cximage/src/tiff/tif_dirinfo.c - toolchain/benchmark - Git at Google

 /* $Header: /cvsroot/osrs/libtiff/libtiff/tif_dirinfo.c,v 1.8 2001/05/09 01:33:16 warmerda Exp $ */

 /*
  * Copyright (c) 1988-1997 Sam Leffler
  * Copyright (c) 1991-1997 Silicon Graphics, Inc.
  *
  * Permission to use, copy, modify, distribute, and sell this software and
  * its documentation for any purpose is hereby granted without fee, provided
  * that (i) the above copyright notices and this permission notice appear in
  * all copies of the software and related documentation, and (ii) the names of
  * Sam Leffler and Silicon Graphics may not be used in any advertising or
  * publicity relating to the software without the specific, prior written
  * permission of Sam Leffler and Silicon Graphics.
  *
  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  *
  * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  * OF THIS SOFTWARE.
  */

 /*
  * TIFF Library.
  *
  * Core Directory Tag Support.
  */
 #include "tiffiop.h"
 #include <stdlib.h>

 /*
  * NB: NB: THIS ARRAY IS ASSUMED TO BE SORTED BY TAG.
  *     If a tag can have both LONG and SHORT types
  *     then the LONG must be placed before the SHORT for
  *     writing to work properly.
  *
  * NOTE: The second field (field_readcount) and third field (field_writecount)
  *       sometimes use the values TIFF_VARIABLE (-1), TIFF_VARIABLE2 (-3)
  *       and TIFFTAG_SPP (-2). The macros should be used but would throw off
  *       the formatting of the code, so please interprete the -1, -2 and -3
  *       values accordingly.
  */
 #ifndef VMS
 static
 #endif
 const TIFFFieldInfo tiffFieldInfo[] = {
     { TIFFTAG_SUBFILETYPE,	 1, 1, TIFF_LONG,	FIELD_SUBFILETYPE,
       TRUE,	FALSE,	"SubfileType" },
 /* XXX SHORT for compatibility w/ old versions of the library */
     { TIFFTAG_SUBFILETYPE,	 1, 1, TIFF_SHORT,	FIELD_SUBFILETYPE,
       TRUE,	FALSE,	"SubfileType" },
     { TIFFTAG_OSUBFILETYPE,	 1, 1, TIFF_SHORT,	FIELD_SUBFILETYPE,
       TRUE,	FALSE,	"OldSubfileType" },
     { TIFFTAG_IMAGEWIDTH,	 1, 1, TIFF_LONG,	FIELD_IMAGEDIMENSIONS,
       FALSE,	FALSE,	"ImageWidth" },
     { TIFFTAG_IMAGEWIDTH,	 1, 1, TIFF_SHORT,	FIELD_IMAGEDIMENSIONS,
       FALSE,	FALSE,	"ImageWidth" },
     { TIFFTAG_IMAGELENGTH,	 1, 1, TIFF_LONG,	FIELD_IMAGEDIMENSIONS,
       TRUE,	FALSE,	"ImageLength" },
     { TIFFTAG_IMAGELENGTH,	 1, 1, TIFF_SHORT,	FIELD_IMAGEDIMENSIONS,
       TRUE,	FALSE,	"ImageLength" },
     { TIFFTAG_BITSPERSAMPLE,	-1,-1, TIFF_SHORT,	FIELD_BITSPERSAMPLE,
       FALSE,	FALSE,	"BitsPerSample" },
     { TIFFTAG_COMPRESSION,	-1, 1, TIFF_SHORT,	FIELD_COMPRESSION,
       FALSE,	FALSE,	"Compression" },
     { TIFFTAG_PHOTOMETRIC,	 1, 1, TIFF_SHORT,	FIELD_PHOTOMETRIC,
       FALSE,	FALSE,	"PhotometricInterpretation" },
     { TIFFTAG_THRESHHOLDING,	 1, 1, TIFF_SHORT,	FIELD_THRESHHOLDING,
       TRUE,	FALSE,	"Threshholding" },
     { TIFFTAG_CELLWIDTH,	 1, 1, TIFF_SHORT,	FIELD_IGNORE,
       TRUE,	FALSE,	"CellWidth" },
     { TIFFTAG_CELLLENGTH,	 1, 1, TIFF_SHORT,	FIELD_IGNORE,
       TRUE,	FALSE,	"CellLength" },
     { TIFFTAG_FILLORDER,	 1, 1, TIFF_SHORT,	FIELD_FILLORDER,
       FALSE,	FALSE,	"FillOrder" },
     { TIFFTAG_DOCUMENTNAME,	-1,-1, TIFF_ASCII,	FIELD_DOCUMENTNAME,
       TRUE,	FALSE,	"DocumentName" },
     { TIFFTAG_IMAGEDESCRIPTION,	-1,-1, TIFF_ASCII,	FIELD_IMAGEDESCRIPTION,
       TRUE,	FALSE,	"ImageDescription" },
     { TIFFTAG_MAKE,		-1,-1, TIFF_ASCII,	FIELD_MAKE,
       TRUE,	FALSE,	"Make" },
     { TIFFTAG_MODEL,		-1,-1, TIFF_ASCII,	FIELD_MODEL,
       TRUE,	FALSE,	"Model" },
     { TIFFTAG_STRIPOFFSETS,	-1,-1, TIFF_LONG,	FIELD_STRIPOFFSETS,
       FALSE,	FALSE,	"StripOffsets" },
     { TIFFTAG_STRIPOFFSETS,	-1,-1, TIFF_SHORT,	FIELD_STRIPOFFSETS,
       FALSE,	FALSE,	"StripOffsets" },
     { TIFFTAG_ORIENTATION,	 1, 1, TIFF_SHORT,	FIELD_ORIENTATION,
       FALSE,	FALSE,	"Orientation" },
     { TIFFTAG_SAMPLESPERPIXEL,	 1, 1, TIFF_SHORT,	FIELD_SAMPLESPERPIXEL,
       FALSE,	FALSE,	"SamplesPerPixel" },
     { TIFFTAG_ROWSPERSTRIP,	 1, 1, TIFF_LONG,	FIELD_ROWSPERSTRIP,
