform_default_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(colour_type) | |
UNUSED(bit_depth) | |
this->next = *that; | |
*that = this; | |
return 1; | |
} | |
#ifdef PNG_READ_EXPAND_SUPPORTED | |
/* png_set_palette_to_rgb */ | |
static void | |
image_transform_png_set_palette_to_rgb_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_palette_to_rgb(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_palette_to_rgb_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
if (that->colour_type == PNG_COLOR_TYPE_PALETTE) | |
image_pixel_convert_PLTE(that); | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_palette_to_rgb_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(bit_depth) | |
this->next = *that; | |
*that = this; | |
return colour_type == PNG_COLOR_TYPE_PALETTE; | |
} | |
IT(palette_to_rgb); | |
#undef PT | |
#define PT ITSTRUCT(palette_to_rgb) | |
#endif /* PNG_READ_EXPAND_SUPPORTED */ | |
#ifdef PNG_READ_EXPAND_SUPPORTED | |
/* png_set_tRNS_to_alpha */ | |
static void | |
image_transform_png_set_tRNS_to_alpha_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_tRNS_to_alpha(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_tRNS_to_alpha_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
/* LIBPNG BUG: this always forces palette images to RGB. */ | |
if (that->colour_type == PNG_COLOR_TYPE_PALETTE) | |
image_pixel_convert_PLTE(that); | |
/* This effectively does an 'expand' only if there is some transparency to | |
* convert to an alpha channel. | |
*/ | |
if (that->have_tRNS) | |
image_pixel_add_alpha(that, &display->this); | |
/* LIBPNG BUG: otherwise libpng still expands to 8 bits! */ | |
else | |
{ | |
if (that->bit_depth < 8) | |
that->bit_depth =8; | |
if (that->sample_depth < 8) | |
that->sample_depth = 8; | |
} | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_tRNS_to_alpha_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(bit_depth) | |
this->next = *that; | |
*that = this; | |
/* We don't know yet whether there will be a tRNS chunk, but we know that | |
* this transformation should do nothing if there already is an alpha | |
* channel. | |
*/ | |
return (colour_type & PNG_COLOR_MASK_ALPHA) == 0; | |
} | |
IT(tRNS_to_alpha); | |
#undef PT | |
#define PT ITSTRUCT(tRNS_to_alpha) | |
#endif /* PNG_READ_EXPAND_SUPPORTED */ | |
#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED | |
/* png_set_gray_to_rgb */ | |
static void | |
image_transform_png_set_gray_to_rgb_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_gray_to_rgb(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_gray_to_rgb_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
/* NOTE: we can actually pend the tRNS processing at this point because we | |
* can correctly recognize the original pixel value even though we have | |
* mapped the one gray channel to the three RGB ones, but in fact libpng | |
* doesn't do this, so we don't either. | |
*/ | |
if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS) | |
image_pixel_add_alpha(that, &display->this); | |
/* Simply expand the bit depth and alter the colour type as required. */ | |
if (that->colour_type == PNG_COLOR_TYPE_GRAY) | |
{ | |
/* RGB images have a bit depth at least equal to '8' */ | |
if (that->bit_depth < 8) | |
that->sample_depth = that->bit_depth = 8; | |
/* And just changing the colour type works here because the green and blue | |
* channels are being maintained in lock-step with the red/gray: | |
*/ | |
that->colour_type = PNG_COLOR_TYPE_RGB; | |
} | |
else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA; | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_gray_to_rgb_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(bit_depth) | |
this->next = *that; | |
*that = this; | |
return (colour_type & PNG_COLOR_MASK_COLOR) == 0; | |
} | |
IT(gray_to_rgb); | |
#undef PT | |
#define PT ITSTRUCT(gray_to_rgb) | |
#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */ | |
#ifdef PNG_READ_EXPAND_SUPPORTED | |
/* png_set_expand */ | |
static void | |
image_transform_png_set_expand_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_expand(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_expand_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
/* The general expand case depends on what the colour type is: */ | |
if (that->colour_type == PNG_COLOR_TYPE_PALETTE) | |
image_pixel_convert_PLTE(that); | |
else if (that->bit_depth < 8) /* grayscale */ | |
that->sample_depth = that->bit_depth = 8; | |
if (that->have_tRNS) | |
image_pixel_add_alpha(that, &display->this); | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_expand_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(bit_depth) | |
this->next = *that; | |
*that = this; | |
/* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit | |
* depth is at least 8 already. | |
*/ | |
return (colour_type & PNG_COLOR_MASK_ALPHA) == 0; | |
} | |
IT(expand); | |
#undef PT | |
#define PT ITSTRUCT(expand) | |
#endif /* PNG_READ_EXPAND_SUPPORTED */ | |
#ifdef PNG_READ_EXPAND_SUPPORTED | |
/* png_set_expand_gray_1_2_4_to_8 | |
* LIBPNG BUG: this just does an 'expand' | |
*/ | |
static void | |
image_transform_png_set_expand_gray_1_2_4_to_8_set( | |
PNG_CONST image_transform *this, transform_display *that, png_structp pp, | |
png_infop pi) | |
{ | |
png_set_expand_gray_1_2_4_to_8(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_expand_gray_1_2_4_to_8_mod( | |
PNG_CONST image_transform *this, image_pixel *that, png_structp pp, | |
PNG_CONST transform_display *display) | |
{ | |
image_transform_png_set_expand_mod(this, that, pp, display); | |
} | |
static int | |
image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
return image_transform_png_set_expand_add(this, that, colour_type, | |
bit_depth); | |
} | |
IT(expand_gray_1_2_4_to_8); | |
#undef PT | |
#define PT ITSTRUCT(expand_gray_1_2_4_to_8) | |
#endif /* PNG_READ_EXPAND_SUPPORTED */ | |
#ifdef PNG_READ_EXPAND_16_SUPPORTED | |
/* png_set_expand_16 */ | |
static void | |
image_transform_png_set_expand_16_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_expand_16(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_expand_16_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
/* Expect expand_16 to expand everything to 16 bits as a result of also | |
* causing 'expand' to happen. | |
*/ | |
if (that->colour_type == PNG_COLOR_TYPE_PALETTE) | |
image_pixel_convert_PLTE(that); | |
if (that->have_tRNS) | |
image_pixel_add_alpha(that, &display->this); | |
if (that->bit_depth < 16) | |
that->sample_depth = that->bit_depth = 16; | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_expand_16_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(colour_type) | |
this->next = *that; | |
*that = this; | |
/* expand_16 does something unless the bit depth is already 16. */ | |
return bit_depth < 16; | |
} | |
IT(expand_16); | |
#undef PT | |
#define PT ITSTRUCT(expand_16) | |
#endif /* PNG_READ_EXPAND_16_SUPPORTED */ | |
#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* API added in 1.5.4 */ | |
/* png_set_scale_16 */ | |
static void | |
image_transform_png_set_scale_16_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_scale_16(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_scale_16_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
if (that->bit_depth == 16) | |
{ | |
that->sample_depth = that->bit_depth = 8; | |
if (that->red_sBIT > 8) that->red_sBIT = 8; | |
if (that->green_sBIT > 8) that->green_sBIT = 8; | |
if (that->blue_sBIT > 8) that->blue_sBIT = 8; | |
if (that->alpha_sBIT > 8) that->alpha_sBIT = 8; | |
} | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_scale_16_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(colour_type) | |
this->next = *that; | |
*that = this; | |
return bit_depth > 8; | |
} | |
IT(scale_16); | |
#undef PT | |
#define PT ITSTRUCT(scale_16) | |
#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */ | |
#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */ | |
/* png_set_strip_16 */ | |
static void | |
image_transform_png_set_strip_16_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_strip_16(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_strip_16_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
if (that->bit_depth == 16) | |
{ | |
that->sample_depth = that->bit_depth = 8; | |
if (that->red_sBIT > 8) that->red_sBIT = 8; | |
if (that->green_sBIT > 8) that->green_sBIT = 8; | |
if (that->blue_sBIT > 8) that->blue_sBIT = 8; | |
if (that->alpha_sBIT > 8) that->alpha_sBIT = 8; | |
/* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this | |
* configuration option is set. From 1.5.4 the flag is never set and the | |
* 'scale' API (above) must be used. | |
*/ | |
# ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED | |
# if PNG_LIBPNG_VER >= 10504 | |
# error PNG_READ_ACCURATE_SCALE should not be set | |
# endif | |
/* The strip 16 algorithm drops the low 8 bits rather than calculating | |
* 1/257, so we need to adjust the permitted errors appropriately: | |
* Notice that this is only relevant prior to the addition of the | |
* png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!) | |
*/ | |
{ | |
PNG_CONST double d = (255-128.5)/65535; | |
that->rede += d; | |
that->greene += d; | |
that->bluee += d; | |
that->alphae += d; | |
} | |
# endif | |
} | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_strip_16_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(colour_type) | |
this->next = *that; | |
*that = this; | |
return bit_depth > 8; | |
} | |
IT(strip_16); | |
#undef PT | |
#define PT ITSTRUCT(strip_16) | |
#endif /* PNG_READ_16_TO_8_SUPPORTED */ | |
#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED | |
/* png_set_strip_alpha */ | |
static void | |
image_transform_png_set_strip_alpha_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_strip_alpha(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_strip_alpha_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
that->colour_type = PNG_COLOR_TYPE_GRAY; | |
else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
that->colour_type = PNG_COLOR_TYPE_RGB; | |
that->have_tRNS = 0; | |
that->alphaf = 1; | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_strip_alpha_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(bit_depth) | |
this->next = *that; | |
*that = this; | |
return (colour_type & PNG_COLOR_MASK_ALPHA) != 0; | |
} | |
IT(strip_alpha); | |
#undef PT | |
#define PT ITSTRUCT(strip_alpha) | |
#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */ | |
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED | |
/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green) | |
* png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red, | |
* png_fixed_point green) | |
* png_get_rgb_to_gray_status | |
* | |
* At present the APIs are simply tested using the 16.16 fixed point conversion | |
* values known to be used inside libpng: | |
* | |
* red: 6968 | |
* green: 23434 | |
* blue: 2366 | |
* | |
* NOTE: this currently ignores the gamma because no gamma is being set, the | |
* tests on gamma need to happen in the gamma test set. | |
*/ | |
static void | |
image_transform_png_set_rgb_to_gray_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
PNG_CONST int error_action = 1; /* no error, no defines in png.h */ | |
# ifdef PNG_FLOATING_POINT_SUPPORTED | |
png_set_rgb_to_gray(pp, error_action, -1, -1); | |
# else | |
png_set_rgb_to_gray_fixed(pp, error_action, -1, -1); | |
# endif | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_rgb_to_gray_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0) | |
{ | |
if (that->colour_type == PNG_COLOR_TYPE_PALETTE) | |
image_pixel_convert_PLTE(that); | |
/* Image now has RGB channels... */ | |
that->bluef = that->greenf = that->redf = (that->redf * 6968 + | |
that->greenf * 23434 + that->bluef * 2366) / 32768; | |
that->bluee = that->greene = that->rede = (that->rede * 6968 + | |
that->greene * 23434 + that->bluee * 2366) / 32768 * | |
(1 + DBL_EPSILON * 6); | |
/* The sBIT is the minium of the three colour channel sBITs. */ | |
if (that->red_sBIT > that->green_sBIT) | |
that->red_sBIT = that->green_sBIT; | |
if (that->red_sBIT > that->blue_sBIT) | |
that->red_sBIT = that->blue_sBIT; | |
that->blue_sBIT = that->green_sBIT = that->red_sBIT; | |
/* And zap the colour bit in the type: */ | |
if (that->colour_type == PNG_COLOR_TYPE_RGB) | |
that->colour_type = PNG_COLOR_TYPE_GRAY; | |
else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA; | |
} | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_rgb_to_gray_add(image_transform *this, | |
PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth) | |
{ | |
UNUSED(bit_depth) | |
this->next = *that; | |
*that = this; | |
return (colour_type & PNG_COLOR_MASK_COLOR) != 0; | |
} | |
IT(rgb_to_gray); | |
#undef PT | |
#define PT ITSTRUCT(rgb_to_gray) | |
