Source/LibTIFF/tif_read.c - platform/external/free-image - Git at Google

 /* $Id: tif_read.c,v 1.27 2009/09/06 13:11:29 drolon 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.
  * Scanline-oriented Read Support
  */
 #include "tiffiop.h"
 #include <stdio.h>

 	int TIFFFillStrip(TIFF*, tstrip_t);
 	int TIFFFillTile(TIFF*, ttile_t);
 static	int TIFFStartStrip(TIFF*, tstrip_t);
 static	int TIFFStartTile(TIFF*, ttile_t);
 static	int TIFFCheckRead(TIFF*, int);

 #define	NOSTRIP	((tstrip_t) -1)			/* undefined state */
 #define	NOTILE	((ttile_t) -1)			/* undefined state */

 /*
  * Seek to a random row+sample in a file.
  */
 static int
 TIFFSeek(TIFF* tif, uint32 row, tsample_t sample)
 {
 	register TIFFDirectory *td = &tif->tif_dir;
 	tstrip_t strip;

 	if (row >= td->td_imagelength) {	/* out of range */
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 			     "%lu: Row out of range, max %lu",
 			     (unsigned long) row,
 			     (unsigned long) td->td_imagelength);
 		return (0);
 	}
 	if (td->td_planarconfig == PLANARCONFIG_SEPARATE) {
 		if (sample >= td->td_samplesperpixel) {
 			TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 			    "%lu: Sample out of range, max %lu",
 			    (unsigned long) sample, (unsigned long) td->td_samplesperpixel);
 			return (0);
 		}
 		strip = sample*td->td_stripsperimage + row/td->td_rowsperstrip;
 	} else
 		strip = row / td->td_rowsperstrip;
 	if (strip != tif->tif_curstrip) {	/* different strip, refill */
 		if (!TIFFFillStrip(tif, strip))
 			return (0);
 	} else if (row < tif->tif_row) {
 		/*
 		 * Moving backwards within the same strip: backup
 		 * to the start and then decode forward (below).
 		 *
 		 * NB: If you're planning on lots of random access within a
 		 * strip, it's better to just read and decode the entire
 		 * strip, and then access the decoded data in a random fashion.
 		 */
 		if (!TIFFStartStrip(tif, strip))
 			return (0);
 	}
 	if (row != tif->tif_row) {
 		/*
 		 * Seek forward to the desired row.
 		 */
 		if (!(*tif->tif_seek)(tif, row - tif->tif_row))
 			return (0);
 		tif->tif_row = row;
 	}
 	return (1);
 }

 int
 TIFFReadScanline(TIFF* tif, tdata_t buf, uint32 row, tsample_t sample)
 {
 	int e;

 	if (!TIFFCheckRead(tif, 0))
 		return (-1);
 	if( (e = TIFFSeek(tif, row, sample)) != 0) {
 		/*
 		 * Decompress desired row into user buffer.
 		 */
 		e = (*tif->tif_decoderow)
 		    (tif, (tidata_t) buf, tif->tif_scanlinesize, sample);

 		/* we are now poised at the beginning of the next row */
 		tif->tif_row = row + 1;

 		if (e)
 			(*tif->tif_postdecode)(tif, (tidata_t) buf,
 			    tif->tif_scanlinesize);
 	}
 	return (e > 0 ? 1 : -1);
 }

 /*
  * Read a strip of data and decompress the specified
  * amount into the user-supplied buffer.
  */
 tsize_t
 TIFFReadEncodedStrip(TIFF* tif, tstrip_t strip, tdata_t buf, tsize_t size)
 {
 	TIFFDirectory *td = &tif->tif_dir;
 	uint32 nrows;
 	tsize_t stripsize;
         tstrip_t sep_strip, strips_per_sep;

 	if (!TIFFCheckRead(tif, 0))
 		return (-1);
 	if (strip >= td->td_nstrips) {
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 			     "%ld: Strip out of range, max %ld",
 			     (long) strip, (long) td->td_nstrips);
 		return (-1);
 	}
 	/*
 	 * Calculate the strip size according to the number of
 	 * rows in the strip (check for truncated last strip on any
 	 * of the separations).
 	 */
 	if( td->td_rowsperstrip >= td->td_imagelength )
 		strips_per_sep = 1;
 	else
 		strips_per_sep = (td->td_imagelength+td->td_rowsperstrip-1)
 		    / td->td_rowsperstrip;

 	sep_strip = strip % strips_per_sep;

 	if (sep_strip != strips_per_sep-1 ||
 	    (nrows = td->td_imagelength % td->td_rowsperstrip) == 0)
 		nrows = td->td_rowsperstrip;

 	stripsize = TIFFVStripSize(tif, nrows);
 	if (size == (tsize_t) -1)
 		size = stripsize;
 	else if (size > stripsize)
 		size = stripsize;
 	if (TIFFFillStrip(tif, strip)
 	    && (*tif->tif_decodestrip)(tif, (tidata_t) buf, size,
 	    (tsample_t)(strip / td->td_stripsperimage)) > 0 ) {
 		(*tif->tif_postdecode)(tif, (tidata_t) buf, size);
 		return (size);
 	} else
 		return ((tsize_t) -1);
 }

 static tsize_t
 TIFFReadRawStrip1(TIFF* tif,
     tstrip_t strip, tdata_t buf, tsize_t size, const char* module)
 {
 	TIFFDirectory *td = &tif->tif_dir;

 	assert((tif->tif_flags&TIFF_NOREADRAW)==0);
 	if (!isMapped(tif)) {
 		tsize_t cc;

 		if (!SeekOK(tif, td->td_stripoffset[strip])) {
 			TIFFErrorExt(tif->tif_clientdata, module,
 			    "%s: Seek error at scanline %lu, strip %lu",
 			    tif->tif_name,
 			    (unsigned long) tif->tif_row, (unsigned long) strip);
 			return (-1);
 		}
 		cc = TIFFReadFile(tif, buf, size);
 		if (cc != size) {
 			TIFFErrorExt(tif->tif_clientdata, module,
 		"%s: Read error at scanline %lu; got %lu bytes, expected %lu",
 			    tif->tif_name,
 			    (unsigned long) tif->tif_row,
 			    (unsigned long) cc,
 			    (unsigned long) size);
 			return (-1);
 		}
 	} else {
 		if (td->td_stripoffset[strip] + size > tif->tif_size) {
 			TIFFErrorExt(tif->tif_clientdata, module,
     "%s: Read error at scanline %lu, strip %lu; got %lu bytes, expected %lu",
 			    tif->tif_name,
 			    (unsigned long) tif->tif_row,
 			    (unsigned long) strip,
 			    (unsigned long) tif->tif_size - td->td_stripoffset[strip],
 			    (unsigned long) size);
 			return (-1);
 		}
 		_TIFFmemcpy(buf, tif->tif_base + td->td_stripoffset[strip],
                             size);
 	}
 	return (size);
 }

