Rearrange source files.

1 files changed, 867 insertions, 0 deletions

diff --git a/source/fitz/load-tiff.c b/source/fitz/load-tiff.c
new file mode 100644
index 00000000..5806bc00
--- /dev/null
+++ b/source/fitz/load-tiff.c
@@ -0,0 +1,867 @@
+#include "mupdf/fitz.h"
+
+/*
+ * TIFF image loader. Should be enough to support TIFF files in XPS.
+ * Baseline TIFF 6.0 plus CMYK, LZW, Flate and JPEG support.
+ * Limited bit depths (1,2,4,8).
+ * Limited planar configurations (1=chunky).
+ * No tiles (easy fix if necessary).
+ * TODO: RGBPal images
+ */
+
+struct tiff
+{
+	fz_context *ctx;
+
+	/* "file" */
+	unsigned char *bp, *rp, *ep;
+
+	/* byte order */
+	unsigned order;
+
+	/* where we can find the strips of image data */
+	unsigned rowsperstrip;
+	unsigned *stripoffsets;
+	unsigned *stripbytecounts;
+
+	/* colormap */
+	unsigned *colormap;
+
+	unsigned stripoffsetslen;
+	unsigned stripbytecountslen;
+	unsigned colormaplen;
+
+	/* assorted tags */
+	unsigned subfiletype;
+	unsigned photometric;
+	unsigned compression;
+	unsigned imagewidth;
+	unsigned imagelength;
+	unsigned samplesperpixel;
+	unsigned bitspersample;
+	unsigned planar;
+	unsigned extrasamples;
+	unsigned xresolution;
+	unsigned yresolution;
+	unsigned resolutionunit;
+	unsigned fillorder;
+	unsigned g3opts;
+	unsigned g4opts;
+	unsigned predictor;
+
+	unsigned ycbcrsubsamp[2];
+
+	unsigned char *jpegtables; /* point into "file" buffer */
+	unsigned jpegtableslen;
+
+	unsigned char *profile;
+	int profilesize;
+
+	/* decoded data */
+	fz_colorspace *colorspace;
+	unsigned char *samples;
+	int stride;
+};
+
+enum
+{
+	TII = 0x4949, /* 'II' */
+	TMM = 0x4d4d, /* 'MM' */
+	TBYTE = 1,
+	TASCII = 2,
+	TSHORT = 3,
+	TLONG = 4,
+	TRATIONAL = 5
+};
+
+#define NewSubfileType 254
+#define ImageWidth 256
+#define ImageLength 257
+#define BitsPerSample 258
+#define Compression 259
+#define PhotometricInterpretation 262
+#define FillOrder 266
+#define StripOffsets 273
+#define SamplesPerPixel 277
+#define RowsPerStrip 278
+#define StripByteCounts 279
+#define XResolution 282
+#define YResolution 283
+#define PlanarConfiguration 284
+#define T4Options 292
+#define T6Options 293
+#define ResolutionUnit 296
+#define Predictor 317
+#define ColorMap 320
+#define TileWidth 322
+#define TileLength 323
+#define TileOffsets 324
+#define TileByteCounts 325
+#define ExtraSamples 338
+#define JPEGTables 347
+#define YCbCrSubSampling 520
+#define ICCProfile 34675
+
+static const unsigned char bitrev[256] =
+{
+	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
+	0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
+	0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
+	0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
+	0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
+	0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
+	0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
+	0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
+	0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
+	0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
+	0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
+	0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
+	0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
+	0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
+	0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
+	0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
+	0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
+	0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
+	0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
+	0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
+	0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
