tif_dirread.c

奇趣公司比较新的qt/emd版本

			}
			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";

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

	/* Check for overflow. */
	if (!dir->tdir_count || !w || cc / w != (tsize_t)dir->tdir_count)
		goto bad;

	if (!isMapped(tif)) {
		if (!SeekOK(tif, dir->tdir_offset))
			goto bad;
		if (!ReadOK(tif, cp, cc))
			goto bad;
	} else {
		/* Check for overflow. */
		if ((tsize_t)dir->tdir_offset + cc < (tsize_t)dir->tdir_offset
		    || (tsize_t)dir->tdir_offset + cc < cc
		    || (tsize_t)dir->tdir_offset + cc > (tsize_t)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:
	TIFFErrorExt(tif->tif_clientdata, 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) {
		TIFFErrorExt(tif->tif_clientdata, 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, uint8* 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] = dir->tdir_offset & 0xff;
                    case 3: v[2] = (dir->tdir_offset >> 8) & 0xff;
                    case 2: v[1] = (dir->tdir_offset >> 16) & 0xff;
		    case 1: v[0] = dir->tdir_offset >> 24;
                }
	    else
                switch (dir->tdir_count) {
                    case 4: v[3] = dir->tdir_offset & 0xff;
                    case 3: v[2] = (dir->tdir_offset >> 8) & 0xff;
                    case 2: v[1] = (dir->tdir_offset >> 16) & 0xff;
		    case 1: v[0] = dir->tdir_offset >> 24;
                }
	} else {
	    if (dir->tdir_type == TIFF_SBYTE)
                switch (dir->tdir_count) {
                    case 4: v[3] = dir->tdir_offset >> 24;
                    case 3: v[2] = (dir->tdir_offset >> 16) & 0xff;
                    case 2: v[1] = (dir->tdir_offset >> 8) & 0xff;
                    case 1: v[0] = dir->tdir_offset & 0xff;
		}
	    else
                switch (dir->tdir_count) {
                    case 4: v[3] = dir->tdir_offset >> 24;
                    case 3: v[2] = (dir->tdir_offset >> 16) & 0xff;
                    case 2: v[1] = (dir->tdir_offset >> 8) & 0xff;
                    case 1: v[0] = 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. Some tags may have either BYTE
 * or SHORT type and this function works with both ones.
 */
static int
TIFFFetchShortPair(TIFF* tif, TIFFDirEntry* dir)
{
	switch (dir->tdir_type) {
		case TIFF_BYTE:
		case TIFF_SBYTE:
			{
			uint8 v[4];
			return TIFFFetchByteArray(tif, dir, v)
				&& TIFFSetField(tif, dir->tdir_tag, v[0], v[1]);
			}
		case TIFF_SHORT:
		case TIFF_SSHORT:
			{
			uint16 v[2];
			return TIFFFetchShortArray(tif, dir, v)
				&& TIFFSetField(tif, dir->tdir_tag, v[0], v[1]);
			}
		default:
			return 0;
	}
}

/*
 * 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*)_TIFFCheckMalloc(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, (uint8*) v))
			return (0);
		if (dir->tdir_type == TIFF_BYTE) {
			uint8* vp = (uint8*) v;
			for (i = dir->tdir_count-1; i >= 0; i--)
				v[i] = vp[i];
		} else {
			int8* vp = (int8*) 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 */
		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
			     "cannot read TIFF_ANY type %d for field \"%s\"",
			     dir->tdir_type,
			     _TIFFFieldWithTag(tif, dir->tdir_tag)->field_name);
		return (0);
	}
	return (1);
}

/*