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/* $Id$ */
/*
* Copyright (c) 1994-1996 Sam Leffler
* Copyright (c) 1994-1996 Silicon Graphics, Inc.
* HylaFAX is a trademark of Silicon Graphics
*
* Permission to use, copy, modify, distribute, and sell this software and
* its documentation for any purpose is hereby granted without fee, provided
* that (i) the above copyright notices and this permission notice appear in
* all copies of the software and related documentation, and (ii) the names of
* Sam Leffler and Silicon Graphics may not be used in any advertising or
* publicity relating to the software without the specific, prior written
* permission of Sam Leffler and Silicon Graphics.
*
* THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
* EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
* WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
*
* IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
* ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
* OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
* WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
* LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
* OF THIS SOFTWARE.
*/
/*
* Group 3 Facsimile Writer Support.
*
* The 2-D encoding functionality was taken from the libtiff 3.5.7 distribution.
*/
#include "G3Encoder.h"
#include "StackBuffer.h"
#include "tiffio.h"
#include "t4.h"
G3Encoder::G3Encoder(fxStackBuffer& b) : buf(b) {}
G3Encoder::~G3Encoder() {}
/*
* Reset encoding state.
*/
void
G3Encoder::setupEncoder(u_int fillOrder, bool is2d, bool isg4)
{
is2D = is2d;
isG4 = isg4;
/*
* G3-encoded data is generated in MSB2LSB bit order, so we
* need to bit reverse only if the desired order is different.
*/
bitmap = TIFFGetBitRevTable(fillOrder != FILLORDER_MSB2LSB);
data = 0;
bit = 8;
firstEOL = true;
}
/*
* Flush 8-bits of encoded data to the output buffer.
*/
inline void
G3Encoder::flushBits()
{
buf.put(bitmap[data]);
data = 0;
bit = 8;
}
static const tableentry horizcode =
{ 3, 0x1 }; /* 001 */
static const tableentry passcode =
{ 4, 0x1 }; /* 0001 */
static const tableentry vcodes[7] = {
{ 7, 0x03 }, /* 0000 011 */
{ 6, 0x03 }, /* 0000 11 */
{ 3, 0x03 }, /* 011 */
{ 1, 0x1 }, /* 1 */
{ 3, 0x2 }, /* 010 */
{ 6, 0x02 }, /* 0000 10 */
{ 7, 0x02 } /* 0000 010 */
};
#define isAligned(p,t) ((((u_long)(p)) & (sizeof (t)-1)) == 0)
/*
* Find a span of ones or zeros using the supplied
* table. The byte-aligned start of the bit string
* is supplied along with the start+end bit indices.
* The table gives the number of consecutive ones or
* zeros starting from the msb and is indexed by byte
* value.
*/
int
G3Encoder::findspan(const u_char** bpp, int bs, int be, const u_char* tab)
{
const u_char *bp = *bpp;
int bits = be - bs;
int n, span;
/*
* Check partial byte on lhs.
*/
if (bits > 0 && (n = (bs & 7))) {
span = tab[(*bp << n) & 0xff];
if (span > 8-n) /* table value too generous */
span = 8-n;
if (span > bits) /* constrain span to bit range */
span = bits;
if (n+span < 8) /* doesn't extend to edge of byte */
goto done;
bits -= span;
bp++;
} else
span = 0;
/*
* Scan full bytes for all 1's or all 0's.
*/
while (bits >= 8) {
n = tab[*bp];
span += n;
bits -= n;
if (n < 8) /* end of run */
goto done;
bp++;
}
/*
* Check partial byte on rhs.
*/
if (bits > 0) {
n = tab[*bp];
span += (n > bits ? bits : n);
}
done:
*bpp = bp;
return (span);
}
/*
* Find a span of ones or zeros using the supplied
* table. The ``base'' of the bit string is supplied
* along with the start+end bit indices.
*/
int
G3Encoder::find0span(const u_char* bp, int bs, int be)
{
int32 bits = be - bs;
int32 n, span;
bp += bs>>3;
/*
* Check partial byte on lhs.