       FALSE,	FALSE,	"RowsPerStrip" },
     { TIFFTAG_ROWSPERSTRIP,	 1, 1, TIFF_SHORT,	FIELD_ROWSPERSTRIP,
       FALSE,	FALSE,	"RowsPerStrip" },
     { TIFFTAG_STRIPBYTECOUNTS,	-1,-1, TIFF_LONG,	FIELD_STRIPBYTECOUNTS,
       FALSE,	FALSE,	"StripByteCounts" },
     { TIFFTAG_STRIPBYTECOUNTS,	-1,-1, TIFF_SHORT,	FIELD_STRIPBYTECOUNTS,
       FALSE,	FALSE,	"StripByteCounts" },
     { TIFFTAG_MINSAMPLEVALUE,	-2,-1, TIFF_SHORT,	FIELD_MINSAMPLEVALUE,
       TRUE,	FALSE,	"MinSampleValue" },
     { TIFFTAG_MAXSAMPLEVALUE,	-2,-1, TIFF_SHORT,	FIELD_MAXSAMPLEVALUE,
       TRUE,	FALSE,	"MaxSampleValue" },
     { TIFFTAG_XRESOLUTION,	 1, 1, TIFF_RATIONAL,	FIELD_RESOLUTION,
       FALSE,	FALSE,	"XResolution" },
     { TIFFTAG_YRESOLUTION,	 1, 1, TIFF_RATIONAL,	FIELD_RESOLUTION,
       FALSE,	FALSE,	"YResolution" },
     { TIFFTAG_PLANARCONFIG,	 1, 1, TIFF_SHORT,	FIELD_PLANARCONFIG,
       FALSE,	FALSE,	"PlanarConfiguration" },
     { TIFFTAG_PAGENAME,		-1,-1, TIFF_ASCII,	FIELD_PAGENAME,
       TRUE,	FALSE,	"PageName" },
     { TIFFTAG_XPOSITION,	 1, 1, TIFF_RATIONAL,	FIELD_POSITION,
       TRUE,	FALSE,	"XPosition" },
     { TIFFTAG_YPOSITION,	 1, 1, TIFF_RATIONAL,	FIELD_POSITION,
       TRUE,	FALSE,	"YPosition" },
     { TIFFTAG_FREEOFFSETS,	-1,-1, TIFF_LONG,	FIELD_IGNORE,
       FALSE,	FALSE,	"FreeOffsets" },
     { TIFFTAG_FREEBYTECOUNTS,	-1,-1, TIFF_LONG,	FIELD_IGNORE,
       FALSE,	FALSE,	"FreeByteCounts" },
     { TIFFTAG_GRAYRESPONSEUNIT,	 1, 1, TIFF_SHORT,	FIELD_IGNORE,
       TRUE,	FALSE,	"GrayResponseUnit" },
     { TIFFTAG_GRAYRESPONSECURVE,-1,-1, TIFF_SHORT,	FIELD_IGNORE,
       TRUE,	FALSE,	"GrayResponseCurve" },
     { TIFFTAG_RESOLUTIONUNIT,	 1, 1, TIFF_SHORT,	FIELD_RESOLUTIONUNIT,
       FALSE,	FALSE,	"ResolutionUnit" },
     { TIFFTAG_PAGENUMBER,	 2, 2, TIFF_SHORT,	FIELD_PAGENUMBER,
       TRUE,	FALSE,	"PageNumber" },
     { TIFFTAG_COLORRESPONSEUNIT, 1, 1, TIFF_SHORT,	FIELD_IGNORE,
       TRUE,	FALSE,	"ColorResponseUnit" },
 #ifdef COLORIMETRY_SUPPORT
     { TIFFTAG_TRANSFERFUNCTION,	-1,-1, TIFF_SHORT,	FIELD_TRANSFERFUNCTION,
       TRUE,	FALSE,	"TransferFunction" },
 #endif
     { TIFFTAG_SOFTWARE,		-1,-1, TIFF_ASCII,	FIELD_SOFTWARE,
       TRUE,	FALSE,	"Software" },
     { TIFFTAG_DATETIME,		20,20, TIFF_ASCII,	FIELD_DATETIME,
       TRUE,	FALSE,	"DateTime" },
     { TIFFTAG_ARTIST,		-1,-1, TIFF_ASCII,	FIELD_ARTIST,
       TRUE,	FALSE,	"Artist" },
     { TIFFTAG_HOSTCOMPUTER,	-1,-1, TIFF_ASCII,	FIELD_HOSTCOMPUTER,
       TRUE,	FALSE,	"HostComputer" },
 #ifdef COLORIMETRY_SUPPORT
     { TIFFTAG_WHITEPOINT,	 2, 2, TIFF_RATIONAL,FIELD_WHITEPOINT,
       TRUE,	FALSE,	"WhitePoint" },
     { TIFFTAG_PRIMARYCHROMATICITIES,6,6,TIFF_RATIONAL,FIELD_PRIMARYCHROMAS,
       TRUE,	FALSE,	"PrimaryChromaticities" },
 #endif
     { TIFFTAG_COLORMAP,		-1,-1, TIFF_SHORT,	FIELD_COLORMAP,
       TRUE,	FALSE,	"ColorMap" },
     { TIFFTAG_HALFTONEHINTS,	 2, 2, TIFF_SHORT,	FIELD_HALFTONEHINTS,
       TRUE,	FALSE,	"HalftoneHints" },
     { TIFFTAG_TILEWIDTH,	 1, 1, TIFF_LONG,	FIELD_TILEDIMENSIONS,
       FALSE,	FALSE,	"TileWidth" },
     { TIFFTAG_TILEWIDTH,	 1, 1, TIFF_SHORT,	FIELD_TILEDIMENSIONS,
       FALSE,	FALSE,	"TileWidth" },
     { TIFFTAG_TILELENGTH,	 1, 1, TIFF_LONG,	FIELD_TILEDIMENSIONS,
       FALSE,	FALSE,	"TileLength" },
     { TIFFTAG_TILELENGTH,	 1, 1, TIFF_SHORT,	FIELD_TILEDIMENSIONS,
       FALSE,	FALSE,	"TileLength" },
     { TIFFTAG_TILEOFFSETS,	-1, 1, TIFF_LONG,	FIELD_STRIPOFFSETS,
       FALSE,	FALSE,	"TileOffsets" },
     { TIFFTAG_TILEBYTECOUNTS,	-1, 1, TIFF_LONG,	FIELD_STRIPBYTECOUNTS,
       FALSE,	FALSE,	"TileByteCounts" },
     { TIFFTAG_TILEBYTECOUNTS,	-1, 1, TIFF_SHORT,	FIELD_STRIPBYTECOUNTS,
       FALSE,	FALSE,	"TileByteCounts" },
 #ifdef TIFFTAG_SUBIFD
     { TIFFTAG_SUBIFD,		-1,-1, TIFF_LONG,	FIELD_SUBIFD,
       TRUE,	TRUE,	"SubIFD" },
 #endif
 #ifdef CMYK_SUPPORT		/* 6.0 CMYK tags */
     { TIFFTAG_INKSET,		 1, 1, TIFF_SHORT,	FIELD_INKSET,
       FALSE,	FALSE,	"InkSet" },
     { TIFFTAG_INKNAMES,		-1,-1, TIFF_ASCII,	FIELD_INKNAMES,
       TRUE,	TRUE,	"InkNames" },
