/* $Id: tif_dir.c,v 1.4 2005/11/19 16:02:59 malaterre 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 Tag Get & Set Routines.
 * (and also some miscellaneous stuff)
 */
#include "tiffiop.h"

/*
 * These are used in the backwards compatibility code...
 */
#define DATATYPE_VOID    0       /* !untyped data */
#define DATATYPE_INT    1       /* !signed integer data */
#define DATATYPE_UINT    2       /* !unsigned integer data */
#define DATATYPE_IEEEFP    3       /* !IEEE floating point data */

static void
setByteArray(void** vpp, void* vp, size_t nmemb, size_t elem_size)
{
  if (*vpp)
    _TIFFfree(*vpp), *vpp = 0;
  if (vp) {
    tsize_t  bytes = nmemb * elem_size;
    if (elem_size && bytes / elem_size == nmemb)
      *vpp = (void*) _TIFFmalloc(bytes);
    if (*vpp)
      _TIFFmemcpy(*vpp, vp, bytes);
  }
}
void _TIFFsetByteArray(void** vpp, void* vp, long n)
    { setByteArray(vpp, vp, n, 1); }
void _TIFFsetString(char** cpp, char* cp)
    { setByteArray((void**) cpp, (void*) cp, strlen(cp)+1, 1); }
void _TIFFsetNString(char** cpp, char* cp, long n)
    { setByteArray((void**) cpp, (void*) cp, n, 1); }
void _TIFFsetShortArray(uint16** wpp, uint16* wp, long n)
    { setByteArray((void**) wpp, (void*) wp, n, sizeof (uint16)); }
void _TIFFsetLongArray(uint32** lpp, uint32* lp, long n)
    { setByteArray((void**) lpp, (void*) lp, n, sizeof (uint32)); }
void _TIFFsetFloatArray(float** fpp, float* fp, long n)
    { setByteArray((void**) fpp, (void*) fp, n, sizeof (float)); }
void _TIFFsetDoubleArray(double** dpp, double* dp, long n)
    { setByteArray((void**) dpp, (void*) dp, n, sizeof (double)); }

/*
 * Install extra samples information.
 */
static int
setExtraSamples(TIFFDirectory* td, va_list ap, int* v)
{
  uint16* va;
  int i;

  *v = va_arg(ap, int);
  if ((uint16) *v > td->td_samplesperpixel)
    return (0);
  va = va_arg(ap, uint16*);
  if (*v > 0 && va == NULL)    /* typically missing param */
    return (0);
  for (i = 0; i < *v; i++)
    if (va[i] > EXTRASAMPLE_UNASSALPHA)
      return (0);
  td->td_extrasamples = (uint16) *v;
  _TIFFsetShortArray(&td->td_sampleinfo, va, td->td_extrasamples);
  return (1);
}

static int
checkInkNamesString(TIFF* tif, int slen, const char* s)
{
  TIFFDirectory* td = &tif->tif_dir;
  int i = td->td_samplesperpixel;

  if (slen > 0) {
    const char* ep = s+slen;
    const char* cp = s;
    for (; i > 0; i--) {
      for (; *cp != '\0'; cp++)
        if (cp >= ep)
          goto bad;
      cp++;        /* skip \0 */
    }
    return (cp-s);
  }
bad:
  TIFFError("TIFFSetField",
      "%s: Invalid InkNames value; expecting %d names, found %d",
      tif->tif_name,
      td->td_samplesperpixel,
      td->td_samplesperpixel-i);
  return (0);
}

static int
_TIFFVSetField(TIFF* tif, ttag_t tag, va_list ap)
{
  static const char module[] = "_TIFFVSetField";
  
  TIFFDirectory* td = &tif->tif_dir;
  int status = 1;
  uint32 v32;
  int i, v;
  double d;
  char* s;

