Rearrange source files.

1 files changed, 776 insertions, 0 deletions

diff --git a/source/fitz/filter-fax.c b/source/fitz/filter-fax.c
new file mode 100644
index 00000000..8ac98f42
--- /dev/null
+++ b/source/fitz/filter-fax.c
@@ -0,0 +1,776 @@
+#include "mupdf/fitz.h"
+
+/* Fax G3/G4 decoder */
+
+/* TODO: uncompressed */
+
+/*
+<raph> the first 2^(initialbits) entries map bit patterns to decodes
+<raph> let's say initial_bits is 8 for the sake of example
+<raph> and that the code is 1001
+<raph> that means that entries 0x90 .. 0x9f have the entry { val, 4 }
+<raph> because those are all the bytes that start with the code
+<raph> and the 4 is the length of the code
+... if (n_bits > initial_bits) ...
+<raph> anyway, in that case, it basically points to a mini table
+<raph> the n_bits is the maximum length of all codes beginning with that byte
+<raph> so 2^(n_bits - initial_bits) is the size of the mini-table
+<raph> peter came up with this, and it makes sense
+*/
+
+typedef struct cfd_node_s cfd_node;
+
+struct cfd_node_s
+{
+	short val;
+	short nbits;
+};
+
+enum
+{
+	cfd_white_initial_bits = 8,
+	cfd_black_initial_bits = 7,
+	cfd_2d_initial_bits = 7,
+	cfd_uncompressed_initial_bits = 6 /* must be 6 */
+};
+
+/* non-run codes in tables */
+enum
+{
+	ERROR = -1,
+	ZEROS = -2, /* EOL follows, possibly with more padding first */
+	UNCOMPRESSED = -3
+};
+
+/* semantic codes for cf_2d_decode */
+enum
+{
+	P = -4,
+	H = -5,
+	VR3 = 0,
+	VR2 = 1,
+	VR1 = 2,
+	V0 = 3,
+	VL1 = 4,
+	VL2 = 5,
+	VL3 = 6
+};
+
+/* White decoding table. */
+static const cfd_node cf_white_decode[] = {
+	{256,12},{272,12},{29,8},{30,8},{45,8},{46,8},{22,7},{22,7},
+	{23,7},{23,7},{47,8},{48,8},{13,6},{13,6},{13,6},{13,6},{20,7},
+	{20,7},{33,8},{34,8},{35,8},{36,8},{37,8},{38,8},{19,7},{19,7},
+	{31,8},{32,8},{1,6},{1,6},{1,6},{1,6},{12,6},{12,6},{12,6},{12,6},
+	{53,8},{54,8},{26,7},{26,7},{39,8},{40,8},{41,8},{42,8},{43,8},
+	{44,8},{21,7},{21,7},{28,7},{28,7},{61,8},{62,8},{63,8},{0,8},
+	{320,8},{384,8},{10,5},{10,5},{10,5},{10,5},{10,5},{10,5},{10,5},
+	{10,5},{11,5},{11,5},{11,5},{11,5},{11,5},{11,5},{11,5},{11,5},
+	{27,7},{27,7},{59,8},{60,8},{288,9},{290,9},{18,7},{18,7},{24,7},
+	{24,7},{49,8},{50,8},{51,8},{52,8},{25,7},{25,7},{55,8},{56,8},
+	{57,8},{58,8},{192,6},{192,6},{192,6},{192,6},{1664,6},{1664,6},
+	{1664,6},{1664,6},{448,8},{512,8},{292,9},{640,8},{576,8},{294,9},
+	{296,9},{298,9},{300,9},{302,9},{256,7},{256,7},{2,4},{2,4},{2,4},
+	{2,4},{2,4},{2,4},{2,4},{2,4},{2,4},{2,4},{2,4},{2,4},{2,4},{2,4},
+	{2,4},{2,4},{3,4},{3,4},{3,4},{3,4},{3,4},{3,4},{3,4},{3,4},{3,4},
+	{3,4},{3,4},{3,4},{3,4},{3,4},{3,4},{3,4},{128,5},{128,5},{128,5},
+	{128,5},{128,5},{128,5},{128,5},{128,5},{8,5},{8,5},{8,5},{8,5},
+	{8,5},{8,5},{8,5},{8,5},{9,5},{9,5},{9,5},{9,5},{9,5},{9,5},{9,5},
+	{9,5},{16,6},{16,6},{16,6},{16,6},{17,6},{17,6},{17,6},{17,6},
+	{4,4},{4,4},{4,4},{4,4},{4,4},{4,4},{4,4},{4,4},{4,4},{4,4},{4,4},
+	{4,4},{4,4},{4,4},{4,4},{4,4},{5,4},{5,4},{5,4},{5,4},{5,4},{5,4},