     { TIFFTAG_NUMBEROFINKS,	 1, 1, TIFF_SHORT,	FIELD_NUMBEROFINKS,
       TRUE,	FALSE,	"NumberOfInks" },
     { TIFFTAG_DOTRANGE,		 2, 2, TIFF_SHORT,	FIELD_DOTRANGE,
       FALSE,	FALSE,	"DotRange" },
     { TIFFTAG_DOTRANGE,		 2, 2, TIFF_BYTE,	FIELD_DOTRANGE,
       FALSE,	FALSE,	"DotRange" },
     { TIFFTAG_TARGETPRINTER,	-1,-1, TIFF_ASCII,	FIELD_TARGETPRINTER,
       TRUE,	FALSE,	"TargetPrinter" },
 #endif
     { TIFFTAG_EXTRASAMPLES,	-1,-1, TIFF_SHORT,	FIELD_EXTRASAMPLES,
       FALSE,	FALSE,	"ExtraSamples" },
 /* XXX for bogus Adobe Photoshop v2.5 files */
     { TIFFTAG_EXTRASAMPLES,	-1,-1, TIFF_BYTE,	FIELD_EXTRASAMPLES,
       FALSE,	FALSE,	"ExtraSamples" },
     { TIFFTAG_SAMPLEFORMAT,	-1,-1, TIFF_SHORT,	FIELD_SAMPLEFORMAT,
       FALSE,	FALSE,	"SampleFormat" },
     { TIFFTAG_SMINSAMPLEVALUE,	-2,-1, TIFF_ANY,	FIELD_SMINSAMPLEVALUE,
       TRUE,	FALSE,	"SMinSampleValue" },
     { TIFFTAG_SMAXSAMPLEVALUE,	-2,-1, TIFF_ANY,	FIELD_SMAXSAMPLEVALUE,
       TRUE,	FALSE,	"SMaxSampleValue" },
 #ifdef YCBCR_SUPPORT		/* 6.0 YCbCr tags */
     { TIFFTAG_YCBCRCOEFFICIENTS, 3, 3, TIFF_RATIONAL,	FIELD_YCBCRCOEFFICIENTS,
       FALSE,	FALSE,	"YCbCrCoefficients" },
     { TIFFTAG_YCBCRSUBSAMPLING,	 2, 2, TIFF_SHORT,	FIELD_YCBCRSUBSAMPLING,
       FALSE,	FALSE,	"YCbCrSubsampling" },
     { TIFFTAG_YCBCRPOSITIONING,	 1, 1, TIFF_SHORT,	FIELD_YCBCRPOSITIONING,
       FALSE,	FALSE,	"YCbCrPositioning" },
 #endif
 #ifdef COLORIMETRY_SUPPORT
     { TIFFTAG_REFERENCEBLACKWHITE,6,6,TIFF_RATIONAL,	FIELD_REFBLACKWHITE,
       TRUE,	FALSE,	"ReferenceBlackWhite" },
 /* XXX temporarily accept LONG for backwards compatibility */
     { TIFFTAG_REFERENCEBLACKWHITE,6,6,TIFF_LONG,	FIELD_REFBLACKWHITE,
       TRUE,	FALSE,	"ReferenceBlackWhite" },
 #endif
 /* begin SGI tags */
     { TIFFTAG_MATTEING,		 1, 1, TIFF_SHORT,	FIELD_EXTRASAMPLES,
       FALSE,	FALSE,	"Matteing" },
     { TIFFTAG_DATATYPE,		-2,-1, TIFF_SHORT,	FIELD_SAMPLEFORMAT,
       FALSE,	FALSE,	"DataType" },
     { TIFFTAG_IMAGEDEPTH,	 1, 1, TIFF_LONG,	FIELD_IMAGEDEPTH,
       FALSE,	FALSE,	"ImageDepth" },
     { TIFFTAG_IMAGEDEPTH,	 1, 1, TIFF_SHORT,	FIELD_IMAGEDEPTH,
       FALSE,	FALSE,	"ImageDepth" },
     { TIFFTAG_TILEDEPTH,	 1, 1, TIFF_LONG,	FIELD_TILEDEPTH,
       FALSE,	FALSE,	"TileDepth" },
     { TIFFTAG_TILEDEPTH,	 1, 1, TIFF_SHORT,	FIELD_TILEDEPTH,
       FALSE,	FALSE,	"TileDepth" },
 /* end SGI tags */
 /* begin Pixar tags */
     { TIFFTAG_PIXAR_IMAGEFULLWIDTH,  1, 1, TIFF_LONG,	FIELD_IMAGEFULLWIDTH,
       TRUE,	FALSE,	"ImageFullWidth" },
     { TIFFTAG_PIXAR_IMAGEFULLLENGTH, 1, 1, TIFF_LONG,	FIELD_IMAGEFULLLENGTH,
       TRUE,	FALSE,	"ImageFullLength" },
     { TIFFTAG_PIXAR_TEXTUREFORMAT,  -1,-1, TIFF_ASCII,	FIELD_TEXTUREFORMAT,
       TRUE,	FALSE,	"TextureFormat" },
     { TIFFTAG_PIXAR_WRAPMODES,	    -1,-1, TIFF_ASCII,	FIELD_WRAPMODES,
       TRUE,	FALSE,	"TextureWrapModes" },
     { TIFFTAG_PIXAR_FOVCOT,	     1, 1, TIFF_FLOAT,	FIELD_FOVCOT,
       TRUE,	FALSE,	"FieldOfViewCotan" },
     { TIFFTAG_PIXAR_MATRIX_WORLDTOSCREEN,	16,16,	TIFF_FLOAT,
       FIELD_MATRIX_WORLDTOSCREEN,	TRUE,	FALSE,	"MatrixWorldToScreen" },
     { TIFFTAG_PIXAR_MATRIX_WORLDTOCAMERA,	16,16,	TIFF_FLOAT,
        FIELD_MATRIX_WORLDTOCAMERA,	TRUE,	FALSE,	"MatrixWorldToCamera" },
     { TIFFTAG_COPYRIGHT,	-1,-1, TIFF_ASCII,	FIELD_COPYRIGHT,
       TRUE,	FALSE,	"Copyright" },
 /* end Pixar tags */
 #ifdef IPTC_SUPPORT
 #ifdef PHOTOSHOP_SUPPORT
     { TIFFTAG_RICHTIFFIPTC, -1,-1, TIFF_LONG,   FIELD_RICHTIFFIPTC,
       FALSE,    TRUE,   "RichTIFFIPTC" },
 #else
     { TIFFTAG_RICHTIFFIPTC, -1,-3, TIFF_UNDEFINED, FIELD_RICHTIFFIPTC,
       FALSE,    TRUE,   "RichTIFFIPTC" },
 #endif
 #endif
 #ifdef PHOTOSHOP_SUPPORT
     { TIFFTAG_PHOTOSHOP,    -1,-3, TIFF_BYTE,   FIELD_PHOTOSHOP,
       FALSE,    TRUE,   "Photoshop" },
 #endif
 #ifdef ICC_SUPPORT
     { TIFFTAG_ICCPROFILE,	-1,-3, TIFF_UNDEFINED,	FIELD_ICCPROFILE,
       FALSE,	TRUE,	"ICC Profile" },
 #endif
     { TIFFTAG_STONITS,		 1, 1, TIFF_DOUBLE,	FIELD_STONITS,
       FALSE,	FALSE,	"StoNits" },
 };
 #define	N(a)	(sizeof (a) / sizeof (a[0]))