  switch (tag) {
  case TIFFTAG_SUBFILETYPE:
    td->td_subfiletype = va_arg(ap, uint32);
    break;
  case TIFFTAG_IMAGEWIDTH:
    td->td_imagewidth = va_arg(ap, uint32);
    break;
  case TIFFTAG_IMAGELENGTH:
    td->td_imagelength = va_arg(ap, uint32);
    break;
  case TIFFTAG_BITSPERSAMPLE:
    td->td_bitspersample = (uint16) va_arg(ap, int);
    /*
     * If the data require post-decoding processing
     * to byte-swap samples, set it up here.  Note
     * that since tags are required to be ordered,
     * compression code can override this behaviour
     * in the setup method if it wants to roll the
     * post decoding work in with its normal work.
     */
    if (tif->tif_flags & TIFF_SWAB) {
      if (td->td_bitspersample == 16)
        tif->tif_postdecode = _TIFFSwab16BitData;
      else if (td->td_bitspersample == 32)
        tif->tif_postdecode = _TIFFSwab32BitData;
      else if (td->td_bitspersample == 64)
        tif->tif_postdecode = _TIFFSwab64BitData;
    }
    break;
  case TIFFTAG_COMPRESSION:
    v = va_arg(ap, int) & 0xffff;
    /*
     * If we're changing the compression scheme,
     * the notify the previous module so that it
     * can cleanup any state it's setup.
     */
    if (TIFFFieldSet(tif, FIELD_COMPRESSION)) {
      if (td->td_compression == v)
        break;
      (*tif->tif_cleanup)(tif);
      tif->tif_flags &= ~TIFF_CODERSETUP;
    }
    /*
     * Setup new compression routine state.
     */
    if( (status = TIFFSetCompressionScheme(tif, v)) != 0 )
                    td->td_compression = (uint16) v;
                else
                    status = 0;
    break;
  case TIFFTAG_PHOTOMETRIC:
    td->td_photometric = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_THRESHHOLDING:
    td->td_threshholding = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_FILLORDER:
    v = va_arg(ap, int);
    if (v != FILLORDER_LSB2MSB && v != FILLORDER_MSB2LSB)
      goto badvalue;
    td->td_fillorder = (uint16) v;
    break;
  case TIFFTAG_DOCUMENTNAME:
    _TIFFsetString(&td->td_documentname, va_arg(ap, char*));
    break;
  case TIFFTAG_ARTIST:
    _TIFFsetString(&td->td_artist, va_arg(ap, char*));
    break;
  case TIFFTAG_DATETIME:
    _TIFFsetString(&td->td_datetime, va_arg(ap, char*));
    break;
  case TIFFTAG_HOSTCOMPUTER:
    _TIFFsetString(&td->td_hostcomputer, va_arg(ap, char*));
    break;
  case TIFFTAG_IMAGEDESCRIPTION:
    _TIFFsetString(&td->td_imagedescription, va_arg(ap, char*));
    break;
  case TIFFTAG_MAKE:
    _TIFFsetString(&td->td_make, va_arg(ap, char*));
    break;
  case TIFFTAG_MODEL:
    _TIFFsetString(&td->td_model, va_arg(ap, char*));
    break;
  case TIFFTAG_COPYRIGHT:
    _TIFFsetString(&td->td_copyright, va_arg(ap, char*));
    break;
  case TIFFTAG_ORIENTATION:
    v = va_arg(ap, int);
    if (v < ORIENTATION_TOPLEFT || ORIENTATION_LEFTBOT < v) {
      TIFFWarning(tif->tif_name,
          "Bad value %ld for \"%s\" tag ignored",
          v, _TIFFFieldWithTag(tif, tag)->field_name);
    } else
      td->td_orientation = (uint16) v;
    break;
  case TIFFTAG_SAMPLESPERPIXEL:
    /* XXX should cross check -- e.g. if pallette, then 1 */
    v = va_arg(ap, int);
    if (v == 0)
      goto badvalue;
    td->td_samplesperpixel = (uint16) v;
    break;
  case TIFFTAG_ROWSPERSTRIP:
    v32 = va_arg(ap, uint32);
    if (v32 == 0)
      goto badvalue32;
    td->td_rowsperstrip = v32;
    if (!TIFFFieldSet(tif, FIELD_TILEDIMENSIONS)) {
      td->td_tilelength = v32;
      td->td_tilewidth = td->td_imagewidth;
    }
    break;
  case TIFFTAG_MINSAMPLEVALUE:
    td->td_minsamplevalue = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_MAXSAMPLEVALUE:
    td->td_maxsamplevalue = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_SMINSAMPLEVALUE:
    td->td_sminsamplevalue = (double) va_arg(ap, dblparam_t);
    break;
  case TIFFTAG_SMAXSAMPLEVALUE:
    td->td_smaxsamplevalue = (double) va_arg(ap, dblparam_t);
    break;
  case TIFFTAG_XRESOLUTION:
    td->td_xresolution = (float) va_arg(ap, dblparam_t);
    break;
  case TIFFTAG_YRESOLUTION:
    td->td_yresolution = (float) va_arg(ap, dblparam_t);
    break;
  case TIFFTAG_PLANARCONFIG:
    v = va_arg(ap, int);
    if (v != PLANARCONFIG_CONTIG && v != PLANARCONFIG_SEPARATE)
      goto badvalue;
    td->td_planarconfig = (uint16) v;
    break;
  case TIFFTAG_PAGENAME:
    _TIFFsetString(&td->td_pagename, va_arg(ap, char*));
    break;
  case TIFFTAG_XPOSITION:
    td->td_xposition = (float) va_arg(ap, dblparam_t);
    break;
  case TIFFTAG_YPOSITION:
    td->td_yposition = (float) va_arg(ap, dblparam_t);
    break;
  case TIFFTAG_RESOLUTIONUNIT:
    v = va_arg(ap, int);
    if (v < RESUNIT_NONE || RESUNIT_CENTIMETER < v)
      goto badvalue;
    td->td_resolutionunit = (uint16) v;
    break;
  case TIFFTAG_PAGENUMBER:
    td->td_pagenumber[0] = (uint16) va_arg(ap, int);
    td->td_pagenumber[1] = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_HALFTONEHINTS:
    td->td_halftonehints[0] = (uint16) va_arg(ap, int);
    td->td_halftonehints[1] = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_COLORMAP:
    v32 = (uint32)(1L<<td->td_bitspersample);
    _TIFFsetShortArray(&td->td_colormap[0], va_arg(ap, uint16*), v32);
    _TIFFsetShortArray(&td->td_colormap[1], va_arg(ap, uint16*), v32);
    _TIFFsetShortArray(&td->td_colormap[2], va_arg(ap, uint16*), v32);
    break;
  case TIFFTAG_EXTRASAMPLES:
    if (!setExtraSamples(td, ap, &v))
      goto badvalue;
    break;
  case TIFFTAG_MATTEING:
    td->td_extrasamples = (uint16) (va_arg(ap, int) != 0);
    if (td->td_extrasamples) {
      uint16 sv = EXTRASAMPLE_ASSOCALPHA;
      _TIFFsetShortArray(&td->td_sampleinfo, &sv, 1);
    }
    break;
  case TIFFTAG_TILEWIDTH:
    v32 = va_arg(ap, uint32);
    if (v32 % 16) {
      if (tif->tif_mode != O_RDONLY)
        goto badvalue32;
      TIFFWarning(tif->tif_name,
          "Nonstandard tile width %d, convert file", v32);
    }
    td->td_tilewidth = v32;
    tif->tif_flags |= TIFF_ISTILED;
    break;
  case TIFFTAG_TILELENGTH:
    v32 = va_arg(ap, uint32);
    if (v32 % 16) {
      if (tif->tif_mode != O_RDONLY)
        goto badvalue32;
      TIFFWarning(tif->tif_name,
          "Nonstandard tile length %d, convert file", v32);
    }
    td->td_tilelength = v32;
    tif->tif_flags |= TIFF_ISTILED;
    break;
  case TIFFTAG_TILEDEPTH:
    v32 = va_arg(ap, uint32);
    if (v32 == 0)
      goto badvalue32;
    td->td_tiledepth = v32;
    break;
  case TIFFTAG_DATATYPE:
    v = va_arg(ap, int);
    switch (v) {
    case DATATYPE_VOID:  v = SAMPLEFORMAT_VOID;  break;
    case DATATYPE_INT:  v = SAMPLEFORMAT_INT;  break;
    case DATATYPE_UINT:  v = SAMPLEFORMAT_UINT;  break;
    case DATATYPE_IEEEFP:  v = SAMPLEFORMAT_IEEEFP;break;
    default:    goto badvalue;
    }
    td->td_sampleformat = (uint16) v;
    break;
  case TIFFTAG_SAMPLEFORMAT:
    v = va_arg(ap, int);
    if (v < SAMPLEFORMAT_UINT || SAMPLEFORMAT_COMPLEXIEEEFP < v)
      goto badvalue;
    td->td_sampleformat = (uint16) v;