+	{5,4},{5,4},{5,4},{5,4},{5,4},{5,4},{5,4},{5,4},{5,4},{5,4},
+	{14,6},{14,6},{14,6},{14,6},{15,6},{15,6},{15,6},{15,6},{64,5},
+	{64,5},{64,5},{64,5},{64,5},{64,5},{64,5},{64,5},{6,4},{6,4},
+	{6,4},{6,4},{6,4},{6,4},{6,4},{6,4},{6,4},{6,4},{6,4},{6,4},{6,4},
+	{6,4},{6,4},{6,4},{7,4},{7,4},{7,4},{7,4},{7,4},{7,4},{7,4},{7,4},
+	{7,4},{7,4},{7,4},{7,4},{7,4},{7,4},{7,4},{7,4},{-2,3},{-2,3},
+	{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},
+	{-1,0},{-1,0},{-1,0},{-1,0},{-3,4},{1792,3},{1792,3},{1984,4},
+	{2048,4},{2112,4},{2176,4},{2240,4},{2304,4},{1856,3},{1856,3},
+	{1920,3},{1920,3},{2368,4},{2432,4},{2496,4},{2560,4},{1472,1},
+	{1536,1},{1600,1},{1728,1},{704,1},{768,1},{832,1},{896,1},
+	{960,1},{1024,1},{1088,1},{1152,1},{1216,1},{1280,1},{1344,1},
+	{1408,1}
+};
+
+/* Black decoding table. */
+static const cfd_node cf_black_decode[] = {
+	{128,12},{160,13},{224,12},{256,12},{10,7},{11,7},{288,12},{12,7},
+	{9,6},{9,6},{8,6},{8,6},{7,5},{7,5},{7,5},{7,5},{6,4},{6,4},{6,4},
+	{6,4},{6,4},{6,4},{6,4},{6,4},{5,4},{5,4},{5,4},{5,4},{5,4},{5,4},
+	{5,4},{5,4},{1,3},{1,3},{1,3},{1,3},{1,3},{1,3},{1,3},{1,3},{1,3},
+	{1,3},{1,3},{1,3},{1,3},{1,3},{1,3},{1,3},{4,3},{4,3},{4,3},{4,3},
+	{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},
+	{4,3},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},
+	{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},
+	{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},{3,2},
+	{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},
+	{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},
+	{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},{2,2},
+	{-2,4},{-2,4},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},
+	{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-3,5},{1792,4},
+	{1792,4},{1984,5},{2048,5},{2112,5},{2176,5},{2240,5},{2304,5},
+	{1856,4},{1856,4},{1920,4},{1920,4},{2368,5},{2432,5},{2496,5},
+	{2560,5},{18,3},{18,3},{18,3},{18,3},{18,3},{18,3},{18,3},{18,3},
+	{52,5},{52,5},{640,6},{704,6},{768,6},{832,6},{55,5},{55,5},
+	{56,5},{56,5},{1280,6},{1344,6},{1408,6},{1472,6},{59,5},{59,5},
+	{60,5},{60,5},{1536,6},{1600,6},{24,4},{24,4},{24,4},{24,4},
+	{25,4},{25,4},{25,4},{25,4},{1664,6},{1728,6},{320,5},{320,5},
+	{384,5},{384,5},{448,5},{448,5},{512,6},{576,6},{53,5},{53,5},
+	{54,5},{54,5},{896,6},{960,6},{1024,6},{1088,6},{1152,6},{1216,6},
+	{64,3},{64,3},{64,3},{64,3},{64,3},{64,3},{64,3},{64,3},{13,1},
+	{13,1},{13,1},{13,1},{13,1},{13,1},{13,1},{13,1},{13,1},{13,1},
+	{13,1},{13,1},{13,1},{13,1},{13,1},{13,1},{23,4},{23,4},{50,5},
+	{51,5},{44,5},{45,5},{46,5},{47,5},{57,5},{58,5},{61,5},{256,5},
+	{16,3},{16,3},{16,3},{16,3},{17,3},{17,3},{17,3},{17,3},{48,5},
+	{49,5},{62,5},{63,5},{30,5},{31,5},{32,5},{33,5},{40,5},{41,5},
+	{22,4},{22,4},{14,1},{14,1},{14,1},{14,1},{14,1},{14,1},{14,1},
+	{14,1},{14,1},{14,1},{14,1},{14,1},{14,1},{14,1},{14,1},{14,1},
+	{15,2},{15,2},{15,2},{15,2},{15,2},{15,2},{15,2},{15,2},{128,5},
+	{192,5},{26,5},{27,5},{28,5},{29,5},{19,4},{19,4},{20,4},{20,4},