 /*
  * Read a strip of data from the file.
  */
 tsize_t
 TIFFReadRawStrip(TIFF* tif, tstrip_t strip, tdata_t buf, tsize_t size)
 {
 	static const char module[] = "TIFFReadRawStrip";
 	TIFFDirectory *td = &tif->tif_dir;
 	/*
 	 * FIXME: butecount should have tsize_t type, but for now libtiff
 	 * defines tsize_t as a signed 32-bit integer and we are losing
 	 * ability to read arrays larger than 2^31 bytes. So we are using
 	 * uint32 instead of tsize_t here.
 	 */
 	uint32 bytecount;

 	if (!TIFFCheckRead(tif, 0))
 		return ((tsize_t) -1);
 	if (strip >= td->td_nstrips) {
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 			     "%lu: Strip out of range, max %lu",
 			     (unsigned long) strip,
 			     (unsigned long) td->td_nstrips);
 		return ((tsize_t) -1);
 	}
 	if (tif->tif_flags&TIFF_NOREADRAW)
 	{
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 	"Compression scheme does not support access to raw uncompressed data");
 		return ((tsize_t) -1);
 	}
 	bytecount = td->td_stripbytecount[strip];
 	if (bytecount <= 0) {
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 		    "%lu: Invalid strip byte count, strip %lu",
 		    (unsigned long) bytecount, (unsigned long) strip);
 		return ((tsize_t) -1);
 	}
 	if (size != (tsize_t)-1 && (uint32)size < bytecount)
 		bytecount = size;
 	return (TIFFReadRawStrip1(tif, strip, buf, bytecount, module));
 }

 /*
  * Read the specified strip and setup for decoding. The data buffer is
  * expanded, as necessary, to hold the strip's data.
  */
 int
 TIFFFillStrip(TIFF* tif, tstrip_t strip)
 {
 	static const char module[] = "TIFFFillStrip";
 	TIFFDirectory *td = &tif->tif_dir;

 	if ((tif->tif_flags&TIFF_NOREADRAW)==0)
 	{
 		/*
 		 * FIXME: butecount should have tsize_t type, but for now
 		 * libtiff defines tsize_t as a signed 32-bit integer and we
 		 * are losing ability to read arrays larger than 2^31 bytes.
 		 * So we are using uint32 instead of tsize_t here.
 		 */
 		uint32 bytecount = td->td_stripbytecount[strip];
 		if (bytecount <= 0) {
 			TIFFErrorExt(tif->tif_clientdata, module,
 			    "%s: Invalid strip byte count %lu, strip %lu",
 			    tif->tif_name, (unsigned long) bytecount,
 			    (unsigned long) strip);
 			return (0);
 		}
 		if (isMapped(tif) &&
 		    (isFillOrder(tif, td->td_fillorder)
 		    || (tif->tif_flags & TIFF_NOBITREV))) {
 			/*
 			 * The image is mapped into memory and we either don't
 			 * need to flip bits or the compression routine is
 			 * going to handle this operation itself.  In this
 			 * case, avoid copying the raw data and instead just
 			 * reference the data from the memory mapped file
 			 * image.  This assumes that the decompression
 			 * routines do not modify the contents of the raw data
 			 * buffer (if they try to, the application will get a
 			 * fault since the file is mapped read-only).
 			 */
 			if ((tif->tif_flags & TIFF_MYBUFFER) && tif->tif_rawdata)
 				_TIFFfree(tif->tif_rawdata);
 			tif->tif_flags &= ~TIFF_MYBUFFER;
 			/*
 			 * We must check for overflow, potentially causing
 			 * an OOB read. Instead of simple
 			 *
 			 *  td->td_stripoffset[strip]+bytecount > tif->tif_size
 			 *
 			 * comparison (which can overflow) we do the following
 			 * two comparisons:
 			 */
 			if (bytecount > tif->tif_size ||
 			    td->td_stripoffset[strip] > tif->tif_size - bytecount) {
 				/*
 				 * This error message might seem strange, but
 				 * it's what would happen if a read were done
 				 * instead.
 				 */
 				TIFFErrorExt(tif->tif_clientdata, module,

 					"%s: Read error on strip %lu; "
 					"got %lu bytes, expected %lu",
 					tif->tif_name, (unsigned long) strip,
 					(unsigned long) tif->tif_size - td->td_stripoffset[strip],
 					(unsigned long) bytecount);
 				tif->tif_curstrip = NOSTRIP;
 				return (0);
 			}
 			tif->tif_rawdatasize = bytecount;
 			tif->tif_rawdata = tif->tif_base + td->td_stripoffset[strip];
 		} else {
 			/*
 			 * Expand raw data buffer, if needed, to hold data
 			 * strip coming from file (perhaps should set upper
 			 * bound on the size of a buffer we'll use?).
 			 */
 			if (bytecount > (uint32)tif->tif_rawdatasize) {
 				tif->tif_curstrip = NOSTRIP;
 				if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
 					TIFFErrorExt(tif->tif_clientdata,
 						     module,
 				"%s: Data buffer too small to hold strip %lu",
 						     tif->tif_name,
 						     (unsigned long) strip);
 					return (0);
 				}
 				if (!TIFFReadBufferSetup(tif, 0,
 				    TIFFroundup(bytecount, 1024)))
 					return (0);
 			}
 			if ((uint32)TIFFReadRawStrip1(tif, strip,
 				(unsigned char *)tif->tif_rawdata,
 				bytecount, module) != bytecount)
 				return (0);
 			if (!isFillOrder(tif, td->td_fillorder) &&
 			    (tif->tif_flags & TIFF_NOBITREV) == 0)
 				TIFFReverseBits(tif->tif_rawdata, bytecount);
 		}
 	}
 	return (TIFFStartStrip(tif, strip));
 }

 /*
  * Tile-oriented Read Support
  * Contributed by Nancy Cam (Silicon Graphics).
  */