                /*  Try to fix up the SWAB function for complex data. */
                if( td->td_sampleformat == SAMPLEFORMAT_COMPLEXINT 
                    && td->td_bitspersample == 32
                    && tif->tif_postdecode == _TIFFSwab32BitData )
                    tif->tif_postdecode = _TIFFSwab16BitData;
                else if( (td->td_sampleformat == SAMPLEFORMAT_COMPLEXINT 
                          || td->td_sampleformat == SAMPLEFORMAT_COMPLEXIEEEFP)
                         && td->td_bitspersample == 64
                         && tif->tif_postdecode == _TIFFSwab64BitData )
                    tif->tif_postdecode = _TIFFSwab32BitData;
                else if( td->td_sampleformat == SAMPLEFORMAT_COMPLEXIEEEFP
                         && td->td_bitspersample == 128
                         && tif->tif_postdecode == NULL )
                    tif->tif_postdecode = _TIFFSwab64BitData;
    break;
  case TIFFTAG_IMAGEDEPTH:
    td->td_imagedepth = va_arg(ap, uint32);
    break;
  case TIFFTAG_STONITS:
    d = va_arg(ap, dblparam_t);
    if (d <= 0.)
      goto badvaluedbl;
    td->td_stonits = d;
    break;
  /* Begin Pixar Tags */
   case TIFFTAG_PIXAR_IMAGEFULLWIDTH:
     td->td_imagefullwidth = va_arg(ap, uint32);
     break;
   case TIFFTAG_PIXAR_IMAGEFULLLENGTH:
     td->td_imagefulllength = va_arg(ap, uint32);
     break;
   case TIFFTAG_PIXAR_TEXTUREFORMAT:
     _TIFFsetString(&td->td_textureformat, va_arg(ap, char*));
     break;
   case TIFFTAG_PIXAR_WRAPMODES:
     _TIFFsetString(&td->td_wrapmodes, va_arg(ap, char*));
     break;
   case TIFFTAG_PIXAR_FOVCOT:
     td->td_fovcot = (float) va_arg(ap, dblparam_t);
     break;
   case TIFFTAG_PIXAR_MATRIX_WORLDTOSCREEN:
     _TIFFsetFloatArray(&td->td_matrixWorldToScreen,
       va_arg(ap, float*), 16);
     break;
   case TIFFTAG_PIXAR_MATRIX_WORLDTOCAMERA:
     _TIFFsetFloatArray(&td->td_matrixWorldToCamera,
       va_arg(ap, float*), 16);
     break;
   /* End Pixar Tags */         

  case TIFFTAG_SUBIFD:
    if ((tif->tif_flags & TIFF_INSUBIFD) == 0) {
      td->td_nsubifd = (uint16) va_arg(ap, int);
      _TIFFsetLongArray(&td->td_subifd, va_arg(ap, uint32*),
          (long) td->td_nsubifd);
    } else {
      TIFFError(module, "%s: Sorry, cannot nest SubIFDs",
          tif->tif_name);
      status = 0;
    }
    break;
  case TIFFTAG_YCBCRCOEFFICIENTS:
    _TIFFsetFloatArray(&td->td_ycbcrcoeffs, va_arg(ap, float*), 3);
    break;
  case TIFFTAG_YCBCRPOSITIONING:
    td->td_ycbcrpositioning = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_YCBCRSUBSAMPLING:
    td->td_ycbcrsubsampling[0] = (uint16) va_arg(ap, int);
    td->td_ycbcrsubsampling[1] = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_WHITEPOINT:
    _TIFFsetFloatArray(&td->td_whitepoint, va_arg(ap, float*), 2);
    break;
  case TIFFTAG_PRIMARYCHROMATICITIES:
    _TIFFsetFloatArray(&td->td_primarychromas, va_arg(ap, float*), 6);
    break;
  case TIFFTAG_TRANSFERFUNCTION:
    v = (td->td_samplesperpixel - td->td_extrasamples) > 1 ? 3 : 1;
    for (i = 0; i < v; i++)
      _TIFFsetShortArray(&td->td_transferfunction[i],
          va_arg(ap, uint16*), 1L<<td->td_bitspersample);
    break;
  case TIFFTAG_REFERENCEBLACKWHITE:
    /* XXX should check for null range */
    _TIFFsetFloatArray(&td->td_refblackwhite, va_arg(ap, float*), 6);
    break;
  case TIFFTAG_INKSET:
    td->td_inkset = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_DOTRANGE:
    /* XXX should check for null range */
    td->td_dotrange[0] = (uint16) va_arg(ap, int);
    td->td_dotrange[1] = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_INKNAMES:
    i = va_arg(ap, int);
    s = va_arg(ap, char*);
    i = checkInkNamesString(tif, i, s);
                status = i > 0;
    if( i > 0 ) {
      _TIFFsetNString(&td->td_inknames, s, i);
      td->td_inknameslen = i;
    }
    break;
  case TIFFTAG_NUMBEROFINKS:
    td->td_ninks = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_TARGETPRINTER:
    _TIFFsetString(&td->td_targetprinter, va_arg(ap, char*));
    break;
  case TIFFTAG_ICCPROFILE:
    td->td_profileLength = (uint32) va_arg(ap, uint32);
    _TIFFsetByteArray(&td->td_profileData, va_arg(ap, void*),
        td->td_profileLength);
    break;
   case TIFFTAG_PHOTOSHOP:
      td->td_photoshopLength = (uint32) va_arg(ap, uint32);
      _TIFFsetByteArray (&td->td_photoshopData, va_arg(ap, void*),
       td->td_photoshopLength);
     break;
  case TIFFTAG_RICHTIFFIPTC: 
      td->td_richtiffiptcLength = (uint32) va_arg(ap, uint32);
      _TIFFsetLongArray ((uint32**)&td->td_richtiffiptcData,
           va_arg(ap, uint32*),
           td->td_richtiffiptcLength);
     break;
  case TIFFTAG_XMLPACKET:
    td->td_xmlpacketLength = (uint32) va_arg(ap, uint32);
    _TIFFsetByteArray(&td->td_xmlpacketData, va_arg(ap, void*),
        td->td_xmlpacketLength);
    break;
        default: {
            const TIFFFieldInfo* fip = _TIFFFindFieldInfo(tif, tag, TIFF_ANY);
            TIFFTagValue *tv;
            int tv_size, iCustom;

            /*
             * This can happen if multiple images are open with
             * different codecs which have private tags.  The
             * global tag information table may then have tags
             * that are valid for one file but not the other. 
             * If the client tries to set a tag that is not valid
             * for the image's codec then we'll arrive here.  This
             * happens, for example, when tiffcp is used to convert
             * between compression schemes and codec-specific tags
             * are blindly copied.
             */
            if( fip == NULL || fip->field_bit != FIELD_CUSTOM )
            {
    TIFFError(module,
        "%s: Invalid %stag \"%s\" (not supported by codec)",
        tif->tif_name, isPseudoTag(tag) ? "pseudo-" : "",
        _TIFFFieldWithTag(tif, tag)->field_name);
    status = 0;
    break;
            }

            /*
             * Find the existing entry for this custom value.
             */
            tv = NULL;
            for( iCustom = 0; iCustom < td->td_customValueCount; iCustom++ )
            {
                if( td->td_customValues[iCustom].info == fip )
                {
                    tv = td->td_customValues + iCustom;
                    if( tv->value != NULL )
                        _TIFFfree( tv->value );
                    break;
                }
            }