+	{34,5},{35,5},{36,5},{37,5},{38,5},{39,5},{21,4},{21,4},{42,5},
+	{43,5},{0,3},{0,3},{0,3},{0,3}
+};
+
+/* 2-D decoding table. */
+static const cfd_node cf_2d_decode[] = {
+	{128,11},{144,10},{6,7},{0,7},{5,6},{5,6},{1,6},{1,6},{-4,4},
+	{-4,4},{-4,4},{-4,4},{-4,4},{-4,4},{-4,4},{-4,4},{-5,3},{-5,3},
+	{-5,3},{-5,3},{-5,3},{-5,3},{-5,3},{-5,3},{-5,3},{-5,3},{-5,3},
+	{-5,3},{-5,3},{-5,3},{-5,3},{-5,3},{4,3},{4,3},{4,3},{4,3},{4,3},
+	{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},{4,3},
+	{2,3},{2,3},{2,3},{2,3},{2,3},{2,3},{2,3},{2,3},{2,3},{2,3},{2,3},
+	{2,3},{2,3},{2,3},{2,3},{2,3},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},
+	{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},
+	{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},
+	{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},
+	{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},
+	{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},{3,1},
+	{3,1},{3,1},{3,1},{-2,4},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},
+	{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},
+	{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-1,0},{-3,3}
+};
+
+/* Uncompressed decoding table. */
+static const cfd_node cf_uncompressed_decode[] = {
+	{64,12},{5,6},{4,5},{4,5},{3,4},{3,4},{3,4},{3,4},{2,3},{2,3},
+	{2,3},{2,3},{2,3},{2,3},{2,3},{2,3},{1,2},{1,2},{1,2},{1,2},{1,2},
+	{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},
+	{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},
+	{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},
+	{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},{0,1},
+	{-1,0},{-1,0},{8,6},{9,6},{6,5},{6,5},{7,5},{7,5},{4,4},{4,4},
+	{4,4},{4,4},{5,4},{5,4},{5,4},{5,4},{2,3},{2,3},{2,3},{2,3},{2,3},
+	{2,3},{2,3},{2,3},{3,3},{3,3},{3,3},{3,3},{3,3},{3,3},{3,3},{3,3},
+	{0,2},{0,2},{0,2},{0,2},{0,2},{0,2},{0,2},{0,2},{0,2},{0,2},{0,2},
+	{0,2},{0,2},{0,2},{0,2},{0,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},
+	{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2},{1,2}
+};
+
+/* bit magic */
+
+static inline int getbit(const unsigned char *buf, int x)
+{
+	return ( buf[x >> 3] >> ( 7 - (x & 7) ) ) & 1;
+}
+
+static const unsigned char mask[8] = {
+	0x7F, 0x3F, 0x1F, 0x0F, 0x07, 0x03, 0x01, 0
+};
+
+static const unsigned char clz[256] = {
+	8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
+	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
+	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+	1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+};
+
+static inline int
+find_changing(const unsigned char *line, int x, int w)
+{
+	int a, b, m, W;
+
+	if (!line)
+		return w;
+
+	/* We assume w > 0, -1 <= x < w */
+	if (x < 0)
+	{
+		x = 0;
+		m = 0xFF;
+	}
+	else
+	{
+		/* Mask out the bits we've already used (including the one
+		 * we started from) */
+		m = mask[x & 7];
+	}
+	/* We have 'w' pixels (bits) in line. The last pixel that can be
+	 * safely accessed is the (w-1)th bit of line.
