/* deflate.c -- compress data using the deflation algorithm | |
* Copyright (C) 1995-2005 Jean-loup Gailly. | |
* For conditions of distribution and use, see copyright notice in zlib.h | |
*/ | |
/* | |
* ALGORITHM | |
* | |
* The "deflation" process depends on being able to identify portions | |
* of the input text which are identical to earlier input (within a | |
* sliding window trailing behind the input currently being processed). | |
* | |
* The most straightforward technique turns out to be the fastest for | |
* most input files: try all possible matches and select the longest. | |
* The key feature of this algorithm is that insertions into the string | |
* dictionary are very simple and thus fast, and deletions are avoided | |
* completely. Insertions are performed at each input character, whereas | |
* string matches are performed only when the previous match ends. So it | |
* is preferable to spend more time in matches to allow very fast string | |
* insertions and avoid deletions. The matching algorithm for small | |
* strings is inspired from that of Rabin & Karp. A brute force approach | |
* is used to find longer strings when a small match has been found. | |
* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze | |
* (by Leonid Broukhis). | |
* A previous version of this file used a more sophisticated algorithm | |
* (by Fiala and Greene) which is guaranteed to run in linear amortized | |
* time, but has a larger average cost, uses more memory and is patented. | |
* However the F&G algorithm may be faster for some highly redundant | |
* files if the parameter max_chain_length (described below) is too large. | |
* | |
* ACKNOWLEDGEMENTS | |
* | |
* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and | |
* I found it in 'freeze' written by Leonid Broukhis. | |
* Thanks to many people for bug reports and testing. | |
* | |
* REFERENCES | |
* | |
* Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". | |
* Available in http://www.ietf.org/rfc/rfc1951.txt | |
* | |
* A description of the Rabin and Karp algorithm is given in the book | |
* "Algorithms" by R. Sedgewick, Addison-Wesley, p252. | |
* | |
* Fiala,E.R., and Greene,D.H. | |
* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 | |
* | |
*/ | |
/* @(#) $Id$ */ | |
#include "deflate.h" | |
const char deflate_copyright[] = | |
" deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly "; | |
/* | |
If you use the zlib library in a product, an acknowledgment is welcome | |
in the documentation of your product. If for some reason you cannot | |
include such an acknowledgment, I would appreciate that you keep this | |
copyright string in the executable of your product. | |
*/ | |
/* =========================================================================== | |
* Function prototypes. | |
*/ | |
typedef enum { | |
need_more, /* block not completed, need more input or more output */ | |
block_done, /* block flush performed */ | |
finish_started, /* finish started, need only more output at next deflate */ | |
finish_done /* finish done, accept no more input or output */ | |
} block_state; | |
typedef block_state (*compress_func) OF((deflate_state *s, int flush)); | |
/* Compression function. Returns the block state after the call. */ | |
local void fill_window OF((deflate_state *s)); | |
local block_state deflate_stored OF((deflate_state *s, int flush)); | |
local block_state deflate_fast OF((deflate_state *s, int flush)); | |
#ifndef FASTEST | |
local block_state deflate_slow OF((deflate_state *s, int flush)); | |
#endif | |
local void lm_init OF((deflate_state *s)); | |
local void putShortMSB OF((deflate_state *s, uInt b)); | |
local void flush_pending OF((z_streamp strm)); | |
local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); | |
#ifndef FASTEST | |
#ifdef ASMV | |
void match_init OF((void)); /* asm code initialization */ | |
uInt longest_match OF((deflate_state *s, IPos cur_match)); | |
#else | |
local uInt longest_match OF((deflate_state *s, IPos cur_match)); | |
#endif | |
#endif | |
local uInt longest_match_fast OF((deflate_state *s, IPos cur_match)); | |
#ifdef DEBUG | |
local void check_match OF((deflate_state *s, IPos start, IPos match, | |
int length)); | |
#endif | |
/* =========================================================================== | |
* Local data | |
*/ | |
#define NIL 0 | |
/* Tail of hash chains */ | |
#ifndef TOO_FAR | |
# define TOO_FAR 4096 | |
#endif | |
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ | |
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) | |
/* Minimum amount of lookahead, except at the end of the input file. | |
* See deflate.c for comments about the MIN_MATCH+1. | |
*/ | |
/* Values for max_lazy_match, good_match and max_chain_length, depending on | |
* the desired pack level (0..9). The values given below have been tuned to | |
* exclude worst case performance for pathological files. Better values may be | |
* found for specific files. | |
*/ | |
typedef struct config_s { | |
ush good_length; /* reduce lazy search above this match length */ | |
ush max_lazy; /* do not perform lazy search above this match length */ | |
ush nice_length; /* quit search above this match length */ | |
ush max_chain; | |
compress_func func; | |
} config; | |
#ifdef FASTEST | |
local const config configuration_table[2] = { | |
/* good lazy nice chain */ | |
/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | |
/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ | |
#else | |
local const config configuration_table[10] = { | |
/* good lazy nice chain */ | |
/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ | |
/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ | |
/* 2 */ {4, 5, 16, 8, deflate_fast}, | |
/* 3 */ {4, 6, 32, 32, deflate_fast}, | |
/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ | |
/* 5 */ {8, 16, 32, 32, deflate_slow}, | |
/* 6 */ {8, 16, 128, 128, deflate_slow}, | |
/* 7 */ {8, 32, 128, 256, deflate_slow}, | |
/* 8 */ {32, 128, 258, 1024, deflate_slow}, | |
/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ | |
#endif | |
/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 | |
* For deflate_fast() (levels <= 3) good is ignored and lazy has a different | |
* meaning. | |
*/ | |
#define EQUAL 0 | |
/* result of memcmp for equal strings */ | |
#ifndef NO_DUMMY_DECL | |
struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ | |
#endif | |
/* =========================================================================== | |
* Update a hash value with the given input byte | |
* IN assertion: all calls to to UPDATE_HASH are made with consecutive | |
* input characters, so that a running hash key can be computed from the | |
* previous key instead of complete recalculation each time. | |
*/ | |
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) | |
/* =========================================================================== | |
* Insert string str in the dictionary and set match_head to the previous head | |
* of the hash chain (the most recent string with same hash key). Return | |
* the previous length of the hash chain. | |
* If this file is compiled with -DFASTEST, the compression level is forced | |