+	0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
+	0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
+	0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
+	0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
+	0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
+	0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
+	0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
+	0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
+	0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
+	0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
+	0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
+};
+
+static void
+fz_decode_tiff_uncompressed(struct tiff *tiff, fz_stream *stm, unsigned char *wp, int wlen)
+{
+	fz_read(stm, wp, wlen);
+	fz_close(stm);
+}
+
+static void
+fz_decode_tiff_packbits(struct tiff *tiff, fz_stream *chain, unsigned char *wp, int wlen)
+{
+	fz_stream *stm = fz_open_rld(chain);
+	fz_read(stm, wp, wlen);
+	fz_close(stm);
+}
+
+static void
+fz_decode_tiff_lzw(struct tiff *tiff, fz_stream *chain, unsigned char *wp, int wlen)
+{
+	fz_stream *stm = fz_open_lzwd(chain, 1);
+	fz_read(stm, wp, wlen);
+	fz_close(stm);
+}
+
+static void
+fz_decode_tiff_flate(struct tiff *tiff, fz_stream *chain, unsigned char *wp, int wlen)
+{
+	fz_stream *stm = fz_open_flated(chain);
+	fz_read(stm, wp, wlen);
+	fz_close(stm);
+}
+
+static void
+fz_decode_tiff_fax(struct tiff *tiff, int comp, fz_stream *chain, unsigned char *wp, int wlen)
+{
+	fz_stream *stm;
+	int black_is_1 = tiff->photometric == 0;
+	int k = comp == 4 ? -1 : 0;
+	int encoded_byte_align = comp == 2;
+	stm = fz_open_faxd(chain,
+			k, 0, encoded_byte_align,
+			tiff->imagewidth, tiff->imagelength, 0, black_is_1);
+	fz_read(stm, wp, wlen);
+	fz_close(stm);
+}
+
+static void
+fz_decode_tiff_jpeg(struct tiff *tiff, fz_stream *chain, unsigned char *wp, int wlen)
+{
+	fz_stream *stm = fz_open_dctd(chain, -1);
+	fz_read(stm, wp, wlen);
+	fz_close(stm);
+}
+
+static inline int getcomp(unsigned char *line, int x, int bpc)
+{
+	switch (bpc)
+	{
+	case 1: return (line[x >> 3] >> ( 7 - (x & 7) ) ) & 1;
+	case 2: return (line[x >> 2] >> ( ( 3 - (x & 3) ) << 1 ) ) & 3;
+	case 4: return (line[x >> 1] >> ( ( 1 - (x & 1) ) << 2 ) ) & 15;
+	case 8: return line[x];
+	case 16: return line[x << 1] << 8 | line[(x << 1) + 1];
+	}
+	return 0;
+}
+
+static inline void putcomp(unsigned char *line, int x, int bpc, int value)
+{
+	int maxval = (1 << bpc) - 1;
+
+	switch (bpc)
+	{
+	case 1: line[x >> 3] &= ~(maxval << (7 - (x & 7))); break;
+	case 2: line[x >> 2] &= ~(maxval << ((3 - (x & 3)) << 1)); break;
+	case 4: line[x >> 1] &= ~(maxval << ((1 - (x & 1)) << 2)); break;
+	}
+
+	switch (bpc)
+	{
+	case 1: line[x >> 3] |= value << (7 - (x & 7)); break;
+	case 2: line[x >> 2] |= value << ((3 - (x & 3)) << 1); break;
+	case 4: line[x >> 1] |= value << ((1 - (x & 1)) << 2); break;
+	case 8: line[x] = value; break;
+	case 16: line[x << 1] = value >> 8; line[(x << 1) + 1] = value & 0xFF; break;
+	}
+}
+
+static void
+fz_unpredict_tiff(unsigned char *line, int width, int comps, int bits)
+{
+	unsigned char left[32];
+	int i, k, v;
+
+	for (k = 0; k < comps; k++)
+		left[k] = 0;
+
+	for (i = 0; i < width; i++)
+	{
+		for (k = 0; k < comps; k++)
+		{
+			v = getcomp(line, i * comps + k, bits);
+			v = v + left[k];
+			v = v % (1 << bits);
+			putcomp(line, i * comps + k, bits, v);
+			left[k] = v;
+		}
+	}
+}
+
+static void
+fz_invert_tiff(unsigned char *line, int width, int comps, int bits, int alpha)
+{
+	int i, k, v;
+	int m = (1 << bits) - 1;
+
+	for (i = 0; i < width; i++)
+	{
+		for (k = 0; k < comps; k++)
+		{
+			v = getcomp(line, i * comps + k, bits);
