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eBookReaderSwitch/source/fitz/filter-fax.c

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#include "mupdf/fitz.h"
#include <string.h>
#include <limits.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}
};
/* 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_INIT, /* initial state, optionally waiting for EOL */
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_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;
unsigned char buffer[4096];
};
static inline void eat_bits(fz_faxd *fax, int nbits)
{
fax->word <<= nbits;
fax->bidx += nbits;
}
static int
fill_bits(fz_context *ctx, fz_faxd *fax)
{
/* The longest length of bits we'll ever need is 13. Never read more
* than we need to avoid unnecessary overreading of the end of the
* stream. */
while (fax->bidx > (32-13))
{
int c = fz_read_byte(ctx, fax->chain);
if (c == EOF)
return EOF;
fax->bidx -= 8;
fax->word |= c << fax->bidx;
}
return 0;
}
static int
get_code(fz_context *ctx, 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(ctx, fax, cf_black_decode, cfd_black_initial_bits);
else
code = get_code(ctx, 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(ctx, fax, cf_black_decode, cfd_black_initial_bits);
else
code = get_code(ctx, 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(ctx, 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
next_faxd(fz_context *ctx, fz_stream *stm, size_t max)
{
fz_faxd *fax = stm->state;
unsigned char *p = fax->buffer;
unsigned char *ep;
unsigned char *tmp;
if (max > sizeof(fax->buffer))
max = sizeof(fax->buffer);
ep = p + max;
if (fax->stage == STATE_INIT && fax->end_of_line)
{
fill_bits(ctx, fax);
if ((fax->word >> (32 - 12)) != 1)
{
fz_warn(ctx, "faxd stream doesn't start with EOL");
while (!fill_bits(ctx, fax) && (fax->word >> (32 - 12)) != 1)
eat_bits(fax, 1);
}
if ((fax->word >> (32 - 12)) != 1)
fz_throw(ctx, FZ_ERROR_GENERIC, "initial EOL not found");
}
if (fax->stage == STATE_INIT)
fax->stage = STATE_NORMAL;
if (fax->stage == STATE_DONE)
return EOF;
if (fax->stage == STATE_EOL)
goto eol;
loop:
if (fill_bits(ctx, 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;
fz_try(ctx)
{
dec1d(ctx, fax);
}
fz_catch(ctx)
{
goto error;
}
}
else if (fax->dim == 2)
{
fax->eolc = 0;
fz_try(ctx)
{
dec2d(ctx, fax);
}
fz_catch(ctx)
{
goto error;
}
}
/* 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)
{
stm->rp = fax->buffer;
stm->wp = p;
stm->pos += (p - fax->buffer);
if (p == fax->buffer)
return EOF;
return *stm->rp++;
}
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 && 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 == fax->buffer + max)
{
stm->rp = fax->buffer;
stm->wp = p;
stm->pos += (p - fax->buffer);
if (p == fax->buffer)
return EOF;
return *stm->rp++;
}
goto loop;
error:
/* decode the remaining pixels up to where the error occurred */
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;
}
/* fallthrough */
rtc:
fax->stage = STATE_DONE;
stm->rp = fax->buffer;
stm->wp = p;
stm->pos += (p - fax->buffer);
if (p == fax->buffer)
return EOF;
return *stm->rp++;
}
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(ctx, fax->chain);
fz_drop_stream(ctx, 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_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)
{
fz_faxd *fax;
if (columns < 0 || columns >= INT_MAX - 7)
fz_throw(ctx, FZ_ERROR_GENERIC, "too many columns lead to an integer overflow (%d)", columns);
fax = fz_malloc_struct(ctx, fz_faxd);
fz_try(ctx)
{
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_INIT;
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);
fax->chain = fz_keep_stream(ctx, chain);
}
fz_catch(ctx)
{
fz_free(ctx, fax->dst);
fz_free(ctx, fax->ref);
fz_free(ctx, fax);
fz_rethrow(ctx);
}
return fz_new_stream(ctx, fax, next_faxd, close_faxd);
}
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