remove .cvsignore files, they're useless with svn

[wxWidgets.git] / src / tiff / tif_dirread.c

/* $Header$ */

/*
 * 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.
 *
 * Directory Read Support Routines.
 */
#include "tiffiop.h"

#define IGNORE  0               /* tag placeholder used below */

#if HAVE_IEEEFP
#define TIFFCvtIEEEFloatToNative(tif, n, fp)
#define TIFFCvtIEEEDoubleToNative(tif, n, dp)
#else
extern  void TIFFCvtIEEEFloatToNative(TIFF*, uint32, float*);
extern  void TIFFCvtIEEEDoubleToNative(TIFF*, uint32, double*);
#endif

static  int EstimateStripByteCounts(TIFF*, TIFFDirEntry*, uint16);
static  void MissingRequired(TIFF*, const char*);
static  int CheckDirCount(TIFF*, TIFFDirEntry*, uint32);
static  tsize_t TIFFFetchData(TIFF*, TIFFDirEntry*, char*);
static  tsize_t TIFFFetchString(TIFF*, TIFFDirEntry*, char*);
static  float TIFFFetchRational(TIFF*, TIFFDirEntry*);
static  int TIFFFetchNormalTag(TIFF*, TIFFDirEntry*);
static  int TIFFFetchPerSampleShorts(TIFF*, TIFFDirEntry*, int*);
static  int TIFFFetchPerSampleAnys(TIFF*, TIFFDirEntry*, double*);
static  int TIFFFetchShortArray(TIFF*, TIFFDirEntry*, uint16*);
static  int TIFFFetchStripThing(TIFF*, TIFFDirEntry*, long, uint32**);
static  int TIFFFetchExtraSamples(TIFF*, TIFFDirEntry*);
static  int TIFFFetchRefBlackWhite(TIFF*, TIFFDirEntry*);
static  float TIFFFetchFloat(TIFF*, TIFFDirEntry*);
static  int TIFFFetchFloatArray(TIFF*, TIFFDirEntry*, float*);
static  int TIFFFetchDoubleArray(TIFF*, TIFFDirEntry*, double*);
static  int TIFFFetchAnyArray(TIFF*, TIFFDirEntry*, double*);
static  int TIFFFetchShortPair(TIFF*, TIFFDirEntry*);
static  void ChopUpSingleUncompressedStrip(TIFF*);

static char *
CheckMalloc(TIFF* tif, size_t nmemb, size_t elem_size, const char* what)
{
        char    *cp = NULL;
        tsize_t bytes = nmemb * elem_size;

        if (nmemb && elem_size && bytes / elem_size == nmemb)
                cp = (char*)_TIFFmalloc(bytes);

        if (cp == NULL)
                TIFFError(tif->tif_name, "No space %s", what);
        
        return (cp);
}

/*
 * Read the next TIFF directory from a file
 * and convert it to the internal format.
 * We read directories sequentially.
 */
int
TIFFReadDirectory(TIFF* tif)
{
        static const char module[] = "TIFFReadDirectory";

        register TIFFDirEntry* dp;
        register int n;
        register TIFFDirectory* td;
        TIFFDirEntry* dir;
        int iv;
        long v;
        double dv;
        const TIFFFieldInfo* fip;
        int fix;
        uint16 dircount;
        toff_t nextdiroff;
        char* cp;
        int diroutoforderwarning = 0;
        toff_t* new_dirlist;

        tif->tif_diroff = tif->tif_nextdiroff;
        if (tif->tif_diroff == 0)               /* no more directories */
                return (0);

        /*
         * XXX: Trick to prevent IFD looping. The one can create TIFF file
         * with looped directory pointers. We will maintain a list of already
         * seen directories and check every IFD offset against this list.
         */
        for (n = 0; n < tif->tif_dirnumber; n++) {
                if (tif->tif_dirlist[n] == tif->tif_diroff)
                        return (0);
        }
        tif->tif_dirnumber++;
        new_dirlist = _TIFFrealloc(tif->tif_dirlist,
                                   tif->tif_dirnumber * sizeof(toff_t));
        if (!new_dirlist) {
                TIFFError(module,
                          "%.1000s: Failed to allocate space for IFD list",
                          tif->tif_name);
                return (0);
        }
        tif->tif_dirlist = new_dirlist;
        tif->tif_dirlist[tif->tif_dirnumber - 1] = tif->tif_diroff;

        /*
         * Cleanup any previous compression state.
         */
        (*tif->tif_cleanup)(tif);
        tif->tif_curdir++;
        nextdiroff = 0;
        if (!isMapped(tif)) {
                if (!SeekOK(tif, tif->tif_diroff)) {
                        TIFFError(module,
                            "%.1000s: Seek error accessing TIFF directory",
                            tif->tif_name);
                        return (0);
                }
                if (!ReadOK(tif, &dircount, sizeof (uint16))) {
                        TIFFError(module,
                            "%.1000s: Can not read TIFF directory count",
                            tif->tif_name);
                        return (0);
                }
                if (tif->tif_flags & TIFF_SWAB)
                        TIFFSwabShort(&dircount);
                dir = (TIFFDirEntry *)CheckMalloc(tif,
                    dircount, sizeof (TIFFDirEntry), "to read TIFF directory");
                if (dir == NULL)
                        return (0);
                if (!ReadOK(tif, dir, dircount*sizeof (TIFFDirEntry))) {
                        TIFFError(module,
                                  "%.100s: Can not read TIFF directory",
                                  tif->tif_name);
                        goto bad;
                }
                /*
                 * Read offset to next directory for sequential scans.
                 */
                (void) ReadOK(tif, &nextdiroff, sizeof (uint32));
        } else {
                toff_t off = tif->tif_diroff;

                if (off + sizeof (uint16) > tif->tif_size) {
                        TIFFError(module,
                            "%.1000s: Can not read TIFF directory count",
                            tif->tif_name);
                        return (0);
                } else
                        _TIFFmemcpy(&dircount, tif->tif_base + off, sizeof (uint16));
                off += sizeof (uint16);
                if (tif->tif_flags & TIFF_SWAB)
                        TIFFSwabShort(&dircount);
                dir = (TIFFDirEntry *)CheckMalloc(tif,
                    dircount, sizeof (TIFFDirEntry), "to read TIFF directory");
                if (dir == NULL)
                        return (0);
                if (off + dircount*sizeof (TIFFDirEntry) > tif->tif_size) {
                        TIFFError(module,
                                  "%.1000s: Can not read TIFF directory",
                                  tif->tif_name);
                        goto bad;
                } else {
                        _TIFFmemcpy(dir, tif->tif_base + off,
                                    dircount*sizeof (TIFFDirEntry));
                }
                off += dircount* sizeof (TIFFDirEntry);
                if (off + sizeof (uint32) <= tif->tif_size)
                        _TIFFmemcpy(&nextdiroff, tif->tif_base+off, sizeof (uint32));
        }
        if (tif->tif_flags & TIFF_SWAB)
                TIFFSwabLong(&nextdiroff);
        tif->tif_nextdiroff = nextdiroff;

        tif->tif_flags &= ~TIFF_BEENWRITING;    /* reset before new dir */
        /*
         * Setup default value and then make a pass over
         * the fields to check type and tag information,
         * and to extract info required to size data
         * structures.  A second pass is made afterwards
         * to read in everthing not taken in the first pass.
         */
        td = &tif->tif_dir;
        /* free any old stuff and reinit */
        TIFFFreeDirectory(tif);
        TIFFDefaultDirectory(tif);
        /*
         * Electronic Arts writes gray-scale TIFF files
         * without a PlanarConfiguration directory entry.
         * Thus we setup a default value here, even though
         * the TIFF spec says there is no default value.
         */
        TIFFSetField(tif, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);