 void
 _TIFFSetupFieldInfo(TIFF* tif)
 {
 	if (tif->tif_fieldinfo) {
 		_TIFFfree(tif->tif_fieldinfo);
 		tif->tif_nfields = 0;
 	}
 	_TIFFMergeFieldInfo(tif, tiffFieldInfo, N(tiffFieldInfo));
 }

 static int
 tagCompare(const void* a, const void* b)
 {
 	const TIFFFieldInfo* ta = *(const TIFFFieldInfo**) a;
 	const TIFFFieldInfo* tb = *(const TIFFFieldInfo**) b;
 	/* NB: be careful of return values for 16-bit platforms */
 	if (ta->field_tag != tb->field_tag)
 		return (ta->field_tag < tb->field_tag ? -1 : 1);
 	else
 		return (tb->field_type < ta->field_type ? -1 : 1);
 }

 void
 _TIFFMergeFieldInfo(TIFF* tif, const TIFFFieldInfo info[], int n)
 {
 	TIFFFieldInfo** tp;
 	int i;

 	if (tif->tif_nfields > 0) {
 		tif->tif_fieldinfo = (TIFFFieldInfo**)
 		    _TIFFrealloc(tif->tif_fieldinfo,
 			(tif->tif_nfields+n) * sizeof (TIFFFieldInfo*));
 	} else {
 		tif->tif_fieldinfo = (TIFFFieldInfo**)
 		    _TIFFmalloc(n * sizeof (TIFFFieldInfo*));
 	}
 	tp = &tif->tif_fieldinfo[tif->tif_nfields];
 	for (i = 0; i < n; i++)
 		tp[i] = (TIFFFieldInfo*) &info[i];	/* XXX */
 	/*
 	 * NB: the core tags are presumed sorted correctly.
 	 */
 	if (tif->tif_nfields > 0)
 		qsort(tif->tif_fieldinfo, (size_t) (tif->tif_nfields += n),
 		    sizeof (TIFFFieldInfo*), tagCompare);
 	else
 		tif->tif_nfields += n;
 }

 void
 _TIFFPrintFieldInfo(TIFF* tif, FILE* fd)
 {
 	int i;

 	fprintf(fd, "%s: \n", tif->tif_name);
 	for (i = 0; i < tif->tif_nfields; i++) {
 		const TIFFFieldInfo* fip = tif->tif_fieldinfo[i];
 		fprintf(fd, "field[%2d] %5lu, %2d, %2d, %d, %2d, %5s, %5s, %s\n"
 			, i
 			, (unsigned long) fip->field_tag
 			, fip->field_readcount, fip->field_writecount
 			, fip->field_type
 			, fip->field_bit
 			, fip->field_oktochange ? "TRUE" : "FALSE"
 			, fip->field_passcount ? "TRUE" : "FALSE"
 			, fip->field_name
 		);
 	}
 }

 const int tiffDataWidth[] = {
     1,	/* nothing */
     1,	/* TIFF_BYTE */
     1,	/* TIFF_ASCII */
     2,	/* TIFF_SHORT */
     4,	/* TIFF_LONG */
     8,	/* TIFF_RATIONAL */
     1,	/* TIFF_SBYTE */
     1,	/* TIFF_UNDEFINED */
     2,	/* TIFF_SSHORT */
     4,	/* TIFF_SLONG */
     8,	/* TIFF_SRATIONAL */
     4,	/* TIFF_FLOAT */
     8,	/* TIFF_DOUBLE */
 };

 /*
  * Return nearest TIFFDataType to the sample type of an image.
  */
 TIFFDataType
 _TIFFSampleToTagType(TIFF* tif)
 {
 	int bps = (int) TIFFhowmany(tif->tif_dir.td_bitspersample, 8);

 	switch (tif->tif_dir.td_sampleformat) {
 	case SAMPLEFORMAT_IEEEFP:
 		return (bps == 4 ? TIFF_FLOAT : TIFF_DOUBLE);
 	case SAMPLEFORMAT_INT:
 		return (bps <= 1 ? TIFF_SBYTE :
 		    bps <= 2 ? TIFF_SSHORT : TIFF_SLONG);
 	case SAMPLEFORMAT_UINT:
 		return (bps <= 1 ? TIFF_BYTE :
 		    bps <= 2 ? TIFF_SHORT : TIFF_LONG);
 	case SAMPLEFORMAT_VOID:
 		return (TIFF_UNDEFINED);
 	}
 	/*NOTREACHED*/
 	return (TIFF_UNDEFINED);
 }

 const TIFFFieldInfo*
 _TIFFFindFieldInfo(TIFF* tif, ttag_t tag, TIFFDataType dt)
 {
 	static const TIFFFieldInfo *last = NULL;
 	int i, n;

 	if (last && last->field_tag == tag &&
 	    (dt == TIFF_ANY || dt == last->field_type))
 		return (last);
 	/* NB: if table gets big, use sorted search (e.g. binary search) */
 	for (i = 0, n = tif->tif_nfields; i < n; i++) {
 		const TIFFFieldInfo* fip = tif->tif_fieldinfo[i];
 		if (fip->field_tag == tag &&
 		    (dt == TIFF_ANY || fip->field_type == dt))
 			return (last = fip);
 	}
 	return ((const TIFFFieldInfo *)0);
 }