 /*
  * Read and decompress a tile of data.  The
  * tile is selected by the (x,y,z,s) coordinates.
  */
 tsize_t
 TIFFReadTile(TIFF* tif,
     tdata_t buf, uint32 x, uint32 y, uint32 z, tsample_t s)
 {
 	if (!TIFFCheckRead(tif, 1) || !TIFFCheckTile(tif, x, y, z, s))
 		return (-1);
 	return (TIFFReadEncodedTile(tif,
 	    TIFFComputeTile(tif, x, y, z, s), buf, (tsize_t) -1));
 }

 /*
  * Read a tile of data and decompress the specified
  * amount into the user-supplied buffer.
  */
 tsize_t
 TIFFReadEncodedTile(TIFF* tif, ttile_t tile, tdata_t buf, tsize_t size)
 {
 	TIFFDirectory *td = &tif->tif_dir;
 	tsize_t tilesize = tif->tif_tilesize;

 	if (!TIFFCheckRead(tif, 1))
 		return (-1);
 	if (tile >= td->td_nstrips) {
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 			     "%ld: Tile out of range, max %ld",
 			     (long) tile, (unsigned long) td->td_nstrips);
 		return (-1);
 	}
 	if (size == (tsize_t) -1)
 		size = tilesize;
 	else if (size > tilesize)
 		size = tilesize;
 	if (TIFFFillTile(tif, tile) && (*tif->tif_decodetile)(tif,
 	    (tidata_t) buf, size, (tsample_t)(tile/td->td_stripsperimage))) {
 		(*tif->tif_postdecode)(tif, (tidata_t) buf, size);
 		return (size);
 	} else
 		return (-1);
 }

 static tsize_t
 TIFFReadRawTile1(TIFF* tif,
     ttile_t tile, tdata_t buf, tsize_t size, const char* module)
 {
 	TIFFDirectory *td = &tif->tif_dir;

 	assert((tif->tif_flags&TIFF_NOREADRAW)==0);
 	if (!isMapped(tif)) {
 		tsize_t cc;

 		if (!SeekOK(tif, td->td_stripoffset[tile])) {
 			TIFFErrorExt(tif->tif_clientdata, module,
 			    "%s: Seek error at row %ld, col %ld, tile %ld",
 			    tif->tif_name,
 			    (long) tif->tif_row,
 			    (long) tif->tif_col,
 			    (long) tile);
 			return ((tsize_t) -1);
 		}
 		cc = TIFFReadFile(tif, buf, size);
 		if (cc != size) {
 			TIFFErrorExt(tif->tif_clientdata, module,
 	    "%s: Read error at row %ld, col %ld; got %lu bytes, expected %lu",
 			    tif->tif_name,
 			    (long) tif->tif_row,
 			    (long) tif->tif_col,
 			    (unsigned long) cc,
 			    (unsigned long) size);
 			return ((tsize_t) -1);
 		}
 	} else {
 		if (td->td_stripoffset[tile] + size > tif->tif_size) {
 			TIFFErrorExt(tif->tif_clientdata, module,
     "%s: Read error at row %ld, col %ld, tile %ld; got %lu bytes, expected %lu",
 			    tif->tif_name,
 			    (long) tif->tif_row,
 			    (long) tif->tif_col,
 			    (long) tile,
 			    (unsigned long) tif->tif_size - td->td_stripoffset[tile],
 			    (unsigned long) size);
 			return ((tsize_t) -1);
 		}
 		_TIFFmemcpy(buf, tif->tif_base + td->td_stripoffset[tile], size);
 	}
 	return (size);
 }

 /*
  * Read a tile of data from the file.
  */
 tsize_t
 TIFFReadRawTile(TIFF* tif, ttile_t tile, tdata_t buf, tsize_t size)
 {
 	static const char module[] = "TIFFReadRawTile";
 	TIFFDirectory *td = &tif->tif_dir;
 	/*
 	 * FIXME: butecount should have tsize_t type, but for now libtiff
 	 * defines tsize_t as a signed 32-bit integer and we are losing
 	 * ability to read arrays larger than 2^31 bytes. So we are using
 	 * uint32 instead of tsize_t here.
 	 */
 	uint32 bytecount;

 	if (!TIFFCheckRead(tif, 1))
 		return ((tsize_t) -1);
 	if (tile >= td->td_nstrips) {
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 			     "%lu: Tile out of range, max %lu",
 		    (unsigned long) tile, (unsigned long) td->td_nstrips);
 		return ((tsize_t) -1);
 	}
 	if (tif->tif_flags&TIFF_NOREADRAW)
 	{
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 	"Compression scheme does not support access to raw uncompressed data");
 		return ((tsize_t) -1);
 	}
 	bytecount = td->td_stripbytecount[tile];
 	if (size != (tsize_t) -1 && (uint32)size < bytecount)
 		bytecount = size;
 	return (TIFFReadRawTile1(tif, tile, buf, bytecount, module));
 }

 /*
  * Read the specified tile and setup for decoding. The data buffer is
  * expanded, as necessary, to hold the tile's data.
  */
 int
 TIFFFillTile(TIFF* tif, ttile_t tile)
 {
 	static const char module[] = "TIFFFillTile";
 	TIFFDirectory *td = &tif->tif_dir;