* to 1, and no hash chains are maintained. | |
* IN assertion: all calls to to INSERT_STRING are made with consecutive | |
* input characters and the first MIN_MATCH bytes of str are valid | |
* (except for the last MIN_MATCH-1 bytes of the input file). | |
*/ | |
#ifdef FASTEST | |
#define INSERT_STRING(s, str, match_head) \ | |
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | |
match_head = s->head[s->ins_h], \ | |
s->head[s->ins_h] = (Pos)(str)) | |
#else | |
#define INSERT_STRING(s, str, match_head) \ | |
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ | |
match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ | |
s->head[s->ins_h] = (Pos)(str)) | |
#endif | |
/* =========================================================================== | |
* Initialize the hash table (avoiding 64K overflow for 16 bit systems). | |
* prev[] will be initialized on the fly. | |
*/ | |
#define CLEAR_HASH(s) \ | |
s->head[s->hash_size-1] = NIL; \ | |
zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); | |
/* ========================================================================= */ | |
int ZEXPORT deflateInit_(strm, level, version, stream_size) | |
z_streamp strm; | |
int level; | |
const char *version; | |
int stream_size; | |
{ | |
return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, | |
Z_DEFAULT_STRATEGY, version, stream_size); | |
/* To do: ignore strm->next_in if we use it as window */ | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, | |
version, stream_size) | |
z_streamp strm; | |
int level; | |
int method; | |
int windowBits; | |
int memLevel; | |
int strategy; | |
const char *version; | |
int stream_size; | |
{ | |
deflate_state *s; | |
int wrap = 1; | |
static const char my_version[] = ZLIB_VERSION; | |
ushf *overlay; | |
/* We overlay pending_buf and d_buf+l_buf. This works since the average | |
* output size for (length,distance) codes is <= 24 bits. | |
*/ | |
if (version == Z_NULL || version[0] != my_version[0] || | |
stream_size != sizeof(z_stream)) { | |
return Z_VERSION_ERROR; | |
} | |
if (strm == Z_NULL) return Z_STREAM_ERROR; | |
strm->msg = Z_NULL; | |
if (strm->zalloc == (alloc_func)0) { | |
strm->zalloc = zcalloc; | |
strm->opaque = (voidpf)0; | |
} | |
if (strm->zfree == (free_func)0) strm->zfree = zcfree; | |
#ifdef FASTEST | |
if (level != 0) level = 1; | |
#else | |
if (level == Z_DEFAULT_COMPRESSION) level = 6; | |
#endif | |
if (windowBits < 0) { /* suppress zlib wrapper */ | |
wrap = 0; | |
windowBits = -windowBits; | |
} | |
#ifdef GZIP | |
else if (windowBits > 15) { | |
wrap = 2; /* write gzip wrapper instead */ | |
windowBits -= 16; | |
} | |
#endif | |
if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || | |
windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || | |
strategy < 0 || strategy > Z_FIXED) { | |
return Z_STREAM_ERROR; | |
} | |
if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ | |
s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); | |
if (s == Z_NULL) return Z_MEM_ERROR; | |
strm->state = (struct internal_state FAR *)s; | |
s->strm = strm; | |
s->wrap = wrap; | |
s->gzhead = Z_NULL; | |
s->w_bits = windowBits; | |
s->w_size = 1 << s->w_bits; | |
s->w_mask = s->w_size - 1; | |
s->hash_bits = memLevel + 7; | |
s->hash_size = 1 << s->hash_bits; | |
s->hash_mask = s->hash_size - 1; | |
s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); | |
s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); | |
s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); | |
s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); | |
s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ | |
overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); | |
s->pending_buf = (uchf *) overlay; | |
s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); | |
if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || | |
s->pending_buf == Z_NULL) { | |
s->status = FINISH_STATE; | |
strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); | |
deflateEnd (strm); | |
return Z_MEM_ERROR; | |
} | |
s->d_buf = overlay + s->lit_bufsize/sizeof(ush); | |
s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; | |
s->level = level; | |
s->strategy = strategy; | |
s->method = (Byte)method; | |
return deflateReset(strm); | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) | |
z_streamp strm; | |
const Bytef *dictionary; | |
uInt dictLength; | |
{ | |
deflate_state *s; | |
uInt length = dictLength; | |
uInt n; | |
IPos hash_head = 0; | |
if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || | |
strm->state->wrap == 2 || | |
(strm->state->wrap == 1 && strm->state->status != INIT_STATE)) | |
return Z_STREAM_ERROR; | |
s = strm->state; | |
if (s->wrap) | |
strm->adler = adler32(strm->adler, dictionary, dictLength); | |
if (length < MIN_MATCH) return Z_OK; | |
if (length > MAX_DIST(s)) { | |
length = MAX_DIST(s); | |
dictionary += dictLength - length; /* use the tail of the dictionary */ | |
} | |
zmemcpy(s->window, dictionary, length); | |
s->strstart = length; | |
s->block_start = (long)length; | |
/* Insert all strings in the hash table (except for the last two bytes). | |
* s->lookahead stays null, so s->ins_h will be recomputed at the next | |
* call of fill_window. | |
*/ | |
s->ins_h = s->window[0]; | |
UPDATE_HASH(s, s->ins_h, s->window[1]); | |
for (n = 0; n <= length - MIN_MATCH; n++) { | |
INSERT_STRING(s, n, hash_head); | |
} | |
if (hash_head) hash_head = 0; /* to make compiler happy */ | |
return Z_OK; | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflateReset (strm) | |
z_streamp strm; | |
{ | |
deflate_state *s; | |
if (strm == Z_NULL || strm->state == Z_NULL || | |
strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { | |
return Z_STREAM_ERROR; | |
} | |
strm->total_in = strm->total_out = 0; | |
strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ | |
strm->data_type = Z_UNKNOWN; | |
s = (deflate_state *)strm->state; | |
s->pending = 0; | |
s->pending_out = s->pending_buf; | |
if (s->wrap < 0) { | |
s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ | |
} | |
s->status = s->wrap ? INIT_STATE : BUSY_STATE; | |
strm->adler = | |
#ifdef GZIP | |
s->wrap == 2 ? crc32(0L, Z_NULL, 0) : | |
#endif | |
adler32(0L, Z_NULL, 0); | |
s->last_flush = Z_NO_FLUSH; | |
_tr_init(s); | |
lm_init(s); | |
return Z_OK; | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflateSetHeader (strm, head) | |
z_streamp strm; | |
gz_headerp head; | |
{ | |
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
if (strm->state->wrap != 2) return Z_STREAM_ERROR; | |
strm->state->gzhead = head; | |
return Z_OK; | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflatePrime (strm, bits, value) | |
z_streamp strm; | |
int bits; | |
int value; | |
{ | |
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
strm->state->bi_valid = bits; | |
strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); | |
return Z_OK; | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflateParams(strm, level, strategy) | |
z_streamp strm; | |
int level; | |
int strategy; | |
{ | |
deflate_state *s; | |
compress_func func; | |
int err = Z_OK; | |
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
s = strm->state; | |
#ifdef FASTEST | |
if (level != 0) level = 1; | |