+			if (!alpha || k < comps - 1)
+				v = m - v;
+			putcomp(line, i * comps + k, bits, v);
+		}
+	}
+}
+
+static void
+fz_expand_tiff_colormap(struct tiff *tiff)
+{
+	int maxval = 1 << tiff->bitspersample;
+	unsigned char *samples;
+	unsigned char *src, *dst;
+	unsigned int x, y;
+	unsigned int stride;
+
+	/* colormap has first all red, then all green, then all blue values */
+	/* colormap values are 0..65535, bits is 4 or 8 */
+	/* image can be with or without extrasamples: comps is 1 or 2 */
+
+	if (tiff->samplesperpixel != 1 && tiff->samplesperpixel != 2)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "invalid number of samples for RGBPal");
+
+	if (tiff->bitspersample != 4 && tiff->bitspersample != 8)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "invalid number of bits for RGBPal");
+
+	if (tiff->colormaplen < (unsigned)maxval * 3)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "insufficient colormap data");
+
+	stride = tiff->imagewidth * (tiff->samplesperpixel + 2);
+
+	samples = fz_malloc(tiff->ctx, stride * tiff->imagelength);
+
+	for (y = 0; y < tiff->imagelength; y++)
+	{
+		src = tiff->samples + (unsigned int)(tiff->stride * y);
+		dst = samples + (unsigned int)(stride * y);
+
+		for (x = 0; x < tiff->imagewidth; x++)
+		{
+			if (tiff->extrasamples)
+			{
+				int c = getcomp(src, x * 2, tiff->bitspersample);
+				int a = getcomp(src, x * 2 + 1, tiff->bitspersample);
+				*dst++ = tiff->colormap[c + 0] >> 8;
+				*dst++ = tiff->colormap[c + maxval] >> 8;
+				*dst++ = tiff->colormap[c + maxval * 2] >> 8;
+				*dst++ = a << (8 - tiff->bitspersample);
+			}
+			else
+			{
+				int c = getcomp(src, x, tiff->bitspersample);
+				*dst++ = tiff->colormap[c + 0] >> 8;
+				*dst++ = tiff->colormap[c + maxval] >> 8;
+				*dst++ = tiff->colormap[c + maxval * 2] >> 8;
+			}
+		}
+	}
+
+	tiff->samplesperpixel += 2;
+	tiff->bitspersample = 8;
+	tiff->stride = stride;
+	fz_free(tiff->ctx, tiff->samples);
+	tiff->samples = samples;
+}
+
+static void
+fz_decode_tiff_strips(struct tiff *tiff)
+{
+	fz_stream *stm;
+
+	/* switch on compression to create a filter */
+	/* feed each strip to the filter */
+	/* read out the data and pack the samples into a pixmap */
+
+	/* type 32773 / packbits -- nothing special (same row-padding as PDF) */
+	/* type 2 / ccitt rle -- no EOL, no RTC, rows are byte-aligned */
+	/* type 3 and 4 / g3 and g4 -- each strip starts new section */
+	/* type 5 / lzw -- each strip is handled separately */
+
+	unsigned char *wp;
+	unsigned row;
+	unsigned strip;
+	unsigned i;
+
+	if (!tiff->rowsperstrip || !tiff->stripoffsets || !tiff->stripbytecounts)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "no image data in tiff; maybe it is tiled");
+
+	if (tiff->stripoffsetslen < (tiff->imagelength - 1) / tiff->rowsperstrip + 1 ||
+		tiff->stripbytecountslen < (tiff->imagelength - 1) / tiff->rowsperstrip + 1)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "insufficient strip offset data");
+
+	if (tiff->planar != 1)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "image data is not in chunky format");
+
+	tiff->stride = (tiff->imagewidth * tiff->samplesperpixel * tiff->bitspersample + 7) / 8;
+
+	switch (tiff->photometric)
+	{
+	case 0: /* WhiteIsZero -- inverted */
+		tiff->colorspace = fz_device_gray(tiff->ctx);
+		break;
+	case 1: /* BlackIsZero */
+		tiff->colorspace = fz_device_gray(tiff->ctx);
+		break;
+	case 2: /* RGB */
+		tiff->colorspace = fz_device_rgb(tiff->ctx);
+		break;
+	case 3: /* RGBPal */
+		tiff->colorspace = fz_device_rgb(tiff->ctx);
+		break;
+	case 5: /* CMYK */
+		tiff->colorspace = fz_device_cmyk(tiff->ctx);
+		break;
+	case 6: /* YCbCr */
