tif_dirread.c

奇趣公司比较新的qt/emd版本

					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:
			{
				char* cp;
				/*
				 * 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 = (char *)_TIFFCheckMalloc(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;
		}
		TIFFWarningExt(tif->tif_clientdata, 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 
                   && td->td_stripoffset[0] != 0 
                   && BYTECOUNTLOOKSBAD) {
		/*
		 * XXX: 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.
		 */
		TIFFWarningExt(tif->tif_clientdata, 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;
	} else if (td->td_planarconfig == PLANARCONFIG_CONTIG
		   && td->td_nstrips > 2
		   && td->td_compression == COMPRESSION_NONE
		   && td->td_stripbytecount[0] != td->td_stripbytecount[1]) {
		/*
		 * XXX: Some vendors fill StripByteCount array with absolutely
		 * wrong values (it can be equal to StripOffset array, for
		 * example). Catch this case here.
		 */
		TIFFWarningExt(tif->tif_clientdata, module,
	"%s: Wrong \"%s\" field, ignoring and calculating from imagelength",
                            tif->tif_name,
		            _TIFFFieldWithTag(tif,TIFFTAG_STRIPBYTECOUNTS)->field_name);
		if (EstimateStripByteCounts(tif, dir, dircount) < 0)
		    goto bad;
	}
	if (dir) {
		_TIFFfree((char *)dir);
		dir = NULL;
	}
	if (!TIFFFieldSet(tif, FIELD_MAXSAMPLEVALUE))
		td->td_maxsamplevalue = (uint16)((1L<<td->td_bitspersample)-1);
	/*
	 * Setup default compression scheme.
	 */

	/*
	 * 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) {
		TIFFErrorExt(tif->tif_clientdata, module, "%s: cannot handle zero scanline size",
			  tif->tif_name);
		return (0);
	}

	if (isTiled(tif)) {
		tif->tif_tilesize = TIFFTileSize(tif);
		if (!tif->tif_tilesize) {
			TIFFErrorExt(tif->tif_clientdata, module, "%s: cannot handle zero tile size",
				  tif->tif_name);
			return (0);
		}
	} else {
		if (!TIFFStripSize(tif)) {
			TIFFErrorExt(tif->tif_clientdata, module, "%s: cannot handle zero strip size",
				  tif->tif_name);
			return (0);
		}
	}
	return (1);
bad:
	if (dir)
		_TIFFfree(dir);
	return (0);
}

/* 
 * Read custom directory from the arbitarry offset.
 * The code is very similar to TIFFReadDirectory().
 */
int
TIFFReadCustomDirectory(TIFF* tif, toff_t diroff,
			const TIFFFieldInfo info[], size_t n)
{
	static const char module[] = "TIFFReadCustomDirectory";

	TIFFDirectory* td = &tif->tif_dir;
	TIFFDirEntry *dp, *dir = NULL;
	const TIFFFieldInfo* fip;
	size_t fix;
	uint16 i, dircount;

	_TIFFSetupFieldInfo(tif, info, n);

	tif->tif_diroff = diroff;

	if (!isMapped(tif)) {
		if (!SeekOK(tif, diroff)) {
			TIFFErrorExt(tif->tif_clientdata, module,
			    "%s: Seek error accessing TIFF directory",
                            tif->tif_name);
			return (0);
		}
		if (!ReadOK(tif, &dircount, sizeof (uint16))) {
			TIFFErrorExt(tif->tif_clientdata, module,
			    "%s: Can not read TIFF directory count",
                            tif->tif_name);
			return (0);
		}
		if (tif->tif_flags & TIFF_SWAB)
			TIFFSwabShort(&dircount);
		dir = (TIFFDirEntry *)_TIFFCheckMalloc(tif, dircount,
						       sizeof (TIFFDirEntry),
					"to read TIFF custom directory");
		if (dir == NULL)
			return (0);
		if (!ReadOK(tif, dir, dircount * sizeof (TIFFDirEntry))) {
			TIFFErrorExt(tif->tif_clientdata, module,
                                  "%.100s: Can not read TIFF directory",
                                  tif->tif_name);
			goto bad;
		}
	} else {
		toff_t off = diroff;

		if (off + sizeof (uint16) > tif->tif_size) {
			TIFFErrorExt(tif->tif_clientdata, 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 *)_TIFFCheckMalloc(tif, dircount,
						       sizeof (TIFFDirEntry),
					"to read TIFF custom directory");
		if (dir == NULL)
			return (0);
		if (off + dircount * sizeof (TIFFDirEntry) > tif->tif_size) {
			TIFFErrorExt(tif->tif_clientdata, module,
                                  "%s: Can not read TIFF directory",
                                  tif->tif_name);
			goto bad;
		} else {
			_TIFFmemcpy(dir, tif->tif_base + off,
				    dircount * sizeof (TIFFDirEntry));
		}
	}

	TIFFFreeDirectory(tif);

	fix = 0;
	for (dp = dir, i = dircount; i > 0; i--, dp++) {
		if (tif->tif_flags & TIFF_SWAB) {
			TIFFSwabArrayOfShort(&dp->tdir_tag, 2);
			TIFFSwabArrayOfLong(&dp->tdir_count, 2);
		}

		if (fix >= tif->tif_nfields || dp->tdir_tag == IGNORE)
			continue;

		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) {

			TIFFWarningExt(tif->tif_clientdata, 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) {
				TIFFWarningExt(tif->tif_clientdata, 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;
		}

		(void) TIFFFetchNormalTag(tif, dp);
	}
	
	if (dir)
		_TIFFfree(dir);
	return 1;

bad:
	if (dir)
		_TIFFfree(dir);
	return 0;
}

/*
 * EXIF is important special case of custom IFD, so we have a special
 * function to read it.
 */
int
TIFFReadEXIFDirectory(TIFF* tif, toff_t diroff)
{
	size_t exifFieldInfoCount;
	const TIFFFieldInfo *exifFieldInfo =
		_TIFFGetExifFieldInfo(&exifFieldInfoCount);
	return TIFFReadCustomDirectory(tif, diroff, exifFieldInfo,
				       exifFieldInfoCount);
}

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*)
	    _TIFFCheckMalloc(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) {
				TIFFErrorExt(tif->tif_clientdata, module,
			"%s: Cannot determine size of unknown tag type %d",
					  tif->tif_name, dp->tdir_type);
				return -1;