+	 * By taking W = w>>3, we know that the first W bytes of line are
+	 * full, with w&7 stray bits following. */
+	W = w>>3;
+	x >>= 3;
+	a = line[x]; /* Safe as x < w => x <= w-1 => x>>3 <= (w-1)>>3 */
+	b = a ^ (a>>1);
+	b &= m;
+	if (x >= W)
+	{
+		/* Within the last byte already */
+		x = (x<<3) + clz[b];
+		if (x > w)
+			x = w;
+		return x;
+	}
+	while (b == 0)
+	{
+		if (++x >= W)
+			goto nearend;
+		b = a & 1;
+		a = line[x];
+		b = (b<<7) ^ a ^ (a>>1);
+	}
+	return (x<<3) + clz[b];
+nearend:
+	/* We have less than a byte to go. If no stray bits, exit now. */
+	if ((x<<3) == w)
+		return w;
+	b = a&1;
+	a = line[x];
+	b = (b<<7) ^ a ^ (a>>1);
+	x = (x<<3) + clz[b];
+	if (x > w)
+		x = w;
+	return x;
+}
+
+static inline int
+find_changing_color(const unsigned char *line, int x, int w, int color)
+{
+	if (!line || x >= w)
+		return w;
+
+	x = find_changing(line, (x > 0 || !color) ? x : -1, w);
+
+	if (x < w && getbit(line, x) != color)
+		x = find_changing(line, x, w);
+
+	return x;
+}
+
+static const unsigned char lm[8] = {
+	0xFF, 0x7F, 0x3F, 0x1F, 0x0F, 0x07, 0x03, 0x01
+};
+
+static const unsigned char rm[8] = {
+	0x00, 0x80, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC, 0xFE
+};
+
+static inline void setbits(unsigned char *line, int x0, int x1)
+{
+	int a0, a1, b0, b1, a;
+
+	if (x1 <= x0)
+		return;
+
+	a0 = x0 >> 3;
+	a1 = x1 >> 3;
+
+	b0 = x0 & 7;
+	b1 = x1 & 7;
+
+	if (a0 == a1)
+	{
+		if (b1)
+			line[a0] |= lm[b0] & rm[b1];
+	}
+	else
+	{
+		line[a0] |= lm[b0];
+		for (a = a0 + 1; a < a1; a++)
+			line[a] = 0xFF;
+		if (b1)
+			line[a1] |= rm[b1];
+	}
+}
+
+typedef struct fz_faxd_s fz_faxd;
+
+enum
+{
+	STATE_NORMAL,	/* neutral state, waiting for any code */
+	STATE_MAKEUP,	/* got a 1d makeup code, waiting for terminating code */
+	STATE_EOL,		/* at eol, needs output buffer space */
+	STATE_H1, STATE_H2,	/* in H part 1 and 2 (both makeup and terminating codes) */
+	STATE_DONE		/* all done */
+};
+
+struct fz_faxd_s
+{
+	fz_context *ctx;
+	fz_stream *chain;
+
+	int k;
+	int end_of_line;
+	int encoded_byte_align;
+	int columns;
+	int rows;
+	int end_of_block;
+	int black_is_1;
+
+	int stride;
+	int ridx;
+
+	int bidx;
+	unsigned int word;
+
+	int stage;
+
+	int a, c, dim, eolc;
+	unsigned char *ref;
+	unsigned char *dst;
+	unsigned char *rp, *wp;
+};
+
+static inline void eat_bits(fz_faxd *fax, int nbits)
+{
+	fax->word <<= nbits;
+	fax->bidx += nbits;
+}
+
+static int
+fill_bits(fz_faxd *fax)
+{
+	while (fax->bidx >= 8)
+	{
+		int c = fz_read_byte(fax->chain);
+		if (c == EOF)
+			return EOF;
+		fax->bidx -= 8;
+		fax->word |= c << fax->bidx;
+	}
+	return 0;
+}
+
+static int
+get_code(fz_faxd *fax, const cfd_node *table, int initialbits)
+{
+	unsigned int word = fax->word;
+	int tidx = word >> (32 - initialbits);