 	if ((tif->tif_flags&TIFF_NOREADRAW)==0)
 	{
 		/*
 		 * FIXME: butecount should have tsize_t type, but for now
 		 * libtiff defines tsize_t as a signed 32-bit integer and we
 		 * are losing ability to read arrays larger than 2^31 bytes.
 		 * So we are using uint32 instead of tsize_t here.
 		 */
 		uint32 bytecount = td->td_stripbytecount[tile];
 		if (bytecount <= 0) {
 			TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
 			    "%lu: Invalid tile byte count, tile %lu",
 			    (unsigned long) bytecount, (unsigned long) tile);
 			return (0);
 		}
 		if (isMapped(tif) &&
 		    (isFillOrder(tif, td->td_fillorder)
 		     || (tif->tif_flags & TIFF_NOBITREV))) {
 			/*
 			 * The image is mapped into memory and we either don't
 			 * need to flip bits or the compression routine is
 			 * going to handle this operation itself.  In this
 			 * case, avoid copying the raw data and instead just
 			 * reference the data from the memory mapped file
 			 * image.  This assumes that the decompression
 			 * routines do not modify the contents of the raw data
 			 * buffer (if they try to, the application will get a
 			 * fault since the file is mapped read-only).
 			 */
 			if ((tif->tif_flags & TIFF_MYBUFFER) && tif->tif_rawdata)
 				_TIFFfree(tif->tif_rawdata);
 			tif->tif_flags &= ~TIFF_MYBUFFER;
 			/*
 			 * We must check for overflow, potentially causing
 			 * an OOB read. Instead of simple
 			 *
 			 *  td->td_stripoffset[tile]+bytecount > tif->tif_size
 			 *
 			 * comparison (which can overflow) we do the following
 			 * two comparisons:
 			 */
 			if (bytecount > tif->tif_size ||
 			    td->td_stripoffset[tile] > tif->tif_size - bytecount) {
 				tif->tif_curtile = NOTILE;
 				return (0);
 			}
 			tif->tif_rawdatasize = bytecount;
 			tif->tif_rawdata =
 				tif->tif_base + td->td_stripoffset[tile];
 		} else {
 			/*
 			 * Expand raw data buffer, if needed, to hold data
 			 * tile coming from file (perhaps should set upper
 			 * bound on the size of a buffer we'll use?).
 			 */
 			if (bytecount > (uint32)tif->tif_rawdatasize) {
 				tif->tif_curtile = NOTILE;
 				if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
 					TIFFErrorExt(tif->tif_clientdata,
 						     module,
 				"%s: Data buffer too small to hold tile %ld",
 						     tif->tif_name,
 						     (long) tile);
 					return (0);
 				}
 				if (!TIFFReadBufferSetup(tif, 0,
 				    TIFFroundup(bytecount, 1024)))
 					return (0);
 			}
 			if ((uint32)TIFFReadRawTile1(tif, tile,
 				(unsigned char *)tif->tif_rawdata,
 				bytecount, module) != bytecount)
 				return (0);
 			if (!isFillOrder(tif, td->td_fillorder) &&
 			    (tif->tif_flags & TIFF_NOBITREV) == 0)
 				TIFFReverseBits(tif->tif_rawdata, bytecount);
 		}
 	}
 	return (TIFFStartTile(tif, tile));
 }

 /*
  * Setup the raw data buffer in preparation for
  * reading a strip of raw data.  If the buffer
  * is specified as zero, then a buffer of appropriate
  * size is allocated by the library.  Otherwise,
  * the client must guarantee that the buffer is
  * large enough to hold any individual strip of
  * raw data.
  */
 int
 TIFFReadBufferSetup(TIFF* tif, tdata_t bp, tsize_t size)
 {
 	static const char module[] = "TIFFReadBufferSetup";

 	assert((tif->tif_flags&TIFF_NOREADRAW)==0);
 	if (tif->tif_rawdata) {
 		if (tif->tif_flags & TIFF_MYBUFFER)
 			_TIFFfree(tif->tif_rawdata);
 		tif->tif_rawdata = NULL;
 	}
 	if (bp) {
 		tif->tif_rawdatasize = size;
 		tif->tif_rawdata = (tidata_t) bp;
 		tif->tif_flags &= ~TIFF_MYBUFFER;
 	} else {
 		tif->tif_rawdatasize = TIFFroundup(size, 1024);
 		tif->tif_rawdata = (tidata_t) _TIFFmalloc(tif->tif_rawdatasize);
 		tif->tif_flags |= TIFF_MYBUFFER;
 	}
 	if (tif->tif_rawdata == NULL) {
 		TIFFErrorExt(tif->tif_clientdata, module,
 		    "%s: No space for data buffer at scanline %ld",
 		    tif->tif_name, (long) tif->tif_row);
 		tif->tif_rawdatasize = 0;
 		return (0);
 	}
 	return (1);
 }

 /*
  * Set state to appear as if a
  * strip has just been read in.
  */
 static int
 TIFFStartStrip(TIFF* tif, tstrip_t strip)
 {
 	TIFFDirectory *td = &tif->tif_dir;

 	if ((tif->tif_flags & TIFF_CODERSETUP) == 0) {
 		if (!(*tif->tif_setupdecode)(tif))
 			return (0);
 		tif->tif_flags |= TIFF_CODERSETUP;
 	}
 	tif->tif_curstrip = strip;
 	tif->tif_row = (strip % td->td_stripsperimage) * td->td_rowsperstrip;
 	if (tif->tif_flags&TIFF_NOREADRAW)
 	{
 		tif->tif_rawcp = NULL;
 		tif->tif_rawcc = 0;
 	}
 	else
 	{
 		tif->tif_rawcp = tif->tif_rawdata;
 		tif->tif_rawcc = td->td_stripbytecount[strip];
 	}
 	return ((*tif->tif_predecode)(tif,
 			(tsample_t)(strip / td->td_stripsperimage)));
 }

 /*
  * Set state to appear as if a
  * tile has just been read in.
  */
 static int
 TIFFStartTile(TIFF* tif, ttile_t tile)
 {
 	TIFFDirectory *td = &tif->tif_dir;

 	if ((tif->tif_flags & TIFF_CODERSETUP) == 0) {
 		if (!(*tif->tif_setupdecode)(tif))
 			return (0);
 		tif->tif_flags |= TIFF_CODERSETUP;
 	}
 	tif->tif_curtile = tile;
 	tif->tif_row =
 	    (tile % TIFFhowmany(td->td_imagewidth, td->td_tilewidth)) *
 		td->td_tilelength;
 	tif->tif_col =
 	    (tile % TIFFhowmany(td->td_imagelength, td->td_tilelength)) *
 		td->td_tilewidth;
 	if (tif->tif_flags&TIFF_NOREADRAW)
 	{
 		tif->tif_rawcp = NULL;
 		tif->tif_rawcc = 0;
 	}
 	else
 	{
 		tif->tif_rawcp = tif->tif_rawdata;
 		tif->tif_rawcc = td->td_stripbytecount[tile];
 	}
 	return ((*tif->tif_predecode)(tif,
 			(tsample_t)(tile/td->td_stripsperimage)));
 }

 static int
 TIFFCheckRead(TIFF* tif, int tiles)
 {
 	if (tif->tif_mode == O_WRONLY) {
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "File not open for reading");
 		return (0);
 	}
 	if (tiles ^ isTiled(tif)) {
 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name, tiles ?
 		    "Can not read tiles from a stripped image" :
 		    "Can not read scanlines from a tiled image");
 		return (0);
 	}
 	return (1);
 }

 void
 _TIFFNoPostDecode(TIFF* tif, tidata_t buf, tsize_t cc)
 {
     (void) tif; (void) buf; (void) cc;
 }

 void
 _TIFFSwab16BitData(TIFF* tif, tidata_t buf, tsize_t cc)
 {
     (void) tif;
     assert((cc & 1) == 0);
     TIFFSwabArrayOfShort((uint16*) buf, cc/2);
 }

 void
 _TIFFSwab24BitData(TIFF* tif, tidata_t buf, tsize_t cc)
 {
     (void) tif;
     assert((cc % 3) == 0);
     TIFFSwabArrayOfTriples((uint8*) buf, cc/3);
 }

 void
 _TIFFSwab32BitData(TIFF* tif, tidata_t buf, tsize_t cc)
 {
     (void) tif;
     assert((cc & 3) == 0);
     TIFFSwabArrayOfLong((uint32*) buf, cc/4);
 }

 void
 _TIFFSwab64BitData(TIFF* tif, tidata_t buf, tsize_t cc)
 {
     (void) tif;
     assert((cc & 7) == 0);
     TIFFSwabArrayOfDouble((double*) buf, cc/8);
 }