#else | |
if (level == Z_DEFAULT_COMPRESSION) level = 6; | |
#endif | |
if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { | |
return Z_STREAM_ERROR; | |
} | |
func = configuration_table[s->level].func; | |
if (func != configuration_table[level].func && strm->total_in != 0) { | |
/* Flush the last buffer: */ | |
err = deflate(strm, Z_PARTIAL_FLUSH); | |
} | |
if (s->level != level) { | |
s->level = level; | |
s->max_lazy_match = configuration_table[level].max_lazy; | |
s->good_match = configuration_table[level].good_length; | |
s->nice_match = configuration_table[level].nice_length; | |
s->max_chain_length = configuration_table[level].max_chain; | |
} | |
s->strategy = strategy; | |
return err; | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain) | |
z_streamp strm; | |
int good_length; | |
int max_lazy; | |
int nice_length; | |
int max_chain; | |
{ | |
deflate_state *s; | |
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
s = strm->state; | |
s->good_match = good_length; | |
s->max_lazy_match = max_lazy; | |
s->nice_match = nice_length; | |
s->max_chain_length = max_chain; | |
return Z_OK; | |
} | |
/* ========================================================================= | |
* For the default windowBits of 15 and memLevel of 8, this function returns | |
* a close to exact, as well as small, upper bound on the compressed size. | |
* They are coded as constants here for a reason--if the #define's are | |
* changed, then this function needs to be changed as well. The return | |
* value for 15 and 8 only works for those exact settings. | |
* | |
* For any setting other than those defaults for windowBits and memLevel, | |
* the value returned is a conservative worst case for the maximum expansion | |
* resulting from using fixed blocks instead of stored blocks, which deflate | |
* can emit on compressed data for some combinations of the parameters. | |
* | |
* This function could be more sophisticated to provide closer upper bounds | |
* for every combination of windowBits and memLevel, as well as wrap. | |
* But even the conservative upper bound of about 14% expansion does not | |
* seem onerous for output buffer allocation. | |
*/ | |
uLong ZEXPORT deflateBound(strm, sourceLen) | |
z_streamp strm; | |
uLong sourceLen; | |
{ | |
deflate_state *s; | |
uLong destLen; | |
/* conservative upper bound */ | |
destLen = sourceLen + | |
((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11; | |
/* if can't get parameters, return conservative bound */ | |
if (strm == Z_NULL || strm->state == Z_NULL) | |
return destLen; | |
/* if not default parameters, return conservative bound */ | |
s = strm->state; | |
if (s->w_bits != 15 || s->hash_bits != 8 + 7) | |
return destLen; | |
/* default settings: return tight bound for that case */ | |
return compressBound(sourceLen); | |
} | |
/* ========================================================================= | |
* Put a short in the pending buffer. The 16-bit value is put in MSB order. | |
* IN assertion: the stream state is correct and there is enough room in | |
* pending_buf. | |
*/ | |
local void putShortMSB (s, b) | |
deflate_state *s; | |
uInt b; | |
{ | |
put_byte(s, (Byte)(b >> 8)); | |
put_byte(s, (Byte)(b & 0xff)); | |
} | |
/* ========================================================================= | |
* Flush as much pending output as possible. All deflate() output goes | |
* through this function so some applications may wish to modify it | |
* to avoid allocating a large strm->next_out buffer and copying into it. | |
* (See also read_buf()). | |
*/ | |
local void flush_pending(strm) | |
z_streamp strm; | |
{ | |
unsigned len = strm->state->pending; | |
if (len > strm->avail_out) len = strm->avail_out; | |
if (len == 0) return; | |
zmemcpy(strm->next_out, strm->state->pending_out, len); | |
strm->next_out += len; | |
strm->state->pending_out += len; | |
strm->total_out += len; | |
strm->avail_out -= len; | |
strm->state->pending -= len; | |
if (strm->state->pending == 0) { | |
strm->state->pending_out = strm->state->pending_buf; | |
} | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflate (strm, flush) | |
z_streamp strm; | |
int flush; | |
{ | |
int old_flush; /* value of flush param for previous deflate call */ | |
deflate_state *s; | |
if (strm == Z_NULL || strm->state == Z_NULL || | |
flush > Z_FINISH || flush < 0) { | |
return Z_STREAM_ERROR; | |
} | |
s = strm->state; | |
if (strm->next_out == Z_NULL || | |
(strm->next_in == Z_NULL && strm->avail_in != 0) || | |
(s->status == FINISH_STATE && flush != Z_FINISH)) { | |
ERR_RETURN(strm, Z_STREAM_ERROR); | |
} | |
if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); | |
s->strm = strm; /* just in case */ | |
old_flush = s->last_flush; | |
s->last_flush = flush; | |
/* Write the header */ | |
if (s->status == INIT_STATE) { | |
#ifdef GZIP | |
if (s->wrap == 2) { | |
strm->adler = crc32(0L, Z_NULL, 0); | |
put_byte(s, 31); | |
put_byte(s, 139); | |
put_byte(s, 8); | |
if (s->gzhead == NULL) { | |
put_byte(s, 0); | |
put_byte(s, 0); | |
put_byte(s, 0); | |
put_byte(s, 0); | |
put_byte(s, 0); | |
put_byte(s, s->level == 9 ? 2 : | |
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | |
4 : 0)); | |
put_byte(s, OS_CODE); | |
s->status = BUSY_STATE; | |
} | |
else { | |
put_byte(s, (s->gzhead->text ? 1 : 0) + | |
(s->gzhead->hcrc ? 2 : 0) + | |
(s->gzhead->extra == Z_NULL ? 0 : 4) + | |
(s->gzhead->name == Z_NULL ? 0 : 8) + | |
(s->gzhead->comment == Z_NULL ? 0 : 16) | |
); | |
put_byte(s, (Byte)(s->gzhead->time & 0xff)); | |
put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); | |
put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); | |
put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); | |
put_byte(s, s->level == 9 ? 2 : | |
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? | |
4 : 0)); | |
put_byte(s, s->gzhead->os & 0xff); | |
if (s->gzhead->extra != NULL) { | |
put_byte(s, s->gzhead->extra_len & 0xff); | |
put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); | |
} | |
if (s->gzhead->hcrc) | |
strm->adler = crc32(strm->adler, s->pending_buf, | |
s->pending); | |
s->gzindex = 0; | |
s->status = EXTRA_STATE; | |
} | |
} | |
else | |
#endif | |
{ | |
uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; | |
uInt level_flags; | |
if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) | |
level_flags = 0; | |
else if (s->level < 6) | |
level_flags = 1; | |
else if (s->level == 6) | |
level_flags = 2; | |
else | |
level_flags = 3; | |
header |= (level_flags << 6); | |
if (s->strstart != 0) header |= PRESET_DICT; | |
header += 31 - (header % 31); | |
s->status = BUSY_STATE; | |
putShortMSB(s, header); | |
/* Save the adler32 of the preset dictionary: */ | |
if (s->strstart != 0) { | |
putShortMSB(s, (uInt)(strm->adler >> 16)); | |
putShortMSB(s, (uInt)(strm->adler & 0xffff)); | |
} | |
strm->adler = adler32(0L, Z_NULL, 0); | |
} | |
} | |
#ifdef GZIP | |
if (s->status == EXTRA_STATE) { | |
if (s->gzhead->extra != NULL) { | |
uInt beg = s->pending; /* start of bytes to update crc */ | |
while (s->gzindex < (s->gzhead->extra_len & 0xffff)) { | |
if (s->pending == s->pending_buf_size) { | |
if (s->gzhead->hcrc && s->pending > beg) | |
strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
s->pending - beg); | |
flush_pending(strm); | |
beg = s->pending; | |
if (s->pending == s->pending_buf_size) | |
break; | |
} | |
put_byte(s, s->gzhead->extra[s->gzindex]); | |
s->gzindex++; | |
} | |
if (s->gzhead->hcrc && s->pending > beg) | |
strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
s->pending - beg); | |
if (s->gzindex == s->gzhead->extra_len) { | |
s->gzindex = 0; | |
s->status = NAME_STATE; | |
} | |
} | |
else | |
s->status = NAME_STATE; | |
} | |
if (s->status == NAME_STATE) { | |
if (s->gzhead->name != NULL) { | |
uInt beg = s->pending; /* start of bytes to update crc */ | |
int val; | |
do { | |
if (s->pending == s->pending_buf_size) { | |
if (s->gzhead->hcrc && s->pending > beg) | |
strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
s->pending - beg); | |
flush_pending(strm); | |
beg = s->pending; | |
if (s->pending == s->pending_buf_size) { | |
val = 1; | |
break; | |
} | |
} | |
val = s->gzhead->name[s->gzindex++]; | |
put_byte(s, val); | |
} while (val != 0); | |
if (s->gzhead->hcrc && s->pending > beg) | |
strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
s->pending - beg); | |
if (val == 0) { | |
s->gzindex = 0; | |
s->status = COMMENT_STATE; | |
} | |
} | |
else | |
s->status = COMMENT_STATE; | |
} | |
if (s->status == COMMENT_STATE) { | |
if (s->gzhead->comment != NULL) { | |
uInt beg = s->pending; /* start of bytes to update crc */ | |
int val; | |
do { | |
if (s->pending == s->pending_buf_size) { | |
if (s->gzhead->hcrc && s->pending > beg) | |
strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
s->pending - beg); | |
flush_pending(strm); | |
beg = s->pending; | |
if (s->pending == s->pending_buf_size) { | |
val = 1; | |
break; | |
} | |
} | |
val = s->gzhead->comment[s->gzindex++]; | |
put_byte(s, val); | |
} while (val != 0); | |
if (s->gzhead->hcrc && s->pending > beg) | |
strm->adler = crc32(strm->adler, s->pending_buf + beg, | |
s->pending - beg); | |
if (val == 0) | |
s->status = HCRC_STATE; | |
} | |
else | |
s->status = HCRC_STATE; | |
} | |
if (s->status == HCRC_STATE) { | |
if (s->gzhead->hcrc) { | |
if (s->pending + 2 > s->pending_buf_size) | |
flush_pending(strm); | |
if (s->pending + 2 <= s->pending_buf_size) { | |
put_byte(s, (Byte)(strm->adler & 0xff)); | |
put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | |
strm->adler = crc32(0L, Z_NULL, 0); | |
s->status = BUSY_STATE; | |
} | |
} | |
else | |
s->status = BUSY_STATE; | |
} | |
#endif | |
/* Flush as much pending output as possible */ | |
if (s->pending != 0) { | |
flush_pending(strm); | |
if (strm->avail_out == 0) { | |
/* Since avail_out is 0, deflate will be called again with | |
* more output space, but possibly with both pending and | |
* avail_in equal to zero. There won't be anything to do, | |
* but this is not an error situation so make sure we | |
* return OK instead of BUF_ERROR at next call of deflate: | |
*/ | |
s->last_flush = -1; | |
return Z_OK; | |
} | |
/* Make sure there is something to do and avoid duplicate consecutive | |
* flushes. For repeated and useless calls with Z_FINISH, we keep | |
* returning Z_STREAM_END instead of Z_BUF_ERROR. | |
*/ | |
} else if (strm->avail_in == 0 && flush <= old_flush && | |
flush != Z_FINISH) { | |
ERR_RETURN(strm, Z_BUF_ERROR); | |
} | |
/* User must not provide more input after the first FINISH: */ | |
if (s->status == FINISH_STATE && strm->avail_in != 0) { | |
ERR_RETURN(strm, Z_BUF_ERROR); | |
} | |
/* Start a new block or continue the current one. | |
*/ | |
if (strm->avail_in != 0 || s->lookahead != 0 || | |
(flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { | |
block_state bstate; | |
bstate = (*(configuration_table[s->level].func))(s, flush); | |
if (bstate == finish_started || bstate == finish_done) { | |
s->status = FINISH_STATE; | |
} | |
if (bstate == need_more || bstate == finish_started) { | |
if (strm->avail_out == 0) { | |
s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ | |
} | |
return Z_OK; | |
/* If flush != Z_NO_FLUSH && avail_out == 0, the next call | |
* of deflate should use the same flush parameter to make sure | |
* that the flush is complete. So we don't have to output an | |
* empty block here, this will be done at next call. This also | |
* ensures that for a very small output buffer, we emit at most | |
* one empty block. | |
*/ | |
} | |
if (bstate == block_done) { | |
if (flush == Z_PARTIAL_FLUSH) { | |
_tr_align(s); | |
} else { /* FULL_FLUSH or SYNC_FLUSH */ | |
_tr_stored_block(s, (char*)0, 0L, 0); | |
/* For a full flush, this empty block will be recognized | |
* as a special marker by inflate_sync(). | |
*/ | |
if (flush == Z_FULL_FLUSH) { | |
CLEAR_HASH(s); /* forget history */ | |
} | |
} | |
flush_pending(strm); | |
if (strm->avail_out == 0) { | |
s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ | |
return Z_OK; | |
} | |
} | |
} | |
Assert(strm->avail_out > 0, "bug2"); | |
if (flush != Z_FINISH) return Z_OK; | |
if (s->wrap <= 0) return Z_STREAM_END; | |
/* Write the trailer */ | |
#ifdef GZIP | |
if (s->wrap == 2) { | |
put_byte(s, (Byte)(strm->adler & 0xff)); | |
put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); | |
put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); | |
put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); | |
put_byte(s, (Byte)(strm->total_in & 0xff)); | |
put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); | |
put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); | |
put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); | |
} | |
else | |
#endif | |
{ | |
putShortMSB(s, (uInt)(strm->adler >> 16)); | |
putShortMSB(s, (uInt)(strm->adler & 0xffff)); | |
} | |
flush_pending(strm); | |
/* If avail_out is zero, the application will call deflate again | |
* to flush the rest. | |
*/ | |
if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ | |
return s->pending != 0 ? Z_OK : Z_STREAM_END; | |
} | |
/* ========================================================================= */ | |
int ZEXPORT deflateEnd (strm) | |
z_streamp strm; | |
{ | |
int status; | |
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
status = strm->state->status; | |
if (status != INIT_STATE && | |
status != EXTRA_STATE && | |
status != NAME_STATE && | |
status != COMMENT_STATE && | |
status != HCRC_STATE && | |
status != BUSY_STATE && | |
status != FINISH_STATE) { | |
return Z_STREAM_ERROR; | |
} | |
/* Deallocate in reverse order of allocations: */ | |
TRY_FREE(strm, strm->state->pending_buf); | |
TRY_FREE(strm, strm->state->head); | |
TRY_FREE(strm, strm->state->prev); | |
TRY_FREE(strm, strm->state->window); | |
ZFREE(strm, strm->state); | |
strm->state = Z_NULL; | |
return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; | |
} | |
/* ========================================================================= | |
* Copy the source state to the destination state. | |
* To simplify the source, this is not supported for 16-bit MSDOS (which | |
* doesn't have enough memory anyway to duplicate compression states). | |
*/ | |
int ZEXPORT deflateCopy (dest, source) | |
z_streamp dest; | |
z_streamp source; | |
{ | |
#ifdef MAXSEG_64K | |