            /*
             * Grow the custom list if the entry was not found.
             */
            if( tv == NULL )
            {
    TIFFTagValue  *new_customValues;
    
    td->td_customValueCount++;
    new_customValues = (TIFFTagValue *)
      _TIFFrealloc(td->td_customValues,
             sizeof(TIFFTagValue) * td->td_customValueCount);
    if (!new_customValues) {
      TIFFError(module,
    "%s: Failed to allocate space for list of custom values",
          tif->tif_name);
      status = 0;
      goto end;
    }

    td->td_customValues = new_customValues;

                tv = td->td_customValues + (td->td_customValueCount-1);
                tv->info = fip;
                tv->value = NULL;
                tv->count = 0;
            }

            /*
             * Set custom value ... save a copy of the custom tag value.
             */
      switch (fip->field_type) {
        /*
         * XXX: We can't use TIFFDataWidth() to determine the
         * space needed to store the value. For TIFF_RATIONAL
         * values TIFFDataWidth() returns 8, but we use 4-byte
         * float to represent rationals.
         */
        case TIFF_BYTE:
        case TIFF_ASCII:
        case TIFF_SBYTE:
        case TIFF_UNDEFINED:
      tv_size = 1;
      break;

        case TIFF_SHORT:
        case TIFF_SSHORT:
      tv_size = 2;
      break;

        case TIFF_LONG:
        case TIFF_SLONG:
        case TIFF_FLOAT:
        case TIFF_IFD:
        case TIFF_RATIONAL:
        case TIFF_SRATIONAL:
      tv_size = 4;
      break;

        case TIFF_DOUBLE:
      tv_size = 8;
      break;

        default:
      status = 0;
      TIFFError(module, "%s: Bad field type %d for \"%s\"",
          tif->tif_name, fip->field_type,
          fip->field_name);
      goto end;
        
      }
            
            if(fip->field_passcount)
                tv->count = (int) va_arg(ap, int);
            else
                tv->count = 1;
            
      if (fip->field_passcount) {
                tv->value = _TIFFmalloc(tv_size * tv->count);
    if ( !tv->value ) {
      status = 0;
      goto end;
    }
                _TIFFmemcpy(tv->value, (void *) va_arg(ap,void*),
                            tv->count * tv_size);
            } else if (fip->field_type == TIFF_ASCII) {
                const char *value = (const char *) va_arg(ap,const char *);
                tv->count = strlen(value)+1;
                tv->value = _TIFFmalloc(tv->count);
    if (!tv->value) {
      status = 0;
      goto end;
    }
                strcpy(tv->value, value);
            } else {
                /* not supporting "pass by value" types yet */
    TIFFError(module,
        "%s: Pass by value is not implemented.",
        tif->tif_name);

                tv->value = _TIFFmalloc(tv_size * tv->count);
    if (!tv->value) {
      status = 0;
      goto end;
    }
                _TIFFmemset(tv->value, 0, tv->count * tv_size);
                status = 0;
            }
          }
  }
  if (status) {
            TIFFSetFieldBit(tif, _TIFFFieldWithTag(tif, tag)->field_bit);
            tif->tif_flags |= TIFF_DIRTYDIRECT;
  }

end:
  va_end(ap);
  return (status);
badvalue:
  TIFFError(module, "%s: Bad value %d for \"%s\"",
      tif->tif_name, v, _TIFFFieldWithTag(tif, tag)->field_name);
  va_end(ap);
  return (0);
badvalue32:
  TIFFError(module, "%s: Bad value %ld for \"%s\"",
       tif->tif_name, v32, _TIFFFieldWithTag(tif, tag)->field_name);
  va_end(ap);
  return (0);
badvaluedbl:
  TIFFError(module, "%s: Bad value %f for \"%s\"",
      tif->tif_name, d, _TIFFFieldWithTag(tif, tag)->field_name);
  va_end(ap);
  return (0);
}

/*
 * Return 1/0 according to whether or not
 * it is permissible to set the tag's value.
 * Note that we allow ImageLength to be changed
 * so that we can append and extend to images.
 * Any other tag may not be altered once writing
 * has commenced, unless its value has no effect
 * on the format of the data that is written.
 */
static int
OkToChangeTag(TIFF* tif, ttag_t tag)
{
  const TIFFFieldInfo* fip = _TIFFFindFieldInfo(tif, tag, TIFF_ANY);
  if (!fip) {      /* unknown tag */
    TIFFError("TIFFSetField", "%s: Unknown %stag %u",
        tif->tif_name, isPseudoTag(tag) ? "pseudo-" : "", tag);
    return (0);
  }
  if (tag != TIFFTAG_IMAGELENGTH && (tif->tif_flags & TIFF_BEENWRITING) &&
      !fip->field_oktochange) {
    /*
     * Consult info table to see if tag can be changed
     * after we've started writing.  We only allow changes
     * to those tags that don't/shouldn't affect the
     * compression and/or format of the data.
     */
    TIFFError("TIFFSetField",
        "%s: Cannot modify tag \"%s\" while writing",
        tif->tif_name, fip->field_name);
    return (0);
  }
  return (1);
}

/*
 * Record the value of a field in the
 * internal directory structure.  The
 * field will be written to the file
 * when/if the directory structure is
 * updated.
 */
int
TIFFSetField(TIFF* tif, ttag_t tag, ...)
{
  va_list ap;
  int status;

  va_start(ap, tag);
  status = TIFFVSetField(tif, tag, ap);
  va_end(ap);
  return (status);
}

/*
 * Like TIFFSetField, but taking a varargs
 * parameter list.  This routine is useful
 * for building higher-level interfaces on
 * top of the library.
 */
int
TIFFVSetField(TIFF* tif, ttag_t tag, va_list ap)
{
  return OkToChangeTag(tif, tag) ?
      (*tif->tif_tagmethods.vsetfield)(tif, tag, ap) : 0;
}

static int
_TIFFVGetField(TIFF* tif, ttag_t tag, va_list ap)
{
    TIFFDirectory* td = &tif->tif_dir;
    int            ret_val = 1;