        /*
         * Sigh, we must make a separate pass through the
         * directory for the following reason:
         *
         * We must process the Compression tag in the first pass
         * in order to merge in codec-private tag definitions (otherwise
         * we may get complaints about unknown tags).  However, the
         * Compression tag may be dependent on the SamplesPerPixel
         * tag value because older TIFF specs permited Compression
         * to be written as a SamplesPerPixel-count tag entry.
         * Thus if we don't first figure out the correct SamplesPerPixel
         * tag value then we may end up ignoring the Compression tag
         * value because it has an incorrect count value (if the
         * true value of SamplesPerPixel is not 1).
         *
         * It sure would have been nice if Aldus had really thought
         * this stuff through carefully.
         */ 
        for (dp = dir, n = dircount; n > 0; n--, dp++) {
                if (tif->tif_flags & TIFF_SWAB) {
                        TIFFSwabArrayOfShort(&dp->tdir_tag, 2);
                        TIFFSwabArrayOfLong(&dp->tdir_count, 2);
                }
                if (dp->tdir_tag == TIFFTAG_SAMPLESPERPIXEL) {
                        if (!TIFFFetchNormalTag(tif, dp))
                                goto bad;
                        dp->tdir_tag = IGNORE;
                }
        }
        /*
         * First real pass over the directory.
         */
        fix = 0;
        for (dp = dir, n = dircount; n > 0; n--, dp++) {

                /*
                 * Find the field information entry for this tag.
                 * Added check for tags to ignore ... [BFC]
                 */
                if( TIFFReassignTagToIgnore(TIS_EXTRACT, dp->tdir_tag) )
                    dp->tdir_tag = IGNORE;

                if (fix >= tif->tif_nfields || dp->tdir_tag == IGNORE)
                        continue;
               
                /*
                 * Silicon Beach (at least) writes unordered
                 * directory tags (violating the spec).  Handle
                 * it here, but be obnoxious (maybe they'll fix it?).
                 */
                if (dp->tdir_tag < tif->tif_fieldinfo[fix]->field_tag) {
                        if (!diroutoforderwarning) {
                                TIFFWarning(module,
"%.1000s: invalid TIFF directory; tags are not sorted in ascending order",
                                            tif->tif_name);
                                diroutoforderwarning = 1;
                        }
                        fix = 0;                        /* O(n^2) */
                }
                while (fix < tif->tif_nfields &&
                       tif->tif_fieldinfo[fix]->field_tag < dp->tdir_tag)
                        fix++;
                if (fix >= tif->tif_nfields ||
                    tif->tif_fieldinfo[fix]->field_tag != dp->tdir_tag) {

                    TIFFWarning(module,
                        "%.1000s: unknown field with tag %d (0x%x) encountered",
                                tif->tif_name, dp->tdir_tag,  dp->tdir_tag);

                    TIFFMergeFieldInfo( tif,
                                        _TIFFCreateAnonFieldInfo( tif,
                                              dp->tdir_tag,
                                              (TIFFDataType) dp->tdir_type ),
                                        1 );
                    fix = 0;
                    while (fix < tif->tif_nfields &&
                           tif->tif_fieldinfo[fix]->field_tag < dp->tdir_tag)
                        fix++;
                }
                /*
                 * Null out old tags that we ignore.
                 */
                if (tif->tif_fieldinfo[fix]->field_bit == FIELD_IGNORE) {
        ignore:
                        dp->tdir_tag = IGNORE;
                        continue;
                }
                /*
                 * Check data type.
                 */
                fip = tif->tif_fieldinfo[fix];
                while (dp->tdir_type != (u_short) fip->field_type) {
                        if (fip->field_type == TIFF_ANY)        /* wildcard */
                                break;
                        fip++, fix++;
                        if (fix == tif->tif_nfields ||
                            fip->field_tag != dp->tdir_tag) {
                                TIFFWarning(module,
                        "%.1000s: wrong data type %d for \"%s\"; tag ignored",
                                            tif->tif_name, dp->tdir_type,
                                            fip[-1].field_name);
                                goto ignore;
                        }
                }
                /*
                 * Check count if known in advance.
                 */
                if (fip->field_readcount != TIFF_VARIABLE) {
                        uint32 expected = (fip->field_readcount == TIFF_SPP) ?
                            (uint32) td->td_samplesperpixel :
                            (uint32) fip->field_readcount;
                        if (!CheckDirCount(tif, dp, expected))
                                goto ignore;
                }

                switch (dp->tdir_tag) {
                case TIFFTAG_COMPRESSION:
                        /*
                         * The 5.0 spec says the Compression tag has
                         * one value, while earlier specs say it has
                         * one value per sample.  Because of this, we
                         * accept the tag if one value is supplied.
                         */
                        if (dp->tdir_count == 1) {
                                v = TIFFExtractData(tif,
                                    dp->tdir_type, dp->tdir_offset);
                                if (!TIFFSetField(tif, dp->tdir_tag, (int)v))
                                        goto bad;
                                break;
                        }
                        if (!TIFFFetchPerSampleShorts(tif, dp, &iv) ||
                            !TIFFSetField(tif, dp->tdir_tag, iv))
                                goto bad;
                        dp->tdir_tag = IGNORE;
                        break;
                case TIFFTAG_STRIPOFFSETS:
                case TIFFTAG_STRIPBYTECOUNTS:
                case TIFFTAG_TILEOFFSETS:
                case TIFFTAG_TILEBYTECOUNTS:
                        TIFFSetFieldBit(tif, fip->field_bit);
                        break;
                case TIFFTAG_IMAGEWIDTH:
                case TIFFTAG_IMAGELENGTH:
                case TIFFTAG_IMAGEDEPTH:
                case TIFFTAG_TILELENGTH:
                case TIFFTAG_TILEWIDTH:
                case TIFFTAG_TILEDEPTH:
                case TIFFTAG_PLANARCONFIG:
                case TIFFTAG_ROWSPERSTRIP:
                        if (!TIFFFetchNormalTag(tif, dp))
                                goto bad;
                        dp->tdir_tag = IGNORE;
                        break;
                case TIFFTAG_EXTRASAMPLES:
                        (void) TIFFFetchExtraSamples(tif, dp);
                        dp->tdir_tag = IGNORE;
                        break;
                }
        }