 /* vim: set ts=8 sts=8 sw=8 noet: */
	/* $Id: tif_read.c,v 1.27 2009/09/06 13:11:29 drolon 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.
	* Scanline-oriented Read Support
	*/
	#include "tiffiop.h"
	#include <stdio.h>

	int TIFFFillStrip(TIFF*, tstrip_t);
	int TIFFFillTile(TIFF*, ttile_t);
	static int TIFFStartStrip(TIFF*, tstrip_t);
	static int TIFFStartTile(TIFF*, ttile_t);
	static int TIFFCheckRead(TIFF*, int);

	#define NOSTRIP ((tstrip_t) -1) /* undefined state */
	#define NOTILE ((ttile_t) -1) /* undefined state */

	/*
	* Seek to a random row+sample in a file.
	*/
	static int
	TIFFSeek(TIFF* tif, uint32 row, tsample_t sample)
	{
	register TIFFDirectory *td = &tif->tif_dir;
	tstrip_t strip;

	if (row >= td->td_imagelength) { /* out of range */
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"%lu: Row out of range, max %lu",
	(unsigned long) row,
	(unsigned long) td->td_imagelength);
	return (0);
	}
	if (td->td_planarconfig == PLANARCONFIG_SEPARATE) {
	if (sample >= td->td_samplesperpixel) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"%lu: Sample out of range, max %lu",
	(unsigned long) sample, (unsigned long) td->td_samplesperpixel);
	return (0);
	}
	strip = sample*td->td_stripsperimage + row/td->td_rowsperstrip;
	} else
	strip = row / td->td_rowsperstrip;
	if (strip != tif->tif_curstrip) { /* different strip, refill */
	if (!TIFFFillStrip(tif, strip))
	return (0);
	} else if (row < tif->tif_row) {
	/*
	* Moving backwards within the same strip: backup
	* to the start and then decode forward (below).
	*
	* NB: If you're planning on lots of random access within a
	* strip, it's better to just read and decode the entire
	* strip, and then access the decoded data in a random fashion.
	*/
	if (!TIFFStartStrip(tif, strip))
	return (0);
	}
	if (row != tif->tif_row) {
	/*
	* Seek forward to the desired row.
	*/
	if (!(*tif->tif_seek)(tif, row - tif->tif_row))
	return (0);
	tif->tif_row = row;
	}
	return (1);
	}

	int
	TIFFReadScanline(TIFF* tif, tdata_t buf, uint32 row, tsample_t sample)
	{
	int e;

	if (!TIFFCheckRead(tif, 0))
	return (-1);
	if( (e = TIFFSeek(tif, row, sample)) != 0) {
	/*
	* Decompress desired row into user buffer.
	*/
	e = (*tif->tif_decoderow)
	(tif, (tidata_t) buf, tif->tif_scanlinesize, sample);

	/* we are now poised at the beginning of the next row */
	tif->tif_row = row + 1;

	if (e)
	(*tif->tif_postdecode)(tif, (tidata_t) buf,
	tif->tif_scanlinesize);
	}
	return (e > 0 ? 1 : -1);
	}

	/*
	* Read a strip of data and decompress the specified
	* amount into the user-supplied buffer.
	*/
	tsize_t
	TIFFReadEncodedStrip(TIFF* tif, tstrip_t strip, tdata_t buf, tsize_t size)
	{
	TIFFDirectory *td = &tif->tif_dir;
	uint32 nrows;
	tsize_t stripsize;
	tstrip_t sep_strip, strips_per_sep;

	if (!TIFFCheckRead(tif, 0))
	return (-1);
	if (strip >= td->td_nstrips) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"%ld: Strip out of range, max %ld",
	(long) strip, (long) td->td_nstrips);
	return (-1);
	}
	/*
	* Calculate the strip size according to the number of
	* rows in the strip (check for truncated last strip on any
	* of the separations).
	*/
	if( td->td_rowsperstrip >= td->td_imagelength )
	strips_per_sep = 1;
	else
	strips_per_sep = (td->td_imagelength+td->td_rowsperstrip-1)
	/ td->td_rowsperstrip;

	sep_strip = strip % strips_per_sep;

	if (sep_strip != strips_per_sep-1 \|\|
	(nrows = td->td_imagelength % td->td_rowsperstrip) == 0)
	nrows = td->td_rowsperstrip;

	stripsize = TIFFVStripSize(tif, nrows);
	if (size == (tsize_t) -1)
	size = stripsize;
	else if (size > stripsize)
	size = stripsize;
	if (TIFFFillStrip(tif, strip)
	&& (*tif->tif_decodestrip)(tif, (tidata_t) buf, size,
	(tsample_t)(strip / td->td_stripsperimage)) > 0 ) {
	(*tif->tif_postdecode)(tif, (tidata_t) buf, size);
	return (size);
	} else
	return ((tsize_t) -1);
	}

	static tsize_t
	TIFFReadRawStrip1(TIFF* tif,
	tstrip_t strip, tdata_t buf, tsize_t size, const char* module)
	{
	TIFFDirectory *td = &tif->tif_dir;

	assert((tif->tif_flags&TIFF_NOREADRAW)==0);
	if (!isMapped(tif)) {
	tsize_t cc;

	if (!SeekOK(tif, td->td_stripoffset[strip])) {
	TIFFErrorExt(tif->tif_clientdata, module,
	"%s: Seek error at scanline %lu, strip %lu",
	tif->tif_name,
	(unsigned long) tif->tif_row, (unsigned long) strip);
	return (-1);
	}
	cc = TIFFReadFile(tif, buf, size);
	if (cc != size) {
	TIFFErrorExt(tif->tif_clientdata, module,
	"%s: Read error at scanline %lu; got %lu bytes, expected %lu",
	tif->tif_name,
	(unsigned long) tif->tif_row,
	(unsigned long) cc,
	(unsigned long) size);
	return (-1);
	}
	} else {
	if (td->td_stripoffset[strip] + size > tif->tif_size) {
	TIFFErrorExt(tif->tif_clientdata, module,
	"%s: Read error at scanline %lu, strip %lu; got %lu bytes, expected %lu",
	tif->tif_name,
	(unsigned long) tif->tif_row,
	(unsigned long) strip,
	(unsigned long) tif->tif_size - td->td_stripoffset[strip],
	(unsigned long) size);
	return (-1);
	}
	_TIFFmemcpy(buf, tif->tif_base + td->td_stripoffset[strip],
	size);
	}
	return (size);
	}