    switch (tag) {
  case TIFFTAG_SUBFILETYPE:
            *va_arg(ap, uint32*) = td->td_subfiletype;
            break;
  case TIFFTAG_IMAGEWIDTH:
            *va_arg(ap, uint32*) = td->td_imagewidth;
            break;
  case TIFFTAG_IMAGELENGTH:
            *va_arg(ap, uint32*) = td->td_imagelength;
            break;
  case TIFFTAG_BITSPERSAMPLE:
            *va_arg(ap, uint16*) = td->td_bitspersample;
            break;
  case TIFFTAG_COMPRESSION:
            *va_arg(ap, uint16*) = td->td_compression;
            break;
  case TIFFTAG_PHOTOMETRIC:
            *va_arg(ap, uint16*) = td->td_photometric;
            break;
  case TIFFTAG_THRESHHOLDING:
            *va_arg(ap, uint16*) = td->td_threshholding;
            break;
  case TIFFTAG_FILLORDER:
            *va_arg(ap, uint16*) = td->td_fillorder;
            break;
  case TIFFTAG_DOCUMENTNAME:
            *va_arg(ap, char**) = td->td_documentname;
            break;
  case TIFFTAG_ARTIST:
            *va_arg(ap, char**) = td->td_artist;
            break;
  case TIFFTAG_DATETIME:
            *va_arg(ap, char**) = td->td_datetime;
            break;
  case TIFFTAG_HOSTCOMPUTER:
            *va_arg(ap, char**) = td->td_hostcomputer;
            break;
  case TIFFTAG_IMAGEDESCRIPTION:
            *va_arg(ap, char**) = td->td_imagedescription;
            break;
  case TIFFTAG_MAKE:
            *va_arg(ap, char**) = td->td_make;
            break;
  case TIFFTAG_MODEL:
            *va_arg(ap, char**) = td->td_model;
            break;
  case TIFFTAG_COPYRIGHT:
            *va_arg(ap, char**) = td->td_copyright;
            break;
  case TIFFTAG_ORIENTATION:
            *va_arg(ap, uint16*) = td->td_orientation;
            break;
  case TIFFTAG_SAMPLESPERPIXEL:
            *va_arg(ap, uint16*) = td->td_samplesperpixel;
            break;
  case TIFFTAG_ROWSPERSTRIP:
            *va_arg(ap, uint32*) = td->td_rowsperstrip;
            break;
  case TIFFTAG_MINSAMPLEVALUE:
            *va_arg(ap, uint16*) = td->td_minsamplevalue;
            break;
  case TIFFTAG_MAXSAMPLEVALUE:
            *va_arg(ap, uint16*) = td->td_maxsamplevalue;
            break;
  case TIFFTAG_SMINSAMPLEVALUE:
            *va_arg(ap, double*) = td->td_sminsamplevalue;
            break;
  case TIFFTAG_SMAXSAMPLEVALUE:
            *va_arg(ap, double*) = td->td_smaxsamplevalue;
            break;
  case TIFFTAG_XRESOLUTION:
            *va_arg(ap, float*) = td->td_xresolution;
            break;
  case TIFFTAG_YRESOLUTION:
            *va_arg(ap, float*) = td->td_yresolution;
            break;
  case TIFFTAG_PLANARCONFIG:
            *va_arg(ap, uint16*) = td->td_planarconfig;
            break;
  case TIFFTAG_XPOSITION:
            *va_arg(ap, float*) = td->td_xposition;
            break;
  case TIFFTAG_YPOSITION:
            *va_arg(ap, float*) = td->td_yposition;
            break;
  case TIFFTAG_PAGENAME:
            *va_arg(ap, char**) = td->td_pagename;
            break;
  case TIFFTAG_RESOLUTIONUNIT:
            *va_arg(ap, uint16*) = td->td_resolutionunit;
            break;
  case TIFFTAG_PAGENUMBER:
            *va_arg(ap, uint16*) = td->td_pagenumber[0];
            *va_arg(ap, uint16*) = td->td_pagenumber[1];
            break;
  case TIFFTAG_HALFTONEHINTS:
            *va_arg(ap, uint16*) = td->td_halftonehints[0];
            *va_arg(ap, uint16*) = td->td_halftonehints[1];
            break;
  case TIFFTAG_COLORMAP:
            *va_arg(ap, uint16**) = td->td_colormap[0];
            *va_arg(ap, uint16**) = td->td_colormap[1];
            *va_arg(ap, uint16**) = td->td_colormap[2];
            break;
  case TIFFTAG_STRIPOFFSETS:
  case TIFFTAG_TILEOFFSETS:
            *va_arg(ap, uint32**) = td->td_stripoffset;
            break;
  case TIFFTAG_STRIPBYTECOUNTS:
  case TIFFTAG_TILEBYTECOUNTS:
            *va_arg(ap, uint32**) = td->td_stripbytecount;
            break;
  case TIFFTAG_MATTEING:
            *va_arg(ap, uint16*) =
                (td->td_extrasamples == 1 &&
                 td->td_sampleinfo[0] == EXTRASAMPLE_ASSOCALPHA);
            break;
  case TIFFTAG_EXTRASAMPLES:
            *va_arg(ap, uint16*) = td->td_extrasamples;
            *va_arg(ap, uint16**) = td->td_sampleinfo;
            break;
  case TIFFTAG_TILEWIDTH:
            *va_arg(ap, uint32*) = td->td_tilewidth;
            break;
  case TIFFTAG_TILELENGTH:
            *va_arg(ap, uint32*) = td->td_tilelength;
            break;
  case TIFFTAG_TILEDEPTH:
            *va_arg(ap, uint32*) = td->td_tiledepth;
            break;
  case TIFFTAG_DATATYPE:
            switch (td->td_sampleformat) {
    case SAMPLEFORMAT_UINT:
                    *va_arg(ap, uint16*) = DATATYPE_UINT;
                    break;
    case SAMPLEFORMAT_INT:
                    *va_arg(ap, uint16*) = DATATYPE_INT;
                    break;
    case SAMPLEFORMAT_IEEEFP:
                    *va_arg(ap, uint16*) = DATATYPE_IEEEFP;
                    break;
    case SAMPLEFORMAT_VOID:
                    *va_arg(ap, uint16*) = DATATYPE_VOID;
                    break;
            }
            break;
  case TIFFTAG_SAMPLEFORMAT:
            *va_arg(ap, uint16*) = td->td_sampleformat;
            break;
  case TIFFTAG_IMAGEDEPTH:
            *va_arg(ap, uint32*) = td->td_imagedepth;
            break;
  case TIFFTAG_STONITS:
            *va_arg(ap, double*) = td->td_stonits;
            break;
  case TIFFTAG_SUBIFD:
            *va_arg(ap, uint16*) = td->td_nsubifd;
            *va_arg(ap, uint32**) = td->td_subifd;
            break;
  case TIFFTAG_YCBCRCOEFFICIENTS:
            *va_arg(ap, float**) = td->td_ycbcrcoeffs;
            break;
  case TIFFTAG_YCBCRPOSITIONING:
            *va_arg(ap, uint16*) = td->td_ycbcrpositioning;
            break;
  case TIFFTAG_YCBCRSUBSAMPLING:
            *va_arg(ap, uint16*) = td->td_ycbcrsubsampling[0];
            *va_arg(ap, uint16*) = td->td_ycbcrsubsampling[1];
            break;
  case TIFFTAG_WHITEPOINT:
            *va_arg(ap, float**) = td->td_whitepoint;
            break;
  case TIFFTAG_PRIMARYCHROMATICITIES:
            *va_arg(ap, float**) = td->td_primarychromas;
            break;
  case TIFFTAG_TRANSFERFUNCTION:
            *va_arg(ap, uint16**) = td->td_transferfunction[0];
            if (td->td_samplesperpixel - td->td_extrasamples > 1) {
                *va_arg(ap, uint16**) = td->td_transferfunction[1];
                *va_arg(ap, uint16**) = td->td_transferfunction[2];
            }
            break;
  case TIFFTAG_REFERENCEBLACKWHITE:
            *va_arg(ap, float**) = td->td_refblackwhite;
            break;
  case TIFFTAG_INKSET:
            *va_arg(ap, uint16*) = td->td_inkset;
            break;
  case TIFFTAG_DOTRANGE:
            *va_arg(ap, uint16*) = td->td_dotrange[0];
            *va_arg(ap, uint16*) = td->td_dotrange[1];
            break;
  case TIFFTAG_INKNAMES:
            *va_arg(ap, char**) = td->td_inknames;
            break;
  case TIFFTAG_NUMBEROFINKS:
            *va_arg(ap, uint16*) = td->td_ninks;
            break;
  case TIFFTAG_TARGETPRINTER:
            *va_arg(ap, char**) = td->td_targetprinter;
            break;
  case TIFFTAG_ICCPROFILE:
            *va_arg(ap, uint32*) = td->td_profileLength;
            *va_arg(ap, void**) = td->td_profileData;
            break;
   case TIFFTAG_PHOTOSHOP:
            *va_arg(ap, uint32*) = td->td_photoshopLength;
            *va_arg(ap, void**) = td->td_photoshopData;
            break;
   case TIFFTAG_RICHTIFFIPTC:
            *va_arg(ap, uint32*) = td->td_richtiffiptcLength;
            *va_arg(ap, void**) = td->td_richtiffiptcData;
            break;
  case TIFFTAG_XMLPACKET:
            *va_arg(ap, uint32*) = td->td_xmlpacketLength;
            *va_arg(ap, void**) = td->td_xmlpacketData;
            break;
            /* Begin Pixar Tags */
   case TIFFTAG_PIXAR_IMAGEFULLWIDTH:
            *va_arg(ap, uint32*) = td->td_imagefullwidth;
            break;
   case TIFFTAG_PIXAR_IMAGEFULLLENGTH:
            *va_arg(ap, uint32*) = td->td_imagefulllength;
            break;
   case TIFFTAG_PIXAR_TEXTUREFORMAT:
            *va_arg(ap, char**) = td->td_textureformat;
            break;
   case TIFFTAG_PIXAR_WRAPMODES:
            *va_arg(ap, char**) = td->td_wrapmodes;
            break;
   case TIFFTAG_PIXAR_FOVCOT:
            *va_arg(ap, float*) = td->td_fovcot;
            break;
   case TIFFTAG_PIXAR_MATRIX_WORLDTOSCREEN:
            *va_arg(ap, float**) = td->td_matrixWorldToScreen;
            break;
   case TIFFTAG_PIXAR_MATRIX_WORLDTOCAMERA:
            *va_arg(ap, float**) = td->td_matrixWorldToCamera;
            break;
            /* End Pixar Tags */