        /*
         * Allocate directory structure and setup defaults.
         */
        if (!TIFFFieldSet(tif, FIELD_IMAGEDIMENSIONS)) {
                MissingRequired(tif, "ImageLength");
                goto bad;
        }
        if (!TIFFFieldSet(tif, FIELD_PLANARCONFIG)) {
                MissingRequired(tif, "PlanarConfiguration");
                goto bad;
        }
        /* 
         * Setup appropriate structures (by strip or by tile)
         */
        if (!TIFFFieldSet(tif, FIELD_TILEDIMENSIONS)) {
                td->td_nstrips = TIFFNumberOfStrips(tif);
                td->td_tilewidth = td->td_imagewidth;
                td->td_tilelength = td->td_rowsperstrip;
                td->td_tiledepth = td->td_imagedepth;
                tif->tif_flags &= ~TIFF_ISTILED;
        } else {
                td->td_nstrips = TIFFNumberOfTiles(tif);
                tif->tif_flags |= TIFF_ISTILED;
        }
        if (!td->td_nstrips) {
                TIFFError(module, "%s: cannot handle zero number of %s",
                          tif->tif_name, isTiled(tif) ? "tiles" : "strips");
                goto bad;
        }
        td->td_stripsperimage = td->td_nstrips;
        if (td->td_planarconfig == PLANARCONFIG_SEPARATE)
                td->td_stripsperimage /= td->td_samplesperpixel;
        if (!TIFFFieldSet(tif, FIELD_STRIPOFFSETS)) {
                MissingRequired(tif,
                    isTiled(tif) ? "TileOffsets" : "StripOffsets");
                goto bad;
        }

        /*
         * Second pass: extract other information.
         */
        for (dp = dir, n = dircount; n > 0; n--, dp++) {
                if (dp->tdir_tag == IGNORE)
                        continue;
                switch (dp->tdir_tag) {
                case TIFFTAG_MINSAMPLEVALUE:
                case TIFFTAG_MAXSAMPLEVALUE:
                case TIFFTAG_BITSPERSAMPLE:
                        /*
                         * The 5.0 spec says the Compression tag has
                         * one value, while earlier specs say it has
                         * one value per sample.  Because of this, we
                         * accept the tag if one value is supplied.
                         *
                         * The MinSampleValue, MaxSampleValue and
                         * BitsPerSample tags are supposed to be written
                         * as one value/sample, but some vendors incorrectly
                         * write one value only -- so we accept that
                         * as well (yech).
                         */
                        if (dp->tdir_count == 1) {
                                v = TIFFExtractData(tif,
                                    dp->tdir_type, dp->tdir_offset);
                                if (!TIFFSetField(tif, dp->tdir_tag, (int)v))
                                        goto bad;
                                break;
                        }
                        /* fall thru... */
                case TIFFTAG_DATATYPE:
                case TIFFTAG_SAMPLEFORMAT:
                        if (!TIFFFetchPerSampleShorts(tif, dp, &iv) ||
                            !TIFFSetField(tif, dp->tdir_tag, iv))
                                goto bad;
                        break;
                case TIFFTAG_SMINSAMPLEVALUE:
                case TIFFTAG_SMAXSAMPLEVALUE:
                        if (!TIFFFetchPerSampleAnys(tif, dp, &dv) ||
                            !TIFFSetField(tif, dp->tdir_tag, dv))
                                goto bad;
                        break;
                case TIFFTAG_STRIPOFFSETS:
                case TIFFTAG_TILEOFFSETS:
                        if (!TIFFFetchStripThing(tif, dp,
                            td->td_nstrips, &td->td_stripoffset))
                                goto bad;
                        break;
                case TIFFTAG_STRIPBYTECOUNTS:
                case TIFFTAG_TILEBYTECOUNTS:
                        if (!TIFFFetchStripThing(tif, dp,
                            td->td_nstrips, &td->td_stripbytecount))
                                goto bad;
                        break;
                case TIFFTAG_COLORMAP:
                case TIFFTAG_TRANSFERFUNCTION:
                        /*
                         * TransferFunction can have either 1x or 3x data
                         * values; Colormap can have only 3x items.
                         */
                        v = 1L<<td->td_bitspersample;
                        if (dp->tdir_tag == TIFFTAG_COLORMAP ||
                            dp->tdir_count != (uint32) v) {
                                if (!CheckDirCount(tif, dp, (uint32)(3*v)))
                                        break;
                        }
                        v *= sizeof (uint16);
                        cp = CheckMalloc(tif, dp->tdir_count, sizeof (uint16),
                            "to read \"TransferFunction\" tag");
                        if (cp != NULL) {
                                if (TIFFFetchData(tif, dp, cp)) {
                                        /*
                                         * This deals with there being only
                                         * one array to apply to all samples.
                                         */
                                        uint32 c =
                                            (uint32)1 << td->td_bitspersample;
                                        if (dp->tdir_count == c)
                                                v = 0;
                                        TIFFSetField(tif, dp->tdir_tag,
                                            cp, cp+v, cp+2*v);
                                }
                                _TIFFfree(cp);
                        }
                        break;
                case TIFFTAG_PAGENUMBER:
                case TIFFTAG_HALFTONEHINTS:
                case TIFFTAG_YCBCRSUBSAMPLING:
                case TIFFTAG_DOTRANGE:
                        (void) TIFFFetchShortPair(tif, dp);
                        break;
#ifdef COLORIMETRY_SUPPORT
                case TIFFTAG_REFERENCEBLACKWHITE:
                        (void) TIFFFetchRefBlackWhite(tif, dp);
                        break;
#endif
/* BEGIN REV 4.0 COMPATIBILITY */
                case TIFFTAG_OSUBFILETYPE:
                        v = 0;
                        switch (TIFFExtractData(tif, dp->tdir_type,
                            dp->tdir_offset)) {
                        case OFILETYPE_REDUCEDIMAGE:
                                v = FILETYPE_REDUCEDIMAGE;
                                break;
                        case OFILETYPE_PAGE:
                                v = FILETYPE_PAGE;
                                break;
                        }
                        if (v)
                                (void) TIFFSetField(tif,
                                    TIFFTAG_SUBFILETYPE, (int)v);
                        break;
/* END REV 4.0 COMPATIBILITY */
                default:
                        (void) TIFFFetchNormalTag(tif, dp);
                        break;
                }
        }
        /*
         * Verify Palette image has a Colormap.
         */
        if (td->td_photometric == PHOTOMETRIC_PALETTE &&
            !TIFFFieldSet(tif, FIELD_COLORMAP)) {
                MissingRequired(tif, "Colormap");
                goto bad;
        }
        /*
         * Attempt to deal with a missing StripByteCounts tag.
         */
        if (!TIFFFieldSet(tif, FIELD_STRIPBYTECOUNTS)) {
                /*
                 * Some manufacturers violate the spec by not giving
                 * the size of the strips.  In this case, assume there
                 * is one uncompressed strip of data.
                 */
                if ((td->td_planarconfig == PLANARCONFIG_CONTIG &&
                    td->td_nstrips > 1) ||
                    (td->td_planarconfig == PLANARCONFIG_SEPARATE &&
                     td->td_nstrips != td->td_samplesperpixel)) {
                    MissingRequired(tif, "StripByteCounts");
                    goto bad;
                }
                TIFFWarning(module,
                        "%.1000s: TIFF directory is missing required "
                        "\"%s\" field, calculating from imagelength",
                        tif->tif_name,
                        _TIFFFieldWithTag(tif,TIFFTAG_STRIPBYTECOUNTS)->field_name);
                if (EstimateStripByteCounts(tif, dir, dircount) < 0)
                    goto bad;
/* 
 * Assume we have wrong StripByteCount value (in case of single strip) in
 * following cases:
 *   - it is equal to zero along with StripOffset;
 *   - it is larger than file itself (in case of uncompressed image).
 */
#define BYTECOUNTLOOKSBAD \
    ( (td->td_stripbytecount[0] == 0 && td->td_stripoffset[0] != 0) || \
      (td->td_compression == COMPRESSION_NONE && \
       td->td_stripbytecount[0] > TIFFGetFileSize(tif) - td->td_stripoffset[0]) )
        } else if (td->td_nstrips == 1 && BYTECOUNTLOOKSBAD) {
                /*
                 * Plexus (and others) sometimes give a value
                 * of zero for a tag when they don't know what
                 * the correct value is!  Try and handle the
                 * simple case of estimating the size of a one
                 * strip image.
                 */
                TIFFWarning(module,
        "%.1000s: Bogus \"%s\" field, ignoring and calculating from imagelength",
                            tif->tif_name,
                            _TIFFFieldWithTag(tif,TIFFTAG_STRIPBYTECOUNTS)->field_name);
                if(EstimateStripByteCounts(tif, dir, dircount) < 0)
                    goto bad;
        }
        if (dir) {
                _TIFFfree((char *)dir);
                dir = NULL;
        }
        if (!TIFFFieldSet(tif, FIELD_MAXSAMPLEVALUE))
                td->td_maxsamplevalue = (uint16)((1L<<td->td_bitspersample)-1);
        /*
         * Setup default compression scheme.
         */
        if (!TIFFFieldSet(tif, FIELD_COMPRESSION))
                TIFFSetField(tif, TIFFTAG_COMPRESSION, COMPRESSION_NONE);
        /*
         * Some manufacturers make life difficult by writing
         * large amounts of uncompressed data as a single strip.
         * This is contrary to the recommendations of the spec.
         * The following makes an attempt at breaking such images
         * into strips closer to the recommended 8k bytes.  A
         * side effect, however, is that the RowsPerStrip tag
         * value may be changed.
         */
        if (td->td_nstrips == 1 && td->td_compression == COMPRESSION_NONE &&
            (tif->tif_flags & (TIFF_STRIPCHOP|TIFF_ISTILED)) == TIFF_STRIPCHOP)
                ChopUpSingleUncompressedStrip(tif);
        /*
         * Reinitialize i/o since we are starting on a new directory.
         */
        tif->tif_row = (uint32) -1;
        tif->tif_curstrip = (tstrip_t) -1;
        tif->tif_col = (uint32) -1;
        tif->tif_curtile = (ttile_t) -1;
        tif->tif_tilesize = TIFFTileSize(tif);
        tif->tif_scanlinesize = TIFFScanlineSize(tif);