return Z_STREAM_ERROR; | |
#else | |
deflate_state *ds; | |
deflate_state *ss; | |
ushf *overlay; | |
if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { | |
return Z_STREAM_ERROR; | |
} | |
ss = source->state; | |
zmemcpy(dest, source, sizeof(z_stream)); | |
ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); | |
if (ds == Z_NULL) return Z_MEM_ERROR; | |
dest->state = (struct internal_state FAR *) ds; | |
zmemcpy(ds, ss, sizeof(deflate_state)); | |
ds->strm = dest; | |
ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); | |
ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); | |
ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); | |
overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); | |
ds->pending_buf = (uchf *) overlay; | |
if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || | |
ds->pending_buf == Z_NULL) { | |
deflateEnd (dest); | |
return Z_MEM_ERROR; | |
} | |
/* following zmemcpy do not work for 16-bit MSDOS */ | |
zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); | |
zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); | |
zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); | |
zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); | |
ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); | |
ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); | |
ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; | |
ds->l_desc.dyn_tree = ds->dyn_ltree; | |
ds->d_desc.dyn_tree = ds->dyn_dtree; | |
ds->bl_desc.dyn_tree = ds->bl_tree; | |
return Z_OK; | |
#endif /* MAXSEG_64K */ | |
} | |
/* =========================================================================== | |
* Read a new buffer from the current input stream, update the adler32 | |
* and total number of bytes read. All deflate() input goes through | |
* this function so some applications may wish to modify it to avoid | |
* allocating a large strm->next_in buffer and copying from it. | |
* (See also flush_pending()). | |
*/ | |
local int read_buf(strm, buf, size) | |
z_streamp strm; | |
Bytef *buf; | |
unsigned size; | |
{ | |
unsigned len = strm->avail_in; | |
if (len > size) len = size; | |
if (len == 0) return 0; | |
strm->avail_in -= len; | |
if (strm->state->wrap == 1) { | |
strm->adler = adler32(strm->adler, strm->next_in, len); | |
} | |
#ifdef GZIP | |
else if (strm->state->wrap == 2) { | |
strm->adler = crc32(strm->adler, strm->next_in, len); | |
} | |
#endif | |
zmemcpy(buf, strm->next_in, len); | |
strm->next_in += len; | |
strm->total_in += len; | |
return (int)len; | |
} | |
/* =========================================================================== | |
* Initialize the "longest match" routines for a new zlib stream | |
*/ | |
local void lm_init (s) | |
deflate_state *s; | |
{ | |
s->window_size = (ulg)2L*s->w_size; | |
CLEAR_HASH(s); | |
/* Set the default configuration parameters: | |
*/ | |
s->max_lazy_match = configuration_table[s->level].max_lazy; | |
s->good_match = configuration_table[s->level].good_length; | |
s->nice_match = configuration_table[s->level].nice_length; | |
s->max_chain_length = configuration_table[s->level].max_chain; | |
s->strstart = 0; | |
s->block_start = 0L; | |
s->lookahead = 0; | |
s->match_length = s->prev_length = MIN_MATCH-1; | |
s->match_available = 0; | |
s->ins_h = 0; | |
#ifndef FASTEST | |
#ifdef ASMV | |
match_init(); /* initialize the asm code */ | |
#endif | |
#endif | |
} | |
#ifndef FASTEST | |
/* =========================================================================== | |
* Set match_start to the longest match starting at the given string and | |
* return its length. Matches shorter or equal to prev_length are discarded, | |
* in which case the result is equal to prev_length and match_start is | |
* garbage. | |
* IN assertions: cur_match is the head of the hash chain for the current | |
* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 | |
* OUT assertion: the match length is not greater than s->lookahead. | |
*/ | |
#ifndef ASMV | |
/* For 80x86 and 680x0, an optimized version will be provided in match.asm or | |
* match.S. The code will be functionally equivalent. | |
*/ | |
local uInt longest_match(s, cur_match) | |
deflate_state *s; | |
IPos cur_match; /* current match */ | |
{ | |
unsigned chain_length = s->max_chain_length;/* max hash chain length */ | |
register Bytef *scan = s->window + s->strstart; /* current string */ | |
register Bytef *match; /* matched string */ | |
register int len; /* length of current match */ | |
int best_len = s->prev_length; /* best match length so far */ | |
int nice_match = s->nice_match; /* stop if match long enough */ | |
IPos limit = s->strstart > (IPos)MAX_DIST(s) ? | |
s->strstart - (IPos)MAX_DIST(s) : NIL; | |
/* Stop when cur_match becomes <= limit. To simplify the code, | |
* we prevent matches with the string of window index 0. | |
*/ | |
Posf *prev = s->prev; | |
uInt wmask = s->w_mask; | |
#ifdef UNALIGNED_OK | |
/* Compare two bytes at a time. Note: this is not always beneficial. | |
* Try with and without -DUNALIGNED_OK to check. | |
*/ | |
register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; | |
register ush scan_start = *(ushf*)scan; | |
register ush scan_end = *(ushf*)(scan+best_len-1); | |
#else | |
register Bytef *strend = s->window + s->strstart + MAX_MATCH; | |
register Byte scan_end1 = scan[best_len-1]; | |
register Byte scan_end = scan[best_len]; | |
#endif | |
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |
* It is easy to get rid of this optimization if necessary. | |
*/ | |
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | |
/* Do not waste too much time if we already have a good match: */ | |
if (s->prev_length >= s->good_match) { | |
chain_length >>= 2; | |
} | |
/* Do not look for matches beyond the end of the input. This is necessary | |
* to make deflate deterministic. | |
*/ | |
if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; | |
Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | |
do { | |
Assert(cur_match < s->strstart, "no future"); | |
match = s->window + cur_match; | |
/* Skip to next match if the match length cannot increase | |
* or if the match length is less than 2. Note that the checks below | |
* for insufficient lookahead only occur occasionally for performance | |
* reasons. Therefore uninitialized memory will be accessed, and | |
* conditional jumps will be made that depend on those values. | |
* However the length of the match is limited to the lookahead, so | |
* the output of deflate is not affected by the uninitialized values. | |
*/ | |
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258) | |
/* This code assumes sizeof(unsigned short) == 2. Do not use | |
* UNALIGNED_OK if your compiler uses a different size. | |
*/ | |
if (*(ushf*)(match+best_len-1) != scan_end || | |
*(ushf*)match != scan_start) continue; | |
/* It is not necessary to compare scan[2] and match[2] since they are | |
* always equal when the other bytes match, given that the hash keys | |
* are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at | |
* strstart+3, +5, ... up to strstart+257. We check for insufficient | |
* lookahead only every 4th comparison; the 128th check will be made | |