 #include <assert.h>
 #include <stdio.h>

 const TIFFFieldInfo*
 _TIFFFieldWithTag(TIFF* tif, ttag_t tag)
 {
 	const TIFFFieldInfo* fip = _TIFFFindFieldInfo(tif, tag, TIFF_ANY);
 	if (!fip) {
 		TIFFError("TIFFFieldWithTag",
 		    "Internal error, unknown tag 0x%x", (u_int) tag);
 		assert(fip != NULL);
 		/*NOTREACHED*/
 	}
 	return (fip);
 }
	/* $Header: /cvsroot/osrs/libtiff/libtiff/tif_dirinfo.c,v 1.8 2001/05/09 01:33:16 warmerda Exp $ */

	/*
	* Copyright (c) 1988-1997 Sam Leffler
	* Copyright (c) 1991-1997 Silicon Graphics, Inc.
	*
	* Permission to use, copy, modify, distribute, and sell this software and
	* its documentation for any purpose is hereby granted without fee, provided
	* that (i) the above copyright notices and this permission notice appear in
	* all copies of the software and related documentation, and (ii) the names of
	* Sam Leffler and Silicon Graphics may not be used in any advertising or
	* publicity relating to the software without the specific, prior written
	* permission of Sam Leffler and Silicon Graphics.
	*
	* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
	* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	*
	* IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
	* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
	* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
	* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
	* OF THIS SOFTWARE.
	*/

	/*
	* TIFF Library.
	*
	* Core Directory Tag Support.
	*/
	#include "tiffiop.h"
	#include <stdlib.h>