        if (!tif->tif_tilesize) {
                TIFFError(module, "%s: cannot handle zero tile size",
                          tif->tif_name);
                return (0);
        }
        if (!tif->tif_scanlinesize) {
                TIFFError(module, "%s: cannot handle zero scanline size",
                          tif->tif_name);
                return (0);
        }
        return (1);
bad:
        if (dir)
                _TIFFfree(dir);
        return (0);
}

static int
EstimateStripByteCounts(TIFF* tif, TIFFDirEntry* dir, uint16 dircount)
{
        static const char module[] = "EstimateStripByteCounts";

        register TIFFDirEntry *dp;
        register TIFFDirectory *td = &tif->tif_dir;
        uint16 i;

        if (td->td_stripbytecount)
                _TIFFfree(td->td_stripbytecount);
        td->td_stripbytecount = (uint32*)
            CheckMalloc(tif, td->td_nstrips, sizeof (uint32),
                "for \"StripByteCounts\" array");
        if (td->td_compression != COMPRESSION_NONE) {
                uint32 space = (uint32)(sizeof (TIFFHeader)
                    + sizeof (uint16)
                    + (dircount * sizeof (TIFFDirEntry))
                    + sizeof (uint32));
                toff_t filesize = TIFFGetFileSize(tif);
                uint16 n;

                /* calculate amount of space used by indirect values */
                for (dp = dir, n = dircount; n > 0; n--, dp++)
                {
                        uint32 cc = TIFFDataWidth((TIFFDataType) dp->tdir_type);
                        if (cc == 0) {
                                TIFFError(module,
                        "%.1000s: Cannot determine size of unknown tag type %d",
                                          tif->tif_name, dp->tdir_type);
                                return -1;
                        }
                        cc = cc * dp->tdir_count;
                        if (cc > sizeof (uint32))
                                space += cc;
                }
                space = filesize - space;
                if (td->td_planarconfig == PLANARCONFIG_SEPARATE)
                        space /= td->td_samplesperpixel;
                for (i = 0; i < td->td_nstrips; i++)
                        td->td_stripbytecount[i] = space;
                /*
                 * This gross hack handles the case were the offset to
                 * the last strip is past the place where we think the strip
                 * should begin.  Since a strip of data must be contiguous,
                 * it's safe to assume that we've overestimated the amount
                 * of data in the strip and trim this number back accordingly.
                 */ 
                i--;
                if (((toff_t)(td->td_stripoffset[i]+td->td_stripbytecount[i]))
                                                               > filesize)
                        td->td_stripbytecount[i] =
                            filesize - td->td_stripoffset[i];
        } else {
                uint32 rowbytes = TIFFScanlineSize(tif);
                uint32 rowsperstrip = td->td_imagelength/td->td_stripsperimage;
                for (i = 0; i < td->td_nstrips; i++)
                        td->td_stripbytecount[i] = rowbytes*rowsperstrip;
        }
        TIFFSetFieldBit(tif, FIELD_STRIPBYTECOUNTS);
        if (!TIFFFieldSet(tif, FIELD_ROWSPERSTRIP))
                td->td_rowsperstrip = td->td_imagelength;
        return 1;
}

static void
MissingRequired(TIFF* tif, const char* tagname)
{
        static const char module[] = "MissingRequired";

        TIFFError(module,
                  "%.1000s: TIFF directory is missing required \"%s\" field",
                  tif->tif_name, tagname);
}