+		/* it's probably a jpeg ... we let jpeg convert to rgb */
+		tiff->colorspace = fz_device_rgb(tiff->ctx);
+		break;
+	default:
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "unknown photometric: %d", tiff->photometric);
+	}
+
+	switch (tiff->resolutionunit)
+	{
+	case 2:
+		/* no unit conversion needed */
+		break;
+	case 3:
+		tiff->xresolution = tiff->xresolution * 254 / 100;
+		tiff->yresolution = tiff->yresolution * 254 / 100;
+		break;
+	default:
+		tiff->xresolution = 96;
+		tiff->yresolution = 96;
+		break;
+	}
+
+	/* Note xres and yres could be 0 even if unit was set. If so default to 96dpi. */
+	if (tiff->xresolution == 0 || tiff->yresolution == 0)
+	{
+		tiff->xresolution = 96;
+		tiff->yresolution = 96;
+	}
+
+	tiff->samples = fz_malloc_array(tiff->ctx, tiff->imagelength, tiff->stride);
+	memset(tiff->samples, 0x55, tiff->imagelength * tiff->stride);
+	wp = tiff->samples;
+
+	strip = 0;
+	for (row = 0; row < tiff->imagelength; row += tiff->rowsperstrip)
+	{
+		unsigned offset = tiff->stripoffsets[strip];
+		unsigned rlen = tiff->stripbytecounts[strip];
+		unsigned wlen = tiff->stride * tiff->rowsperstrip;
+		unsigned char *rp = tiff->bp + offset;
+
+		if (wp + wlen > tiff->samples + (unsigned int)(tiff->stride * tiff->imagelength))
+			wlen = tiff->samples + (unsigned int)(tiff->stride * tiff->imagelength) - wp;
+
+		if (rp + rlen > tiff->ep)
+			fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "strip extends beyond the end of the file");
+
+		/* the bits are in un-natural order */
+		if (tiff->fillorder == 2)
+			for (i = 0; i < rlen; i++)
+				rp[i] = bitrev[rp[i]];
+
+		/* the strip decoders will close this */
+		stm = fz_open_memory(tiff->ctx, rp, rlen);
+
+		switch (tiff->compression)
+		{
+		case 1:
+			fz_decode_tiff_uncompressed(tiff, stm, wp, wlen);
+			break;
+		case 2:
+			fz_decode_tiff_fax(tiff, 2, stm, wp, wlen);
+			break;
+		case 3:
+			fz_decode_tiff_fax(tiff, 3, stm, wp, wlen);
+			break;
+		case 4:
+			fz_decode_tiff_fax(tiff, 4, stm, wp, wlen);
+			break;
+		case 5:
+			fz_decode_tiff_lzw(tiff, stm, wp, wlen);
+			break;
+		case 6:
+			fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "deprecated JPEG in TIFF compression not supported");
+			break;
+		case 7:
+			fz_decode_tiff_jpeg(tiff, stm, wp, wlen);
+			break;
+		case 8:
+			fz_decode_tiff_flate(tiff, stm, wp, wlen);
+			break;
+		case 32773:
+			fz_decode_tiff_packbits(tiff, stm, wp, wlen);
+			break;
+		default:
+			fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "unknown TIFF compression: %d", tiff->compression);
+		}
+
+		/* scramble the bits back into original order */
+		if (tiff->fillorder == 2)
+			for (i = 0; i < rlen; i++)
+				rp[i] = bitrev[rp[i]];
+
+		wp += tiff->stride * tiff->rowsperstrip;
+		strip ++;
+	}
+
+	/* Predictor (only for LZW and Flate) */
+	if ((tiff->compression == 5 || tiff->compression == 8) && tiff->predictor == 2)
+	{
+		unsigned char *p = tiff->samples;
+		for (i = 0; i < tiff->imagelength; i++)
+		{
+			fz_unpredict_tiff(p, tiff->imagewidth, tiff->samplesperpixel, tiff->bitspersample);
+			p += tiff->stride;
+		}
+	}
+
+	/* RGBPal */
+	if (tiff->photometric == 3 && tiff->colormap)
+		fz_expand_tiff_colormap(tiff);
+
+	/* WhiteIsZero .. invert */
+	if (tiff->photometric == 0)
+	{
+		unsigned char *p = tiff->samples;
+		for (i = 0; i < tiff->imagelength; i++)
+		{
+			fz_invert_tiff(p, tiff->imagewidth, tiff->samplesperpixel, tiff->bitspersample, tiff->extrasamples);
+			p += tiff->stride;
+		}
+	}
+
+	/* Premultiplied transparency */
+	if (tiff->extrasamples == 1)
+	{
+		/* In GhostXPS we undo the premultiplication here; muxps holds
+		 * all our images premultiplied by default, so nothing to do.