+	int val = table[tidx].val;
+	int nbits = table[tidx].nbits;
+
+	if (nbits > initialbits)
+	{
+		int mask = (1 << (32 - initialbits)) - 1;
+		tidx = val + ((word & mask) >> (32 - nbits));
+		val = table[tidx].val;
+		nbits = initialbits + table[tidx].nbits;
+	}
+
+	eat_bits(fax, nbits);
+
+	return val;
+}
+
+/* decode one 1d code */
+static void
+dec1d(fz_context *ctx, fz_faxd *fax)
+{
+	int code;
+
+	if (fax->a == -1)
+		fax->a = 0;
+
+	if (fax->c)
+		code = get_code(fax, cf_black_decode, cfd_black_initial_bits);
+	else
+		code = get_code(fax, cf_white_decode, cfd_white_initial_bits);
+
+	if (code == UNCOMPRESSED)
+		fz_throw(ctx, FZ_ERROR_GENERIC, "uncompressed data in faxd");
+
+	if (code < 0)
+		fz_throw(ctx, FZ_ERROR_GENERIC, "negative code in 1d faxd");
+
+	if (fax->a + code > fax->columns)
+		fz_throw(ctx, FZ_ERROR_GENERIC, "overflow in 1d faxd");
+
+	if (fax->c)
+		setbits(fax->dst, fax->a, fax->a + code);
+
+	fax->a += code;
+
+	if (code < 64)
+	{
+		fax->c = !fax->c;
+		fax->stage = STATE_NORMAL;
+	}
+	else
+		fax->stage = STATE_MAKEUP;
+}
+
+/* decode one 2d code */
+static void
+dec2d(fz_context *ctx, fz_faxd *fax)
+{
+	int code, b1, b2;
+
+	if (fax->stage == STATE_H1 || fax->stage == STATE_H2)
+	{
+		if (fax->a == -1)
+			fax->a = 0;
+
+		if (fax->c)
+			code = get_code(fax, cf_black_decode, cfd_black_initial_bits);
+		else
+			code = get_code(fax, cf_white_decode, cfd_white_initial_bits);
+
+		if (code == UNCOMPRESSED)
+			fz_throw(ctx, FZ_ERROR_GENERIC, "uncompressed data in faxd");
+
+		if (code < 0)
+			fz_throw(ctx, FZ_ERROR_GENERIC, "negative code in 2d faxd");
+
+		if (fax->a + code > fax->columns)
+			fz_throw(ctx, FZ_ERROR_GENERIC, "overflow in 2d faxd");
+
+		if (fax->c)
+			setbits(fax->dst, fax->a, fax->a + code);
+
+		fax->a += code;
+
+		if (code < 64)
+		{
+			fax->c = !fax->c;
+			if (fax->stage == STATE_H1)
+				fax->stage = STATE_H2;
+			else if (fax->stage == STATE_H2)
+				fax->stage = STATE_NORMAL;
+		}
+
+		return;
+	}
+
+	code = get_code(fax, cf_2d_decode, cfd_2d_initial_bits);
+
+	switch (code)
+	{
+	case H:
+		fax->stage = STATE_H1;
+		break;
+
+	case P:
+		b1 = find_changing_color(fax->ref, fax->a, fax->columns, !fax->c);
+		if (b1 >= fax->columns)
+			b2 = fax->columns;
+		else
+			b2 = find_changing(fax->ref, b1, fax->columns);
+		if (fax->c) setbits(fax->dst, fax->a, b2);
+		fax->a = b2;
+		break;
+
+	case V0:
+		b1 = find_changing_color(fax->ref, fax->a, fax->columns, !fax->c);
+		if (fax->c) setbits(fax->dst, fax->a, b1);
+		fax->a = b1;
+		fax->c = !fax->c;
+		break;
+
+	case VR1:
+		b1 = 1 + find_changing_color(fax->ref, fax->a, fax->columns, !fax->c);
+		if (b1 >= fax->columns) b1 = fax->columns;
+		if (fax->c) setbits(fax->dst, fax->a, b1);
+		fax->a = b1;
+		fax->c = !fax->c;
+		break;
+