#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */ | |
#ifdef PNG_READ_BACKGROUND_SUPPORTED | |
/* png_set_background(png_structp, png_const_color_16p background_color, | |
* int background_gamma_code, int need_expand, double background_gamma) | |
* png_set_background_fixed(png_structp, png_const_color_16p background_color, | |
* int background_gamma_code, int need_expand, | |
* png_fixed_point background_gamma) | |
* | |
* As with rgb_to_gray this ignores the gamma. | |
*/ | |
static void | |
image_transform_png_set_background_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_byte colour_type, bit_depth; | |
png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */ | |
png_color_16 back; | |
/* We need a background colour, because we don't know exactly what transforms | |
* have been set we have to supply the colour in the original file format and | |
* so we need to know what that is! The background colour is stored in the | |
* transform_display. | |
*/ | |
RANDOMIZE(random_bytes); | |
/* Read the random value, for colour type 3 the background colour is actually | |
* expressed as a 24bit rgb, not an index. | |
*/ | |
colour_type = that->this.colour_type; | |
if (colour_type == 3) | |
{ | |
colour_type = PNG_COLOR_TYPE_RGB; | |
bit_depth = 8; | |
} | |
else | |
bit_depth = that->this.bit_depth; | |
image_pixel_init(&that->background_colour, random_bytes, colour_type, | |
bit_depth, 0/*x*/, 0/*unused: palette*/); | |
/* Extract the background colour from this image_pixel, but make sure the | |
* unused fields of 'back' are garbage. | |
*/ | |
RANDOMIZE(back); | |
if (colour_type & PNG_COLOR_MASK_COLOR) | |
{ | |
back.red = (png_uint_16)that->background_colour.red; | |
back.green = (png_uint_16)that->background_colour.green; | |
back.blue = (png_uint_16)that->background_colour.blue; | |
} | |
else | |
back.gray = (png_uint_16)that->background_colour.red; | |
# ifdef PNG_FLOATING_POINT_SUPPORTED | |
png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, 1/*need expand*/, | |
0); | |
# else | |
png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE, | |
1/*need expand*/, 0); | |
# endif | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_background_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
/* Check for tRNS first: */ | |
if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE) | |
image_pixel_add_alpha(that, &display->this); | |
/* This is only necessary if the alpha value is less than 1. */ | |
if (that->alphaf < 1) | |
{ | |
PNG_CONST image_pixel *back = &display->background_colour; | |
/* Now we do the background calculation without any gamma correction. */ | |
if (that->alphaf <= 0) | |
{ | |
that->redf = back->redf; | |
that->greenf = back->greenf; | |
that->bluef = back->bluef; | |
that->rede = back->rede; | |
that->greene = back->greene; | |
that->bluee = back->bluee; | |
that->red_sBIT= back->red_sBIT; | |
that->green_sBIT= back->green_sBIT; | |
that->blue_sBIT= back->blue_sBIT; | |
} | |
else /* 0 < alpha < 1 */ | |
{ | |
double alf = 1 - that->alphaf; | |
that->redf = that->redf * that->alphaf + back->redf * alf; | |
that->rede = that->rede * that->alphaf + back->rede * alf + | |
DBL_EPSILON; | |
that->greenf = that->greenf * that->alphaf + back->greenf * alf; | |
that->greene = that->greene * that->alphaf + back->greene * alf + | |
DBL_EPSILON; | |
that->bluef = that->bluef * that->alphaf + back->bluef * alf; | |
that->bluee = that->bluee * that->alphaf + back->bluee * alf + | |
DBL_EPSILON; | |
} | |
/* Remove the alpha type and set the alpha (not in that order.) */ | |
that->alphaf = 1; | |
that->alphae = 0; | |
if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA) | |
that->colour_type = PNG_COLOR_TYPE_RGB; | |
else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA) | |
that->colour_type = PNG_COLOR_TYPE_GRAY; | |
/* PNG_COLOR_TYPE_PALETTE is not changed */ | |
} | |
this->next->mod(this->next, that, pp, display); | |
} | |
#define image_transform_png_set_background_add image_transform_default_add | |
IT(background); | |
#undef PT | |
#define PT ITSTRUCT(background) | |
#endif /* PNG_READ_BACKGROUND_SUPPORTED */ | |
/* This may just be 'end' if all the transforms are disabled! */ | |
static image_transform *PNG_CONST image_transform_first = &PT; | |
static void | |
transform_enable(PNG_CONST char *name) | |
{ | |
/* Everything starts out enabled, so if we see an 'enable' disabled | |
* everything else the first time round. | |
*/ | |
static int all_disabled = 0; | |
int found_it = 0; | |
image_transform *list = image_transform_first; | |
while (list != &image_transform_end) | |
{ | |
if (strcmp(list->name, name) == 0) | |
{ | |
list->enable = 1; | |
found_it = 1; | |
} | |
else if (!all_disabled) | |
list->enable = 0; | |
list = list->list; | |
} | |
all_disabled = 1; | |
if (!found_it) | |
{ | |
fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n", | |
name); | |
exit(1); | |
} | |
} | |
static void | |
transform_disable(PNG_CONST char *name) | |
{ | |
image_transform *list = image_transform_first; | |
while (list != &image_transform_end) | |
{ | |
if (strcmp(list->name, name) == 0) | |
{ | |
list->enable = 0; | |
return; | |
} | |
list = list->list; | |
} | |
fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n", | |
name); | |
exit(1); | |
} | |
static void | |
image_transform_reset_count(void) | |
{ | |
image_transform *next = image_transform_first; | |
int count = 0; | |
while (next != &image_transform_end) | |
{ | |
next->local_use = 0; | |
next->next = 0; | |
next = next->list; | |
++count; | |
} | |
/* This can only happen if we every have more than 32 transforms (excluding | |
* the end) in the list. | |
*/ | |
if (count > 32) abort(); | |
} | |
static int | |
image_transform_test_counter(png_uint_32 counter, unsigned int max) | |
{ | |
/* Test the list to see if there is any point contining, given a current | |
* counter and a 'max' value. | |
*/ | |
image_transform *next = image_transform_first; | |
while (next != &image_transform_end) | |
{ | |
/* For max 0 or 1 continue until the counter overflows: */ | |
counter >>= 1; | |
/* Continue if any entry hasn't reacked the max. */ | |
if (max > 1 && next->local_use < max) | |
return 1; | |
next = next->list; | |
} | |
return max <= 1 && counter == 0; | |
} | |
static png_uint_32 | |
image_transform_add(PNG_CONST image_transform **this, unsigned int max, | |
png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos, | |
png_byte colour_type, png_byte bit_depth) | |
{ | |
for (;;) /* until we manage to add something */ | |
{ | |
png_uint_32 mask; | |
image_transform *list; | |
/* Find the next counter value, if the counter is zero this is the start | |
* of the list. This routine always returns the current counter (not the | |
* next) so it returns 0 at the end and expects 0 at the beginning. | |
*/ | |
if (counter == 0) /* first time */ | |
{ | |
image_transform_reset_count(); | |
if (max <= 1) | |
counter = 1; | |
else | |
counter = random_32(); | |
} | |
else /* advance the counter */ | |
{ | |
switch (max) | |
{ | |
case 0: ++counter; break; | |
case 1: counter <<= 1; break; | |
default: counter = random_32(); break; | |
} | |
} | |
/* Now add all these items, if possible */ | |
*this = &image_transform_end; | |
list = image_transform_first; | |
mask = 1; | |
/* Go through the whole list adding anything that the counter selects: */ | |
while (list != &image_transform_end) | |
{ | |
if ((counter & mask) != 0 && list->enable && | |
(max == 0 || list->local_use < max)) | |
{ | |
/* Candidate to add: */ | |
if (list->add(list, this, colour_type, bit_depth) || max == 0) | |
{ | |
/* Added, so add to the name too. */ | |
*pos = safecat(name, sizeof_name, *pos, " +"); | |
*pos = safecat(name, sizeof_name, *pos, list->name); | |
} | |
else | |
{ | |
/* Not useful and max>0, so remvoe it from *this: */ | |
*this = list->next; | |
list->next = 0; | |
/* And, since we know it isn't useful, stop it being added again | |
* in this run: | |
*/ | |
list->local_use = max; | |
} | |
} | |
mask <<= 1; | |
list = list->list; | |
} | |
/* Now if anything was added we have something to do. */ | |
if (*this != &image_transform_end) | |
return counter; | |
/* Nothing added, but was there anything in there to add? */ | |
if (!image_transform_test_counter(counter, max)) | |
return 0; | |
} | |
} | |
#ifdef THIS_IS_THE_PROFORMA | |
static void | |
image_transform_png_set_@_set(PNG_CONST image_transform *this, | |
transform_display *that, png_structp pp, png_infop pi) | |
{ | |
png_set_@(pp); | |
this->next->set(this->next, that, pp, pi); | |
} | |
static void | |
image_transform_png_set_@_mod(PNG_CONST image_transform *this, | |
image_pixel *that, png_structp pp, PNG_CONST transform_display *display) | |
{ | |
this->next->mod(this->next, that, pp, display); | |
} | |
static int | |
image_transform_png_set_@_add(image_transform *this, | |
PNG_CONST image_transform **that, char *name, size_t sizeof_name, | |
size_t *pos, png_byte colour_type, png_byte bit_depth) | |
{ | |
this->next = *that; | |
*that = this; | |
*pos = safecat(name, sizeof_name, *pos, " +@"); | |
return 1; | |
} | |
IT(@); | |
#endif | |
/* png_set_quantize(png_structp, png_colorp palette, int num_palette, | |
* int maximum_colors, png_const_uint_16p histogram, int full_quantize) | |
* | |
* Very difficult to validate this! | |
*/ | |
/*NOTE: TBD NYI */ | |
/* The data layout transforms are handled by swapping our own channel data, | |
* necessarily these need to happen at the end of the transform list because the | |
* semantic of the channels changes after these are executed. Some of these, | |
* like set_shift and set_packing, can't be done at present because they change | |
* the layout of the data at the sub-sample level so sample() won't get the | |
* right answer. | |
*/ | |
/* png_set_invert_alpha */ | |
/*NOTE: TBD NYI */ | |
/* png_set_bgr */ | |
/*NOTE: TBD NYI */ | |
/* png_set_swap_alpha */ | |
/*NOTE: TBD NYI */ | |
/* png_set_swap */ | |
/*NOTE: TBD NYI */ | |
/* png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags)); */ | |
/*NOTE: TBD NYI */ | |
/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */ | |
/*NOTE: TBD NYI */ | |
/* png_set_packing */ | |
/*NOTE: TBD NYI */ | |
/* png_set_packswap */ | |
/*NOTE: TBD NYI */ | |
/* png_set_invert_mono */ | |
/*NOTE: TBD NYI */ | |
/* png_set_shift(png_structp, png_const_color_8p true_bits) */ | |
/*NOTE: TBD NYI */ | |
static void | |
perform_transform_test(png_modifier *pm) | |
{ | |
png_byte colour_type = 0; | |
png_byte bit_depth = 0; | |
int palette_number = 0; | |
while (next_format(&colour_type, &bit_depth, &palette_number)) | |
{ | |
png_uint_32 counter = 0; | |
size_t base_pos; | |
char name[64]; | |
base_pos = safecat(name, sizeof name, 0, "transform:"); | |
for (;;) | |
{ | |
size_t pos = base_pos; | |
PNG_CONST image_transform *list = 0; | |
/* 'max' is currently hardwired to '1'; this should be settable on the | |
* command line. | |
*/ | |
counter = image_transform_add(&list, 1/*max*/, counter, | |
name, sizeof name, &pos, colour_type, bit_depth); | |
if (counter == 0) | |
break; | |
/* The command line can change this to checking interlaced images. */ | |
transform_test(pm, FILEID(colour_type, bit_depth, palette_number, | |
pm->interlace_type, 0, 0, 0), list, name); | |
if (fail(pm)) | |
return; | |
} | |
} | |
} | |
#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ | |
/********************************* GAMMA TESTS ********************************/ | |
#ifdef PNG_READ_GAMMA_SUPPORTED | |
/* Gamma test images. */ | |
typedef struct gamma_modification | |
{ | |
png_modification this; | |
png_fixed_point gamma; | |
} gamma_modification; | |
static int | |
gamma_modify(png_modifier *pm, png_modification *me, int add) | |
{ | |
UNUSED(add) | |
/* This simply dumps the given gamma value into the buffer. */ | |
png_save_uint_32(pm->buffer, 4); | |
png_save_uint_32(pm->buffer+4, CHUNK_gAMA); | |
png_save_uint_32(pm->buffer+8, ((gamma_modification*)me)->gamma); | |
return 1; | |
} | |
static void | |
gamma_modification_init(gamma_modification *me, png_modifier *pm, double gammad) | |
{ | |
double g; | |
modification_init(&me->this); | |
me->this.chunk = CHUNK_gAMA; | |
me->this.modify_fn = gamma_modify; | |
me->this.add = CHUNK_PLTE; | |
g = floor(gammad * 100000 + .5); | |
me->gamma = (png_fixed_point)g; | |
me->this.next = pm->modifications; | |
pm->modifications = &me->this; | |
} | |
typedef struct srgb_modification | |
{ | |
png_modification this; | |
png_byte intent; | |
} srgb_modification; | |
static int | |
srgb_modify(png_modifier *pm, png_modification *me, int add) | |
{ | |
UNUSED(add) | |
/* As above, ignore add and just make a new chunk */ | |
png_save_uint_32(pm->buffer, 1); | |
png_save_uint_32(pm->buffer+4, CHUNK_sRGB); | |
pm->buffer[8] = ((srgb_modification*)me)->intent; | |
return 1; | |