+		 */
+	}
+
+	/* Non-premultiplied transparency */
+	if (tiff->extrasamples == 2)
+	{
+		/* Premultiplied files are corrected for elsewhere */
+	}
+}
+
+static inline int readbyte(struct tiff *tiff)
+{
+	if (tiff->rp < tiff->ep)
+		return *tiff->rp++;
+	return EOF;
+}
+
+static inline unsigned readshort(struct tiff *tiff)
+{
+	unsigned a = readbyte(tiff);
+	unsigned b = readbyte(tiff);
+	if (tiff->order == TII)
+		return (b << 8) | a;
+	return (a << 8) | b;
+}
+
+static inline unsigned readlong(struct tiff *tiff)
+{
+	unsigned a = readbyte(tiff);
+	unsigned b = readbyte(tiff);
+	unsigned c = readbyte(tiff);
+	unsigned d = readbyte(tiff);
+	if (tiff->order == TII)
+		return (d << 24) | (c << 16) | (b << 8) | a;
+	return (a << 24) | (b << 16) | (c << 8) | d;
+}
+
+static void
+fz_read_tiff_bytes(unsigned char *p, struct tiff *tiff, unsigned ofs, unsigned n)
+{
+	tiff->rp = tiff->bp + ofs;
+	if (tiff->rp > tiff->ep)
+		tiff->rp = tiff->bp;
+
+	while (n--)
+		*p++ = readbyte(tiff);
+}
+
+static void
+fz_read_tiff_tag_value(unsigned *p, struct tiff *tiff, unsigned type, unsigned ofs, unsigned n)
+{
+	tiff->rp = tiff->bp + ofs;
+	if (tiff->rp > tiff->ep)
+		tiff->rp = tiff->bp;
+
+	while (n--)
+	{
+		switch (type)
+		{
+		case TRATIONAL:
+			*p = readlong(tiff);
+			*p = *p / readlong(tiff);
+			p ++;
+			break;
+		case TBYTE: *p++ = readbyte(tiff); break;
+		case TSHORT: *p++ = readshort(tiff); break;
+		case TLONG: *p++ = readlong(tiff); break;
+		default: *p++ = 0; break;
+		}
+	}
+}
+
+static void
+fz_read_tiff_tag(struct tiff *tiff, unsigned offset)
+{
+	unsigned tag;
+	unsigned type;
+	unsigned count;
+	unsigned value;
+
+	tiff->rp = tiff->bp + offset;
+
+	tag = readshort(tiff);
+	type = readshort(tiff);
+	count = readlong(tiff);
+
+	if ((type == TBYTE && count <= 4) ||
+			(type == TSHORT && count <= 2) ||
+			(type == TLONG && count <= 1))
+		value = tiff->rp - tiff->bp;
+	else
+		value = readlong(tiff);
+
+	switch (tag)
+	{
+	case NewSubfileType:
+		fz_read_tiff_tag_value(&tiff->subfiletype, tiff, type, value, 1);
+		break;
+	case ImageWidth:
+		fz_read_tiff_tag_value(&tiff->imagewidth, tiff, type, value, 1);
+		break;
+	case ImageLength:
+		fz_read_tiff_tag_value(&tiff->imagelength, tiff, type, value, 1);
+		break;
+	case BitsPerSample:
+		fz_read_tiff_tag_value(&tiff->bitspersample, tiff, type, value, 1);
+		break;
+	case Compression:
+		fz_read_tiff_tag_value(&tiff->compression, tiff, type, value, 1);
+		break;
+	case PhotometricInterpretation:
+		fz_read_tiff_tag_value(&tiff->photometric, tiff, type, value, 1);
+		break;
+	case FillOrder:
+		fz_read_tiff_tag_value(&tiff->fillorder, tiff, type, value, 1);
+		break;
+	case SamplesPerPixel:
+		fz_read_tiff_tag_value(&tiff->samplesperpixel, tiff, type, value, 1);
+		break;
+	case RowsPerStrip:
+		fz_read_tiff_tag_value(&tiff->rowsperstrip, tiff, type, value, 1);
+		break;
+	case XResolution:
+		fz_read_tiff_tag_value(&tiff->xresolution, tiff, type, value, 1);
+		break;
+	case YResolution:
+		fz_read_tiff_tag_value(&tiff->yresolution, tiff, type, value, 1);
+		break;
+	case PlanarConfiguration:
+		fz_read_tiff_tag_value(&tiff->planar, tiff, type, value, 1);
+		break;
+	case T4Options:
+		fz_read_tiff_tag_value(&tiff->g3opts, tiff, type, value, 1);
+		break;
+	case T6Options:
+		fz_read_tiff_tag_value(&tiff->g4opts, tiff, type, value, 1);
+		break;
+	case Predictor:
+		fz_read_tiff_tag_value(&tiff->predictor, tiff, type, value, 1);
+		break;
+	case ResolutionUnit:
+		fz_read_tiff_tag_value(&tiff->resolutionunit, tiff, type, value, 1);
+		break;
+	case YCbCrSubSampling:
+		fz_read_tiff_tag_value(tiff->ycbcrsubsamp, tiff, type, value, 2);
+		break;
+	case ExtraSamples:
+		fz_read_tiff_tag_value(&tiff->extrasamples, tiff, type, value, 1);
+		break;
+
+	case ICCProfile:
+		tiff->profile = fz_malloc(tiff->ctx, count);
+		/* ICC profile data type is set to UNDEFINED.