/*
 * Check the count field of a directory
 * entry against a known value.  The caller
 * is expected to skip/ignore the tag if
 * there is a mismatch.
 */
static int
CheckDirCount(TIFF* tif, TIFFDirEntry* dir, uint32 count)
{
        if (count != dir->tdir_count) {
                TIFFWarning(tif->tif_name,
        "incorrect count for field \"%s\" (%lu, expecting %lu); tag ignored",
                    _TIFFFieldWithTag(tif, dir->tdir_tag)->field_name,
                    dir->tdir_count, count);
                return (0);
        }
        return (1);
}

/*
 * Fetch a contiguous directory item.
 */
static tsize_t
TIFFFetchData(TIFF* tif, TIFFDirEntry* dir, char* cp)
{
        int w = TIFFDataWidth((TIFFDataType) dir->tdir_type);
        tsize_t cc = dir->tdir_count * w;

        if (!isMapped(tif)) {
                if (!SeekOK(tif, dir->tdir_offset))
                        goto bad;
                if (!ReadOK(tif, cp, cc))
                        goto bad;
        } else {
                if (dir->tdir_offset + cc > tif->tif_size)
                        goto bad;
                _TIFFmemcpy(cp, tif->tif_base + dir->tdir_offset, cc);
        }
        if (tif->tif_flags & TIFF_SWAB) {
                switch (dir->tdir_type) {
                case TIFF_SHORT:
                case TIFF_SSHORT:
                        TIFFSwabArrayOfShort((uint16*) cp, dir->tdir_count);
                        break;
                case TIFF_LONG:
                case TIFF_SLONG:
                case TIFF_FLOAT:
                        TIFFSwabArrayOfLong((uint32*) cp, dir->tdir_count);
                        break;
                case TIFF_RATIONAL:
                case TIFF_SRATIONAL:
                        TIFFSwabArrayOfLong((uint32*) cp, 2*dir->tdir_count);
                        break;
                case TIFF_DOUBLE:
                        TIFFSwabArrayOfDouble((double*) cp, dir->tdir_count);
                        break;
                }
        }
        return (cc);
bad:
        TIFFError(tif->tif_name, "Error fetching data for field \"%s\"",
            _TIFFFieldWithTag(tif, dir->tdir_tag)->field_name);
        return ((tsize_t) 0);
}

/*
 * Fetch an ASCII item from the file.
 */
static tsize_t
TIFFFetchString(TIFF* tif, TIFFDirEntry* dir, char* cp)
{
        if (dir->tdir_count <= 4) {
                uint32 l = dir->tdir_offset;
                if (tif->tif_flags & TIFF_SWAB)
                        TIFFSwabLong(&l);
                _TIFFmemcpy(cp, &l, dir->tdir_count);
                return (1);
        }
        return (TIFFFetchData(tif, dir, cp));
}

/*
 * Convert numerator+denominator to float.
 */
static int
cvtRational(TIFF* tif, TIFFDirEntry* dir, uint32 num, uint32 denom, float* rv)
{
        if (denom == 0) {
                TIFFError(tif->tif_name,
                    "%s: Rational with zero denominator (num = %lu)",
                    _TIFFFieldWithTag(tif, dir->tdir_tag)->field_name, num);
                return (0);
        } else {
                if (dir->tdir_type == TIFF_RATIONAL)
                        *rv = ((float)num / (float)denom);
                else
                        *rv = ((float)(int32)num / (float)(int32)denom);
                return (1);
        }
}

/*
 * Fetch a rational item from the file
 * at offset off and return the value
 * as a floating point number.
 */
static float
TIFFFetchRational(TIFF* tif, TIFFDirEntry* dir)
{
        uint32 l[2];
        float v;

        return (!TIFFFetchData(tif, dir, (char *)l) ||
            !cvtRational(tif, dir, l[0], l[1], &v) ? 1.0f : v);
}

/*
 * Fetch a single floating point value
 * from the offset field and return it
 * as a native float.
 */
static float
TIFFFetchFloat(TIFF* tif, TIFFDirEntry* dir)
{
        long l = TIFFExtractData(tif, dir->tdir_type, dir->tdir_offset);
        float v = *(float*) &l;
        TIFFCvtIEEEFloatToNative(tif, 1, &v);
        return (v);
}

/*
 * Fetch an array of BYTE or SBYTE values.
 */
static int
TIFFFetchByteArray(TIFF* tif, TIFFDirEntry* dir, uint16* v)
{
    if (dir->tdir_count <= 4) {
        /*
         * Extract data from offset field.
         */
        if (tif->tif_header.tiff_magic == TIFF_BIGENDIAN) {
            if (dir->tdir_type == TIFF_SBYTE)
                switch (dir->tdir_count) {
                    case 4: v[3] = (signed char)(dir->tdir_offset & 0xff);
                    case 3: v[2] = (signed char)((dir->tdir_offset >> 8) & 0xff);
                    case 2: v[1] = (signed char)((dir->tdir_offset >> 16) & 0xff);
                    case 1: v[0] = (signed char)(dir->tdir_offset >> 24);       
                }
            else
                switch (dir->tdir_count) {
                    case 4: v[3] = (uint16)(dir->tdir_offset & 0xff);
                    case 3: v[2] = (uint16)((dir->tdir_offset >> 8) & 0xff);
                    case 2: v[1] = (uint16)((dir->tdir_offset >> 16) & 0xff);
                    case 1: v[0] = (uint16)(dir->tdir_offset >> 24);    
                }
        } else {
            if (dir->tdir_type == TIFF_SBYTE)
                switch (dir->tdir_count) {
                    case 4: v[3] = (signed char)(dir->tdir_offset >> 24);
                    case 3: v[2] = (signed char)((dir->tdir_offset >> 16) & 0xff);
                    case 2: v[1] = (signed char)((dir->tdir_offset >> 8) & 0xff);
                    case 1: v[0] = (signed char)(dir->tdir_offset & 0xff);
                }
            else
                switch (dir->tdir_count) {
                    case 4: v[3] = (uint16)(dir->tdir_offset >> 24);
                    case 3: v[2] = (uint16)((dir->tdir_offset >> 16) & 0xff);
                    case 2: v[1] = (uint16)((dir->tdir_offset >> 8) & 0xff);
                    case 1: v[0] = (uint16)(dir->tdir_offset & 0xff);
                }
        }
        return (1);
    } else
        return (TIFFFetchData(tif, dir, (char*) v) != 0);       /* XXX */
}

/*
 * Fetch an array of SHORT or SSHORT values.
 */
static int
TIFFFetchShortArray(TIFF* tif, TIFFDirEntry* dir, uint16* v)
{
        if (dir->tdir_count <= 2) {
                if (tif->tif_header.tiff_magic == TIFF_BIGENDIAN) {
                        switch (dir->tdir_count) {
                        case 2: v[1] = (uint16) (dir->tdir_offset & 0xffff);
                        case 1: v[0] = (uint16) (dir->tdir_offset >> 16);
                        }
                } else {
                        switch (dir->tdir_count) {
                        case 2: v[1] = (uint16) (dir->tdir_offset >> 16);
                        case 1: v[0] = (uint16) (dir->tdir_offset & 0xffff);
                        }
                }
                return (1);
        } else
                return (TIFFFetchData(tif, dir, (char *)v) != 0);
}