	/*
	* Read a strip of data from the file.
	*/
	tsize_t
	TIFFReadRawStrip(TIFF* tif, tstrip_t strip, tdata_t buf, tsize_t size)
	{
	static const char module[] = "TIFFReadRawStrip";
	TIFFDirectory *td = &tif->tif_dir;
	/*
	* FIXME: butecount should have tsize_t type, but for now libtiff
	* defines tsize_t as a signed 32-bit integer and we are losing
	* ability to read arrays larger than 2^31 bytes. So we are using
	* uint32 instead of tsize_t here.
	*/
	uint32 bytecount;

	if (!TIFFCheckRead(tif, 0))
	return ((tsize_t) -1);
	if (strip >= td->td_nstrips) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"%lu: Strip out of range, max %lu",
	(unsigned long) strip,
	(unsigned long) td->td_nstrips);
	return ((tsize_t) -1);
	}
	if (tif->tif_flags&TIFF_NOREADRAW)
	{
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"Compression scheme does not support access to raw uncompressed data");
	return ((tsize_t) -1);
	}
	bytecount = td->td_stripbytecount[strip];
	if (bytecount <= 0) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"%lu: Invalid strip byte count, strip %lu",
	(unsigned long) bytecount, (unsigned long) strip);
	return ((tsize_t) -1);
	}
	if (size != (tsize_t)-1 && (uint32)size < bytecount)
	bytecount = size;
	return (TIFFReadRawStrip1(tif, strip, buf, bytecount, module));
	}

	/*
	* Read the specified strip and setup for decoding. The data buffer is
	* expanded, as necessary, to hold the strip's data.
	*/
	int
	TIFFFillStrip(TIFF* tif, tstrip_t strip)
	{
	static const char module[] = "TIFFFillStrip";
	TIFFDirectory *td = &tif->tif_dir;

	if ((tif->tif_flags&TIFF_NOREADRAW)==0)
	{
	/*
	* FIXME: butecount should have tsize_t type, but for now
	* libtiff defines tsize_t as a signed 32-bit integer and we
	* are losing ability to read arrays larger than 2^31 bytes.
	* So we are using uint32 instead of tsize_t here.
	*/
	uint32 bytecount = td->td_stripbytecount[strip];
	if (bytecount <= 0) {
	TIFFErrorExt(tif->tif_clientdata, module,
	"%s: Invalid strip byte count %lu, strip %lu",
	tif->tif_name, (unsigned long) bytecount,
	(unsigned long) strip);
	return (0);
	}
	if (isMapped(tif) &&
	(isFillOrder(tif, td->td_fillorder)
	\|\| (tif->tif_flags & TIFF_NOBITREV))) {
	/*
	* The image is mapped into memory and we either don't
	* need to flip bits or the compression routine is
	* going to handle this operation itself. In this
	* case, avoid copying the raw data and instead just
	* reference the data from the memory mapped file
	* image. This assumes that the decompression
	* routines do not modify the contents of the raw data
	* buffer (if they try to, the application will get a
	* fault since the file is mapped read-only).
	*/
	if ((tif->tif_flags & TIFF_MYBUFFER) && tif->tif_rawdata)
	_TIFFfree(tif->tif_rawdata);
	tif->tif_flags &= ~TIFF_MYBUFFER;
	/*
	* We must check for overflow, potentially causing
	* an OOB read. Instead of simple
	*
	* td->td_stripoffset[strip]+bytecount > tif->tif_size
	*
	* comparison (which can overflow) we do the following
	* two comparisons:
	*/
	if (bytecount > tif->tif_size \|\|
	td->td_stripoffset[strip] > tif->tif_size - bytecount) {
	/*
	* This error message might seem strange, but
	* it's what would happen if a read were done
	* instead.
	*/
	TIFFErrorExt(tif->tif_clientdata, module,

	"%s: Read error on strip %lu; "
	"got %lu bytes, expected %lu",
	tif->tif_name, (unsigned long) strip,
	(unsigned long) tif->tif_size - td->td_stripoffset[strip],
	(unsigned long) bytecount);
	tif->tif_curstrip = NOSTRIP;
	return (0);
	}
	tif->tif_rawdatasize = bytecount;
	tif->tif_rawdata = tif->tif_base + td->td_stripoffset[strip];
	} else {
	/*
	* Expand raw data buffer, if needed, to hold data
	* strip coming from file (perhaps should set upper
	* bound on the size of a buffer we'll use?).
	*/
	if (bytecount > (uint32)tif->tif_rawdatasize) {
	tif->tif_curstrip = NOSTRIP;
	if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
	TIFFErrorExt(tif->tif_clientdata,
	module,
	"%s: Data buffer too small to hold strip %lu",
	tif->tif_name,
	(unsigned long) strip);
	return (0);
	}
	if (!TIFFReadBufferSetup(tif, 0,
	TIFFroundup(bytecount, 1024)))
	return (0);
	}
	if ((uint32)TIFFReadRawStrip1(tif, strip,
	(unsigned char *)tif->tif_rawdata,
	bytecount, module) != bytecount)
	return (0);
	if (!isFillOrder(tif, td->td_fillorder) &&
	(tif->tif_flags & TIFF_NOBITREV) == 0)
	TIFFReverseBits(tif->tif_rawdata, bytecount);
	}
	}
	return (TIFFStartStrip(tif, strip));
	}

	/*
	* Tile-oriented Read Support
	* Contributed by Nancy Cam (Silicon Graphics).
	*/

	/*
	* Read and decompress a tile of data. The
	* tile is selected by the (x,y,z,s) coordinates.
	*/
	tsize_t
	TIFFReadTile(TIFF* tif,
	tdata_t buf, uint32 x, uint32 y, uint32 z, tsample_t s)
	{
	if (!TIFFCheckRead(tif, 1) \|\| !TIFFCheckTile(tif, x, y, z, s))
	return (-1);
	return (TIFFReadEncodedTile(tif,
	TIFFComputeTile(tif, x, y, z, s), buf, (tsize_t) -1));
	}

