/* $Id: tif_dirread.c,v 1.6 2006/02/24 18:57:38 jjomier 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.
 *
 * Directory Read Support Routines.
 */
#include "tiffiop.h"

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

#if HAVE_IEEEFP
#define itk_TIFFCvtIEEEFloatToNative(tif, n, fp)
#define itk_TIFFCvtIEEEDoubleToNative(tif, n, dp)
#else
extern  void itk_TIFFCvtIEEEFloatToNative(TIFF*, uint32, float*);
extern  void itk_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*, uint16*);
static  int TIFFFetchPerSampleLongs(TIFF*, TIFFDirEntry*, uint32*);
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;

  /*
   * XXX: Check for integer overflow.
   */
  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;
  uint16 iv;
  uint32 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,
        "%s: 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,
          "%s: Seek error accessing TIFF directory",
                            tif->tif_name);
      return (0);
    }
    if (!ReadOK(tif, &dircount, sizeof (uint16))) {
      TIFFError(module,
          "%s: 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,
          "%s: 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,
                                  "%s: 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++) {

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

                    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 != (unsigned short) fip->field_type
                       && fix < tif->tif_nfields) {
      if (fip->field_type == TIFF_ANY)  /* wildcard */
        break;
                        fip = tif->tif_fieldinfo[++fix];
      if (fix >= tif->tif_nfields ||
          fip->field_tag != dp->tdir_tag) {
        TIFFWarning(module,
      "%s: wrong data type %d for \"%s\"; tag ignored",
              tif->tif_name, dp->tdir_type,
              tif->tif_fieldinfo[fix-1]->field_name);
        goto ignore;
      }
    }
    /*
     * Check count if known in advance.
     */
    if (fip->field_readcount != TIFF_VARIABLE
        && fip->field_readcount != TIFF_VARIABLE2) {
      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, (uint16)v))
          goto bad;
        break;
      /* XXX: workaround for broken TIFFs */
      } else if (dp->tdir_type == TIFF_LONG) {
        if (!TIFFFetchPerSampleLongs(tif, dp, &v) ||
            !TIFFSetField(tif, dp->tdir_tag, (uint16)v))
          goto bad;
      } else {
        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:
    case TIFFTAG_DATATYPE:
    case TIFFTAG_SAMPLEFORMAT:
      /*
       * 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, BitsPerSample
                         * DataType and SampleFormat 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). Other vendors write correct
       * value for NumberOfSamples, but incorrect one for
       * BitsPerSample and friends, and we will read this
       * too.
       */
      if (dp->tdir_count == 1) {
        v = TIFFExtractData(tif,
            dp->tdir_type, dp->tdir_offset);
        if (!TIFFSetField(tif, dp->tdir_tag, (uint16)v))
          goto bad;
      /* XXX: workaround for broken TIFFs */
      } else if (dp->tdir_tag == TIFFTAG_BITSPERSAMPLE
           && dp->tdir_type == TIFF_LONG) {
        if (!TIFFFetchPerSampleLongs(tif, dp, &v) ||
            !TIFFSetField(tif, dp->tdir_tag, (uint16)v))
          goto bad;
      } else {
        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 != v) {
        if (!CheckDirCount(tif, dp, 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 = 1L << td->td_bitspersample;
          if (dp->tdir_count == c)
            v = 0L;
          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;
    case TIFFTAG_REFERENCEBLACKWHITE:
      (void) TIFFFetchRefBlackWhite(tif, dp);
      break;
/* BEGIN REV 4.0 COMPATIBILITY */
    case TIFFTAG_OSUBFILETYPE:
      v = 0L;
      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)
        TIFFSetField(tif, TIFFTAG_SUBFILETYPE, 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,
      "%s: 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);
 *   - it is smaller than the size of the bytes per row multiplied on the
 *     number of rows.  The last case should not be checked in the case of
 *     writing new image, because we may do not know the exact strip size
 *     until the whole image will be written and directory dumped out.
 */
#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]) || \
      (tif->tif_mode == O_RDONLY && \
       td->td_compression == COMPRESSION_NONE && \
       td->td_stripbytecount[0] < TIFFScanlineSize(tif) * td->td_imagelength) )
  } 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,
  "%s: 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(dir);
  }
  if (!TIFFFieldSet(tif, FIELD_MAXSAMPLEVALUE))
    td->td_maxsamplevalue = (uint16)((1L<<td->td_bitspersample)-1);
  /*
   * Setup default compression scheme.
   */

  /*
   * XXX: We can optimize checking for the strip bounds using the sorted
   * bytecounts array. See also comments for TIFFAppendToStrip()
   * function in tif_write.c.
   */
  if (td->td_nstrips > 1) {
    tstrip_t strip;

    td->td_stripbytecountsorted = 1;
    for (strip = 1; strip < td->td_nstrips; strip++) {
      if (td->td_stripoffset[strip - 1] >
          td->td_stripoffset[strip]) {
        td->td_stripbytecountsorted = 0;
        break;
      }
    }
  }

  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 = (tsize_t) -1;

  tif->tif_scanlinesize = TIFFScanlineSize(tif);
  if (!tif->tif_scanlinesize) {
    TIFFError(module, "%s: cannot handle zero scanline size",
        tif->tif_name);
    return (0);
  }

  if (isTiled(tif)) {
    tif->tif_tilesize = TIFFTileSize(tif);
    if (!tif->tif_tilesize) {
      TIFFError(module, "%s: cannot handle zero tile size",
          tif->tif_name);
      return (0);
    }
  } else {
    if (!TIFFStripSize(tif)) {
      TIFFError(module, "%s: cannot handle zero strip 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,
      "%s: 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,
      "%s: 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);
  } else if (count < dir->tdir_count) {
    TIFFWarning(tif->tif_name,
  "incorrect count for field \"%s\" (%lu, expecting %lu); tag trimmed",
        _TIFFFieldWithTag(tif, dir->tdir_tag)->field_name,
        dir->tdir_count, count);
    return (1);
  }
  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)
{
  float v;
  int32 l = TIFFExtractData(tif, dir->tdir_type, dir->tdir_offset);
        _TIFFmemcpy(&v, &l, sizeof(float));
  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 = (fip->field_passcount ?
          TIFFSetField(tif, dp->tdir_tag, 1, c)
              : 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, uint16* pl)
{
  uint16 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)) {
      uint16 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);
}

/*
 * Fetch samples/pixel long values for 
 * the specified tag and verify that
 * all values are the same.
 */
static int
TIFFFetchPerSampleLongs(TIFF* tif, TIFFDirEntry* dir, uint32* pl)
{
  uint16 samples = tif->tif_dir.td_samplesperpixel;
  int status = 0;

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

    if (samples > NITEMS(buf))
      v = (uint32*) CheckMalloc(tif, samples, sizeof(uint32),
              "to fetch per-sample values");
    if (v && TIFFFetchLongArray(tif, dir, v)) {
      uint16 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);
}

/*
 * 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)
{
  uint16 samples = 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)) {
      uint16 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;
        _TIFFmemset( 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

/*
 * 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);
}

/*
 * 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;
  td->td_stripbytecountsorted = 1;
}