+	case VR2:
+		b1 = 2 + find_changing_color(fax->ref, fax->a, fax->columns, !fax->c);
+		if (b1 >= fax->columns) b1 = fax->columns;
+		if (fax->c) setbits(fax->dst, fax->a, b1);
+		fax->a = b1;
+		fax->c = !fax->c;
+		break;
+
+	case VR3:
+		b1 = 3 + find_changing_color(fax->ref, fax->a, fax->columns, !fax->c);
+		if (b1 >= fax->columns) b1 = fax->columns;
+		if (fax->c) setbits(fax->dst, fax->a, b1);
+		fax->a = b1;
+		fax->c = !fax->c;
+		break;
+
+	case VL1:
+		b1 = -1 + find_changing_color(fax->ref, fax->a, fax->columns, !fax->c);
+		if (b1 < 0) b1 = 0;
+		if (fax->c) setbits(fax->dst, fax->a, b1);
+		fax->a = b1;
+		fax->c = !fax->c;
+		break;
+
+	case VL2:
+		b1 = -2 + find_changing_color(fax->ref, fax->a, fax->columns, !fax->c);
+		if (b1 < 0) b1 = 0;
+		if (fax->c) setbits(fax->dst, fax->a, b1);
+		fax->a = b1;
+		fax->c = !fax->c;
+		break;
+
+	case VL3:
+		b1 = -3 + find_changing_color(fax->ref, fax->a, fax->columns, !fax->c);
+		if (b1 < 0) b1 = 0;
+		if (fax->c) setbits(fax->dst, fax->a, b1);
+		fax->a = b1;
+		fax->c = !fax->c;
+		break;
+
+	case UNCOMPRESSED:
+		fz_throw(ctx, FZ_ERROR_GENERIC, "uncompressed data in faxd");
+
+	case ERROR:
+		fz_throw(ctx, FZ_ERROR_GENERIC, "invalid code in 2d faxd");
+
+	default:
+		fz_throw(ctx, FZ_ERROR_GENERIC, "invalid code in 2d faxd (%d)", code);
+	}
+}
+
+static int
+read_faxd(fz_stream *stm, unsigned char *buf, int len)
+{
+	fz_faxd *fax = stm->state;
+	unsigned char *p = buf;
+	unsigned char *ep = buf + len;
+	unsigned char *tmp;
+
+	if (fax->stage == STATE_DONE)
+		return 0;
+
+	if (fax->stage == STATE_EOL)
+		goto eol;
+
+loop:
+
+	if (fill_bits(fax))
+	{
+		if (fax->bidx > 31)
+		{
+			if (fax->a > 0)
+				goto eol;
+			goto rtc;
+		}
+	}
+
+	if ((fax->word >> (32 - 12)) == 0)
+	{
+		eat_bits(fax, 1);
+		goto loop;
+	}
+
+	if ((fax->word >> (32 - 12)) == 1)
+	{
+		eat_bits(fax, 12);
+		fax->eolc ++;
+
+		if (fax->k > 0)
+		{
+			if (fax->a == -1)
+				fax->a = 0;
+			if ((fax->word >> (32 - 1)) == 1)
+				fax->dim = 1;
+			else
+				fax->dim = 2;
+			eat_bits(fax, 1);
+		}
+	}
+	else if (fax->k > 0 && fax->a == -1)
+	{
+		fax->a = 0;
+		if ((fax->word >> (32 - 1)) == 1)
+			fax->dim = 1;
+		else
+			fax->dim = 2;
+		eat_bits(fax, 1);
+	}
+	else if (fax->dim == 1)
+	{
+		fax->eolc = 0;
+		dec1d(stm->ctx, fax);
+	}
+	else if (fax->dim == 2)
+	{
+		fax->eolc = 0;
+		dec2d(stm->ctx, fax);
+	}
+
+	/* no eol check after makeup codes nor in the middle of an H code */
+	if (fax->stage == STATE_MAKEUP || fax->stage == STATE_H1 || fax->stage == STATE_H2)
+		goto loop;
+
+	/* check for eol conditions */
+	if (fax->eolc || fax->a >= fax->columns)
+	{
+		if (fax->a > 0)
+			goto eol;
+		if (fax->eolc == (fax->k < 0 ? 2 : 6))
+			goto rtc;
+	}
+
+	goto loop;
+
+eol:
+	fax->stage = STATE_EOL;
+