} | |
static void | |
srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent) | |
{ | |
modification_init(&me->this); | |
me->this.chunk = CHUNK_sBIT; | |
if (intent <= 3) /* if valid, else *delete* sRGB chunks */ | |
{ | |
me->this.modify_fn = srgb_modify; | |
me->this.add = CHUNK_PLTE; | |
me->intent = intent; | |
} | |
else | |
{ | |
me->this.modify_fn = 0; | |
me->this.add = 0; | |
me->intent = 0; | |
} | |
me->this.next = pm->modifications; | |
pm->modifications = &me->this; | |
} | |
typedef struct sbit_modification | |
{ | |
png_modification this; | |
png_byte sbit; | |
} sbit_modification; | |
static int | |
sbit_modify(png_modifier *pm, png_modification *me, int add) | |
{ | |
png_byte sbit = ((sbit_modification*)me)->sbit; | |
if (pm->bit_depth > sbit) | |
{ | |
int cb = 0; | |
switch (pm->colour_type) | |
{ | |
case 0: | |
cb = 1; | |
break; | |
case 2: | |
case 3: | |
cb = 3; | |
break; | |
case 4: | |
cb = 2; | |
break; | |
case 6: | |
cb = 4; | |
break; | |
default: | |
png_error(pm->this.pread, | |
"unexpected colour type in sBIT modification"); | |
} | |
png_save_uint_32(pm->buffer, cb); | |
png_save_uint_32(pm->buffer+4, CHUNK_sBIT); | |
while (cb > 0) | |
(pm->buffer+8)[--cb] = sbit; | |
return 1; | |
} | |
else if (!add) | |
{ | |
/* Remove the sBIT chunk */ | |
pm->buffer_count = pm->buffer_position = 0; | |
return 1; | |
} | |
else | |
return 0; /* do nothing */ | |
} | |
static void | |
sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit) | |
{ | |
modification_init(&me->this); | |
me->this.chunk = CHUNK_sBIT; | |
me->this.modify_fn = sbit_modify; | |
me->this.add = CHUNK_PLTE; | |
me->sbit = sbit; | |
me->this.next = pm->modifications; | |
pm->modifications = &me->this; | |
} | |
/* Reader callbacks and implementations, where they differ from the standard | |
* ones. | |
*/ | |
typedef struct gamma_display | |
{ | |
standard_display this; | |
/* Parameters */ | |
png_modifier* pm; | |
double file_gamma; | |
double screen_gamma; | |
double background_gamma; | |
png_byte sbit; | |
int threshold_test; | |
int use_input_precision; | |
int scale16; | |
int expand16; | |
int do_background; | |
png_color_16 background_color; | |
/* Local variables */ | |
double maxerrout; | |
double maxerrpc; | |
double maxerrabs; | |
} gamma_display; | |
#define ALPHA_MODE_OFFSET 4 | |
static void | |
gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id, | |
double file_gamma, double screen_gamma, png_byte sbit, int threshold_test, | |
int use_input_precision, int scale16, int expand16, | |
int do_background, PNG_CONST png_color_16 *pointer_to_the_background_color, | |
double background_gamma) | |
{ | |
/* Standard fields */ | |
standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/); | |
/* Parameter fields */ | |
dp->pm = pm; | |
dp->file_gamma = file_gamma; | |
dp->screen_gamma = screen_gamma; | |
dp->background_gamma = background_gamma; | |
dp->sbit = sbit; | |
dp->threshold_test = threshold_test; | |
dp->use_input_precision = use_input_precision; | |
dp->scale16 = scale16; | |
dp->expand16 = expand16; | |
dp->do_background = do_background; | |
if (do_background && pointer_to_the_background_color != 0) | |
dp->background_color = *pointer_to_the_background_color; | |
else | |
memset(&dp->background_color, 0, sizeof dp->background_color); | |
/* Local variable fields */ | |
dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0; | |
} | |
static void | |
gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi) | |
{ | |
/* Reuse the standard stuff as appropriate. */ | |
standard_info_part1(&dp->this, pp, pi); | |
/* If requested strip 16 to 8 bits - this is handled automagically below | |
* because the output bit depth is read from the library. Note that there | |
* are interactions with sBIT but, internally, libpng makes sbit at most | |
* PNG_MAX_GAMMA_8 when doing the following. | |
*/ | |
if (dp->scale16) | |
# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED | |
png_set_scale_16(pp); | |
# else | |
/* The following works both in 1.5.4 and earlier versions: */ | |
# ifdef PNG_READ_16_TO_8_SUPPORTED | |
png_set_strip_16(pp); | |
# else | |
png_error(pp, "scale16 (16 to 8 bit conversion) not supported"); | |
# endif | |
# endif | |
if (dp->expand16) | |
# ifdef PNG_READ_EXPAND_16_SUPPORTED | |
png_set_expand_16(pp); | |
# else | |
png_error(pp, "expand16 (8 to 16 bit conversion) not supported"); | |
# endif | |
if (dp->do_background >= ALPHA_MODE_OFFSET) | |
{ | |
# ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
{ | |
/* This tests the alpha mode handling, if supported. */ | |
int mode = dp->do_background - ALPHA_MODE_OFFSET; | |
/* The gamma value is the output gamma, and is in the standard, | |
* non-inverted, represenation. It provides a default for the PNG file | |
* gamma, but since the file has a gAMA chunk this does not matter. | |
*/ | |
PNG_CONST double sg = dp->screen_gamma; | |
# ifndef PNG_FLOATING_POINT_SUPPORTED | |
PNG_CONST png_fixed_point g = (png_fixed_point)(sg*100000+.5); | |
# endif | |
# ifdef PNG_FLOATING_POINT_SUPPORTED | |
png_set_alpha_mode(pp, mode, sg); | |
# else | |
png_set_alpha_mode_fixed(pp, mode, g); | |
# endif | |
/* However, for the standard Porter-Duff algorithm the output defaults | |
* to be linear, so if the test requires non-linear output it must be | |
* corrected here. | |
*/ | |
if (mode == PNG_ALPHA_STANDARD && sg != 1) | |
{ | |
# ifdef PNG_FLOATING_POINT_SUPPORTED | |
png_set_gamma(pp, sg, dp->file_gamma); | |
# else | |
png_fixed_point f = (png_fixed_point)(dp->file_gamma*100000+.5); | |
png_set_gamma_fixed(pp, g, f); | |
# endif | |
} | |
} | |
# else | |
png_error(pp, "alpha mode handling not supported"); | |
# endif | |
} | |
else | |
{ | |
/* Set up gamma processing. */ | |
# ifdef PNG_FLOATING_POINT_SUPPORTED | |
png_set_gamma(pp, dp->screen_gamma, dp->file_gamma); | |
# else | |
{ | |
png_fixed_point s = (png_fixed_point)(dp->screen_gamma*100000+.5); | |
png_fixed_point f = (png_fixed_point)(dp->file_gamma*100000+.5); | |
png_set_gamma_fixed(pp, s, f); | |
} | |
# endif | |
if (dp->do_background) | |
{ | |
# ifdef PNG_READ_BACKGROUND_SUPPORTED | |
/* NOTE: this assumes the caller provided the correct background gamma! | |
*/ | |
PNG_CONST double bg = dp->background_gamma; | |
# ifndef PNG_FLOATING_POINT_SUPPORTED | |
PNG_CONST png_fixed_point g = (png_fixed_point)(bg*100000+.5); | |
# endif | |
# ifdef PNG_FLOATING_POINT_SUPPORTED | |
png_set_background(pp, &dp->background_color, dp->do_background, | |
0/*need_expand*/, bg); | |
# else | |
png_set_background_fixed(pp, &dp->background_color, | |
dp->do_background, 0/*need_expand*/, g); | |
# endif | |
# else | |
png_error(pp, "png_set_background not supported"); | |
# endif | |
} | |
} | |
png_read_update_info(pp, pi); | |
/* Now we may get a different cbRow: */ | |
standard_info_part2(&dp->this, pp, pi, 1 /*images*/); | |
} | |
static void | |
gamma_info(png_structp pp, png_infop pi) | |
{ | |
gamma_info_imp(png_get_progressive_ptr(pp), pp, pi); | |
} | |
/* Validate a single component value - the routine gets the input and output | |
* sample values as unscaled PNG component values along with a cache of all the | |
* information required to validate the values. | |
*/ | |
typedef struct validate_info | |
{ | |
png_structp pp; | |
gamma_display *dp; | |
png_byte sbit; | |
int use_input_precision; | |
int do_background; | |
int scale16; | |
unsigned int sbit_max; | |
unsigned int isbit_shift; | |
unsigned int outmax; | |
double gamma_correction; /* Overall correction required. */ | |
double file_inverse; /* Inverse of file gamma. */ | |
double screen_gamma; | |
double screen_inverse; /* Inverse of screen gamma. */ | |
double background_red; /* Linear background value, red or gray. */ | |
double background_green; | |
double background_blue; | |
double maxabs; | |
double maxpc; | |
double maxcalc; | |
double maxout; | |
double maxout_total; /* Total including quantization error */ | |
double outlog; | |
int outquant; | |
} | |
validate_info; | |
static void | |
init_validate_info(validate_info *vi, gamma_display *dp, png_struct *pp, | |
int in_depth, int out_depth) | |
{ | |
PNG_CONST unsigned int outmax = (1U<<out_depth)-1; | |
vi->pp = pp; | |
vi->dp = dp; | |
if (dp->sbit > 0 && dp->sbit < in_depth) | |
{ | |
vi->sbit = dp->sbit; | |
vi->isbit_shift = in_depth - dp->sbit; | |
} | |
else | |
{ | |
vi->sbit = (png_byte)in_depth; | |
vi->isbit_shift = 0; | |
} | |
vi->sbit_max = (1U << vi->sbit)-1; | |
/* This mimics the libpng threshold test, '0' is used to prevent gamma | |
* correction in the validation test. | |
*/ | |
vi->screen_gamma = dp->screen_gamma; | |
if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD) | |
vi->screen_gamma = vi->screen_inverse = 0; | |
else | |
vi->screen_inverse = 1/vi->screen_gamma; | |
vi->use_input_precision = dp->use_input_precision; | |
vi->outmax = outmax; | |
vi->maxabs = abserr(dp->pm, in_depth, out_depth); | |
vi->maxpc = pcerr(dp->pm, in_depth, out_depth); | |
vi->maxcalc = calcerr(dp->pm, in_depth, out_depth); | |
vi->maxout = outerr(dp->pm, in_depth, out_depth); | |
vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth); | |
vi->maxout_total = vi->maxout + vi->outquant * .5; | |
vi->outlog = outlog(dp->pm, in_depth, out_depth); | |
if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 || | |
(dp->this.colour_type == 3 && dp->this.is_transparent)) | |
{ | |
vi->do_background = dp->do_background; | |
if (vi->do_background != 0) | |
{ | |
PNG_CONST double bg_inverse = 1/dp->background_gamma; | |
double r, g, b; | |
/* Caller must at least put the gray value into the red channel */ | |
r = dp->background_color.red; r /= outmax; | |
g = dp->background_color.green; g /= outmax; | |
b = dp->background_color.blue; b /= outmax; | |
# if 0 | |
/* libpng doesn't do this optimization, if we do pngvalid will fail. | |
*/ | |
if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD) | |
# endif | |
{ | |
r = pow(r, bg_inverse); | |
g = pow(g, bg_inverse); | |
b = pow(b, bg_inverse); | |
} | |
vi->background_red = r; | |
vi->background_green = g; | |
vi->background_blue = b; | |
} | |
} | |
else | |
vi->do_background = 0; | |
if (vi->do_background == 0) | |
vi->background_red = vi->background_green = vi->background_blue = 0; | |
vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma); | |
if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD) | |
vi->gamma_correction = 0; | |
vi->file_inverse = 1/dp->file_gamma; | |
if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD) | |
vi->file_inverse = 0; | |
vi->scale16 = dp->scale16; | |
} | |
/* This function handles composition of a single non-alpha component. The | |
* argument is the input sample value, in the range 0..1, and the alpha value. | |
* The result is the composed, linear, input sample. If alpha is less than zero | |
* this is the alpha component and the function should not be called! | |
*/ | |
static double | |
gamma_component_compose(int do_background, double input_sample, double alpha, | |
double background, int *compose) | |
{ | |
switch (do_background) | |
{ | |
case PNG_BACKGROUND_GAMMA_SCREEN: | |
case PNG_BACKGROUND_GAMMA_FILE: | |
case PNG_BACKGROUND_GAMMA_UNIQUE: | |
/* Standard PNG background processing. */ | |
if (alpha < 1) | |
{ | |
if (alpha > 0) | |
{ | |
input_sample = input_sample * alpha + background * (1-alpha); | |
if (compose != NULL) | |
*compose = 1; | |
} | |
else | |
input_sample = background; | |
} | |
break; | |
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD: | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN: | |
/* The components are premultiplied in either case and the output is | |
* gamma encoded (to get standard Porter-Duff we expect the output | |
* gamma to be set to 1.0!) | |
*/ | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED: | |
/* The optimization is that the partial-alpha entries are linear | |
* while the opaque pixels are gamma encoded, but this only affects the | |
* output encoding. | |
*/ | |
if (alpha < 1) | |
{ | |
if (alpha > 0) | |
{ | |
input_sample *= alpha; | |
if (compose != NULL) | |
*compose = 1; | |
} | |
else | |
input_sample = 0; | |
} | |
break; | |
#endif | |
default: | |
/* Standard cases where no compositing is done (so the component | |
* value is already correct.) | |
*/ | |
break; | |
} | |
return input_sample; | |
} | |
/* This API returns the encoded *input* component, in the range 0..1 */ | |
static double | |
gamma_component_validate(PNG_CONST char *name, PNG_CONST validate_info *vi, | |
PNG_CONST unsigned int id, PNG_CONST unsigned int od, | |
PNG_CONST double alpha /* <0 for the alpha channel itself */, | |
PNG_CONST double background /* component background value */) | |
{ | |
PNG_CONST unsigned int isbit = id >> vi->isbit_shift; | |
PNG_CONST unsigned int sbit_max = vi->sbit_max; | |