* at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is | |
* necessary to put more guard bytes at the end of the window, or | |
* to check more often for insufficient lookahead. | |
*/ | |
Assert(scan[2] == match[2], "scan[2]?"); | |
scan++, match++; | |
do { | |
} while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
*(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
*(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
*(ushf*)(scan+=2) == *(ushf*)(match+=2) && | |
scan < strend); | |
/* The funny "do {}" generates better code on most compilers */ | |
/* Here, scan <= window+strstart+257 */ | |
Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
if (*scan == *match) scan++; | |
len = (MAX_MATCH - 1) - (int)(strend-scan); | |
scan = strend - (MAX_MATCH-1); | |
#else /* UNALIGNED_OK */ | |
if (match[best_len] != scan_end || | |
match[best_len-1] != scan_end1 || | |
*match != *scan || | |
*++match != scan[1]) continue; | |
/* The check at best_len-1 can be removed because it will be made | |
* again later. (This heuristic is not always a win.) | |
* It is not necessary to compare scan[2] and match[2] since they | |
* are always equal when the other bytes match, given that | |
* the hash keys are equal and that HASH_BITS >= 8. | |
*/ | |
scan += 2, match++; | |
Assert(*scan == *match, "match[2]?"); | |
/* We check for insufficient lookahead only every 8th comparison; | |
* the 256th check will be made at strstart+258. | |
*/ | |
do { | |
} while (*++scan == *++match && *++scan == *++match && | |
*++scan == *++match && *++scan == *++match && | |
*++scan == *++match && *++scan == *++match && | |
*++scan == *++match && *++scan == *++match && | |
scan < strend); | |
Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
len = MAX_MATCH - (int)(strend - scan); | |
scan = strend - MAX_MATCH; | |
#endif /* UNALIGNED_OK */ | |
if (len > best_len) { | |
s->match_start = cur_match; | |
best_len = len; | |
if (len >= nice_match) break; | |
#ifdef UNALIGNED_OK | |
scan_end = *(ushf*)(scan+best_len-1); | |
#else | |
scan_end1 = scan[best_len-1]; | |
scan_end = scan[best_len]; | |
#endif | |
} | |
} while ((cur_match = prev[cur_match & wmask]) > limit | |
&& --chain_length != 0); | |
if ((uInt)best_len <= s->lookahead) return (uInt)best_len; | |
return s->lookahead; | |
} | |
#endif /* ASMV */ | |
#endif /* FASTEST */ | |
/* --------------------------------------------------------------------------- | |
* Optimized version for level == 1 or strategy == Z_RLE only | |
*/ | |
local uInt longest_match_fast(s, cur_match) | |
deflate_state *s; | |
IPos cur_match; /* current match */ | |
{ | |
register Bytef *scan = s->window + s->strstart; /* current string */ | |
register Bytef *match; /* matched string */ | |
register int len; /* length of current match */ | |
register Bytef *strend = s->window + s->strstart + MAX_MATCH; | |
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. | |
* It is easy to get rid of this optimization if necessary. | |
*/ | |
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); | |
Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); | |
Assert(cur_match < s->strstart, "no future"); | |
match = s->window + cur_match; | |
/* Return failure if the match length is less than 2: | |
*/ | |
if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; | |
/* The check at best_len-1 can be removed because it will be made | |
* again later. (This heuristic is not always a win.) | |
* It is not necessary to compare scan[2] and match[2] since they | |
* are always equal when the other bytes match, given that | |
* the hash keys are equal and that HASH_BITS >= 8. | |
*/ | |
scan += 2, match += 2; | |
Assert(*scan == *match, "match[2]?"); | |
/* We check for insufficient lookahead only every 8th comparison; | |
* the 256th check will be made at strstart+258. | |
*/ | |
do { | |
} while (*++scan == *++match && *++scan == *++match && | |
*++scan == *++match && *++scan == *++match && | |
*++scan == *++match && *++scan == *++match && | |
*++scan == *++match && *++scan == *++match && | |
scan < strend); | |
Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); | |
len = MAX_MATCH - (int)(strend - scan); | |
if (len < MIN_MATCH) return MIN_MATCH - 1; | |
s->match_start = cur_match; | |
return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; | |
} | |
#ifdef DEBUG | |
/* =========================================================================== | |
* Check that the match at match_start is indeed a match. | |
*/ | |
local void check_match(s, start, match, length) | |
deflate_state *s; | |
IPos start, match; | |
int length; | |
{ | |
/* check that the match is indeed a match */ | |
if (zmemcmp(s->window + match, | |
s->window + start, length) != EQUAL) { | |
fprintf(stderr, " start %u, match %u, length %d\n", | |
start, match, length); | |
do { | |
fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); | |
} while (--length != 0); | |
z_error("invalid match"); | |
} | |
if (z_verbose > 1) { | |
fprintf(stderr,"\\[%d,%d]", start-match, length); | |
do { putc(s->window[start++], stderr); } while (--length != 0); | |
} | |
} | |
#else | |
# define check_match(s, start, match, length) | |
#endif /* DEBUG */ | |
/* =========================================================================== | |
* Fill the window when the lookahead becomes insufficient. | |
* Updates strstart and lookahead. | |
* | |
* IN assertion: lookahead < MIN_LOOKAHEAD | |
* OUT assertions: strstart <= window_size-MIN_LOOKAHEAD | |
* At least one byte has been read, or avail_in == 0; reads are | |
* performed for at least two bytes (required for the zip translate_eol | |
* option -- not supported here). | |
*/ | |
local void fill_window(s) | |
deflate_state *s; | |
{ | |
register unsigned n, m; | |
register Posf *p; | |
unsigned more; /* Amount of free space at the end of the window. */ | |
uInt wsize = s->w_size; | |
do { | |
more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); | |
/* Deal with !@#$% 64K limit: */ | |
if (sizeof(int) <= 2) { | |
if (more == 0 && s->strstart == 0 && s->lookahead == 0) { | |
more = wsize; | |
} else if (more == (unsigned)(-1)) { | |
/* Very unlikely, but possible on 16 bit machine if | |
* strstart == 0 && lookahead == 1 (input done a byte at time) | |
*/ | |
more--; | |
} | |
} | |
/* If the window is almost full and there is insufficient lookahead, | |
* move the upper half to the lower one to make room in the upper half. | |
*/ | |
if (s->strstart >= wsize+MAX_DIST(s)) { | |
zmemcpy(s->window, s->window+wsize, (unsigned)wsize); | |
s->match_start -= wsize; | |
s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ | |
s->block_start -= (long) wsize; | |
/* Slide the hash table (could be avoided with 32 bit values | |
at the expense of memory usage). We slide even when level == 0 | |
to keep the hash table consistent if we switch back to level > 0 | |
later. (Using level 0 permanently is not an optimal usage of | |
zlib, so we don't care about this pathological case.) | |
*/ | |
/* %%% avoid this when Z_RLE */ | |
n = s->hash_size; | |
p = &s->head[n]; | |
do { | |
m = *--p; | |
*p = (Pos)(m >= wsize ? m-wsize : NIL); | |
} while (--n); | |
n = wsize; | |
#ifndef FASTEST | |