        default:
        {
            const TIFFFieldInfo* fip = _TIFFFindFieldInfo(tif, tag, TIFF_ANY);
            int           i;
            
            /*
             * This can happen if multiple images are open with
             * different codecs which have private tags.  The
             * global tag information table may then have tags
             * that are valid for one file but not the other. 
             * If the client tries to get a tag that is not valid
             * for the image's codec then we'll arrive here.
             */
            if( fip == NULL || fip->field_bit != FIELD_CUSTOM )
            {
                TIFFError("_TIFFVGetField",
                          "%s: Invalid %stag \"%s\" (not supported by codec)",
                          tif->tif_name, isPseudoTag(tag) ? "pseudo-" : "",
                          _TIFFFieldWithTag(tif, tag)->field_name);
                ret_val = 0;
                break;
            }

            /*
            ** Do we have a custom value?
            */
            ret_val = 0;
            for (i = 0; i < td->td_customValueCount; i++)
            {
    TIFFTagValue *tv = td->td_customValues + i;

    if (tv->info->field_tag != tag)
      continue;
                
    if (fip->field_passcount) {
      if (fip->field_readcount == TIFF_VARIABLE2) 
        *va_arg(ap, uint32*) = (uint32)tv->count;
      else  /* Assume TIFF_VARIABLE */
        *va_arg(ap, uint16*) = (uint16)tv->count;
      *va_arg(ap, void **) = tv->value;
      ret_val = 1;
      break;
                } else if (fip->field_type == TIFF_ASCII) {
      *va_arg(ap, void **) = tv->value;
      ret_val = 1;
      break;
                } else {
      TIFFError("_TIFFVGetField",
          "%s: Pass by value is not implemented.",
          tif->tif_name);
      break;
                }
            }
        }
    }
    return(ret_val);
}

/*
 * Return the value of a field in the
 * internal directory structure.
 */
int
TIFFGetField(TIFF* tif, ttag_t tag, ...)
{
  int status;
  va_list ap;

  va_start(ap, tag);
  status = TIFFVGetField(tif, tag, ap);
  va_end(ap);
  return (status);
}

/*
 * Like TIFFGetField, but taking a varargs
 * parameter list.  This routine is useful
 * for building higher-level interfaces on
 * top of the library.
 */
int
TIFFVGetField(TIFF* tif, ttag_t tag, va_list ap)
{
  const TIFFFieldInfo* fip = _TIFFFindFieldInfo(tif, tag, TIFF_ANY);
  return (fip && (isPseudoTag(tag) || TIFFFieldSet(tif, fip->field_bit)) ?
      (*tif->tif_tagmethods.vgetfield)(tif, tag, ap) : 0);
}

#define  CleanupField(member) {    \
    if (td->member) {      \
  _TIFFfree(td->member);    \
  td->member = 0;      \
    }          \
}

/*
 * Release storage associated with a directory.
 */
void
TIFFFreeDirectory(TIFF* tif)
{
  TIFFDirectory *td = &tif->tif_dir;
  int            i;