PNG_CONST unsigned int outmax = vi->outmax; | |
PNG_CONST int do_background = vi->do_background; | |
double i; | |
/* First check on the 'perfect' result obtained from the digitized input | |
* value, id, and compare this against the actual digitized result, 'od'. | |
* 'i' is the input result in the range 0..1: | |
*/ | |
i = isbit; i /= sbit_max; | |
/* Check for the fast route: if we don't do any background composition or if | |
* this is the alpha channel ('alpha' < 0) or if the pixel is opaque then | |
* just use the gamma_correction field to correct to the final output gamma. | |
*/ | |
if (alpha == 1 /* opaque pixel component */ || !do_background | |
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
|| do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG | |
#endif | |
|| (alpha < 0 /* alpha channel */ | |
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
&& do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN | |
#endif | |
)) | |
{ | |
/* Then get the gamma corrected version of 'i' and compare to 'od', any | |
* error less than .5 is insignificant - just quantization of the output | |
* value to the nearest digital value (nevertheless the error is still | |
* recorded - it's interesting ;-) | |
*/ | |
double encoded_sample = i; | |
double encoded_error; | |
/* alpha less than 0 indicates the alpha channel, which is always linear | |
*/ | |
if (alpha >= 0 && vi->gamma_correction > 0) | |
encoded_sample = pow(encoded_sample, vi->gamma_correction); | |
encoded_sample *= outmax; | |
encoded_error = fabs(od-encoded_sample); | |
if (encoded_error > vi->dp->maxerrout) | |
vi->dp->maxerrout = encoded_error; | |
if (encoded_error < vi->maxout_total && encoded_error < vi->outlog) | |
return i; | |
} | |
/* The slow route - attempt to do linear calculations. */ | |
/* There may be an error, or background processing is required, so calculate | |
* the actual sample values - unencoded light intensity values. Note that in | |
* practice these are not completely unencoded because they include a | |
* 'viewing correction' to decrease or (normally) increase the perceptual | |
* contrast of the image. There's nothing we can do about this - we don't | |
* know what it is - so assume the unencoded value is perceptually linear. | |
*/ | |
{ | |
double input_sample = i; /* In range 0..1 */ | |
double output, error, encoded_sample, encoded_error; | |
double es_lo, es_hi; | |
int compose = 0; /* Set to one if composition done */ | |
int output_is_encoded; /* Set if encoded to screen gamma */ | |
int log_max_error = 1; /* Check maximum error values */ | |
png_const_charp pass = 0; /* Reason test passes (or 0 for fail) */ | |
/* Convert to linear light (with the above caveat.) The alpha channel is | |
* already linear. | |
*/ | |
if (alpha >= 0) | |
{ | |
int tcompose; | |
if (vi->file_inverse > 0) | |
input_sample = pow(input_sample, vi->file_inverse); | |
/* Handle the compose processing: */ | |
tcompose = 0; | |
input_sample = gamma_component_compose(do_background, input_sample, | |
alpha, background, &tcompose); | |
if (tcompose) | |
compose = 1; | |
} | |
/* And similarly for the output value, but we need to check the background | |
* handling to linearize it correctly. | |
*/ | |
output = od; | |
output /= outmax; | |
output_is_encoded = vi->screen_gamma > 0; | |
if (alpha < 0) /* The alpha channel */ | |
{ | |
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN) | |
#endif | |
{ | |
/* In all other cases the output alpha channel is linear already, | |
* don't log errors here, they are much larger in linear data. | |
*/ | |
output_is_encoded = 0; | |
log_max_error = 0; | |
} | |
} | |
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
else /* A component */ | |
{ | |
if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED && | |
alpha < 1) /* the optimized case - linear output */ | |
{ | |
if (alpha > 0) log_max_error = 0; | |
output_is_encoded = 0; | |
} | |
} | |
#endif | |
if (output_is_encoded) | |
output = pow(output, vi->screen_gamma); | |
/* Calculate (or recalculate) the encoded_sample value and repeat the | |
* check above (unnecessary if we took the fast route, but harmless.) | |
*/ | |
encoded_sample = input_sample; | |
if (output_is_encoded) | |
encoded_sample = pow(encoded_sample, vi->screen_inverse); | |
encoded_sample *= outmax; | |
encoded_error = fabs(od-encoded_sample); | |
/* Don't log errors in the alpha channel, or the 'optimized' case, | |
* neither are significant to the overall perception. | |
*/ | |
if (log_max_error && encoded_error > vi->dp->maxerrout) | |
vi->dp->maxerrout = encoded_error; | |
if (encoded_error < vi->maxout_total) | |
{ | |
if (encoded_error < vi->outlog) | |
return i; | |
/* Test passed but error is bigger than the log limit, record why the | |
* test passed: | |
*/ | |
pass = "less than maxout:\n"; | |
} | |
/* i: the original input value in the range 0..1 | |
* | |
* pngvalid calculations: | |
* input_sample: linear result; i linearized and composed, range 0..1 | |
* encoded_sample: encoded result; input_sample scaled to ouput bit depth | |
* | |
* libpng calculations: | |
* output: linear result; od scaled to 0..1 and linearized | |
* od: encoded result from libpng | |
*/ | |
/* Now we have the numbers for real errors, both absolute values as as a | |
* percentage of the correct value (output): | |
*/ | |
error = fabs(input_sample-output); | |
if (log_max_error && error > vi->dp->maxerrabs) | |
vi->dp->maxerrabs = error; | |
/* The following is an attempt to ignore the tendency of quantization to | |
* dominate the percentage errors for lower result values: | |
*/ | |
if (log_max_error && input_sample > .5) | |
{ | |
double percentage_error = error/input_sample; | |
if (percentage_error > vi->dp->maxerrpc) | |
vi->dp->maxerrpc = percentage_error; | |
} | |
/* Now calculate the digitization limits for 'encoded_sample' using the | |
* 'max' values. Note that maxout is in the encoded space but maxpc and | |
* maxabs are in linear light space. | |
* | |
* First find the maximum error in linear light space, range 0..1: | |
*/ | |
{ | |
double tmp = input_sample * vi->maxpc; | |
if (tmp < vi->maxabs) tmp = vi->maxabs; | |
/* If 'compose' is true the composition was done in linear space using | |
* integer arithmetic. This introduces an extra error of +/- 0.5 (at | |
* least) in the integer space used. 'maxcalc' records this, taking | |
* into account the possibility that even for 16 bit output 8 bit space | |
* may have been used. | |
*/ | |
if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc; | |
/* The 'maxout' value refers to the encoded result, to compare with | |
* this encode input_sample adjusted by the maximum error (tmp) above. | |
*/ | |
es_lo = encoded_sample - vi->maxout; | |
if (es_lo > 0 && input_sample-tmp > 0) | |
{ | |
double low_value = input_sample-tmp; | |
if (output_is_encoded) | |
low_value = pow(low_value, vi->screen_inverse); | |
low_value *= outmax; | |
if (low_value < es_lo) es_lo = low_value; | |
/* Quantize this appropriately: */ | |
es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant; | |
} | |
else | |
es_lo = 0; | |
es_hi = encoded_sample + vi->maxout; | |
if (es_hi < outmax && input_sample+tmp < 1) | |
{ | |
double high_value = input_sample+tmp; | |
if (output_is_encoded) | |
high_value = pow(high_value, vi->screen_inverse); | |
high_value *= outmax; | |
if (high_value > es_hi) es_hi = high_value; | |
es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant; | |
} | |
else | |
es_hi = outmax; | |
} | |
/* The primary test is that the final encoded value returned by the | |
* library should be between the two limits (inclusive) that were | |
* calculated above. | |
*/ | |
if (od >= es_lo && od <= es_hi) | |
{ | |
/* The value passes, but we may need to log the information anyway. */ | |
if (encoded_error < vi->outlog) | |
return i; | |
if (pass == 0) | |
pass = "within digitization limits:\n"; | |
} | |
{ | |
/* There has been an error in processing, or we need to log this | |
* value. | |
*/ | |
double is_lo, is_hi; | |
/* pass is set at this point if either of the tests above would have | |
* passed. Don't do these additional tests here - just log the | |
* original [es_lo..es_hi] values. | |
*/ | |
if (pass == 0 && vi->use_input_precision) | |
{ | |
/* Ok, something is wrong - this actually happens in current libpng | |
* 16-to-8 processing. Assume that the input value (id, adjusted | |
* for sbit) can be anywhere between value-.5 and value+.5 - quite a | |
* large range if sbit is low. | |
*/ | |
double tmp = (isbit - .5)/sbit_max; | |
if (tmp <= 0) | |
tmp = 0; | |
else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1) | |
tmp = pow(tmp, vi->file_inverse); | |
tmp = gamma_component_compose(do_background, tmp, alpha, background, | |
NULL); | |
if (output_is_encoded && tmp > 0 && tmp < 1) | |
tmp = pow(tmp, vi->screen_inverse); | |
is_lo = ceil(outmax * tmp - vi->maxout_total); | |
if (is_lo < 0) | |
is_lo = 0; | |
tmp = (isbit + .5)/sbit_max; | |
if (tmp <= 0) | |
tmp = 0; | |
else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1) | |
tmp = pow(tmp, vi->file_inverse); | |
tmp = gamma_component_compose(do_background, tmp, alpha, background, | |
NULL); | |
if (output_is_encoded && tmp > 0 && tmp < 1) | |
tmp = pow(tmp, vi->screen_inverse); | |
is_hi = floor(outmax * tmp + vi->maxout_total); | |
if (is_hi > outmax) | |
is_hi = outmax; | |
if (!(od < is_lo || od > is_hi)) | |
{ | |
if (encoded_error < vi->outlog) | |
return i; | |
pass = "within input precision limits:\n"; | |
} | |
/* One last chance. If this is an alpha channel and the 16to8 | |
* option has been used and 'inaccurate' scaling is used then the | |
* bit reduction is obtained by simply using the top 8 bits of the | |
* value. | |
* | |
* This is only done for older libpng versions when the 'inaccurate' | |
* (chop) method of scaling was used. | |
*/ | |
# ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED | |
# if PNG_LIBPNG_VER < 10504 | |
/* This may be required for other components in the future, | |
* but at present the presence of gamma correction effectively | |
* prevents the errors in the component scaling (I don't quite | |
* understand why, but since it's better this way I care not | |
* to ask, JB 20110419.) | |
*/ | |
if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 && | |
vi->sbit + vi->isbit_shift == 16) | |
{ | |
tmp = ((id >> 8) - .5)/255; | |
if (tmp > 0) | |
{ | |
is_lo = ceil(outmax * tmp - vi->maxout_total); | |
if (is_lo < 0) is_lo = 0; | |
} | |
else | |
is_lo = 0; | |
tmp = ((id >> 8) + .5)/255; | |
if (tmp < 1) | |
{ | |
is_hi = floor(outmax * tmp + vi->maxout_total); | |
if (is_hi > outmax) is_hi = outmax; | |
} | |
else | |
is_hi = outmax; | |
if (!(od < is_lo || od > is_hi)) | |
{ | |
if (encoded_error < vi->outlog) | |
return i; | |
pass = "within 8 bit limits:\n"; | |
} | |
} | |
# endif | |
# endif | |
} | |
else /* !use_input_precision */ | |
is_lo = es_lo, is_hi = es_hi; | |
/* Attempt to output a meaningful error/warning message: the message | |
* output depends on the background/composite operation being performed | |
* because this changes what parameters were actually used above. | |
*/ | |
{ | |
size_t pos = 0; | |
/* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal | |
* places. Just use outmax to work out which. | |
*/ | |
int precision = (outmax >= 1000 ? 6 : 3); | |
int use_input=1, use_background=0, do_compose=0; | |
char msg[256]; | |
if (pass != 0) | |
pos = safecat(msg, sizeof msg, pos, "\n\t"); | |
/* Set up the various flags, the output_is_encoded flag above | |
* is also used below. do_compose is just a double check. | |
*/ | |
switch (do_background) | |
{ | |
case PNG_BACKGROUND_GAMMA_SCREEN: | |
case PNG_BACKGROUND_GAMMA_FILE: | |
case PNG_BACKGROUND_GAMMA_UNIQUE: | |
use_background = (alpha >= 0 && alpha < 1); | |
/*FALL THROUGH*/ | |
# ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD: | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN: | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED: | |
# endif /* ALPHA_MODE_SUPPORTED */ | |
do_compose = (alpha >= 0 && alpha < 1); | |
use_input = (alpha != 0); | |
break; | |
default: | |
break; | |
} | |
/* Check the 'compose' flag */ | |
if (compose != do_compose) | |
png_error(vi->pp, "internal error (compose)"); | |
/* 'name' is the component name */ | |
pos = safecat(msg, sizeof msg, pos, name); | |
pos = safecat(msg, sizeof msg, pos, "("); | |
pos = safecatn(msg, sizeof msg, pos, id); | |
if (use_input || pass != 0/*logging*/) | |
{ | |
if (isbit != id) | |
{ | |
/* sBIT has reduced the precision of the input: */ | |
pos = safecat(msg, sizeof msg, pos, ", sbit("); | |
pos = safecatn(msg, sizeof msg, pos, vi->sbit); | |
pos = safecat(msg, sizeof msg, pos, "): "); | |
pos = safecatn(msg, sizeof msg, pos, isbit); | |
} | |