	/*
	* Read a tile of data and decompress the specified
	* amount into the user-supplied buffer.
	*/
	tsize_t
	TIFFReadEncodedTile(TIFF* tif, ttile_t tile, tdata_t buf, tsize_t size)
	{
	TIFFDirectory *td = &tif->tif_dir;
	tsize_t tilesize = tif->tif_tilesize;

	if (!TIFFCheckRead(tif, 1))
	return (-1);
	if (tile >= td->td_nstrips) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"%ld: Tile out of range, max %ld",
	(long) tile, (unsigned long) td->td_nstrips);
	return (-1);
	}
	if (size == (tsize_t) -1)
	size = tilesize;
	else if (size > tilesize)
	size = tilesize;
	if (TIFFFillTile(tif, tile) && (*tif->tif_decodetile)(tif,
	(tidata_t) buf, size, (tsample_t)(tile/td->td_stripsperimage))) {
	(*tif->tif_postdecode)(tif, (tidata_t) buf, size);
	return (size);
	} else
	return (-1);
	}

	static tsize_t
	TIFFReadRawTile1(TIFF* tif,
	ttile_t tile, tdata_t buf, tsize_t size, const char* module)
	{
	TIFFDirectory *td = &tif->tif_dir;

	assert((tif->tif_flags&TIFF_NOREADRAW)==0);
	if (!isMapped(tif)) {
	tsize_t cc;

	if (!SeekOK(tif, td->td_stripoffset[tile])) {
	TIFFErrorExt(tif->tif_clientdata, module,
	"%s: Seek error at row %ld, col %ld, tile %ld",
	tif->tif_name,
	(long) tif->tif_row,
	(long) tif->tif_col,
	(long) tile);
	return ((tsize_t) -1);
	}
	cc = TIFFReadFile(tif, buf, size);
	if (cc != size) {
	TIFFErrorExt(tif->tif_clientdata, module,
	"%s: Read error at row %ld, col %ld; got %lu bytes, expected %lu",
	tif->tif_name,
	(long) tif->tif_row,
	(long) tif->tif_col,
	(unsigned long) cc,
	(unsigned long) size);
	return ((tsize_t) -1);
	}
	} else {
	if (td->td_stripoffset[tile] + size > tif->tif_size) {
	TIFFErrorExt(tif->tif_clientdata, module,
	"%s: Read error at row %ld, col %ld, tile %ld; got %lu bytes, expected %lu",
	tif->tif_name,
	(long) tif->tif_row,
	(long) tif->tif_col,
	(long) tile,
	(unsigned long) tif->tif_size - td->td_stripoffset[tile],
	(unsigned long) size);
	return ((tsize_t) -1);
	}
	_TIFFmemcpy(buf, tif->tif_base + td->td_stripoffset[tile], size);
	}
	return (size);
	}

	/*
	* Read a tile of data from the file.
	*/
	tsize_t
	TIFFReadRawTile(TIFF* tif, ttile_t tile, tdata_t buf, tsize_t size)
	{
	static const char module[] = "TIFFReadRawTile";
	TIFFDirectory *td = &tif->tif_dir;
	/*
	* FIXME: butecount should have tsize_t type, but for now libtiff
	* defines tsize_t as a signed 32-bit integer and we are losing
	* ability to read arrays larger than 2^31 bytes. So we are using
	* uint32 instead of tsize_t here.
	*/
	uint32 bytecount;

	if (!TIFFCheckRead(tif, 1))
	return ((tsize_t) -1);
	if (tile >= td->td_nstrips) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"%lu: Tile out of range, max %lu",
	(unsigned long) tile, (unsigned long) td->td_nstrips);
	return ((tsize_t) -1);
	}
	if (tif->tif_flags&TIFF_NOREADRAW)
	{
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"Compression scheme does not support access to raw uncompressed data");
	return ((tsize_t) -1);
	}
	bytecount = td->td_stripbytecount[tile];
	if (size != (tsize_t) -1 && (uint32)size < bytecount)
	bytecount = size;
	return (TIFFReadRawTile1(tif, tile, buf, bytecount, module));
	}

	/*
	* Read the specified tile and setup for decoding. The data buffer is
	* expanded, as necessary, to hold the tile's data.
	*/
	int
	TIFFFillTile(TIFF* tif, ttile_t tile)
	{
	static const char module[] = "TIFFFillTile";
	TIFFDirectory *td = &tif->tif_dir;

	if ((tif->tif_flags&TIFF_NOREADRAW)==0)
	{
	/*
	* FIXME: butecount should have tsize_t type, but for now
	* libtiff defines tsize_t as a signed 32-bit integer and we
	* are losing ability to read arrays larger than 2^31 bytes.
	* So we are using uint32 instead of tsize_t here.
	*/
	uint32 bytecount = td->td_stripbytecount[tile];
	if (bytecount <= 0) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
	"%lu: Invalid tile byte count, tile %lu",
	(unsigned long) bytecount, (unsigned long) tile);
	return (0);
	}
	if (isMapped(tif) &&
	(isFillOrder(tif, td->td_fillorder)
	\|\| (tif->tif_flags & TIFF_NOBITREV))) {
	/*
	* The image is mapped into memory and we either don't
	* need to flip bits or the compression routine is
	* going to handle this operation itself. In this
	* case, avoid copying the raw data and instead just
	* reference the data from the memory mapped file
	* image. This assumes that the decompression
	* routines do not modify the contents of the raw data
	* buffer (if they try to, the application will get a
	* fault since the file is mapped read-only).
	*/
	if ((tif->tif_flags & TIFF_MYBUFFER) && tif->tif_rawdata)
	_TIFFfree(tif->tif_rawdata);
	tif->tif_flags &= ~TIFF_MYBUFFER;
	/*
	* We must check for overflow, potentially causing
	* an OOB read. Instead of simple
	*
	* td->td_stripoffset[tile]+bytecount > tif->tif_size
	*
	* comparison (which can overflow) we do the following
	* two comparisons:
	*/
	if (bytecount > tif->tif_size \|\|
	td->td_stripoffset[tile] > tif->tif_size - bytecount) {
	tif->tif_curtile = NOTILE;
	return (0);
	}
	tif->tif_rawdatasize = bytecount;
	tif->tif_rawdata =
	tif->tif_base + td->td_stripoffset[tile];
	} else {
	/*
	* Expand raw data buffer, if needed, to hold data
	* tile coming from file (perhaps should set upper
	* bound on the size of a buffer we'll use?).
	*/
	if (bytecount > (uint32)tif->tif_rawdatasize) {
	tif->tif_curtile = NOTILE;
	if ((tif->tif_flags & TIFF_MYBUFFER) == 0) {
	TIFFErrorExt(tif->tif_clientdata,
	module,
	"%s: Data buffer too small to hold tile %ld",
	tif->tif_name,
	(long) tile);
	return (0);
	}
	if (!TIFFReadBufferSetup(tif, 0,
	TIFFroundup(bytecount, 1024)))
	return (0);
	}
	if ((uint32)TIFFReadRawTile1(tif, tile,
	(unsigned char *)tif->tif_rawdata,
	bytecount, module) != bytecount)
	return (0);
	if (!isFillOrder(tif, td->td_fillorder) &&
	(tif->tif_flags & TIFF_NOBITREV) == 0)
	TIFFReverseBits(tif->tif_rawdata, bytecount);
	}
	}
	return (TIFFStartTile(tif, tile));
	}