+		 * TBYTE reading not correct in fz_read_tiff_tag_value */
+		fz_read_tiff_bytes(tiff->profile, tiff, value, count);
+		tiff->profilesize = count;
+		break;
+
+	case JPEGTables:
+		fz_warn(tiff->ctx, "jpeg tables in tiff not implemented");
+		tiff->jpegtables = tiff->bp + value;
+		tiff->jpegtableslen = count;
+		break;
+
+	case StripOffsets:
+		tiff->stripoffsets = fz_malloc_array(tiff->ctx, count, sizeof(unsigned));
+		fz_read_tiff_tag_value(tiff->stripoffsets, tiff, type, value, count);
+		tiff->stripoffsetslen = count;
+		break;
+
+	case StripByteCounts:
+		tiff->stripbytecounts = fz_malloc_array(tiff->ctx, count, sizeof(unsigned));
+		fz_read_tiff_tag_value(tiff->stripbytecounts, tiff, type, value, count);
+		tiff->stripbytecountslen = count;
+		break;
+
+	case ColorMap:
+		tiff->colormap = fz_malloc_array(tiff->ctx, count, sizeof(unsigned));
+		fz_read_tiff_tag_value(tiff->colormap, tiff, type, value, count);
+		tiff->colormaplen = count;
+		break;
+
+	case TileWidth:
+	case TileLength:
+	case TileOffsets:
+	case TileByteCounts:
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "tiled tiffs not supported");
+
+	default:
+		/* printf("unknown tag: %d t=%d n=%d\n", tag, type, count); */
+		break;
+	}
+}
+
+static void
+fz_swap_tiff_byte_order(unsigned char *buf, int n)
+{
+	int i, t;
+	for (i = 0; i < n; i++)
+	{
+		t = buf[i * 2 + 0];
+		buf[i * 2 + 0] = buf[i * 2 + 1];
+		buf[i * 2 + 1] = t;
+	}
+}
+
+static void
+fz_decode_tiff_header(fz_context *ctx, struct tiff *tiff, unsigned char *buf, int len)
+{
+	unsigned version;
+	unsigned offset;
+	unsigned count;
+	unsigned i;
+
+	memset(tiff, 0, sizeof(struct tiff));
+	tiff->ctx = ctx;
+	tiff->bp = buf;
+	tiff->rp = buf;
+	tiff->ep = buf + len;
+
+	/* tag defaults, where applicable */
+	tiff->bitspersample = 1;
+	tiff->compression = 1;
+	tiff->samplesperpixel = 1;
+	tiff->resolutionunit = 2;
+	tiff->rowsperstrip = 0xFFFFFFFF;
+	tiff->fillorder = 1;
+	tiff->planar = 1;
+	tiff->subfiletype = 0;
+	tiff->predictor = 1;
+	tiff->ycbcrsubsamp[0] = 2;
+	tiff->ycbcrsubsamp[1] = 2;
+
+	/*
+	 * Read IFH
+	 */
+
+	/* get byte order marker */
+	tiff->order = TII;
+	tiff->order = readshort(tiff);
+	if (tiff->order != TII && tiff->order != TMM)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "not a TIFF file, wrong magic marker");
+
+	/* check version */
+	version = readshort(tiff);
+	if (version != 42)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "not a TIFF file, wrong version marker");
+
+	/* get offset of IFD */
+	offset = readlong(tiff);
+
+	/*
+	 * Read IFD
+	 */
+
+	tiff->rp = tiff->bp + offset;
+
+	if (tiff->rp < tiff->bp || tiff->rp > tiff->ep)
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "invalid IFD offset %u", offset);
+
+	count = readshort(tiff);
+
+	if (count * 12 > (unsigned)(tiff->ep - tiff->rp))