pos = safecat(msg, sizeof msg, pos, "/"); | |
/* The output is either "id/max" or "id sbit(sbit): isbit/max" */ | |
pos = safecatn(msg, sizeof msg, pos, vi->sbit_max); | |
} | |
pos = safecat(msg, sizeof msg, pos, ")"); | |
/* A component may have been multiplied (in linear space) by the | |
* alpha value, 'compose' says whether this is relevant. | |
*/ | |
if (compose || pass != 0) | |
{ | |
/* If any form of composition is being done report our | |
* calculated linear value here (the code above doesn't record | |
* the input value before composition is performed, so what | |
* gets reported is the value after composition.) | |
*/ | |
if (use_input || pass != 0) | |
{ | |
if (vi->file_inverse > 0) | |
{ | |
pos = safecat(msg, sizeof msg, pos, "^"); | |
pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2); | |
} | |
else | |
pos = safecat(msg, sizeof msg, pos, "[linear]"); | |
pos = safecat(msg, sizeof msg, pos, "*(alpha)"); | |
pos = safecatd(msg, sizeof msg, pos, alpha, precision); | |
} | |
/* Now record the *linear* background value if it was used | |
* (this function is not passed the original, non-linear, | |
* value but it is contained in the test name.) | |
*/ | |
if (use_background) | |
{ | |
pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " "); | |
pos = safecat(msg, sizeof msg, pos, "(background)"); | |
pos = safecatd(msg, sizeof msg, pos, background, precision); | |
pos = safecat(msg, sizeof msg, pos, "*"); | |
pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision); | |
} | |
} | |
/* Report the calculated value (input_sample) and the linearized | |
* libpng value (output) unless this is just a component gamma | |
* correction. | |
*/ | |
if (compose || alpha < 0 || pass != 0) | |
{ | |
pos = safecat(msg, sizeof msg, pos, | |
pass != 0 ? " =\n\t" : " = "); | |
pos = safecatd(msg, sizeof msg, pos, input_sample, precision); | |
pos = safecat(msg, sizeof msg, pos, " (libpng: "); | |
pos = safecatd(msg, sizeof msg, pos, output, precision); | |
pos = safecat(msg, sizeof msg, pos, ")"); | |
/* Finally report the output gamma encoding, if any. */ | |
if (output_is_encoded) | |
{ | |
pos = safecat(msg, sizeof msg, pos, " ^"); | |
pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2); | |
pos = safecat(msg, sizeof msg, pos, "(to screen) ="); | |
} | |
else | |
pos = safecat(msg, sizeof msg, pos, " [screen is linear] ="); | |
} | |
if ((!compose && alpha >= 0) || pass != 0) | |
{ | |
if (pass != 0) /* logging */ | |
pos = safecat(msg, sizeof msg, pos, "\n\t[overall:"); | |
/* This is the non-composition case, the internal linear | |
* values are irrelevant (though the log below will reveal | |
* them.) Output a much shorter warning/error message and report | |
* the overall gamma correction. | |
*/ | |
if (vi->gamma_correction > 0) | |
{ | |
pos = safecat(msg, sizeof msg, pos, " ^"); | |
pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2); | |
pos = safecat(msg, sizeof msg, pos, "(gamma correction) ="); | |
} | |
else | |
pos = safecat(msg, sizeof msg, pos, | |
" [no gamma correction] ="); | |
if (pass != 0) | |
pos = safecat(msg, sizeof msg, pos, "]"); | |
} | |
/* This is our calculated encoded_sample which should (but does | |
* not) match od: | |
*/ | |
pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " "); | |
pos = safecatd(msg, sizeof msg, pos, is_lo, 1); | |
pos = safecat(msg, sizeof msg, pos, " < "); | |
pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1); | |
pos = safecat(msg, sizeof msg, pos, " (libpng: "); | |
pos = safecatn(msg, sizeof msg, pos, od); | |
pos = safecat(msg, sizeof msg, pos, ")"); | |
pos = safecat(msg, sizeof msg, pos, "/"); | |
pos = safecatn(msg, sizeof msg, pos, outmax); | |
pos = safecat(msg, sizeof msg, pos, " < "); | |
pos = safecatd(msg, sizeof msg, pos, is_hi, 1); | |
if (pass == 0) /* The error condition */ | |
{ | |
# ifdef PNG_WARNINGS_SUPPORTED | |
png_warning(vi->pp, msg); | |
# else | |
store_warning(vi->pp, msg); | |
# endif | |
} | |
else /* logging this value */ | |
store_verbose(&vi->dp->pm->this, vi->pp, pass, msg); | |
} | |
} | |
} | |
return i; | |
} | |
static void | |
gamma_image_validate(gamma_display *dp, png_structp pp, png_infop pi) | |
{ | |
/* Get some constants derived from the input and output file formats: */ | |
PNG_CONST png_store* PNG_CONST ps = dp->this.ps; | |
PNG_CONST png_byte in_ct = dp->this.colour_type; | |
PNG_CONST png_byte in_bd = dp->this.bit_depth; | |
PNG_CONST png_uint_32 w = dp->this.w; | |
PNG_CONST png_uint_32 h = dp->this.h; | |
PNG_CONST size_t cbRow = dp->this.cbRow; | |
PNG_CONST png_byte out_ct = png_get_color_type(pp, pi); | |
PNG_CONST png_byte out_bd = png_get_bit_depth(pp, pi); | |
/* There are three sources of error, firstly the quantization in the | |
* file encoding, determined by sbit and/or the file depth, secondly | |
* the output (screen) gamma and thirdly the output file encoding. | |
* | |
* Since this API receives the screen and file gamma in double | |
* precision it is possible to calculate an exact answer given an input | |
* pixel value. Therefore we assume that the *input* value is exact - | |
* sample/maxsample - calculate the corresponding gamma corrected | |
* output to the limits of double precision arithmetic and compare with | |
* what libpng returns. | |
* | |
* Since the library must quantize the output to 8 or 16 bits there is | |
* a fundamental limit on the accuracy of the output of +/-.5 - this | |
* quantization limit is included in addition to the other limits | |
* specified by the paramaters to the API. (Effectively, add .5 | |
* everywhere.) | |
* | |
* The behavior of the 'sbit' paramter is defined by section 12.5 | |
* (sample depth scaling) of the PNG spec. That section forces the | |
* decoder to assume that the PNG values have been scaled if sBIT is | |
* present: | |
* | |
* png-sample = floor( input-sample * (max-out/max-in) + .5); | |
* | |
* This means that only a subset of the possible PNG values should | |
* appear in the input. However, the spec allows the encoder to use a | |
* variety of approximations to the above and doesn't require any | |
* restriction of the values produced. | |
* | |
* Nevertheless the spec requires that the upper 'sBIT' bits of the | |
* value stored in a PNG file be the original sample bits. | |
* Consequently the code below simply scales the top sbit bits by | |
* (1<<sbit)-1 to obtain an original sample value. | |
* | |
* Because there is limited precision in the input it is arguable that | |
* an acceptable result is any valid result from input-.5 to input+.5. | |
* The basic tests below do not do this, however if 'use_input_precision' | |
* is set a subsequent test is performed below. | |
*/ | |
PNG_CONST unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U; | |
int processing; | |
png_uint_32 y; | |
PNG_CONST store_palette_entry *in_palette = dp->this.palette; | |
PNG_CONST int in_is_transparent = dp->this.is_transparent; | |
int out_npalette = -1; | |
int out_is_transparent = 0; /* Just refers to the palette case */ | |
store_palette out_palette; | |
validate_info vi; | |
/* Check for row overwrite errors */ | |
store_image_check(dp->this.ps, pp, 0); | |
/* Supply the input and output sample depths here - 8 for an indexed image, | |
* otherwise the bit depth. | |
*/ | |
init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd); | |
processing = (vi.gamma_correction > 0 && !dp->threshold_test) | |
|| in_bd != out_bd || in_ct != out_ct || vi.do_background; | |
/* TODO: FIX THIS: MAJOR BUG! If the transformations all happen inside | |
* the palette there is no way of finding out, because libpng fails to | |
* update the palette on png_read_update_info. Indeed, libpng doesn't | |
* even do the required work until much later, when it doesn't have any | |
* info pointer. Oops. For the moment 'processing' is turned off if | |
* out_ct is palette. | |
*/ | |
if (in_ct == 3 && out_ct == 3) | |
processing = 0; | |
if (processing && out_ct == 3) | |
out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi); | |
for (y=0; y<h; ++y) | |
{ | |
png_const_bytep pRow = store_image_row(ps, pp, 0, y); | |
png_byte std[STANDARD_ROWMAX]; | |
transform_row(pp, std, in_ct, in_bd, y); | |
if (processing) | |
{ | |
unsigned int x; | |
for (x=0; x<w; ++x) | |
{ | |
double alpha = 1; /* serves as a flag value */ | |
/* Record the palette index for index images. */ | |
PNG_CONST unsigned int in_index = | |
in_ct == 3 ? sample(std, 3, in_bd, x, 0) : 256; | |
PNG_CONST unsigned int out_index = | |
out_ct == 3 ? sample(std, 3, out_bd, x, 0) : 256; | |
/* Handle input alpha - png_set_background will cause the output | |
* alpha to disappear so there is nothing to check. | |
*/ | |
if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 || (in_ct == 3 && | |
in_is_transparent)) | |
{ | |
PNG_CONST unsigned int input_alpha = in_ct == 3 ? | |
dp->this.palette[in_index].alpha : | |
sample(std, in_ct, in_bd, x, samples_per_pixel); | |
unsigned int output_alpha = 65536 /* as a flag value */; | |
if (out_ct == 3) | |
{ | |
if (out_is_transparent) | |
output_alpha = out_palette[out_index].alpha; | |
} | |
else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0) | |
output_alpha = sample(pRow, out_ct, out_bd, x, | |
samples_per_pixel); | |
if (output_alpha != 65536) | |
alpha = gamma_component_validate("alpha", &vi, input_alpha, | |
output_alpha, -1/*alpha*/, 0/*background*/); | |
else /* no alpha in output */ | |
{ | |
/* This is a copy of the calculation of 'i' above in order to | |
* have the alpha value to use in the background calculation. | |
*/ | |
alpha = input_alpha >> vi.isbit_shift; | |
alpha /= vi.sbit_max; | |
} | |
} | |
/* Handle greyscale or RGB components. */ | |
if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* greyscale */ | |
(void)gamma_component_validate("gray", &vi, | |
sample(std, in_ct, in_bd, x, 0), | |
sample(pRow, out_ct, out_bd, x, 0), alpha/*component*/, | |
vi.background_red); | |
else /* RGB or palette */ | |
{ | |
(void)gamma_component_validate("red", &vi, | |
in_ct == 3 ? in_palette[in_index].red : | |
sample(std, in_ct, in_bd, x, 0), | |
out_ct == 3 ? out_palette[out_index].red : | |
sample(pRow, out_ct, out_bd, x, 0), | |
alpha/*component*/, vi.background_red); | |
(void)gamma_component_validate("green", &vi, | |
in_ct == 3 ? in_palette[in_index].green : | |
sample(std, in_ct, in_bd, x, 1), | |
out_ct == 3 ? out_palette[out_index].green : | |
sample(pRow, out_ct, out_bd, x, 1), | |
alpha/*component*/, vi.background_green); | |
(void)gamma_component_validate("blue", &vi, | |
in_ct == 3 ? in_palette[in_index].blue : | |
sample(std, in_ct, in_bd, x, 2), | |
out_ct == 3 ? out_palette[out_index].blue : | |
sample(pRow, out_ct, out_bd, x, 2), | |
alpha/*component*/, vi.background_blue); | |
} | |
} | |
} | |
else if (memcmp(std, pRow, cbRow) != 0) | |
{ | |
char msg[64]; | |
/* No transform is expected on the threshold tests. */ | |
sprintf(msg, "gamma: below threshold row %d changed", y); | |
png_error(pp, msg); | |
} | |
} /* row (y) loop */ | |
dp->this.ps->validated = 1; | |
} | |
static void | |
gamma_end(png_structp pp, png_infop pi) | |
{ | |
gamma_display *dp = png_get_progressive_ptr(pp); | |
if (!dp->this.speed) | |
gamma_image_validate(dp, pp, pi); | |
} | |
/* A single test run checking a gamma transformation. | |
* | |
* maxabs: maximum absolute error as a fraction | |
* maxout: maximum output error in the output units | |
* maxpc: maximum percentage error (as a percentage) | |
*/ | |
static void | |
gamma_test(png_modifier *pmIn, PNG_CONST png_byte colour_typeIn, | |
PNG_CONST png_byte bit_depthIn, PNG_CONST int palette_numberIn, | |
PNG_CONST int interlace_typeIn, | |
PNG_CONST double file_gammaIn, PNG_CONST double screen_gammaIn, | |
PNG_CONST png_byte sbitIn, PNG_CONST int threshold_testIn, | |
PNG_CONST char *name, | |
PNG_CONST int use_input_precisionIn, PNG_CONST int scale16In, | |
PNG_CONST int expand16In, PNG_CONST int do_backgroundIn, | |
PNG_CONST png_color_16 *bkgd_colorIn, double bkgd_gammaIn) | |
{ | |
gamma_display d; | |
context(&pmIn->this, fault); | |
gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn, | |
palette_numberIn, interlace_typeIn, 0, 0, 0), | |
file_gammaIn, screen_gammaIn, sbitIn, | |
threshold_testIn, use_input_precisionIn, scale16In, | |
expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn); | |
Try | |
{ | |
png_structp pp; | |
png_infop pi; | |
gamma_modification gamma_mod; | |
srgb_modification srgb_mod; | |
sbit_modification sbit_mod; | |
/* Make an appropriate modifier to set the PNG file gamma to the | |
* given gamma value and the sBIT chunk to the given precision. | |
*/ | |
d.pm->modifications = NULL; | |
gamma_modification_init(&gamma_mod, d.pm, d.file_gamma); | |
srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/); | |
if (d.sbit > 0) | |