	/*
	* NB: NB: THIS ARRAY IS ASSUMED TO BE SORTED BY TAG.
	* If a tag can have both LONG and SHORT types
	* then the LONG must be placed before the SHORT for
	* writing to work properly.
	*
	* NOTE: The second field (field_readcount) and third field (field_writecount)
	* sometimes use the values TIFF_VARIABLE (-1), TIFF_VARIABLE2 (-3)
	* and TIFFTAG_SPP (-2). The macros should be used but would throw off
	* the formatting of the code, so please interprete the -1, -2 and -3
	* values accordingly.
	*/
	#ifndef VMS
	static
	#endif
	const TIFFFieldInfo tiffFieldInfo[] = {
	{ TIFFTAG_SUBFILETYPE, 1, 1, TIFF_LONG, FIELD_SUBFILETYPE,
	TRUE, FALSE, "SubfileType" },
	/* XXX SHORT for compatibility w/ old versions of the library */
	{ TIFFTAG_SUBFILETYPE, 1, 1, TIFF_SHORT, FIELD_SUBFILETYPE,
	TRUE, FALSE, "SubfileType" },
	{ TIFFTAG_OSUBFILETYPE, 1, 1, TIFF_SHORT, FIELD_SUBFILETYPE,
	TRUE, FALSE, "OldSubfileType" },
	{ TIFFTAG_IMAGEWIDTH, 1, 1, TIFF_LONG, FIELD_IMAGEDIMENSIONS,
	FALSE, FALSE, "ImageWidth" },
	{ TIFFTAG_IMAGEWIDTH, 1, 1, TIFF_SHORT, FIELD_IMAGEDIMENSIONS,
	FALSE, FALSE, "ImageWidth" },
	{ TIFFTAG_IMAGELENGTH, 1, 1, TIFF_LONG, FIELD_IMAGEDIMENSIONS,
	TRUE, FALSE, "ImageLength" },
	{ TIFFTAG_IMAGELENGTH, 1, 1, TIFF_SHORT, FIELD_IMAGEDIMENSIONS,
	TRUE, FALSE, "ImageLength" },
	{ TIFFTAG_BITSPERSAMPLE, -1,-1, TIFF_SHORT, FIELD_BITSPERSAMPLE,
	FALSE, FALSE, "BitsPerSample" },
	{ TIFFTAG_COMPRESSION, -1, 1, TIFF_SHORT, FIELD_COMPRESSION,
	FALSE, FALSE, "Compression" },
	{ TIFFTAG_PHOTOMETRIC, 1, 1, TIFF_SHORT, FIELD_PHOTOMETRIC,
	FALSE, FALSE, "PhotometricInterpretation" },
	{ TIFFTAG_THRESHHOLDING, 1, 1, TIFF_SHORT, FIELD_THRESHHOLDING,
	TRUE, FALSE, "Threshholding" },
	{ TIFFTAG_CELLWIDTH, 1, 1, TIFF_SHORT, FIELD_IGNORE,
	TRUE, FALSE, "CellWidth" },
	{ TIFFTAG_CELLLENGTH, 1, 1, TIFF_SHORT, FIELD_IGNORE,
	TRUE, FALSE, "CellLength" },
	{ TIFFTAG_FILLORDER, 1, 1, TIFF_SHORT, FIELD_FILLORDER,
	FALSE, FALSE, "FillOrder" },
	{ TIFFTAG_DOCUMENTNAME, -1,-1, TIFF_ASCII, FIELD_DOCUMENTNAME,
	TRUE, FALSE, "DocumentName" },
	{ TIFFTAG_IMAGEDESCRIPTION, -1,-1, TIFF_ASCII, FIELD_IMAGEDESCRIPTION,
	TRUE, FALSE, "ImageDescription" },
	{ TIFFTAG_MAKE, -1,-1, TIFF_ASCII, FIELD_MAKE,
	TRUE, FALSE, "Make" },
	{ TIFFTAG_MODEL, -1,-1, TIFF_ASCII, FIELD_MODEL,
	TRUE, FALSE, "Model" },
	{ TIFFTAG_STRIPOFFSETS, -1,-1, TIFF_LONG, FIELD_STRIPOFFSETS,
	FALSE, FALSE, "StripOffsets" },
	{ TIFFTAG_STRIPOFFSETS, -1,-1, TIFF_SHORT, FIELD_STRIPOFFSETS,
	FALSE, FALSE, "StripOffsets" },
	{ TIFFTAG_ORIENTATION, 1, 1, TIFF_SHORT, FIELD_ORIENTATION,
	FALSE, FALSE, "Orientation" },
	{ TIFFTAG_SAMPLESPERPIXEL, 1, 1, TIFF_SHORT, FIELD_SAMPLESPERPIXEL,
	FALSE, FALSE, "SamplesPerPixel" },
	{ TIFFTAG_ROWSPERSTRIP, 1, 1, TIFF_LONG, FIELD_ROWSPERSTRIP,
	FALSE, FALSE, "RowsPerStrip" },
	{ TIFFTAG_ROWSPERSTRIP, 1, 1, TIFF_SHORT, FIELD_ROWSPERSTRIP,
	FALSE, FALSE, "RowsPerStrip" },
	{ TIFFTAG_STRIPBYTECOUNTS, -1,-1, TIFF_LONG, FIELD_STRIPBYTECOUNTS,
	FALSE, FALSE, "StripByteCounts" },
	{ TIFFTAG_STRIPBYTECOUNTS, -1,-1, TIFF_SHORT, FIELD_STRIPBYTECOUNTS,
	FALSE, FALSE, "StripByteCounts" },
	{ TIFFTAG_MINSAMPLEVALUE, -2,-1, TIFF_SHORT, FIELD_MINSAMPLEVALUE,
	TRUE, FALSE, "MinSampleValue" },
	{ TIFFTAG_MAXSAMPLEVALUE, -2,-1, TIFF_SHORT, FIELD_MAXSAMPLEVALUE,
	TRUE, FALSE, "MaxSampleValue" },
	{ TIFFTAG_XRESOLUTION, 1, 1, TIFF_RATIONAL, FIELD_RESOLUTION,
	FALSE, FALSE, "XResolution" },
	{ TIFFTAG_YRESOLUTION, 1, 1, TIFF_RATIONAL, FIELD_RESOLUTION,
	FALSE, FALSE, "YResolution" },
	{ TIFFTAG_PLANARCONFIG, 1, 1, TIFF_SHORT, FIELD_PLANARCONFIG,
	FALSE, FALSE, "PlanarConfiguration" },
	{ TIFFTAG_PAGENAME, -1,-1, TIFF_ASCII, FIELD_PAGENAME,
	TRUE, FALSE, "PageName" },
	{ TIFFTAG_XPOSITION, 1, 1, TIFF_RATIONAL, FIELD_POSITION,
	TRUE, FALSE, "XPosition" },
	{ TIFFTAG_YPOSITION, 1, 1, TIFF_RATIONAL, FIELD_POSITION,
	TRUE, FALSE, "YPosition" },
	{ TIFFTAG_FREEOFFSETS, -1,-1, TIFF_LONG, FIELD_IGNORE,
	FALSE, FALSE, "FreeOffsets" },
	{ TIFFTAG_FREEBYTECOUNTS, -1,-1, TIFF_LONG, FIELD_IGNORE,
	FALSE, FALSE, "FreeByteCounts" },
	{ TIFFTAG_GRAYRESPONSEUNIT, 1, 1, TIFF_SHORT, FIELD_IGNORE,
	TRUE, FALSE, "GrayResponseUnit" },
	{ TIFFTAG_GRAYRESPONSECURVE,-1,-1, TIFF_SHORT, FIELD_IGNORE,
	TRUE, FALSE, "GrayResponseCurve" },
	{ TIFFTAG_RESOLUTIONUNIT, 1, 1, TIFF_SHORT, FIELD_RESOLUTIONUNIT,
	FALSE, FALSE, "ResolutionUnit" },
	{ TIFFTAG_PAGENUMBER, 2, 2, TIFF_SHORT, FIELD_PAGENUMBER,
	TRUE, FALSE, "PageNumber" },
	{ TIFFTAG_COLORRESPONSEUNIT, 1, 1, TIFF_SHORT, FIELD_IGNORE,
	TRUE, FALSE, "ColorResponseUnit" },
	#ifdef COLORIMETRY_SUPPORT
	{ TIFFTAG_TRANSFERFUNCTION, -1,-1, TIFF_SHORT, FIELD_TRANSFERFUNCTION,
	TRUE, FALSE, "TransferFunction" },
	#endif
	{ TIFFTAG_SOFTWARE, -1,-1, TIFF_ASCII, FIELD_SOFTWARE,
	TRUE, FALSE, "Software" },
	{ TIFFTAG_DATETIME, 20,20, TIFF_ASCII, FIELD_DATETIME,
	TRUE, FALSE, "DateTime" },
	{ TIFFTAG_ARTIST, -1,-1, TIFF_ASCII, FIELD_ARTIST,
	TRUE, FALSE, "Artist" },
	{ TIFFTAG_HOSTCOMPUTER, -1,-1, TIFF_ASCII, FIELD_HOSTCOMPUTER,
	TRUE, FALSE, "HostComputer" },
	#ifdef COLORIMETRY_SUPPORT