+		fz_throw(tiff->ctx, FZ_ERROR_GENERIC, "overlarge IFD entry count %u", count);
+
+	offset += 2;
+	for (i = 0; i < count; i++)
+	{
+		fz_read_tiff_tag(tiff, offset);
+		offset += 12;
+	}
+}
+
+fz_pixmap *
+fz_load_tiff(fz_context *ctx, unsigned char *buf, int len)
+{
+	fz_pixmap *image;
+	struct tiff tiff;
+
+	fz_try(ctx)
+	{
+		fz_decode_tiff_header(ctx, &tiff, buf, len);
+
+		/* Decode the image strips */
+
+		if (tiff.rowsperstrip > tiff.imagelength)
+			tiff.rowsperstrip = tiff.imagelength;
+
+		fz_decode_tiff_strips(&tiff);
+
+		/* Byte swap 16-bit images to big endian if necessary */
+		if (tiff.bitspersample == 16)
+			if (tiff.order == TII)
+				fz_swap_tiff_byte_order(tiff.samples, tiff.imagewidth * tiff.imagelength * tiff.samplesperpixel);
+
+		/* Expand into fz_pixmap struct */
+		image = fz_new_pixmap(tiff.ctx, tiff.colorspace, tiff.imagewidth, tiff.imagelength);
+		image->xres = tiff.xresolution;
+		image->yres = tiff.yresolution;
+
+		fz_unpack_tile(image, tiff.samples, tiff.samplesperpixel, tiff.bitspersample, tiff.stride, 0);
+
+		/* We should only do this on non-pre-multiplied images, but files in the wild are bad */
+		if (tiff.extrasamples /* == 2 */)
+		{
+			/* CMYK is a subtractive colorspace, we want additive for premul alpha */
+			if (image->n == 5)
+			{
+				fz_pixmap *rgb = fz_new_pixmap(tiff.ctx, fz_device_rgb(ctx), image->w, image->h);
+				fz_convert_pixmap(tiff.ctx, rgb, image);
+				rgb->xres = image->xres;
+				rgb->yres = image->yres;
+				fz_drop_pixmap(ctx, image);
+				image = rgb;
+			}
+			fz_premultiply_pixmap(ctx, image);
+		}
+	}
+	fz_always(ctx)
+	{
+		/* Clean up scratch memory */
+		if (tiff.colormap) fz_free(ctx, tiff.colormap);
+		if (tiff.stripoffsets) fz_free(ctx, tiff.stripoffsets);
+		if (tiff.stripbytecounts) fz_free(ctx, tiff.stripbytecounts);
+		if (tiff.samples) fz_free(ctx, tiff.samples);
+		if (tiff.profile) fz_free(ctx, tiff.profile);
+	}
+	fz_catch(ctx)
+	{
+		fz_rethrow_message(ctx, "out of memory loading tiff");
+	}
+
+	return image;
+}
+
+void
+fz_load_tiff_info(fz_context *ctx, unsigned char *buf, int len, int *wp, int *hp, int *xresp, int *yresp, fz_colorspace **cspacep)
+{
+	struct tiff tiff;
+
+	fz_try(ctx)
+	{
+		fz_decode_tiff_header(ctx, &tiff, buf, len);
+
+		*wp = tiff.imagewidth;
+		*hp = tiff.imagelength;
+		*xresp = tiff.xresolution;
+		*yresp = tiff.yresolution;
+		*cspacep = tiff.colorspace;
+	}
+	fz_always(ctx)
+	{
+		/* Clean up scratch memory */
+		if (tiff.colormap) fz_free(ctx, tiff.colormap);
+		if (tiff.stripoffsets) fz_free(ctx, tiff.stripoffsets);
+		if (tiff.stripbytecounts) fz_free(ctx, tiff.stripbytecounts);
+		if (tiff.samples) fz_free(ctx, tiff.samples);
+		if (tiff.profile) fz_free(ctx, tiff.profile);
+	}
+	fz_catch(ctx)
+	{
+		fz_rethrow_message(ctx, "out of memory loading tiff");
+	}
+}