sbit_modification_init(&sbit_mod, d.pm, d.sbit); | |
modification_reset(d.pm->modifications); | |
/* Get a png_struct for writing the image. */ | |
pp = set_modifier_for_read(d.pm, &pi, d.this.id, name); | |
standard_palette_init(&d.this); | |
/* Introduce the correct read function. */ | |
if (d.pm->this.progressive) | |
{ | |
/* Share the row function with the standard implementation. */ | |
png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row, | |
gamma_end); | |
/* Now feed data into the reader until we reach the end: */ | |
modifier_progressive_read(d.pm, pp, pi); | |
} | |
else | |
{ | |
/* modifier_read expects a png_modifier* */ | |
png_set_read_fn(pp, d.pm, modifier_read); | |
/* Check the header values: */ | |
png_read_info(pp, pi); | |
/* Process the 'info' requirements. Only one image is generated */ | |
gamma_info_imp(&d, pp, pi); | |
sequential_row(&d.this, pp, pi, -1, 0); | |
if (!d.this.speed) | |
gamma_image_validate(&d, pp, pi); | |
} | |
modifier_reset(d.pm); | |
if (d.pm->log && !d.threshold_test && !d.this.speed) | |
fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n", | |
d.this.bit_depth, colour_types[d.this.colour_type], name, | |
d.maxerrout, d.maxerrabs, 100*d.maxerrpc); | |
/* Log the summary values too. */ | |
if (d.this.colour_type == 0 || d.this.colour_type == 4) | |
{ | |
switch (d.this.bit_depth) | |
{ | |
case 1: | |
break; | |
case 2: | |
if (d.maxerrout > d.pm->error_gray_2) | |
d.pm->error_gray_2 = d.maxerrout; | |
break; | |
case 4: | |
if (d.maxerrout > d.pm->error_gray_4) | |
d.pm->error_gray_4 = d.maxerrout; | |
break; | |
case 8: | |
if (d.maxerrout > d.pm->error_gray_8) | |
d.pm->error_gray_8 = d.maxerrout; | |
break; | |
case 16: | |
if (d.maxerrout > d.pm->error_gray_16) | |
d.pm->error_gray_16 = d.maxerrout; | |
break; | |
default: | |
png_error(pp, "bad bit depth (internal: 1)"); | |
} | |
} | |
else if (d.this.colour_type == 2 || d.this.colour_type == 6) | |
{ | |
switch (d.this.bit_depth) | |
{ | |
case 8: | |
if (d.maxerrout > d.pm->error_color_8) | |
d.pm->error_color_8 = d.maxerrout; | |
break; | |
case 16: | |
if (d.maxerrout > d.pm->error_color_16) | |
d.pm->error_color_16 = d.maxerrout; | |
break; | |
default: | |
png_error(pp, "bad bit depth (internal: 2)"); | |
} | |
} | |
else if (d.this.colour_type == 3) | |
{ | |
if (d.maxerrout > d.pm->error_indexed) | |
d.pm->error_indexed = d.maxerrout; | |
} | |
} | |
Catch(fault) | |
modifier_reset((png_modifier*)fault); | |
} | |
static void gamma_threshold_test(png_modifier *pm, png_byte colour_type, | |
png_byte bit_depth, int interlace_type, double file_gamma, | |
double screen_gamma) | |
{ | |
size_t pos = 0; | |
char name[64]; | |
pos = safecat(name, sizeof name, pos, "threshold "); | |
pos = safecatd(name, sizeof name, pos, file_gamma, 3); | |
pos = safecat(name, sizeof name, pos, "/"); | |
pos = safecatd(name, sizeof name, pos, screen_gamma, 3); | |
(void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type, | |
file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name, | |
0 /*no input precision*/, | |
0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/, | |
0 /*no background gamma*/); | |
} | |
static void | |
perform_gamma_threshold_tests(png_modifier *pm) | |
{ | |
png_byte colour_type = 0; | |
png_byte bit_depth = 0; | |
int palette_number = 0; | |
/* Don't test more than one instance of each palette - it's pointless, in | |
* fact this test is somewhat excessive since libpng doesn't make this | |
* decision based on colour type or bit depth! | |
*/ | |
while (next_format(&colour_type, &bit_depth, &palette_number)) | |
if (palette_number == 0) | |
{ | |
double test_gamma = 1.0; | |
while (test_gamma >= .4) | |
{ | |
/* There's little point testing the interlacing vs non-interlacing, | |
* but this can be set from the command line. | |
*/ | |
gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type, | |
test_gamma, 1/test_gamma); | |
test_gamma *= .95; | |
} | |
/* And a special test for sRGB */ | |
gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type, | |
.45455, 2.2); | |
if (fail(pm)) | |
return; | |
} | |
} | |
static void gamma_transform_test(png_modifier *pm, | |
PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth, | |
PNG_CONST int palette_number, | |
PNG_CONST int interlace_type, PNG_CONST double file_gamma, | |
PNG_CONST double screen_gamma, PNG_CONST png_byte sbit, | |
PNG_CONST int use_input_precision, PNG_CONST int scale16) | |
{ | |
size_t pos = 0; | |
char name[64]; | |
if (sbit != bit_depth && sbit != 0) | |
{ | |
pos = safecat(name, sizeof name, pos, "sbit("); | |
pos = safecatn(name, sizeof name, pos, sbit); | |
pos = safecat(name, sizeof name, pos, ") "); | |
} | |
else | |
pos = safecat(name, sizeof name, pos, "gamma "); | |
if (scale16) | |
pos = safecat(name, sizeof name, pos, "16to8 "); | |
pos = safecatd(name, sizeof name, pos, file_gamma, 3); | |
pos = safecat(name, sizeof name, pos, "->"); | |
pos = safecatd(name, sizeof name, pos, screen_gamma, 3); | |
gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type, | |
file_gamma, screen_gamma, sbit, 0, name, use_input_precision, | |
scale16, pm->test_gamma_expand16, 0 , 0, 0); | |
} | |
static void perform_gamma_transform_tests(png_modifier *pm) | |
{ | |
png_byte colour_type = 0; | |
png_byte bit_depth = 0; | |
int palette_number = 0; | |
while (next_format(&colour_type, &bit_depth, &palette_number)) | |
{ | |
unsigned int i, j; | |
for (i=0; i<pm->ngammas; ++i) for (j=0; j<pm->ngammas; ++j) if (i != j) | |
{ | |
gamma_transform_test(pm, colour_type, bit_depth, palette_number, | |
pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/, | |
pm->use_input_precision, 0 /*do not scale16*/); | |
if (fail(pm)) | |
return; | |
} | |
} | |
} | |
static void perform_gamma_sbit_tests(png_modifier *pm) | |
{ | |
png_byte sbit; | |
/* The only interesting cases are colour and grayscale, alpha is ignored here | |
* for overall speed. Only bit depths where sbit is less than the bit depth | |
* are tested. | |
*/ | |
for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit) | |
{ | |
png_byte colour_type, bit_depth; | |
int npalette; | |
colour_type = bit_depth = 0; | |
npalette = 0; | |
while (next_format(&colour_type, &bit_depth, &npalette)) | |
if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 && | |
((colour_type == 3 && sbit < 8) || | |
(colour_type != 3 && sbit < bit_depth))) | |
{ | |
unsigned int i; | |
for (i=0; i<pm->ngammas; ++i) | |
{ | |
unsigned int j; | |
for (j=0; j<pm->ngammas; ++j) if (i != j) | |
{ | |
gamma_transform_test(pm, colour_type, bit_depth, npalette, | |
pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], | |
sbit, pm->use_input_precision_sbit, 0 /*scale16*/); | |
if (fail(pm)) | |
return; | |
} | |
} | |
} | |
} | |
} | |
/* Note that this requires a 16 bit source image but produces 8 bit output, so | |
* we only need the 16bit write support, but the 16 bit images are only | |
* generated if DO_16BIT is defined. | |
*/ | |
#ifdef DO_16BIT | |
static void perform_gamma_scale16_tests(png_modifier *pm) | |
{ | |
# ifndef PNG_MAX_GAMMA_8 | |
# define PNG_MAX_GAMMA_8 11 | |
# endif | |
/* Include the alpha cases here. Note that sbit matches the internal value | |
* used by the library - otherwise we will get spurious errors from the | |
* internal sbit style approximation. | |
* | |
* The threshold test is here because otherwise the 16 to 8 conversion will | |
* proceed *without* gamma correction, and the tests above will fail (but not | |
* by much) - this could be fixed, it only appears with the -g option. | |
*/ | |
unsigned int i, j; | |
for (i=0; i<pm->ngammas; ++i) | |
{ | |
for (j=0; j<pm->ngammas; ++j) | |
{ | |
if (i != j && | |
fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD) | |
{ | |
gamma_transform_test(pm, 0, 16, 0, pm->interlace_type, | |
1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8, | |
pm->use_input_precision_16to8, 1 /*scale16*/); | |
if (fail(pm)) | |
return; | |
gamma_transform_test(pm, 2, 16, 0, pm->interlace_type, | |
1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8, | |
pm->use_input_precision_16to8, 1 /*scale16*/); | |
if (fail(pm)) | |
return; | |
gamma_transform_test(pm, 4, 16, 0, pm->interlace_type, | |
1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8, | |
pm->use_input_precision_16to8, 1 /*scale16*/); | |
if (fail(pm)) | |
return; | |
gamma_transform_test(pm, 6, 16, 0, pm->interlace_type, | |
1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8, | |
pm->use_input_precision_16to8, 1 /*scale16*/); | |
if (fail(pm)) | |
return; | |
} | |
} | |
} | |
} | |
#endif /* 16 to 8 bit conversion */ | |
#if defined PNG_READ_BACKGROUND_SUPPORTED ||\ | |
defined PNG_READ_ALPHA_MODE_SUPPORTED | |
static void gamma_composition_test(png_modifier *pm, | |
PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth, | |
PNG_CONST int palette_number, | |
PNG_CONST int interlace_type, PNG_CONST double file_gamma, | |
PNG_CONST double screen_gamma, | |
PNG_CONST int use_input_precision, PNG_CONST int do_background, | |
PNG_CONST int expand_16) | |
{ | |
size_t pos = 0; | |
png_const_charp base; | |
double bg; | |
char name[128]; | |
png_color_16 background; | |
/* Make up a name and get an appropriate background gamma value. */ | |
switch (do_background) | |
{ | |
default: | |
base = ""; | |
bg = 4; /* should not be used */ | |
break; | |
case PNG_BACKGROUND_GAMMA_SCREEN: | |
base = " bckg(Screen):"; | |
bg = 1/screen_gamma; | |
break; | |
case PNG_BACKGROUND_GAMMA_FILE: | |
base = " bckg(File):"; | |
bg = file_gamma; | |
break; | |
case PNG_BACKGROUND_GAMMA_UNIQUE: | |
base = " bckg(Unique):"; | |
/* This tests the handling of a unique value, the math is such that the | |
* value tends to be <1, but is neither screen nor file (even if they | |
* match!) | |
*/ | |
bg = (file_gamma + screen_gamma) / 3; | |
break; | |
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG: | |
base = " alpha(PNG)"; | |
bg = 4; /* should not be used */ | |
break; | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD: | |
base = " alpha(Porter-Duff)"; | |
bg = 4; /* should not be used */ | |
break; | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED: | |
base = " alpha(Optimized)"; | |
bg = 4; /* should not be used */ | |
break; | |
case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN: | |
base = " alpha(Broken)"; | |
bg = 4; /* should not be used */ | |
break; | |
#endif | |
} | |
/* Use random background values - the background is always presented in the | |
* output space (8 or 16 bit components). | |
*/ | |
if (expand_16 || bit_depth == 16) | |
{ | |
png_uint_32 r = random_32(); | |
background.red = (png_uint_16)r; | |
background.green = (png_uint_16)(r >> 16); | |
r = random_32(); | |
background.blue = (png_uint_16)r; | |
background.gray = (png_uint_16)(r >> 16); | |
} | |
else /* 8 bit colors */ | |
{ | |
png_uint_32 r = random_32(); | |
background.red = (png_byte)r; | |
background.green = (png_byte)(r >> 8); | |
background.blue = (png_byte)(r >> 16); | |
background.gray = (png_byte)(r >> 24); | |
} | |
background.index = 193; /* rgb(193,193,193) to detect errors */ | |
if (!(colour_type & PNG_COLOR_MASK_COLOR)) | |
{ | |
/* Grayscale input, we do not convert to RGB (TBD), so we must set the | |
* background to gray - else libpng seems to fail. | |
*/ | |
background.red = background.green = background.blue = background.gray; | |
} | |
pos = safecat(name, sizeof name, pos, "gamma "); | |
pos = safecatd(name, sizeof name, pos, file_gamma, 3); | |
pos = safecat(name, sizeof name, pos, "->"); | |
pos = safecatd(name, sizeof name, pos, screen_gamma, 3); | |
pos = safecat(name, sizeof name, pos, base); | |
if (do_background < ALPHA_MODE_OFFSET) | |
{ | |
/* Include the background color and gamma in the name: */ | |
pos = safecat(name, sizeof name, pos, "("); | |
/* This assumes no expand gray->rgb - the current code won't handle that! | |
*/ | |
if (colour_type & PNG_COLOR_MASK_COLOR) | |
{ | |
pos = safecatn(name, sizeof name, pos, background.red); | |
pos = safecat(name, sizeof name, pos, ","); | |
pos = safecatn(name, sizeof name, pos, background.green); | |
pos = safecat(name, sizeof name, pos, ","); | |
pos = safecatn(name, sizeof name, pos, background.blue); | |
} | |
else | |
pos = safecatn(name, sizeof name, pos, background.gray); | |
pos = safecat(name, sizeof name, pos, ")^"); | |
pos = safecatd(name, sizeof name, pos, bg, 3); | |
} | |
gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type, | |
file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision, | |
0/*strip 16*/, expand_16, do_background, &background, bg); | |
} | |
static void | |
perform_gamma_composition_tests(png_modifier *pm, int do_background, | |
int expand_16) | |
{ | |
png_byte colour_type = 0; | |
png_byte bit_depth = 0; | |
int palette_number = 0; | |