  CleanupField(td_colormap[0]);
  CleanupField(td_colormap[1]);
  CleanupField(td_colormap[2]);
  CleanupField(td_documentname);
  CleanupField(td_artist);
  CleanupField(td_datetime);
  CleanupField(td_hostcomputer);
  CleanupField(td_imagedescription);
  CleanupField(td_make);
  CleanupField(td_model);
  CleanupField(td_copyright);
  CleanupField(td_pagename);
  CleanupField(td_sampleinfo);
  CleanupField(td_subifd);
  CleanupField(td_ycbcrcoeffs);
  CleanupField(td_inknames);
  CleanupField(td_targetprinter);
  CleanupField(td_whitepoint);
  CleanupField(td_primarychromas);
  CleanupField(td_refblackwhite);
  CleanupField(td_transferfunction[0]);
  CleanupField(td_transferfunction[1]);
  CleanupField(td_transferfunction[2]);
  CleanupField(td_profileData);
  CleanupField(td_photoshopData);
  CleanupField(td_richtiffiptcData);
  CleanupField(td_xmlpacketData);
  CleanupField(td_stripoffset);
  CleanupField(td_stripbytecount);
  /* Begin Pixar Tags */
  CleanupField(td_textureformat);
  CleanupField(td_wrapmodes);
  CleanupField(td_matrixWorldToScreen);
  CleanupField(td_matrixWorldToCamera);
  /* End Pixar Tags */

  /* Cleanup custom tag values */
  for( i = 0; i < td->td_customValueCount; i++ ) {
    if (td->td_customValues[i].value)
      _TIFFfree(td->td_customValues[i].value);
  }

  td->td_customValueCount = 0;
  CleanupField(td_customValues);
}
#undef CleanupField

/*
 * Client Tag extension support (from Niles Ritter).
 */
static TIFFExtendProc _TIFFextender = (TIFFExtendProc) NULL;

TIFFExtendProc
TIFFSetTagExtender(TIFFExtendProc extender)
{
  TIFFExtendProc prev = _TIFFextender;
  _TIFFextender = extender;
  return (prev);
}

/*
 * Setup for a new directory.  Should we automatically call
 * TIFFWriteDirectory() if the current one is dirty?
 *
 * The newly created directory will not exist on the file till
 * TIFFWriteDirectory(), TIFFFlush() or TIFFClose() is called.
 */
int
TIFFCreateDirectory(TIFF* tif)
{
    TIFFDefaultDirectory(tif);
    tif->tif_diroff = 0;
    tif->tif_nextdiroff = 0;
    tif->tif_curoff = 0;
    tif->tif_row = (uint32) -1;
    tif->tif_curstrip = (tstrip_t) -1;

    return 0;
}

/*
 * Setup a default directory structure.
 */
int
TIFFDefaultDirectory(TIFF* tif)
{
  register TIFFDirectory* td = &tif->tif_dir;

  _TIFFSetupFieldInfo(tif);
  _TIFFmemset(td, 0, sizeof (*td));
  td->td_fillorder = FILLORDER_MSB2LSB;
  td->td_bitspersample = 1;
  td->td_threshholding = THRESHHOLD_BILEVEL;
  td->td_orientation = ORIENTATION_TOPLEFT;
  td->td_samplesperpixel = 1;
  td->td_rowsperstrip = (uint32) -1;
  td->td_tilewidth = 0;
  td->td_tilelength = 0;
  td->td_tiledepth = 1;
  td->td_stripbytecountsorted = 1; /* Our own arrays always sorted. */
  td->td_resolutionunit = RESUNIT_INCH;
  td->td_sampleformat = SAMPLEFORMAT_UINT;
  td->td_imagedepth = 1;
  td->td_ycbcrsubsampling[0] = 2;
  td->td_ycbcrsubsampling[1] = 2;
  td->td_ycbcrpositioning = YCBCRPOSITION_CENTERED;
  td->td_inkset = INKSET_CMYK;
  td->td_ninks = 4;
  tif->tif_postdecode = _TIFFNoPostDecode;
        tif->tif_foundfield = NULL;
  tif->tif_tagmethods.vsetfield = _TIFFVSetField;
  tif->tif_tagmethods.vgetfield = _TIFFVGetField;
  tif->tif_tagmethods.printdir = NULL;
  /*
   *  Give client code a chance to install their own
   *  tag extensions & methods, prior to compression overloads.
   */
  if (_TIFFextender)
    (*_TIFFextender)(tif);
  (void) TIFFSetField(tif, TIFFTAG_COMPRESSION, COMPRESSION_NONE);
  /*
   * NB: The directory is marked dirty as a result of setting
   * up the default compression scheme.  However, this really
   * isn't correct -- we want TIFF_DIRTYDIRECT to be set only
   * if the user does something.  We could just do the setup
   * by hand, but it seems better to use the normal mechanism
   * (i.e. TIFFSetField).
   */
  tif->tif_flags &= ~TIFF_DIRTYDIRECT;

        /*
         * As per http://bugzilla.remotesensing.org/show_bug.cgi?id=19
         * we clear the ISTILED flag when setting up a new directory.
         * Should we also be clearing stuff like INSUBIFD?
         */
        tif->tif_flags &= ~TIFF_ISTILED;

  return (1);
}

static int
TIFFAdvanceDirectory(TIFF* tif, uint32* nextdir, toff_t* off)
{
    static const char module[] = "TIFFAdvanceDirectory";
    uint16 dircount;
    if (isMapped(tif))
    {
        toff_t poff=*nextdir;
        if (poff+sizeof(uint16) > tif->tif_size)
        {
            TIFFError(module, "%s: Error fetching directory count",
                      tif->tif_name);
            return (0);
        }
        _TIFFmemcpy(&dircount, tif->tif_base+poff, sizeof (uint16));
        if (tif->tif_flags & TIFF_SWAB)
            TIFFSwabShort(&dircount);
        poff+=sizeof (uint16)+dircount*sizeof (TIFFDirEntry);
        if (off != NULL)
            *off = poff;
        if (((toff_t) (poff+sizeof (uint32))) > tif->tif_size)
        {
            TIFFError(module, "%s: Error fetching directory link",
                      tif->tif_name);
            return (0);
        }
        _TIFFmemcpy(nextdir, tif->tif_base+poff, sizeof (uint32));
        if (tif->tif_flags & TIFF_SWAB)
            TIFFSwabLong(nextdir);
        return (1);
    }
    else
    {
        if (!SeekOK(tif, *nextdir) ||
            !ReadOK(tif, &dircount, sizeof (uint16))) {
            TIFFError(module, "%s: Error fetching directory count",
                      tif->tif_name);
            return (0);
        }
        if (tif->tif_flags & TIFF_SWAB)
            TIFFSwabShort(&dircount);
        if (off != NULL)
            *off = TIFFSeekFile(tif,
                                dircount*sizeof (TIFFDirEntry), SEEK_CUR);
        else
            (void) TIFFSeekFile(tif,
                                dircount*sizeof (TIFFDirEntry), SEEK_CUR);
        if (!ReadOK(tif, nextdir, sizeof (uint32))) {
            TIFFError(module, "%s: Error fetching directory link",
                      tif->tif_name);
            return (0);
        }
        if (tif->tif_flags & TIFF_SWAB)
            TIFFSwabLong(nextdir);
        return (1);
    }
}