	{ TIFFTAG_WHITEPOINT, 2, 2, TIFF_RATIONAL,FIELD_WHITEPOINT,
	TRUE, FALSE, "WhitePoint" },
	{ TIFFTAG_PRIMARYCHROMATICITIES,6,6,TIFF_RATIONAL,FIELD_PRIMARYCHROMAS,
	TRUE, FALSE, "PrimaryChromaticities" },
	#endif
	{ TIFFTAG_COLORMAP, -1,-1, TIFF_SHORT, FIELD_COLORMAP,
	TRUE, FALSE, "ColorMap" },
	{ TIFFTAG_HALFTONEHINTS, 2, 2, TIFF_SHORT, FIELD_HALFTONEHINTS,
	TRUE, FALSE, "HalftoneHints" },
	{ TIFFTAG_TILEWIDTH, 1, 1, TIFF_LONG, FIELD_TILEDIMENSIONS,
	FALSE, FALSE, "TileWidth" },
	{ TIFFTAG_TILEWIDTH, 1, 1, TIFF_SHORT, FIELD_TILEDIMENSIONS,
	FALSE, FALSE, "TileWidth" },
	{ TIFFTAG_TILELENGTH, 1, 1, TIFF_LONG, FIELD_TILEDIMENSIONS,
	FALSE, FALSE, "TileLength" },
	{ TIFFTAG_TILELENGTH, 1, 1, TIFF_SHORT, FIELD_TILEDIMENSIONS,
	FALSE, FALSE, "TileLength" },
	{ TIFFTAG_TILEOFFSETS, -1, 1, TIFF_LONG, FIELD_STRIPOFFSETS,
	FALSE, FALSE, "TileOffsets" },
	{ TIFFTAG_TILEBYTECOUNTS, -1, 1, TIFF_LONG, FIELD_STRIPBYTECOUNTS,
	FALSE, FALSE, "TileByteCounts" },
	{ TIFFTAG_TILEBYTECOUNTS, -1, 1, TIFF_SHORT, FIELD_STRIPBYTECOUNTS,
	FALSE, FALSE, "TileByteCounts" },
	#ifdef TIFFTAG_SUBIFD
	{ TIFFTAG_SUBIFD, -1,-1, TIFF_LONG, FIELD_SUBIFD,
	TRUE, TRUE, "SubIFD" },
	#endif
	#ifdef CMYK_SUPPORT /* 6.0 CMYK tags */
	{ TIFFTAG_INKSET, 1, 1, TIFF_SHORT, FIELD_INKSET,
	FALSE, FALSE, "InkSet" },
	{ TIFFTAG_INKNAMES, -1,-1, TIFF_ASCII, FIELD_INKNAMES,
	TRUE, TRUE, "InkNames" },
	{ TIFFTAG_NUMBEROFINKS, 1, 1, TIFF_SHORT, FIELD_NUMBEROFINKS,
	TRUE, FALSE, "NumberOfInks" },
	{ TIFFTAG_DOTRANGE, 2, 2, TIFF_SHORT, FIELD_DOTRANGE,
	FALSE, FALSE, "DotRange" },
	{ TIFFTAG_DOTRANGE, 2, 2, TIFF_BYTE, FIELD_DOTRANGE,
	FALSE, FALSE, "DotRange" },
	{ TIFFTAG_TARGETPRINTER, -1,-1, TIFF_ASCII, FIELD_TARGETPRINTER,
	TRUE, FALSE, "TargetPrinter" },
	#endif
	{ TIFFTAG_EXTRASAMPLES, -1,-1, TIFF_SHORT, FIELD_EXTRASAMPLES,
	FALSE, FALSE, "ExtraSamples" },
	/* XXX for bogus Adobe Photoshop v2.5 files */
	{ TIFFTAG_EXTRASAMPLES, -1,-1, TIFF_BYTE, FIELD_EXTRASAMPLES,
	FALSE, FALSE, "ExtraSamples" },
	{ TIFFTAG_SAMPLEFORMAT, -1,-1, TIFF_SHORT, FIELD_SAMPLEFORMAT,
	FALSE, FALSE, "SampleFormat" },
	{ TIFFTAG_SMINSAMPLEVALUE, -2,-1, TIFF_ANY, FIELD_SMINSAMPLEVALUE,
	TRUE, FALSE, "SMinSampleValue" },
	{ TIFFTAG_SMAXSAMPLEVALUE, -2,-1, TIFF_ANY, FIELD_SMAXSAMPLEVALUE,
	TRUE, FALSE, "SMaxSampleValue" },
	#ifdef YCBCR_SUPPORT /* 6.0 YCbCr tags */
	{ TIFFTAG_YCBCRCOEFFICIENTS, 3, 3, TIFF_RATIONAL, FIELD_YCBCRCOEFFICIENTS,
	FALSE, FALSE, "YCbCrCoefficients" },
	{ TIFFTAG_YCBCRSUBSAMPLING, 2, 2, TIFF_SHORT, FIELD_YCBCRSUBSAMPLING,
	FALSE, FALSE, "YCbCrSubsampling" },
	{ TIFFTAG_YCBCRPOSITIONING, 1, 1, TIFF_SHORT, FIELD_YCBCRPOSITIONING,
	FALSE, FALSE, "YCbCrPositioning" },
	#endif
	#ifdef COLORIMETRY_SUPPORT
	{ TIFFTAG_REFERENCEBLACKWHITE,6,6,TIFF_RATIONAL, FIELD_REFBLACKWHITE,
	TRUE, FALSE, "ReferenceBlackWhite" },
	/* XXX temporarily accept LONG for backwards compatibility */
	{ TIFFTAG_REFERENCEBLACKWHITE,6,6,TIFF_LONG, FIELD_REFBLACKWHITE,
	TRUE, FALSE, "ReferenceBlackWhite" },
	#endif
	/* begin SGI tags */
	{ TIFFTAG_MATTEING, 1, 1, TIFF_SHORT, FIELD_EXTRASAMPLES,
	FALSE, FALSE, "Matteing" },
	{ TIFFTAG_DATATYPE, -2,-1, TIFF_SHORT, FIELD_SAMPLEFORMAT,
	FALSE, FALSE, "DataType" },
	{ TIFFTAG_IMAGEDEPTH, 1, 1, TIFF_LONG, FIELD_IMAGEDEPTH,
	FALSE, FALSE, "ImageDepth" },
	{ TIFFTAG_IMAGEDEPTH, 1, 1, TIFF_SHORT, FIELD_IMAGEDEPTH,
	FALSE, FALSE, "ImageDepth" },
	{ TIFFTAG_TILEDEPTH, 1, 1, TIFF_LONG, FIELD_TILEDEPTH,
	FALSE, FALSE, "TileDepth" },
	{ TIFFTAG_TILEDEPTH, 1, 1, TIFF_SHORT, FIELD_TILEDEPTH,
	FALSE, FALSE, "TileDepth" },
	/* end SGI tags */
	/* begin Pixar tags */
	{ TIFFTAG_PIXAR_IMAGEFULLWIDTH, 1, 1, TIFF_LONG, FIELD_IMAGEFULLWIDTH,
	TRUE, FALSE, "ImageFullWidth" },
	{ TIFFTAG_PIXAR_IMAGEFULLLENGTH, 1, 1, TIFF_LONG, FIELD_IMAGEFULLLENGTH,
	TRUE, FALSE, "ImageFullLength" },
	{ TIFFTAG_PIXAR_TEXTUREFORMAT, -1,-1, TIFF_ASCII, FIELD_TEXTUREFORMAT,
	TRUE, FALSE, "TextureFormat" },
	{ TIFFTAG_PIXAR_WRAPMODES, -1,-1, TIFF_ASCII, FIELD_WRAPMODES,
	TRUE, FALSE, "TextureWrapModes" },
	{ TIFFTAG_PIXAR_FOVCOT, 1, 1, TIFF_FLOAT, FIELD_FOVCOT,
	TRUE, FALSE, "FieldOfViewCotan" },
	{ TIFFTAG_PIXAR_MATRIX_WORLDTOSCREEN, 16,16, TIFF_FLOAT,
	FIELD_MATRIX_WORLDTOSCREEN, TRUE, FALSE, "MatrixWorldToScreen" },
	{ TIFFTAG_PIXAR_MATRIX_WORLDTOCAMERA, 16,16, TIFF_FLOAT,
	FIELD_MATRIX_WORLDTOCAMERA, TRUE, FALSE, "MatrixWorldToCamera" },
	{ TIFFTAG_COPYRIGHT, -1,-1, TIFF_ASCII, FIELD_COPYRIGHT,
	TRUE, FALSE, "Copyright" },
	/* end Pixar tags */
	#ifdef IPTC_SUPPORT
	#ifdef PHOTOSHOP_SUPPORT
	{ TIFFTAG_RICHTIFFIPTC, -1,-1, TIFF_LONG, FIELD_RICHTIFFIPTC,
	FALSE, TRUE, "RichTIFFIPTC" },
	#else
	{ TIFFTAG_RICHTIFFIPTC, -1,-3, TIFF_UNDEFINED, FIELD_RICHTIFFIPTC,
	FALSE, TRUE, "RichTIFFIPTC" },
	#endif
	#endif
	#ifdef PHOTOSHOP_SUPPORT
	{ TIFFTAG_PHOTOSHOP, -1,-3, TIFF_BYTE, FIELD_PHOTOSHOP,
	FALSE, TRUE, "Photoshop" },
	#endif
	#ifdef ICC_SUPPORT
	{ TIFFTAG_ICCPROFILE, -1,-3, TIFF_UNDEFINED, FIELD_ICCPROFILE,
	FALSE, TRUE, "ICC Profile" },
	#endif
	{ TIFFTAG_STONITS, 1, 1, TIFF_DOUBLE, FIELD_STONITS,
	FALSE, FALSE, "StoNits" },
	};
	#define N(a) (sizeof (a) / sizeof (a[0]))