/* Skip the non-alpha cases - there is no setting of a transparency colour at | |
* present. | |
*/ | |
while (next_format(&colour_type, &bit_depth, &palette_number)) | |
if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0) | |
{ | |
unsigned int i, j; | |
/* Don't skip the i==j case here - it's relevant. */ | |
for (i=0; i<pm->ngammas; ++i) for (j=0; j<pm->ngammas; ++j) | |
{ | |
gamma_composition_test(pm, colour_type, bit_depth, palette_number, | |
pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], | |
pm->use_input_precision, do_background, expand_16); | |
if (fail(pm)) | |
return; | |
} | |
} | |
} | |
#endif /* READ_BACKGROUND || READ_ALPHA_MODE */ | |
static void | |
init_gamma_errors(png_modifier *pm) | |
{ | |
pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0; | |
pm->error_color_8 = 0; | |
pm->error_indexed = 0; | |
pm->error_gray_16 = pm->error_color_16 = 0; | |
} | |
static void | |
summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth) | |
{ | |
if (who) | |
printf("Gamma correction with %s:\n", who); | |
if (low_bit_depth) | |
{ | |
printf(" 2 bit gray: %.5f\n", pm->error_gray_2); | |
printf(" 4 bit gray: %.5f\n", pm->error_gray_4); | |
printf(" 8 bit gray: %.5f\n", pm->error_gray_8); | |
printf(" 8 bit color: %.5f\n", pm->error_color_8); | |
printf(" indexed: %.5f\n", pm->error_indexed); | |
} | |
#ifdef DO_16BIT | |
printf(" 16 bit gray: %.5f\n", pm->error_gray_16); | |
printf(" 16 bit color: %.5f\n", pm->error_color_16); | |
#endif | |
} | |
static void | |
perform_gamma_test(png_modifier *pm, int summary) | |
{ | |
/*TODO: remove this*/ | |
/* Save certain values for the temporary overrides below. */ | |
unsigned int calculations_use_input_precision = | |
pm->calculations_use_input_precision; | |
double maxout8 = pm->maxout8; | |
/* First some arbitrary no-transform tests: */ | |
if (!pm->this.speed && pm->test_gamma_threshold) | |
{ | |
perform_gamma_threshold_tests(pm); | |
if (fail(pm)) | |
return; | |
} | |
/* Now some real transforms. */ | |
if (pm->test_gamma_transform) | |
{ | |
init_gamma_errors(pm); | |
/*TODO: remove this. Necessary because the current libpng | |
* implementation works in 8 bits: | |
*/ | |
if (pm->test_gamma_expand16) | |
pm->calculations_use_input_precision = 1; | |
perform_gamma_transform_tests(pm); | |
if (!calculations_use_input_precision) | |
pm->calculations_use_input_precision = 0; | |
if (summary) | |
{ | |
printf("Gamma correction error summary\n\n"); | |
printf("The printed value is the maximum error in the pixel values\n"); | |
printf("calculated by the libpng gamma correction code. The error\n"); | |
printf("is calculated as the difference between the output pixel\n"); | |
printf("value (always an integer) and the ideal value from the\n"); | |
printf("libpng specification (typically not an integer).\n\n"); | |
printf("Expect this value to be less than .5 for 8 bit formats,\n"); | |
printf("less than 1 for formats with fewer than 8 bits and a small\n"); | |
printf("number (typically less than 5) for the 16 bit formats.\n"); | |
printf("For performance reasons the value for 16 bit formats\n"); | |
printf("increases when the image file includes an sBIT chunk.\n\n"); | |
summarize_gamma_errors(pm, 0/*who*/, 1); | |
} | |
} | |
/* The sbit tests produce much larger errors: */ | |
if (pm->test_gamma_sbit) | |
{ | |
init_gamma_errors(pm); | |
perform_gamma_sbit_tests(pm); | |
if (summary) | |
summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U); | |
} | |
#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */ | |
if (pm->test_gamma_scale16) | |
{ | |
/* The 16 to 8 bit strip operations: */ | |
init_gamma_errors(pm); | |
perform_gamma_scale16_tests(pm); | |
if (summary) | |
{ | |
printf("Gamma correction with 16 to 8 bit reduction:\n"); | |
printf(" 16 bit gray: %.5f\n", pm->error_gray_16); | |
printf(" 16 bit color: %.5f\n", pm->error_color_16); | |
} | |
} | |
#endif | |
#ifdef PNG_READ_BACKGROUND_SUPPORTED | |
if (pm->test_gamma_background) | |
{ | |
init_gamma_errors(pm); | |
/*TODO: remove this. Necessary because the current libpng | |
* implementation works in 8 bits: | |
*/ | |
if (pm->test_gamma_expand16) | |
{ | |
pm->calculations_use_input_precision = 1; | |
pm->maxout8 = .499; /* because the 16 bit background is smashed */ | |
} | |
perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE, | |
pm->test_gamma_expand16); | |
if (!calculations_use_input_precision) | |
pm->calculations_use_input_precision = 0; | |
pm->maxout8 = maxout8; | |
if (summary) | |
summarize_gamma_errors(pm, "background", 1); | |
} | |
#endif | |
#ifdef PNG_READ_ALPHA_MODE_SUPPORTED | |
if (pm->test_gamma_alpha_mode) | |
{ | |
int do_background; | |
init_gamma_errors(pm); | |
/*TODO: remove this. Necessary because the current libpng | |
* implementation works in 8 bits: | |
*/ | |
if (pm->test_gamma_expand16) | |
pm->calculations_use_input_precision = 1; | |
for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD; | |
do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm); | |
++do_background) | |
perform_gamma_composition_tests(pm, do_background, | |
pm->test_gamma_expand16); | |
if (!calculations_use_input_precision) | |
pm->calculations_use_input_precision = 0; | |
if (summary) | |
summarize_gamma_errors(pm, "alpha mode", 1); | |
} | |
#endif | |
} | |
#endif /* PNG_READ_GAMMA_SUPPORTED */ | |
/* INTERLACE MACRO VALIDATION */ | |
/* This is copied verbatim from the specification, it is simply the pass | |
* number in which each pixel in each 8x8 tile appears. The array must | |
* be indexed adam7[y][x] and notice that the pass numbers are based at | |
* 1, not 0 - the base libpng uses. | |
*/ | |
static PNG_CONST | |
png_byte adam7[8][8] = | |
{ | |
{ 1,6,4,6,2,6,4,6 }, | |
{ 7,7,7,7,7,7,7,7 }, | |
{ 5,6,5,6,5,6,5,6 }, | |
{ 7,7,7,7,7,7,7,7 }, | |
{ 3,6,4,6,3,6,4,6 }, | |
{ 7,7,7,7,7,7,7,7 }, | |
{ 5,6,5,6,5,6,5,6 }, | |
{ 7,7,7,7,7,7,7,7 } | |
}; | |
/* This routine validates all the interlace support macros in png.h for | |
* a variety of valid PNG widths and heights. It uses a number of similarly | |
* named internal routines that feed off the above array. | |
*/ | |
static png_uint_32 | |
png_pass_start_row(int pass) | |
{ | |
int x, y; | |
++pass; | |
for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass) | |
return y; | |
return 0xf; | |
} | |
static png_uint_32 | |
png_pass_start_col(int pass) | |
{ | |
int x, y; | |
++pass; | |
for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass) | |
return x; | |
return 0xf; | |
} | |
static int | |
png_pass_row_shift(int pass) | |
{ | |
int x, y, base=(-1), inc=8; | |
++pass; | |
for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass) | |
{ | |
if (base == (-1)) | |
base = y; | |
else if (base == y) | |
{} | |
else if (inc == y-base) | |
base=y; | |
else if (inc == 8) | |
inc = y-base, base=y; | |
else if (inc != y-base) | |
return 0xff; /* error - more than one 'inc' value! */ | |
} | |
if (base == (-1)) return 0xfe; /* error - no row in pass! */ | |
/* The shift is always 1, 2 or 3 - no pass has all the rows! */ | |
switch (inc) | |
{ | |
case 2: return 1; | |
case 4: return 2; | |
case 8: return 3; | |
default: break; | |
} | |
/* error - unrecognized 'inc' */ | |
return (inc << 8) + 0xfd; | |
} | |
static int | |
png_pass_col_shift(int pass) | |
{ | |
int x, y, base=(-1), inc=8; | |
++pass; | |
for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass) | |
{ | |
if (base == (-1)) | |
base = x; | |
else if (base == x) | |
{} | |
else if (inc == x-base) | |
base=x; | |
else if (inc == 8) | |
inc = x-base, base=x; | |
else if (inc != x-base) | |
return 0xff; /* error - more than one 'inc' value! */ | |
} | |
if (base == (-1)) return 0xfe; /* error - no row in pass! */ | |
/* The shift is always 1, 2 or 3 - no pass has all the rows! */ | |
switch (inc) | |
{ | |
case 1: return 0; /* pass 7 has all the columns */ | |
case 2: return 1; | |
case 4: return 2; | |
case 8: return 3; | |
default: break; | |
} | |
/* error - unrecognized 'inc' */ | |
return (inc << 8) + 0xfd; | |
} | |
static png_uint_32 | |
png_row_from_pass_row(png_uint_32 yIn, int pass) | |
{ | |
/* By examination of the array: */ | |
switch (pass) | |
{ | |
case 0: return yIn * 8; | |
case 1: return yIn * 8; | |
case 2: return yIn * 8 + 4; | |
case 3: return yIn * 4; | |
case 4: return yIn * 4 + 2; | |
case 5: return yIn * 2; | |
case 6: return yIn * 2 + 1; | |
default: break; | |
} | |
return 0xff; /* bad pass number */ | |
} | |
static png_uint_32 | |
png_col_from_pass_col(png_uint_32 xIn, int pass) | |
{ | |
/* By examination of the array: */ | |
switch (pass) | |
{ | |
case 0: return xIn * 8; | |
case 1: return xIn * 8 + 4; | |
case 2: return xIn * 4; | |
case 3: return xIn * 4 + 2; | |
case 4: return xIn * 2; | |
case 5: return xIn * 2 + 1; | |
case 6: return xIn; | |
default: break; | |
} | |
return 0xff; /* bad pass number */ | |
} | |
static int | |
png_row_in_interlace_pass(png_uint_32 y, int pass) | |
{ | |
/* Is row 'y' in pass 'pass'? */ | |
int x; | |
y &= 7; | |
++pass; | |
for (x=0; x<8; ++x) if (adam7[y][x] == pass) | |
return 1; | |
return 0; | |
} | |
static int | |
png_col_in_interlace_pass(png_uint_32 x, int pass) | |
{ | |
/* Is column 'x' in pass 'pass'? */ | |
int y; | |
x &= 7; | |
++pass; | |
for (y=0; y<8; ++y) if (adam7[y][x] == pass) | |
return 1; | |
return 0; | |
} | |
static png_uint_32 | |
png_pass_rows(png_uint_32 height, int pass) | |
{ | |
png_uint_32 tiles = height>>3; | |
png_uint_32 rows = 0; | |
unsigned int x, y; | |
height &= 7; | |
++pass; | |
for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass) | |
{ | |
rows += tiles; | |
if (y < height) ++rows; | |
break; /* i.e. break the 'x', column, loop. */ | |
} | |
return rows; | |
} | |
static png_uint_32 | |
png_pass_cols(png_uint_32 width, int pass) | |
{ | |
png_uint_32 tiles = width>>3; | |
png_uint_32 cols = 0; | |
unsigned int x, y; | |
width &= 7; | |
++pass; | |
for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass) | |
{ | |
cols += tiles; | |
if (x < width) ++cols; | |
break; /* i.e. break the 'y', row, loop. */ | |
} | |
return cols; | |
} | |
static void | |
perform_interlace_macro_validation(void) | |
{ | |
/* The macros to validate, first those that depend only on pass: | |
* | |
* PNG_PASS_START_ROW(pass) | |
* PNG_PASS_START_COL(pass) | |
* PNG_PASS_ROW_SHIFT(pass) | |
* PNG_PASS_COL_SHIFT(pass) | |
*/ | |
int pass; | |
for (pass=0; pass<7; ++pass) | |
{ | |
png_uint_32 m, f, v; | |
m = PNG_PASS_START_ROW(pass); | |
f = png_pass_start_row(pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f); | |
exit(1); | |
} | |
m = PNG_PASS_START_COL(pass); | |
f = png_pass_start_col(pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f); | |
exit(1); | |
} | |
m = PNG_PASS_ROW_SHIFT(pass); | |
f = png_pass_row_shift(pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f); | |
exit(1); | |
} | |
m = PNG_PASS_COL_SHIFT(pass); | |
f = png_pass_col_shift(pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f); | |
exit(1); | |
} | |
/* Macros that depend on the image or sub-image height too: | |
* | |
* PNG_PASS_ROWS(height, pass) | |
* PNG_PASS_COLS(width, pass) | |
* PNG_ROW_FROM_PASS_ROW(yIn, pass) | |
* PNG_COL_FROM_PASS_COL(xIn, pass) | |
* PNG_ROW_IN_INTERLACE_PASS(y, pass) | |
* PNG_COL_IN_INTERLACE_PASS(x, pass) | |
*/ | |
for (v=0;;) | |
{ | |
/* First the base 0 stuff: */ | |
m = PNG_ROW_FROM_PASS_ROW(v, pass); | |
f = png_row_from_pass_row(v, pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n", | |
v, pass, m, f); | |
exit(1); | |
} | |
m = PNG_COL_FROM_PASS_COL(v, pass); | |
f = png_col_from_pass_col(v, pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n", | |
v, pass, m, f); | |
exit(1); | |
} | |
m = PNG_ROW_IN_INTERLACE_PASS(v, pass); | |
f = png_row_in_interlace_pass(v, pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n", | |
v, pass, m, f); | |
exit(1); | |
} | |
m = PNG_COL_IN_INTERLACE_PASS(v, pass); | |
f = png_col_in_interlace_pass(v, pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n", | |
v, pass, m, f); | |
exit(1); | |
} | |
/* Then the base 1 stuff: */ | |
++v; | |
m = PNG_PASS_ROWS(v, pass); | |
f = png_pass_rows(v, pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n", | |
v, pass, m, f); | |
exit(1); | |
} | |
m = PNG_PASS_COLS(v, pass); | |
f = png_pass_cols(v, pass); | |
if (m != f) | |
{ | |
fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n", | |
v, pass, m, f); | |
exit(1); | |
} | |
/* Move to the next v - the stepping algorithm starts skipping | |
* values above 1024. | |
*/ | |
if (v > 1024) | |
{ | |
if (v == PNG_UINT_31_MAX) | |
break; | |
v = (v << 1) ^ v; | |
if (v >= PNG_UINT_31_MAX) | |
v = PNG_UINT_31_MAX-1; | |
} | |
} | |
} | |
} | |
/* main program */ | |
int main(int argc, PNG_CONST char **argv) | |
{ | |
volatile int summary = 1; /* Print the error summary at the end */ | |