p = &s->prev[n]; | |
do { | |
m = *--p; | |
*p = (Pos)(m >= wsize ? m-wsize : NIL); | |
/* If n is not on any hash chain, prev[n] is garbage but | |
* its value will never be used. | |
*/ | |
} while (--n); | |
#endif | |
more += wsize; | |
} | |
if (s->strm->avail_in == 0) return; | |
/* If there was no sliding: | |
* strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && | |
* more == window_size - lookahead - strstart | |
* => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) | |
* => more >= window_size - 2*WSIZE + 2 | |
* In the BIG_MEM or MMAP case (not yet supported), | |
* window_size == input_size + MIN_LOOKAHEAD && | |
* strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. | |
* Otherwise, window_size == 2*WSIZE so more >= 2. | |
* If there was sliding, more >= WSIZE. So in all cases, more >= 2. | |
*/ | |
Assert(more >= 2, "more < 2"); | |
n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); | |
s->lookahead += n; | |
/* Initialize the hash value now that we have some input: */ | |
if (s->lookahead >= MIN_MATCH) { | |
s->ins_h = s->window[s->strstart]; | |
UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); | |
#if MIN_MATCH != 3 | |
Call UPDATE_HASH() MIN_MATCH-3 more times | |
#endif | |
} | |
/* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, | |
* but this is not important since only literal bytes will be emitted. | |
*/ | |
} while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); | |
} | |
/* =========================================================================== | |
* Flush the current block, with given end-of-file flag. | |
* IN assertion: strstart is set to the end of the current match. | |
*/ | |
#define FLUSH_BLOCK_ONLY(s, eof) { \ | |
_tr_flush_block(s, (s->block_start >= 0L ? \ | |
(charf *)&s->window[(unsigned)s->block_start] : \ | |
(charf *)Z_NULL), \ | |
(ulg)((long)s->strstart - s->block_start), \ | |
(eof)); \ | |
s->block_start = s->strstart; \ | |
flush_pending(s->strm); \ | |
Tracev((stderr,"[FLUSH]")); \ | |
} | |
/* Same but force premature exit if necessary. */ | |
#define FLUSH_BLOCK(s, eof) { \ | |
FLUSH_BLOCK_ONLY(s, eof); \ | |
if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \ | |
} | |
/* =========================================================================== | |
* Copy without compression as much as possible from the input stream, return | |
* the current block state. | |
* This function does not insert new strings in the dictionary since | |
* uncompressible data is probably not useful. This function is used | |
* only for the level=0 compression option. | |
* NOTE: this function should be optimized to avoid extra copying from | |
* window to pending_buf. | |
*/ | |
local block_state deflate_stored(s, flush) | |
deflate_state *s; | |
int flush; | |
{ | |
/* Stored blocks are limited to 0xffff bytes, pending_buf is limited | |
* to pending_buf_size, and each stored block has a 5 byte header: | |
*/ | |
ulg max_block_size = 0xffff; | |
ulg max_start; | |
if (max_block_size > s->pending_buf_size - 5) { | |
max_block_size = s->pending_buf_size - 5; | |
} | |
/* Copy as much as possible from input to output: */ | |
for (;;) { | |
/* Fill the window as much as possible: */ | |
if (s->lookahead <= 1) { | |
Assert(s->strstart < s->w_size+MAX_DIST(s) || | |
s->block_start >= (long)s->w_size, "slide too late"); | |
fill_window(s); | |
if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; | |
if (s->lookahead == 0) break; /* flush the current block */ | |
} | |
Assert(s->block_start >= 0L, "block gone"); | |
s->strstart += s->lookahead; | |
s->lookahead = 0; | |
/* Emit a stored block if pending_buf will be full: */ | |
max_start = s->block_start + max_block_size; | |
if (s->strstart == 0 || (ulg)s->strstart >= max_start) { | |
/* strstart == 0 is possible when wraparound on 16-bit machine */ | |
s->lookahead = (uInt)(s->strstart - max_start); | |
s->strstart = (uInt)max_start; | |
FLUSH_BLOCK(s, 0); | |
} | |
/* Flush if we may have to slide, otherwise block_start may become | |
* negative and the data will be gone: | |
*/ | |
if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { | |
FLUSH_BLOCK(s, 0); | |
} | |
} | |
FLUSH_BLOCK(s, flush == Z_FINISH); | |
return flush == Z_FINISH ? finish_done : block_done; | |
} | |
/* =========================================================================== | |
* Compress as much as possible from the input stream, return the current | |
* block state. | |
* This function does not perform lazy evaluation of matches and inserts | |
* new strings in the dictionary only for unmatched strings or for short | |
* matches. It is used only for the fast compression options. | |
*/ | |
local block_state deflate_fast(s, flush) | |
deflate_state *s; | |
int flush; | |
{ | |
IPos hash_head = NIL; /* head of the hash chain */ | |
int bflush; /* set if current block must be flushed */ | |
for (;;) { | |
/* Make sure that we always have enough lookahead, except | |
* at the end of the input file. We need MAX_MATCH bytes | |
* for the next match, plus MIN_MATCH bytes to insert the | |
* string following the next match. | |
*/ | |
if (s->lookahead < MIN_LOOKAHEAD) { | |
fill_window(s); | |
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | |
return need_more; | |
} | |
if (s->lookahead == 0) break; /* flush the current block */ | |
} | |
/* Insert the string window[strstart .. strstart+2] in the | |
* dictionary, and set hash_head to the head of the hash chain: | |
*/ | |
if (s->lookahead >= MIN_MATCH) { | |
INSERT_STRING(s, s->strstart, hash_head); | |
} | |
/* Find the longest match, discarding those <= prev_length. | |
* At this point we have always match_length < MIN_MATCH | |
*/ | |
if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { | |
/* To simplify the code, we prevent matches with the string | |
* of window index 0 (in particular we have to avoid a match | |
* of the string with itself at the start of the input file). | |
*/ | |
#ifdef FASTEST | |
if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) || | |
(s->strategy == Z_RLE && s->strstart - hash_head == 1)) { | |
s->match_length = longest_match_fast (s, hash_head); | |
} | |
#else | |
if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { | |
s->match_length = longest_match (s, hash_head); | |
} else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { | |
s->match_length = longest_match_fast (s, hash_head); | |
} | |
#endif | |
/* longest_match() or longest_match_fast() sets match_start */ | |
} | |
if (s->match_length >= MIN_MATCH) { | |
check_match(s, s->strstart, s->match_start, s->match_length); | |
_tr_tally_dist(s, s->strstart - s->match_start, | |
s->match_length - MIN_MATCH, bflush); | |
s->lookahead -= s->match_length; | |
/* Insert new strings in the hash table only if the match length | |
* is not too large. This saves time but degrades compression. | |
*/ | |
#ifndef FASTEST | |
if (s->match_length <= s->max_insert_length && | |
s->lookahead >= MIN_MATCH) { | |
s->match_length--; /* string at strstart already in table */ | |
do { | |
s->strstart++; | |
INSERT_STRING(s, s->strstart, hash_head); | |
/* strstart never exceeds WSIZE-MAX_MATCH, so there are | |
* always MIN_MATCH bytes ahead. | |