/*
 * Count the number of directories in a file.
 */
tdir_t
TIFFNumberOfDirectories(TIFF* tif)
{
    toff_t nextdir = tif->tif_header.tiff_diroff;
    tdir_t n = 0;
    
    while (nextdir != 0 && TIFFAdvanceDirectory(tif, &nextdir, NULL))
        n++;
    return (n);
}

/*
 * Set the n-th directory as the current directory.
 * NB: Directories are numbered starting at 0.
 */
int
TIFFSetDirectory(TIFF* tif, tdir_t dirn)
{
  toff_t nextdir;
  tdir_t n;

  nextdir = tif->tif_header.tiff_diroff;
  for (n = dirn; n > 0 && nextdir != 0; n--)
    if (!TIFFAdvanceDirectory(tif, &nextdir, NULL))
      return (0);
  tif->tif_nextdiroff = nextdir;
  /*
   * Set curdir to the actual directory index.  The
   * -1 is because TIFFReadDirectory will increment
   * tif_curdir after successfully reading the directory.
   */
  tif->tif_curdir = (dirn - n) - 1;
  /*
   * Reset tif_dirnumber counter and start new list of seen directories.
   * We need this to prevent IFD loops.
   */
  tif->tif_dirnumber = 0;
  return (TIFFReadDirectory(tif));
}

/*
 * Set the current directory to be the directory
 * located at the specified file offset.  This interface
 * is used mainly to access directories linked with
 * the SubIFD tag (e.g. thumbnail images).
 */
int
TIFFSetSubDirectory(TIFF* tif, uint32 diroff)
{
  tif->tif_nextdiroff = diroff;
  /*
   * Reset tif_dirnumber counter and start new list of seen directories.
   * We need this to prevent IFD loops.
   */
  tif->tif_dirnumber = 0;
  return (TIFFReadDirectory(tif));
}

/*
 * Return file offset of the current directory.
 */
uint32
TIFFCurrentDirOffset(TIFF* tif)
{
  return (tif->tif_diroff);
}

/*
 * Return an indication of whether or not we are
 * at the last directory in the file.
 */
int
TIFFLastDirectory(TIFF* tif)
{
  return (tif->tif_nextdiroff == 0);
}

/*
 * Unlink the specified directory from the directory chain.
 */
int
TIFFUnlinkDirectory(TIFF* tif, tdir_t dirn)
{
  static const char module[] = "TIFFUnlinkDirectory";
  toff_t nextdir;
  toff_t off;
  tdir_t n;

  if (tif->tif_mode == O_RDONLY) {
    TIFFError(module, "Can not unlink directory in read-only file");
    return (0);
  }
  /*
   * Go to the directory before the one we want
   * to unlink and nab the offset of the link
   * field we'll need to patch.
   */
  nextdir = tif->tif_header.tiff_diroff;
  off = sizeof (uint16) + sizeof (uint16);
  for (n = dirn-1; n > 0; n--) {
    if (nextdir == 0) {
      TIFFError(module, "Directory %d does not exist", dirn);
      return (0);
    }
    if (!TIFFAdvanceDirectory(tif, &nextdir, &off))
      return (0);
  }
  /*
   * Advance to the directory to be unlinked and fetch
   * the offset of the directory that follows.
   */
  if (!TIFFAdvanceDirectory(tif, &nextdir, NULL))
    return (0);
  /*
   * Go back and patch the link field of the preceding
   * directory to point to the offset of the directory
   * that follows.
   */
  (void) TIFFSeekFile(tif, off, SEEK_SET);
  if (tif->tif_flags & TIFF_SWAB)
    TIFFSwabLong(&nextdir);
  if (!WriteOK(tif, &nextdir, sizeof (uint32))) {
    TIFFError(module, "Error writing directory link");
    return (0);
  }
  /*
   * Leave directory state setup safely.  We don't have
   * facilities for doing inserting and removing directories,
   * so it's safest to just invalidate everything.  This
   * means that the caller can only append to the directory
   * chain.
   */
  (*tif->tif_cleanup)(tif);
  if ((tif->tif_flags & TIFF_MYBUFFER) && tif->tif_rawdata) {
    _TIFFfree(tif->tif_rawdata);
    tif->tif_rawdata = NULL;
    tif->tif_rawcc = 0;
  }
  tif->tif_flags &= ~(TIFF_BEENWRITING|TIFF_BUFFERSETUP|TIFF_POSTENCODE);
  TIFFFreeDirectory(tif);
  TIFFDefaultDirectory(tif);
  tif->tif_diroff = 0;      /* force link on next write */
  tif->tif_nextdiroff = 0;    /* next write must be at end */
  tif->tif_curoff = 0;
  tif->tif_row = (uint32) -1;
  tif->tif_curstrip = (tstrip_t) -1;
  return (1);
}

/*      [BFC]
 *
 * Author: Bruce Cameron <cameron@petris.com>
 *
 * Set a table of tags that are to be replaced during directory process by the
 * 'IGNORE' state - or return TRUE/FALSE for the requested tag such that
 * 'ReadDirectory' can use the stored information.
 *
 * FIXME: this is never used properly. Should be removed in the future.
 */
int
TIFFReassignTagToIgnore (enum TIFFIgnoreSense task, int TIFFtagID)
{
    static int TIFFignoretags [FIELD_LAST];
    static int tagcount = 0 ;
    int    i;          /* Loop index */
    int    j;          /* Loop index */

    switch (task)
    {
      case TIS_STORE:
        if ( tagcount < (FIELD_LAST - 1) )
        {
            for ( j = 0 ; j < tagcount ; ++j )
            {          /* Do not add duplicate tag */
                if ( TIFFignoretags [j] == TIFFtagID )
                    return (TRUE) ;
            }
            TIFFignoretags [tagcount++] = TIFFtagID ;
            return (TRUE) ;
        }
        break ;
        
      case TIS_EXTRACT:
        for ( i = 0 ; i < tagcount ; ++i )
        {
            if ( TIFFignoretags [i] == TIFFtagID )
                return (TRUE) ;
        }
        break;
        
      case TIS_EMPTY:
        tagcount = 0 ;      /* Clear the list */
        return (TRUE) ;
        
      default:
        break;
    }
    
    return (FALSE);
}