/*
 * Fetch a pair of SHORT or BYTE values.
 */
static int
TIFFFetchShortPair(TIFF* tif, TIFFDirEntry* dir)
{
        uint16 v[4];
        int ok = 0;

        switch (dir->tdir_type) {
        case TIFF_SHORT:
        case TIFF_SSHORT:
                ok = TIFFFetchShortArray(tif, dir, v);
                break;
        case TIFF_BYTE:
        case TIFF_SBYTE:
                ok  = TIFFFetchByteArray(tif, dir, v);
                break;
        }
        if (ok)
                TIFFSetField(tif, dir->tdir_tag, v[0], v[1]);
        return (ok);
}

/*
 * Fetch an array of LONG or SLONG values.
 */
static int
TIFFFetchLongArray(TIFF* tif, TIFFDirEntry* dir, uint32* v)
{
        if (dir->tdir_count == 1) {
                v[0] = dir->tdir_offset;
                return (1);
        } else
                return (TIFFFetchData(tif, dir, (char*) v) != 0);
}

/*
 * Fetch an array of RATIONAL or SRATIONAL values.
 */
static int
TIFFFetchRationalArray(TIFF* tif, TIFFDirEntry* dir, float* v)
{
        int ok = 0;
        uint32* l;

        l = (uint32*)CheckMalloc(tif,
            dir->tdir_count, TIFFDataWidth((TIFFDataType) dir->tdir_type),
            "to fetch array of rationals");
        if (l) {
                if (TIFFFetchData(tif, dir, (char *)l)) {
                        uint32 i;
                        for (i = 0; i < dir->tdir_count; i++) {
                                ok = cvtRational(tif, dir,
                                    l[2*i+0], l[2*i+1], &v[i]);
                                if (!ok)
                                        break;
                        }
                }
                _TIFFfree((char *)l);
        }
        return (ok);
}

/*
 * Fetch an array of FLOAT values.
 */
static int
TIFFFetchFloatArray(TIFF* tif, TIFFDirEntry* dir, float* v)
{

        if (dir->tdir_count == 1) {
                v[0] = *(float*) &dir->tdir_offset;
                TIFFCvtIEEEFloatToNative(tif, dir->tdir_count, v);
                return (1);
        } else  if (TIFFFetchData(tif, dir, (char*) v)) {
                TIFFCvtIEEEFloatToNative(tif, dir->tdir_count, v);
                return (1);
        } else
                return (0);
}

/*
 * Fetch an array of DOUBLE values.
 */
static int
TIFFFetchDoubleArray(TIFF* tif, TIFFDirEntry* dir, double* v)
{
        if (TIFFFetchData(tif, dir, (char*) v)) {
                TIFFCvtIEEEDoubleToNative(tif, dir->tdir_count, v);
                return (1);
        } else
                return (0);
}

/*
 * Fetch an array of ANY values.  The actual values are
 * returned as doubles which should be able hold all the
 * types.  Yes, there really should be an tany_t to avoid
 * this potential non-portability ...  Note in particular
 * that we assume that the double return value vector is
 * large enough to read in any fundamental type.  We use
 * that vector as a buffer to read in the base type vector
 * and then convert it in place to double (from end
 * to front of course).
 */
static int
TIFFFetchAnyArray(TIFF* tif, TIFFDirEntry* dir, double* v)
{
        int i;

        switch (dir->tdir_type) {
        case TIFF_BYTE:
        case TIFF_SBYTE:
                if (!TIFFFetchByteArray(tif, dir, (uint16*) v))
                        return (0);
                if (dir->tdir_type == TIFF_BYTE) {
                        uint16* vp = (uint16*) v;
                        for (i = dir->tdir_count-1; i >= 0; i--)
                                v[i] = vp[i];
                } else {
                        int16* vp = (int16*) v;
                        for (i = dir->tdir_count-1; i >= 0; i--)
                                v[i] = vp[i];
                }
                break;
        case TIFF_SHORT:
        case TIFF_SSHORT:
                if (!TIFFFetchShortArray(tif, dir, (uint16*) v))
                        return (0);
                if (dir->tdir_type == TIFF_SHORT) {
                        uint16* vp = (uint16*) v;
                        for (i = dir->tdir_count-1; i >= 0; i--)
                                v[i] = vp[i];
                } else {
                        int16* vp = (int16*) v;
                        for (i = dir->tdir_count-1; i >= 0; i--)
                                v[i] = vp[i];
                }
                break;
        case TIFF_LONG:
        case TIFF_SLONG:
                if (!TIFFFetchLongArray(tif, dir, (uint32*) v))
                        return (0);
                if (dir->tdir_type == TIFF_LONG) {
                        uint32* vp = (uint32*) v;
                        for (i = dir->tdir_count-1; i >= 0; i--)
                                v[i] = vp[i];
                } else {
                        int32* vp = (int32*) v;
                        for (i = dir->tdir_count-1; i >= 0; i--)
                                v[i] = vp[i];
                }
                break;
        case TIFF_RATIONAL:
        case TIFF_SRATIONAL:
                if (!TIFFFetchRationalArray(tif, dir, (float*) v))
                        return (0);
                { float* vp = (float*) v;
                  for (i = dir->tdir_count-1; i >= 0; i--)
                        v[i] = vp[i];
                }
                break;
        case TIFF_FLOAT:
                if (!TIFFFetchFloatArray(tif, dir, (float*) v))
                        return (0);
                { float* vp = (float*) v;
                  for (i = dir->tdir_count-1; i >= 0; i--)
                        v[i] = vp[i];
                }
                break;
        case TIFF_DOUBLE:
                return (TIFFFetchDoubleArray(tif, dir, (double*) v));
        default:
                /* TIFF_NOTYPE */
                /* TIFF_ASCII */
                /* TIFF_UNDEFINED */
                TIFFError(tif->tif_name,
                    "cannot read TIFF_ANY type %d for field \"%s\"",
                    _TIFFFieldWithTag(tif, dir->tdir_tag)->field_name);
                return (0);
        }
        return (1);
}