*/ | |
} while (--s->match_length != 0); | |
s->strstart++; | |
} else | |
#endif | |
{ | |
s->strstart += s->match_length; | |
s->match_length = 0; | |
s->ins_h = s->window[s->strstart]; | |
UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); | |
#if MIN_MATCH != 3 | |
Call UPDATE_HASH() MIN_MATCH-3 more times | |
#endif | |
/* If lookahead < MIN_MATCH, ins_h is garbage, but it does not | |
* matter since it will be recomputed at next deflate call. | |
*/ | |
} | |
} else { | |
/* No match, output a literal byte */ | |
Tracevv((stderr,"%c", s->window[s->strstart])); | |
_tr_tally_lit (s, s->window[s->strstart], bflush); | |
s->lookahead--; | |
s->strstart++; | |
} | |
if (bflush) FLUSH_BLOCK(s, 0); | |
} | |
FLUSH_BLOCK(s, flush == Z_FINISH); | |
return flush == Z_FINISH ? finish_done : block_done; | |
} | |
#ifndef FASTEST | |
/* =========================================================================== | |
* Same as above, but achieves better compression. We use a lazy | |
* evaluation for matches: a match is finally adopted only if there is | |
* no better match at the next window position. | |
*/ | |
local block_state deflate_slow(s, flush) | |
deflate_state *s; | |
int flush; | |
{ | |
IPos hash_head = NIL; /* head of hash chain */ | |
int bflush; /* set if current block must be flushed */ | |
/* Process the input block. */ | |
for (;;) { | |
/* Make sure that we always have enough lookahead, except | |
* at the end of the input file. We need MAX_MATCH bytes | |
* for the next match, plus MIN_MATCH bytes to insert the | |
* string following the next match. | |
*/ | |
if (s->lookahead < MIN_LOOKAHEAD) { | |
fill_window(s); | |
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { | |
return need_more; | |
} | |
if (s->lookahead == 0) break; /* flush the current block */ | |
} | |
/* Insert the string window[strstart .. strstart+2] in the | |
* dictionary, and set hash_head to the head of the hash chain: | |
*/ | |
if (s->lookahead >= MIN_MATCH) { | |
INSERT_STRING(s, s->strstart, hash_head); | |
} | |
/* Find the longest match, discarding those <= prev_length. | |
*/ | |
s->prev_length = s->match_length, s->prev_match = s->match_start; | |
s->match_length = MIN_MATCH-1; | |
if (hash_head != NIL && s->prev_length < s->max_lazy_match && | |
s->strstart - hash_head <= MAX_DIST(s)) { | |
/* To simplify the code, we prevent matches with the string | |
* of window index 0 (in particular we have to avoid a match | |
* of the string with itself at the start of the input file). | |
*/ | |
if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) { | |
s->match_length = longest_match (s, hash_head); | |
} else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { | |
s->match_length = longest_match_fast (s, hash_head); | |
} | |
/* longest_match() or longest_match_fast() sets match_start */ | |
if (s->match_length <= 5 && (s->strategy == Z_FILTERED | |
#if TOO_FAR <= 32767 | |
|| (s->match_length == MIN_MATCH && | |
s->strstart - s->match_start > TOO_FAR) | |
#endif | |
)) { | |
/* If prev_match is also MIN_MATCH, match_start is garbage | |
* but we will ignore the current match anyway. | |
*/ | |
s->match_length = MIN_MATCH-1; | |
} | |
} | |
/* If there was a match at the previous step and the current | |
* match is not better, output the previous match: | |
*/ | |
if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { | |
uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; | |
/* Do not insert strings in hash table beyond this. */ | |
check_match(s, s->strstart-1, s->prev_match, s->prev_length); | |
_tr_tally_dist(s, s->strstart -1 - s->prev_match, | |
s->prev_length - MIN_MATCH, bflush); | |
/* Insert in hash table all strings up to the end of the match. | |
* strstart-1 and strstart are already inserted. If there is not | |
* enough lookahead, the last two strings are not inserted in | |
* the hash table. | |
*/ | |
s->lookahead -= s->prev_length-1; | |
s->prev_length -= 2; | |
do { | |
if (++s->strstart <= max_insert) { | |
INSERT_STRING(s, s->strstart, hash_head); | |
} | |
} while (--s->prev_length != 0); | |
s->match_available = 0; | |
s->match_length = MIN_MATCH-1; | |
s->strstart++; | |
if (bflush) FLUSH_BLOCK(s, 0); | |
} else if (s->match_available) { | |
/* If there was no match at the previous position, output a | |
* single literal. If there was a match but the current match | |
* is longer, truncate the previous match to a single literal. | |
*/ | |
Tracevv((stderr,"%c", s->window[s->strstart-1])); | |
_tr_tally_lit(s, s->window[s->strstart-1], bflush); | |
if (bflush) { | |
FLUSH_BLOCK_ONLY(s, 0); | |
} | |
s->strstart++; | |
s->lookahead--; | |
if (s->strm->avail_out == 0) return need_more; | |
} else { | |
/* There is no previous match to compare with, wait for | |
* the next step to decide. | |
*/ | |
s->match_available = 1; | |
s->strstart++; | |
s->lookahead--; | |
} | |
} | |
Assert (flush != Z_NO_FLUSH, "no flush?"); | |
if (s->match_available) { | |
Tracevv((stderr,"%c", s->window[s->strstart-1])); | |
_tr_tally_lit(s, s->window[s->strstart-1], bflush); | |
s->match_available = 0; | |
} | |
FLUSH_BLOCK(s, flush == Z_FINISH); | |
return flush == Z_FINISH ? finish_done : block_done; | |
} | |
#endif /* FASTEST */ | |
#if 0 | |
/* =========================================================================== | |
* For Z_RLE, simply look for runs of bytes, generate matches only of distance | |
* one. Do not maintain a hash table. (It will be regenerated if this run of | |
* deflate switches away from Z_RLE.) | |
*/ | |
local block_state deflate_rle(s, flush) | |
deflate_state *s; | |
int flush; | |
{ | |
int bflush; /* set if current block must be flushed */ | |
uInt run; /* length of run */ | |
uInt max; /* maximum length of run */ | |
uInt prev; /* byte at distance one to match */ | |
Bytef *scan; /* scan for end of run */ | |
for (;;) { | |
/* Make sure that we always have enough lookahead, except | |
* at the end of the input file. We need MAX_MATCH bytes | |
* for the longest encodable run. | |
*/ | |
if (s->lookahead < MAX_MATCH) { | |
fill_window(s); | |
if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) { | |
return need_more; | |
} | |
if (s->lookahead == 0) break; /* flush the current block */ | |
} | |
/* See how many times the previous byte repeats */ | |
run = 0; | |
if (s->strstart > 0) { /* if there is a previous byte, that is */ | |
max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH; | |
scan = s->window + s->strstart - 1; | |
prev = *scan++; | |
do { | |
if (*scan++ != prev) | |
break; | |
} while (++run < max); | |
} | |
/* Emit match if have run of MIN_MATCH or longer, else emit literal */ | |
if (run >= MIN_MATCH) { | |
check_match(s, s->strstart, s->strstart - 1, run); | |
_tr_tally_dist(s, 1, run - MIN_MATCH, bflush); | |
s->lookahead -= run; | |
s->strstart += run; | |
} else { | |
/* No match, output a literal byte */ | |
Tracevv((stderr,"%c", s->window[s->strstart])); | |
_tr_tally_lit (s, s->window[s->strstart], bflush); | |
s->lookahead--; | |
s->strstart++; | |
} | |
if (bflush) FLUSH_BLOCK(s, 0); | |
} | |
FLUSH_BLOCK(s, flush == Z_FINISH); | |
return flush == Z_FINISH ? finish_done : block_done; | |
} | |
#endif |