volatile int memstats = 0; /* Print memory statistics at the end */ | |
/* Create the given output file on success: */ | |
PNG_CONST char *volatile touch = NULL; | |
/* This is an array of standard gamma values (believe it or not I've seen | |
* every one of these mentioned somewhere.) | |
* | |
* In the following list the most useful values are first! | |
*/ | |
static double | |
gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9}; | |
/* This records the command and arguments: */ | |
size_t cp = 0; | |
char command[1024]; | |
png_modifier pm; | |
context(&pm.this, fault); | |
modifier_init(&pm); | |
/* Preallocate the image buffer, because we know how big it needs to be, | |
* note that, for testing purposes, it is deliberately mis-aligned by tag | |
* bytes either side. All rows have an additional five bytes of padding for | |
* overwrite checking. | |
*/ | |
store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX); | |
/* Don't give argv[0], it's normally some horrible libtool string: */ | |
cp = safecat(command, sizeof command, cp, "pngvalid"); | |
/* Default to error on warning: */ | |
pm.this.treat_warnings_as_errors = 1; | |
/* Store the test gammas */ | |
pm.gammas = gammas; | |
pm.ngammas = 0; /* default to off */ | |
pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */ | |
/* The following allows results to pass if they correspond to anything in the | |
* transformed range [input-.5,input+.5]; this is is required because of the | |
* way libpng treates the 16_TO_8 flag when building the gamma tables. | |
* | |
* TODO: review this | |
*/ | |
pm.use_input_precision_16to8 = 1U; | |
/* Some default values (set the behavior for 'make check' here). | |
* These values simply control the maximum error permitted in the gamma | |
* transformations. The practial limits for human perception are described | |
* below (the setting for maxpc16), however for 8 bit encodings it isn't | |
* possible to meet the accepted capabilities of human vision - i.e. 8 bit | |
* images can never be good enough, regardless of encoding. | |
*/ | |
pm.maxout8 = .1; /* Arithmetic error in *encoded* value */ | |
pm.maxabs8 = .00005; /* 1/20000 */ | |
pm.maxcalc8 = .004; /* +/-1 in 8 bits for compose errors */ | |
pm.maxpc8 = .499; /* I.e., .499% fractional error */ | |
pm.maxout16 = .499; /* Error in *encoded* value */ | |
pm.maxabs16 = .00005;/* 1/20000 */ | |
pm.maxcalc16 =.000015;/* +/-1 in 16 bits for compose errors */ | |
/* NOTE: this is a reasonable perceptual limit. We assume that humans can | |
* perceive light level differences of 1% over a 100:1 range, so we need to | |
* maintain 1 in 10000 accuracy (in linear light space), which is what the | |
* following guarantees. It also allows significantly higher errors at | |
* higher 16 bit values, which is important for performance. The actual | |
* maximum 16 bit error is about +/-1.9 in the fixed point implementation but | |
* this is only allowed for values >38149 by the following: | |
*/ | |
pm.maxpc16 = .005; /* I.e., 1/200% - 1/20000 */ | |
/* Now parse the command line options. */ | |
while (--argc >= 1) | |
{ | |
int catmore = 0; /* Set if the argument has an argument. */ | |
/* Record each argument for posterity: */ | |
cp = safecat(command, sizeof command, cp, " "); | |
cp = safecat(command, sizeof command, cp, *++argv); | |
if (strcmp(*argv, "-v") == 0) | |
pm.this.verbose = 1; | |
else if (strcmp(*argv, "-l") == 0) | |
pm.log = 1; | |
else if (strcmp(*argv, "-q") == 0) | |
summary = pm.this.verbose = pm.log = 0; | |
else if (strcmp(*argv, "-w") == 0) | |
pm.this.treat_warnings_as_errors = 0; | |
else if (strcmp(*argv, "--speed") == 0) | |
pm.this.speed = 1, pm.ngammas = (sizeof gammas)/(sizeof gammas[0]), | |
pm.test_standard = 0, summary = 0; | |
else if (strcmp(*argv, "--memory") == 0) | |
memstats = 1; | |
else if (strcmp(*argv, "--size") == 0) | |
pm.test_size = 1; | |
else if (strcmp(*argv, "--nosize") == 0) | |
pm.test_size = 0; | |
else if (strcmp(*argv, "--standard") == 0) | |
pm.test_standard = 1; | |
else if (strcmp(*argv, "--nostandard") == 0) | |
pm.test_standard = 0; | |
else if (strcmp(*argv, "--transform") == 0) | |
pm.test_transform = 1; | |
else if (strcmp(*argv, "--notransform") == 0) | |
pm.test_transform = 0; | |
#ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
else if (strncmp(*argv, "--transform-disable=", | |
sizeof "--transform-disable") == 0) | |
{ | |
pm.test_transform = 1; | |
transform_disable(*argv + sizeof "--transform-disable"); | |
} | |
else if (strncmp(*argv, "--transform-enable=", | |
sizeof "--transform-enable") == 0) | |
{ | |
pm.test_transform = 1; | |
transform_enable(*argv + sizeof "--transform-enable"); | |
} | |
#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ | |
else if (strcmp(*argv, "--gamma") == 0) | |
{ | |
/* Just do two gamma tests here (2.2 and linear) for speed: */ | |
pm.ngammas = 2U; | |
pm.test_gamma_threshold = 1; | |
pm.test_gamma_transform = 1; | |
pm.test_gamma_sbit = 1; | |
pm.test_gamma_scale16 = 1; | |
pm.test_gamma_background = 1; | |
pm.test_gamma_alpha_mode = 1; | |
} | |
else if (strcmp(*argv, "--nogamma") == 0) | |
pm.ngammas = 0; | |
else if (strcmp(*argv, "--gamma-threshold") == 0) | |
pm.ngammas = 2U, pm.test_gamma_threshold = 1; | |
else if (strcmp(*argv, "--nogamma-threshold") == 0) | |
pm.test_gamma_threshold = 0; | |
else if (strcmp(*argv, "--gamma-transform") == 0) | |
pm.ngammas = 2U, pm.test_gamma_transform = 1; | |
else if (strcmp(*argv, "--nogamma-transform") == 0) | |
pm.test_gamma_transform = 0; | |
else if (strcmp(*argv, "--gamma-sbit") == 0) | |
pm.ngammas = 2U, pm.test_gamma_sbit = 1; | |
else if (strcmp(*argv, "--nogamma-sbit") == 0) | |
pm.test_gamma_sbit = 0; | |
else if (strcmp(*argv, "--gamma-16-to-8") == 0) | |
pm.ngammas = 2U, pm.test_gamma_scale16 = 1; | |
else if (strcmp(*argv, "--nogamma-16-to-8") == 0) | |
pm.test_gamma_scale16 = 0; | |
else if (strcmp(*argv, "--gamma-background") == 0) | |
pm.ngammas = 2U, pm.test_gamma_background = 1; | |
else if (strcmp(*argv, "--nogamma-background") == 0) | |
pm.test_gamma_background = 0; | |
else if (strcmp(*argv, "--gamma-alpha-mode") == 0) | |
pm.ngammas = 2U, pm.test_gamma_alpha_mode = 1; | |
else if (strcmp(*argv, "--nogamma-alpha-mode") == 0) | |
pm.test_gamma_alpha_mode = 0; | |
else if (strcmp(*argv, "--expand16") == 0) | |
pm.test_gamma_expand16 = 1; | |
else if (strcmp(*argv, "--noexpand16") == 0) | |
pm.test_gamma_expand16 = 0; | |
else if (strcmp(*argv, "--more-gammas") == 0) | |
pm.ngammas = 3U; | |
else if (strcmp(*argv, "--all-gammas") == 0) | |
pm.ngammas = (sizeof gammas)/(sizeof gammas[0]); | |
else if (strcmp(*argv, "--progressive-read") == 0) | |
pm.this.progressive = 1; | |
else if (strcmp(*argv, "--interlace") == 0) | |
pm.interlace_type = PNG_INTERLACE_ADAM7; | |
else if (strcmp(*argv, "--use-input-precision") == 0) | |
pm.use_input_precision = 1; | |
else if (strcmp(*argv, "--calculations-use-input-precision") == 0) | |
pm.calculations_use_input_precision = 1; | |
else if (strcmp(*argv, "--assume-16-bit-calculations") == 0) | |
pm.assume_16_bit_calculations = 1; | |
else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0) | |
pm.calculations_use_input_precision = | |
pm.assume_16_bit_calculations = 0; | |
else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0) | |
--argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1; | |
else if (argc > 1 && strcmp(*argv, "--touch") == 0) | |
--argc, touch = *++argv, catmore = 1; | |
else if (argc > 1 && strncmp(*argv, "--max", 5) == 0) | |
{ | |
--argc; | |
if (strcmp(5+*argv, "abs8") == 0) | |
pm.maxabs8 = atof(*++argv); | |
else if (strcmp(5+*argv, "abs16") == 0) | |
pm.maxabs16 = atof(*++argv); | |
else if (strcmp(5+*argv, "calc8") == 0) | |
pm.maxcalc8 = atof(*++argv); | |
else if (strcmp(5+*argv, "calc16") == 0) | |
pm.maxcalc16 = atof(*++argv); | |
else if (strcmp(5+*argv, "out8") == 0) | |
pm.maxout8 = atof(*++argv); | |
else if (strcmp(5+*argv, "out16") == 0) | |
pm.maxout16 = atof(*++argv); | |
else if (strcmp(5+*argv, "pc8") == 0) | |
pm.maxpc8 = atof(*++argv); | |
else if (strcmp(5+*argv, "pc16") == 0) | |
pm.maxpc16 = atof(*++argv); | |
else | |
{ | |
fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv); | |
exit(1); | |
} | |
catmore = 1; | |
} | |
else if (strcmp(*argv, "--log8") == 0) | |
--argc, pm.log8 = atof(*++argv), catmore = 1; | |
else if (strcmp(*argv, "--log16") == 0) | |
--argc, pm.log16 = atof(*++argv), catmore = 1; | |
else | |
{ | |
fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv); | |
exit(1); | |
} | |
if (catmore) /* consumed an extra *argv */ | |
{ | |
cp = safecat(command, sizeof command, cp, " "); | |
cp = safecat(command, sizeof command, cp, *argv); | |
} | |
} | |
/* If pngvalid is run with no arguments default to a reasonable set of the | |
* tests. | |
*/ | |
if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 && | |
pm.ngammas == 0) | |
{ | |
/* Make this do all the tests done in the test shell scripts with the same | |
* parameters, where possible. The limitation is that all the progressive | |
* read and interlace stuff has to be done in separate runs, so only the | |
* basic 'standard' and 'size' tests are done. | |
*/ | |
pm.test_standard = 1; | |
pm.test_size = 1; | |
pm.test_transform = 1; | |
pm.ngammas = 2U; | |
} | |
if (pm.ngammas > 0 && | |
pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 && | |
pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 && | |
pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0) | |
{ | |
pm.test_gamma_threshold = 1; | |
pm.test_gamma_transform = 1; | |
pm.test_gamma_sbit = 1; | |
pm.test_gamma_scale16 = 1; | |
pm.test_gamma_background = 1; | |
pm.test_gamma_alpha_mode = 1; | |
} | |
else if (pm.ngammas == 0) | |
{ | |
/* Nothing to test so turn everything off: */ | |
pm.test_gamma_threshold = 0; | |
pm.test_gamma_transform = 0; | |
pm.test_gamma_sbit = 0; | |
pm.test_gamma_scale16 = 0; | |
pm.test_gamma_background = 0; | |
pm.test_gamma_alpha_mode = 0; | |
} | |
Try | |
{ | |
/* Make useful base images */ | |
make_transform_images(&pm.this); | |
/* Perform the standard and gamma tests. */ | |
if (pm.test_standard) | |
{ | |
perform_interlace_macro_validation(); | |
perform_formatting_test(&pm.this); | |
perform_standard_test(&pm); | |
perform_error_test(&pm); | |
} | |
/* Various oddly sized images: */ | |
if (pm.test_size) | |
{ | |
make_size_images(&pm.this); | |
perform_size_test(&pm); | |
} | |
#ifdef PNG_READ_TRANSFORMS_SUPPORTED | |
/* Combinatorial transforms: */ | |
if (pm.test_transform) | |
perform_transform_test(&pm); | |
#endif /* PNG_READ_TRANSFORMS_SUPPORTED */ | |
#ifdef PNG_READ_GAMMA_SUPPORTED | |
if (pm.ngammas > 0) | |
perform_gamma_test(&pm, summary); | |
#endif | |
} | |
Catch(fault) | |
{ | |
fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n"); | |
if (!pm.this.verbose) | |
{ | |
if (pm.this.error[0] != 0) | |
fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error); | |
fprintf(stderr, "pngvalid: run with -v to see what happened\n"); | |
} | |
exit(1); | |
} | |
if (summary) | |
{ | |
printf("%s: %s (%s point arithmetic)\n", | |
(pm.this.nerrors || (pm.this.treat_warnings_as_errors && | |
pm.this.nwarnings)) ? "FAIL" : "PASS", | |
command, | |
#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500 | |
"floating" | |
#else | |
"fixed" | |
#endif | |
); | |
} | |
if (memstats) | |
{ | |
printf("Allocated memory statistics (in bytes):\n" | |
"\tread %lu maximum single, %lu peak, %lu total\n" | |
"\twrite %lu maximum single, %lu peak, %lu total\n", | |
(unsigned long)pm.this.read_memory_pool.max_max, | |
(unsigned long)pm.this.read_memory_pool.max_limit, | |
(unsigned long)pm.this.read_memory_pool.max_total, | |
(unsigned long)pm.this.write_memory_pool.max_max, | |
(unsigned long)pm.this.write_memory_pool.max_limit, | |
(unsigned long)pm.this.write_memory_pool.max_total); | |
} | |
/* Do this here to provoke memory corruption errors in memory not directly | |
* allocated by libpng - not a complete test, but better than nothing. | |
*/ | |
store_delete(&pm.this); | |
/* Error exit if there are any errors, and maybe if there are any | |
* warnings. | |
*/ | |
if (pm.this.nerrors || (pm.this.treat_warnings_as_errors && | |
pm.this.nwarnings)) | |
{ | |
if (!pm.this.verbose) | |
fprintf(stderr, "pngvalid: %s\n", pm.this.error); | |
fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors, | |
pm.this.nwarnings); | |
exit(1); | |
} | |
/* Success case. */ | |
if (touch != NULL) | |
{ | |
FILE *fsuccess = fopen(touch, "wt"); | |
if (fsuccess != NULL) | |
{ | |
int error = 0; | |
fprintf(fsuccess, "PNG validation succeeded\n"); | |
fflush(fsuccess); | |
error = ferror(fsuccess); | |
if (fclose(fsuccess) || error) | |
{ | |
fprintf(stderr, "%s: write failed\n", touch); | |
exit(1); | |
} | |
} | |
} | |
return 0; | |
} |