	void
	_TIFFSetupFieldInfo(TIFF* tif)
	{
	if (tif->tif_fieldinfo) {
	_TIFFfree(tif->tif_fieldinfo);
	tif->tif_nfields = 0;
	}
	_TIFFMergeFieldInfo(tif, tiffFieldInfo, N(tiffFieldInfo));
	}

	static int
	tagCompare(const void* a, const void* b)
	{
	const TIFFFieldInfo* ta = (const TIFFFieldInfo*) a;
	const TIFFFieldInfo* tb = (const TIFFFieldInfo*) b;
	/* NB: be careful of return values for 16-bit platforms */
	if (ta->field_tag != tb->field_tag)
	return (ta->field_tag < tb->field_tag ? -1 : 1);
	else
	return (tb->field_type < ta->field_type ? -1 : 1);
	}

	void
	_TIFFMergeFieldInfo(TIFF* tif, const TIFFFieldInfo info[], int n)
	{
	TIFFFieldInfo** tp;
	int i;

	if (tif->tif_nfields > 0) {
	tif->tif_fieldinfo = (TIFFFieldInfo**)
	_TIFFrealloc(tif->tif_fieldinfo,
	(tif->tif_nfields+n) * sizeof (TIFFFieldInfo*));
	} else {
	tif->tif_fieldinfo = (TIFFFieldInfo**)
	_TIFFmalloc(n * sizeof (TIFFFieldInfo*));
	}
	tp = &tif->tif_fieldinfo[tif->tif_nfields];
	for (i = 0; i < n; i++)
	tp[i] = (TIFFFieldInfo) &info[i]; / XXX */
	/*
	* NB: the core tags are presumed sorted correctly.
	*/
	if (tif->tif_nfields > 0)
	qsort(tif->tif_fieldinfo, (size_t) (tif->tif_nfields += n),
	sizeof (TIFFFieldInfo*), tagCompare);
	else
	tif->tif_nfields += n;
	}

	void
	_TIFFPrintFieldInfo(TIFF* tif, FILE* fd)
	{
	int i;

	fprintf(fd, "%s: \n", tif->tif_name);
	for (i = 0; i < tif->tif_nfields; i++) {
	const TIFFFieldInfo* fip = tif->tif_fieldinfo[i];
	fprintf(fd, "field[%2d] %5lu, %2d, %2d, %d, %2d, %5s, %5s, %s\n"
	, i
	, (unsigned long) fip->field_tag
	, fip->field_readcount, fip->field_writecount
	, fip->field_type
	, fip->field_bit
	, fip->field_oktochange ? "TRUE" : "FALSE"
	, fip->field_passcount ? "TRUE" : "FALSE"
	, fip->field_name
	);
	}
	}

	const int tiffDataWidth[] = {
	1, /* nothing */
	1, /* TIFF_BYTE */
	1, /* TIFF_ASCII */
	2, /* TIFF_SHORT */
	4, /* TIFF_LONG */
	8, /* TIFF_RATIONAL */
	1, /* TIFF_SBYTE */
	1, /* TIFF_UNDEFINED */
	2, /* TIFF_SSHORT */
	4, /* TIFF_SLONG */
	8, /* TIFF_SRATIONAL */
	4, /* TIFF_FLOAT */
	8, /* TIFF_DOUBLE */
	};

	/*
	* Return nearest TIFFDataType to the sample type of an image.
	*/
	TIFFDataType
	_TIFFSampleToTagType(TIFF* tif)
	{
	int bps = (int) TIFFhowmany(tif->tif_dir.td_bitspersample, 8);

	switch (tif->tif_dir.td_sampleformat) {
	case SAMPLEFORMAT_IEEEFP:
	return (bps == 4 ? TIFF_FLOAT : TIFF_DOUBLE);
	case SAMPLEFORMAT_INT:
	return (bps <= 1 ? TIFF_SBYTE :
	bps <= 2 ? TIFF_SSHORT : TIFF_SLONG);
	case SAMPLEFORMAT_UINT:
	return (bps <= 1 ? TIFF_BYTE :
	bps <= 2 ? TIFF_SHORT : TIFF_LONG);
	case SAMPLEFORMAT_VOID:
	return (TIFF_UNDEFINED);
	}
	/NOTREACHED/
	return (TIFF_UNDEFINED);
	}

	const TIFFFieldInfo*
	_TIFFFindFieldInfo(TIFF* tif, ttag_t tag, TIFFDataType dt)
	{
	static const TIFFFieldInfo *last = NULL;
	int i, n;

	if (last && last->field_tag == tag &&
	(dt == TIFF_ANY \|\| dt == last->field_type))
	return (last);
	/* NB: if table gets big, use sorted search (e.g. binary search) */
	for (i = 0, n = tif->tif_nfields; i < n; i++) {
	const TIFFFieldInfo* fip = tif->tif_fieldinfo[i];
	if (fip->field_tag == tag &&
	(dt == TIFF_ANY \|\| fip->field_type == dt))
	return (last = fip);
	}
	return ((const TIFFFieldInfo *)0);
	}

	#include <assert.h>
	#include <stdio.h>

	const TIFFFieldInfo*
	_TIFFFieldWithTag(TIFF* tif, ttag_t tag)
	{
	const TIFFFieldInfo* fip = _TIFFFindFieldInfo(tif, tag, TIFF_ANY);
	if (!fip) {
	TIFFError("TIFFFieldWithTag",
	"Internal error, unknown tag 0x%x", (u_int) tag);
	assert(fip != NULL);
	/NOTREACHED/
	}
	return (fip);
	}