/*
 * Fetch a tag that is not handled by special case code.
 */
static int
TIFFFetchNormalTag(TIFF* tif, TIFFDirEntry* dp)
{
        static const char mesg[] = "to fetch tag value";
        int ok = 0;
        const TIFFFieldInfo* fip = _TIFFFieldWithTag(tif, dp->tdir_tag);

        if (dp->tdir_count > 1) {               /* array of values */
                char* cp = NULL;

                switch (dp->tdir_type) {
                case TIFF_BYTE:
                case TIFF_SBYTE:
                        /* NB: always expand BYTE values to shorts */
                        cp = CheckMalloc(tif,
                            dp->tdir_count, sizeof (uint16), mesg);
                        ok = cp && TIFFFetchByteArray(tif, dp, (uint16*) cp);
                        break;
                case TIFF_SHORT:
                case TIFF_SSHORT:
                        cp = CheckMalloc(tif,
                            dp->tdir_count, sizeof (uint16), mesg);
                        ok = cp && TIFFFetchShortArray(tif, dp, (uint16*) cp);
                        break;
                case TIFF_LONG:
                case TIFF_SLONG:
                        cp = CheckMalloc(tif,
                            dp->tdir_count, sizeof (uint32), mesg);
                        ok = cp && TIFFFetchLongArray(tif, dp, (uint32*) cp);
                        break;
                case TIFF_RATIONAL:
                case TIFF_SRATIONAL:
                        cp = CheckMalloc(tif,
                            dp->tdir_count, sizeof (float), mesg);
                        ok = cp && TIFFFetchRationalArray(tif, dp, (float*) cp);
                        break;
                case TIFF_FLOAT:
                        cp = CheckMalloc(tif,
                            dp->tdir_count, sizeof (float), mesg);
                        ok = cp && TIFFFetchFloatArray(tif, dp, (float*) cp);
                        break;
                case TIFF_DOUBLE:
                        cp = CheckMalloc(tif,
                            dp->tdir_count, sizeof (double), mesg);
                        ok = cp && TIFFFetchDoubleArray(tif, dp, (double*) cp);
                        break;
                case TIFF_ASCII:
                case TIFF_UNDEFINED:            /* bit of a cheat... */
                        /*
                         * Some vendors write strings w/o the trailing
                         * NULL byte, so always append one just in case.
                         */
                        cp = CheckMalloc(tif, dp->tdir_count+1, 1, mesg);
                        if( (ok = (cp && TIFFFetchString(tif, dp, cp))) != 0 )
                                cp[dp->tdir_count] = '\0';      /* XXX */
                        break;
                }
                if (ok) {
                        ok = (fip->field_passcount ?
                            TIFFSetField(tif, dp->tdir_tag, dp->tdir_count, cp)
                          : TIFFSetField(tif, dp->tdir_tag, cp));
                }
                if (cp != NULL)
                        _TIFFfree(cp);
        } else if (CheckDirCount(tif, dp, 1)) { /* singleton value */
                switch (dp->tdir_type) {
                case TIFF_BYTE:
                case TIFF_SBYTE:
                case TIFF_SHORT:
                case TIFF_SSHORT:
                        /*
                         * If the tag is also acceptable as a LONG or SLONG
                         * then TIFFSetField will expect an uint32 parameter
                         * passed to it (through varargs).  Thus, for machines
                         * where sizeof (int) != sizeof (uint32) we must do
                         * a careful check here.  It's hard to say if this
                         * is worth optimizing.
                         *
                         * NB: We use TIFFFieldWithTag here knowing that
                         *     it returns us the first entry in the table
                         *     for the tag and that that entry is for the
                         *     widest potential data type the tag may have.
                         */
                        { TIFFDataType type = fip->field_type;
                          if (type != TIFF_LONG && type != TIFF_SLONG) {
                                uint16 v = (uint16)
                           TIFFExtractData(tif, dp->tdir_type, dp->tdir_offset);
                                ok = (fip->field_passcount ?
                                    TIFFSetField(tif, dp->tdir_tag, 1, &v)
                                  : TIFFSetField(tif, dp->tdir_tag, v));
                                break;
                          }
                        }
                        /* fall thru... */
                case TIFF_LONG:
                case TIFF_SLONG:
                        { uint32 v32 =
                    TIFFExtractData(tif, dp->tdir_type, dp->tdir_offset);
                          ok = (fip->field_passcount ? 
                              TIFFSetField(tif, dp->tdir_tag, 1, &v32)
                            : TIFFSetField(tif, dp->tdir_tag, v32));
                        }
                        break;
                case TIFF_RATIONAL:
                case TIFF_SRATIONAL:
                case TIFF_FLOAT:
                        { float v = (dp->tdir_type == TIFF_FLOAT ? 
                              TIFFFetchFloat(tif, dp)
                            : TIFFFetchRational(tif, dp));
                          ok = (fip->field_passcount ?
                              TIFFSetField(tif, dp->tdir_tag, 1, &v)
                            : TIFFSetField(tif, dp->tdir_tag, v));
                        }
                        break;
                case TIFF_DOUBLE:
                        { double v;
                          ok = (TIFFFetchDoubleArray(tif, dp, &v) &&
                            (fip->field_passcount ?
                              TIFFSetField(tif, dp->tdir_tag, 1, &v)
                            : TIFFSetField(tif, dp->tdir_tag, v))
                          );
                        }
                        break;
                case TIFF_ASCII:
                case TIFF_UNDEFINED:            /* bit of a cheat... */
                        { char c[2];
                          if( (ok = (TIFFFetchString(tif, dp, c) != 0)) != 0 ){
                                c[1] = '\0';            /* XXX paranoid */
                                ok = TIFFSetField(tif, dp->tdir_tag, c);
                          }
                        }
                        break;
                }
        }
        return (ok);
}

#define NITEMS(x)       (sizeof (x) / sizeof (x[0]))
/*
 * Fetch samples/pixel short values for 
 * the specified tag and verify that
 * all values are the same.
 */
static int
TIFFFetchPerSampleShorts(TIFF* tif, TIFFDirEntry* dir, int* pl)
{
        int samples = tif->tif_dir.td_samplesperpixel;
        int status = 0;

        if (CheckDirCount(tif, dir, (uint32) samples)) {
                uint16 buf[10];
                uint16* v = buf;

                if (samples > NITEMS(buf))
                        v = (uint16*) CheckMalloc(tif, samples, sizeof (uint16),
                                                  "to fetch per-sample values");
                if (v && TIFFFetchShortArray(tif, dir, v)) {
                        int i;
                        for (i = 1; i < samples; i++)
                                if (v[i] != v[0]) {
                                        TIFFError(tif->tif_name,
                "Cannot handle different per-sample values for field \"%s\"",
                           _TIFFFieldWithTag(tif, dir->tdir_tag)->field_name);
                                        goto bad;
                                }
                        *pl = v[0];
                        status = 1;
                }
        bad:
                if (v && v != buf)
                        _TIFFfree((char*) v);
        }
        return (status);
}

/*
 * Fetch samples/pixel ANY values for 
 * the specified tag and verify that
 * all values are the same.
 */
static int
TIFFFetchPerSampleAnys(TIFF* tif, TIFFDirEntry* dir, double* pl)
{
        int samples = (int) tif->tif_dir.td_samplesperpixel;
        int status = 0;

        if (CheckDirCount(tif, dir, (uint32) samples)) {
                double buf[10];
                double* v = buf;

                if (samples > NITEMS(buf))
                        v = (double*) CheckMalloc(tif, samples, sizeof (double),
                                                  "to fetch per-sample values");
                if (v && TIFFFetchAnyArray(tif, dir, v)) {
                        int i;
                        for (i = 1; i < samples; i++)
                                if (v[i] != v[0]) {
                                        TIFFError(tif->tif_name,
                "Cannot handle different per-sample values for field \"%s\"",
                           _TIFFFieldWithTag(tif, dir->tdir_tag)->field_name);
                                        goto bad;
                                }
                        *pl = v[0];
                        status = 1;
                }
        bad:
                if (v && v != buf)
                        _TIFFfree(v);
        }
        return (status);
}
#undef NITEMS

