tif_read.c

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/* $Id: tif_read.c,v 1.16.2.3 2010-06-09 14:32:47 bfriesen 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);
        if (tif->tif_rawdatasize > 0)
            tif->tif_rawdata = (tidata_t) _TIFFmalloc(tif->tif_rawdatasize);
        tif->tif_flags |= TIFF_MYBUFFER;
    }
    if ((tif->tif_rawdata == NULL) || (tif->tif_rawdatasize == 0)) {
        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: */
/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 8
 * fill-column: 78
 * End:
 */