+	if (fax->black_is_1)
+	{
+		while (fax->rp < fax->wp && p < ep)
+			*p++ = *fax->rp++;
+	}
+	else
+	{
+		while (fax->rp < fax->wp && p < ep)
+			*p++ = *fax->rp++ ^ 0xff;
+	}
+
+	if (fax->rp < fax->wp)
+		return p - buf;
+
+	tmp = fax->ref;
+	fax->ref = fax->dst;
+	fax->dst = tmp;
+	memset(fax->dst, 0, fax->stride);
+
+	fax->rp = fax->dst;
+	fax->wp = fax->dst + fax->stride;
+
+	fax->stage = STATE_NORMAL;
+	fax->c = 0;
+	fax->a = -1;
+	fax->ridx ++;
+
+	if (!fax->end_of_block && fax->rows)
+	{
+		if (fax->ridx >= fax->rows)
+			goto rtc;
+	}
+
+	/* we have not read dim from eol, make a guess */
+	if (fax->k > 0 && !fax->eolc && fax->a == -1)
+	{
+		if (fax->ridx % fax->k == 0)
+			fax->dim = 1;
+		else
+			fax->dim = 2;
+	}
+
+	/* if end_of_line & encoded_byte_align, EOLs are *not* optional */
+	if (fax->encoded_byte_align)
+	{
+		if (fax->end_of_line)
+			eat_bits(fax, (12 - fax->bidx) & 7);
+		else
+			eat_bits(fax, (8 - fax->bidx) & 7);
+	}
+
+	/* no more space in output, don't decode the next row yet */
+	if (p == buf + len)
+		return p - buf;
+
+	goto loop;
+
+rtc:
+	fax->stage = STATE_DONE;
+	return p - buf;
+}
+
+static void
+close_faxd(fz_context *ctx, void *state_)
+{
+	fz_faxd *fax = (fz_faxd *)state_;
+	int i;
+
+	/* if we read any extra bytes, try to put them back */
+	i = (32 - fax->bidx) / 8;
+	while (i--)
+		fz_unread_byte(fax->chain);
+
+	fz_close(fax->chain);
+	fz_free(ctx, fax->ref);
+	fz_free(ctx, fax->dst);
+	fz_free(ctx, fax);
+}
+
+/* Default: columns = 1728, end_of_block = 1, the rest = 0 */
+fz_stream *
+fz_open_faxd(fz_stream *chain,
+	int k, int end_of_line, int encoded_byte_align,
+	int columns, int rows, int end_of_block, int black_is_1)
+{
+	fz_context *ctx = chain->ctx;
+	fz_faxd *fax = NULL;
+
+	fz_var(fax);
+
+	fz_try(ctx)
+	{
+		fax = fz_malloc_struct(ctx, fz_faxd);
+		fax->chain = chain;
+
+		fax->ref = NULL;
+		fax->dst = NULL;
+
+		fax->k = k;
+		fax->end_of_line = end_of_line;
+		fax->encoded_byte_align = encoded_byte_align;
+		fax->columns = columns;
+		fax->rows = rows;
+		fax->end_of_block = end_of_block;
+		fax->black_is_1 = black_is_1;
+
+		fax->stride = ((fax->columns - 1) >> 3) + 1;
+		fax->ridx = 0;
+		fax->bidx = 32;
+		fax->word = 0;
+
+		fax->stage = STATE_NORMAL;
+		fax->a = -1;
+		fax->c = 0;
+		fax->dim = fax->k < 0 ? 2 : 1;
+		fax->eolc = 0;
+
+		fax->ref = fz_malloc(ctx, fax->stride);
+		fax->dst = fz_malloc(ctx, fax->stride);
+		fax->rp = fax->dst;
+		fax->wp = fax->dst + fax->stride;
+
+		memset(fax->ref, 0, fax->stride);
+		memset(fax->dst, 0, fax->stride);
+	}
+	fz_catch(ctx)
+	{
+		if (fax)
+		{
+			fz_free(ctx, fax->dst);
+			fz_free(ctx, fax->ref);
+		}
+		fz_free(ctx, fax);
+		fz_close(chain);
+		fz_rethrow(ctx);
+	}
+
+	return fz_new_stream(ctx, fax, read_faxd, close_faxd);
+}