/*
 * Fetch a set of offsets or lengths.
 * While this routine says "strips",
 * in fact it's also used for tiles.
 */
static int
TIFFFetchStripThing(TIFF* tif, TIFFDirEntry* dir, long nstrips, uint32** lpp)
{
        register uint32* lp;
        int status;

        CheckDirCount(tif, dir, (uint32) nstrips);

        /*
         * Allocate space for strip information.
         */
        if (*lpp == NULL &&
            (*lpp = (uint32 *)CheckMalloc(tif,
              nstrips, sizeof (uint32), "for strip array")) == NULL)
                return (0);
        lp = *lpp;
        memset( lp, 0, sizeof(uint32) * nstrips );

        if (dir->tdir_type == (int)TIFF_SHORT) {
                /*
                 * Handle uint16->uint32 expansion.
                 */
                uint16* dp = (uint16*) CheckMalloc(tif,
                    dir->tdir_count, sizeof (uint16), "to fetch strip tag");
                if (dp == NULL)
                        return (0);
                if( (status = TIFFFetchShortArray(tif, dir, dp)) != 0 ) {
                    int i;
                    
                    for( i = 0; i < nstrips && i < (int) dir->tdir_count; i++ )
                    {
                        lp[i] = dp[i];
                    }
                }
                _TIFFfree((char*) dp);

        } else if( nstrips != (int) dir->tdir_count ) {
            /* Special case to correct length */

            uint32* dp = (uint32*) CheckMalloc(tif,
                    dir->tdir_count, sizeof (uint32), "to fetch strip tag");
            if (dp == NULL)
                return (0);

            status = TIFFFetchLongArray(tif, dir, dp);
            if( status != 0 ) {
                int i;

                for( i = 0; i < nstrips && i < (int) dir->tdir_count; i++ )
                {
                    lp[i] = dp[i];
                }
            }

            _TIFFfree( (char *) dp );
        } else
            status = TIFFFetchLongArray(tif, dir, lp);
        
        return (status);
}

#define NITEMS(x)       (sizeof (x) / sizeof (x[0]))
/*
 * Fetch and set the ExtraSamples tag.
 */
static int
TIFFFetchExtraSamples(TIFF* tif, TIFFDirEntry* dir)
{
        uint16 buf[10];
        uint16* v = buf;
        int status;

        if (dir->tdir_count > NITEMS(buf)) {
                v = (uint16*) CheckMalloc(tif, dir->tdir_count, sizeof (uint16),
                                          "to fetch extra samples");
                if (!v)
                        return (0);
        }
        if (dir->tdir_type == TIFF_BYTE)
                status = TIFFFetchByteArray(tif, dir, v);
        else
                status = TIFFFetchShortArray(tif, dir, v);
        if (status)
                status = TIFFSetField(tif, dir->tdir_tag, dir->tdir_count, v);
        if (v != buf)
                _TIFFfree((char*) v);
        return (status);
}
#undef NITEMS

#ifdef COLORIMETRY_SUPPORT
/*
 * Fetch and set the RefBlackWhite tag.
 */
static int
TIFFFetchRefBlackWhite(TIFF* tif, TIFFDirEntry* dir)
{
        static const char mesg[] = "for \"ReferenceBlackWhite\" array";
        char* cp;
        int ok;

        if (dir->tdir_type == TIFF_RATIONAL)
                return (TIFFFetchNormalTag(tif, dir));
        /*
         * Handle LONG's for backward compatibility.
         */
        cp = CheckMalloc(tif, dir->tdir_count, sizeof (uint32), mesg);
        if( (ok = (cp && TIFFFetchLongArray(tif, dir, (uint32*) cp))) != 0) {
                float* fp = (float*)
                    CheckMalloc(tif, dir->tdir_count, sizeof (float), mesg);
                if( (ok = (fp != NULL)) != 0 ) {
                        uint32 i;
                        for (i = 0; i < dir->tdir_count; i++)
                                fp[i] = (float)((uint32*) cp)[i];
                        ok = TIFFSetField(tif, dir->tdir_tag, fp);
                        _TIFFfree((char*) fp);
                }
        }
        if (cp)
                _TIFFfree(cp);
        return (ok);
}
#endif

/*
 * Replace a single strip (tile) of uncompressed data by
 * multiple strips (tiles), each approximately 8Kbytes.
 * This is useful for dealing with large images or
 * for dealing with machines with a limited amount
 * memory.
 */
static void
ChopUpSingleUncompressedStrip(TIFF* tif)
{
        register TIFFDirectory *td = &tif->tif_dir;
        uint32 bytecount = td->td_stripbytecount[0];
        uint32 offset = td->td_stripoffset[0];
        tsize_t rowbytes = TIFFVTileSize(tif, 1), stripbytes;
        tstrip_t strip, nstrips, rowsperstrip;
        uint32* newcounts;
        uint32* newoffsets;

        /*
         * Make the rows hold at least one
         * scanline, but fill 8k if possible.
         */
        if (rowbytes > 8192) {
                stripbytes = rowbytes;
                rowsperstrip = 1;
        } else if (rowbytes > 0 ) {
                rowsperstrip = 8192 / rowbytes;
                stripbytes = rowbytes * rowsperstrip;
        }
        else
            return;

        /* never increase the number of strips in an image */
        if (rowsperstrip >= td->td_rowsperstrip)
                return;
        nstrips = (tstrip_t) TIFFhowmany(bytecount, stripbytes);
        newcounts = (uint32*) CheckMalloc(tif, nstrips, sizeof (uint32),
                                "for chopped \"StripByteCounts\" array");
        newoffsets = (uint32*) CheckMalloc(tif, nstrips, sizeof (uint32),
                                "for chopped \"StripOffsets\" array");
        if (newcounts == NULL || newoffsets == NULL) {
                /*
                 * Unable to allocate new strip information, give
                 * up and use the original one strip information.
                 */
                if (newcounts != NULL)
                        _TIFFfree(newcounts);
                if (newoffsets != NULL)
                        _TIFFfree(newoffsets);
                return;
        }
        /*
         * Fill the strip information arrays with
         * new bytecounts and offsets that reflect
         * the broken-up format.
         */
        for (strip = 0; strip < nstrips; strip++) {
                if (stripbytes > (tsize_t) bytecount)
                        stripbytes = bytecount;
                newcounts[strip] = stripbytes;
                newoffsets[strip] = offset;
                offset += stripbytes;
                bytecount -= stripbytes;
        }
        /*
         * Replace old single strip info with multi-strip info.
         */
        td->td_stripsperimage = td->td_nstrips = nstrips;
        TIFFSetField(tif, TIFFTAG_ROWSPERSTRIP, rowsperstrip);

        _TIFFfree(td->td_stripbytecount);
        _TIFFfree(td->td_stripoffset);
        td->td_stripbytecount = newcounts;
        td->td_stripoffset = newoffsets;
}