	/*
	* Setup the raw data buffer in preparation for
	* reading a strip of raw data. If the buffer
	* is specified as zero, then a buffer of appropriate
	* size is allocated by the library. Otherwise,
	* the client must guarantee that the buffer is
	* large enough to hold any individual strip of
	* raw data.
	*/
	int
	TIFFReadBufferSetup(TIFF* tif, tdata_t bp, tsize_t size)
	{
	static const char module[] = "TIFFReadBufferSetup";

	assert((tif->tif_flags&TIFF_NOREADRAW)==0);
	if (tif->tif_rawdata) {
	if (tif->tif_flags & TIFF_MYBUFFER)
	_TIFFfree(tif->tif_rawdata);
	tif->tif_rawdata = NULL;
	}
	if (bp) {
	tif->tif_rawdatasize = size;
	tif->tif_rawdata = (tidata_t) bp;
	tif->tif_flags &= ~TIFF_MYBUFFER;
	} else {
	tif->tif_rawdatasize = TIFFroundup(size, 1024);
	tif->tif_rawdata = (tidata_t) _TIFFmalloc(tif->tif_rawdatasize);
	tif->tif_flags \|= TIFF_MYBUFFER;
	}
	if (tif->tif_rawdata == NULL) {
	TIFFErrorExt(tif->tif_clientdata, module,
	"%s: No space for data buffer at scanline %ld",
	tif->tif_name, (long) tif->tif_row);
	tif->tif_rawdatasize = 0;
	return (0);
	}
	return (1);
	}

	/*
	* Set state to appear as if a
	* strip has just been read in.
	*/
	static int
	TIFFStartStrip(TIFF* tif, tstrip_t strip)
	{
	TIFFDirectory *td = &tif->tif_dir;

	if ((tif->tif_flags & TIFF_CODERSETUP) == 0) {
	if (!(*tif->tif_setupdecode)(tif))
	return (0);
	tif->tif_flags \|= TIFF_CODERSETUP;
	}
	tif->tif_curstrip = strip;
	tif->tif_row = (strip % td->td_stripsperimage) * td->td_rowsperstrip;
	if (tif->tif_flags&TIFF_NOREADRAW)
	{
	tif->tif_rawcp = NULL;
	tif->tif_rawcc = 0;
	}
	else
	{
	tif->tif_rawcp = tif->tif_rawdata;
	tif->tif_rawcc = td->td_stripbytecount[strip];
	}
	return ((*tif->tif_predecode)(tif,
	(tsample_t)(strip / td->td_stripsperimage)));
	}

	/*
	* Set state to appear as if a
	* tile has just been read in.
	*/
	static int
	TIFFStartTile(TIFF* tif, ttile_t tile)
	{
	TIFFDirectory *td = &tif->tif_dir;

	if ((tif->tif_flags & TIFF_CODERSETUP) == 0) {
	if (!(*tif->tif_setupdecode)(tif))
	return (0);
	tif->tif_flags \|= TIFF_CODERSETUP;
	}
	tif->tif_curtile = tile;
	tif->tif_row =
	(tile % TIFFhowmany(td->td_imagewidth, td->td_tilewidth)) *
	td->td_tilelength;
	tif->tif_col =
	(tile % TIFFhowmany(td->td_imagelength, td->td_tilelength)) *
	td->td_tilewidth;
	if (tif->tif_flags&TIFF_NOREADRAW)
	{
	tif->tif_rawcp = NULL;
	tif->tif_rawcc = 0;
	}
	else
	{
	tif->tif_rawcp = tif->tif_rawdata;
	tif->tif_rawcc = td->td_stripbytecount[tile];
	}
	return ((*tif->tif_predecode)(tif,
	(tsample_t)(tile/td->td_stripsperimage)));
	}

	static int
	TIFFCheckRead(TIFF* tif, int tiles)
	{
	if (tif->tif_mode == O_WRONLY) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name, "File not open for reading");
	return (0);
	}
	if (tiles ^ isTiled(tif)) {
	TIFFErrorExt(tif->tif_clientdata, tif->tif_name, tiles ?
	"Can not read tiles from a stripped image" :
	"Can not read scanlines from a tiled image");
	return (0);
	}
	return (1);
	}

	void
	_TIFFNoPostDecode(TIFF* tif, tidata_t buf, tsize_t cc)
	{
	(void) tif; (void) buf; (void) cc;
	}

	void
	_TIFFSwab16BitData(TIFF* tif, tidata_t buf, tsize_t cc)
	{
	(void) tif;
	assert((cc & 1) == 0);
	TIFFSwabArrayOfShort((uint16*) buf, cc/2);
	}

	void
	_TIFFSwab24BitData(TIFF* tif, tidata_t buf, tsize_t cc)
	{
	(void) tif;
	assert((cc % 3) == 0);
	TIFFSwabArrayOfTriples((uint8*) buf, cc/3);
	}

	void
	_TIFFSwab32BitData(TIFF* tif, tidata_t buf, tsize_t cc)
	{
	(void) tif;
	assert((cc & 3) == 0);
	TIFFSwabArrayOfLong((uint32*) buf, cc/4);
	}

	void
	_TIFFSwab64BitData(TIFF* tif, tidata_t buf, tsize_t cc)
	{
	(void) tif;
	assert((cc & 7) == 0);
	TIFFSwabArrayOfDouble((double*) buf, cc/8);
	}

	/* vim: set ts=8 sts=8 sw=8 noet: */