*/
if (bits > 0 && (n = (bs & 7))) {
span = zeroruns[(*bp << n) & 0xff];
if (span > 8-n) /* table value too generous */
span = 8-n;
if (span > bits) /* constrain span to bit range */
span = bits;
if (n+span < 8) /* doesn't extend to edge of byte */
return (span);
bits -= span;
bp++;
} else
span = 0;
if ((uint32) bits >= 2*8*sizeof (long)) {
long* lp;
/*
* Align to longword boundary and check longwords.
*/
while (!isAligned(bp, long)) {
if (*bp != 0x00)
return (span + zeroruns[*bp]);
span += 8, bits -= 8;
bp++;
}
lp = (long*) bp;
while ((uint32) bits >= 8*sizeof (long) && *lp == 0) {
span += 8*sizeof (long), bits -= 8*sizeof (long);
lp++;
}
bp = (u_char*) lp;
}
/*
* Scan full bytes for all 0's.
*/
while (bits >= 8) {
if (*bp != 0x00) /* end of run */
return (span + zeroruns[*bp]);
span += 8, bits -= 8;
bp++;
}
/*
* Check partial byte on rhs.
*/
if (bits > 0) {
n = zeroruns[*bp];
span += (n > bits ? bits : n);
}
return (span);
}
int
G3Encoder::find1span(const u_char* bp, int bs, int be)
{
int32 bits = be - bs;
int32 n, span;
bp += bs>>3;
/*
* Check partial byte on lhs.
*/
if (bits > 0 && (n = (bs & 7))) {
span = oneruns[(*bp << n) & 0xff];
if (span > 8-n) /* table value too generous */
span = 8-n;
if (span > bits) /* constrain span to bit range */
span = bits;
if (n+span < 8) /* doesn't extend to edge of byte */
return (span);
bits -= span;
bp++;
} else
span = 0;
if ((uint32) bits >= 2*8*sizeof (long)) {
long* lp;
/*
* Align to longword boundary and check longwords.
*/
while (!isAligned(bp, long)) {
if (*bp != 0xff)
return (span + oneruns[*bp]);
span += 8, bits -= 8;
bp++;
}
lp = (long*) bp;
while ((uint32) bits >= 8*sizeof (long) && *lp == ~0) {
span += 8*sizeof (long), bits -= 8*sizeof (long);
lp++;
}
bp = (u_char*) lp;
}
/*
* Scan full bytes for all 1's.
*/
while (bits >= 8) {
if (*bp != 0xff) /* end of run */
return (span + oneruns[*bp]);
span += 8, bits -= 8;
bp++;
}
/*
* Check partial byte on rhs.
*/
if (bits > 0) {
n = oneruns[*bp];
span += (n > bits ? bits : n);
}
return (span);
}
/*
* Write a code to the output stream.
*/
inline void
G3Encoder::putcode(const tableentry& te)
{
putBits(te.code, te.length);
}
/*
* Return the offset of the next bit in the range
* [bs..be] that is different from the specified
* color. The end, be, is returned if no such bit
* exists.
*/
#define finddiff(_cp, _bs, _be, _color) \
(_bs + (_color ? find1span(_cp,_bs,_be) : find0span(_cp,_bs,_be)))
/*
* Like finddiff, but also check the starting bit
* against the end in case start > end.
*/
#define finddiff2(_cp, _bs, _be, _color) \
(_bs < _be ? finddiff(_cp,_bs,_be,_color) : _be)
/*
* Encode a multi-line raster. For MH and MR we can do everything with
* 1D-data, if desired, inserting the appropriate tag bits in MR. For
* MMR we must do everything with 2D-data, thus when coding 2D-data a
* reference line, rp, is required.
*/
void
G3Encoder::encode(const void* vp, u_int w, u_int h, u_char* rp)
{
#define PIXEL(buf,ix) ((((buf)[(ix)>>3]) >> (7-((ix)&7))) & 1)
u_int rowbytes = howmany(w, 8);
const u_char* bp = (const unsigned char*) vp;
while (h-- > 0) {
if (!isG4) { // put the EOL
if( firstEOL ) // according to T.4 first EOL
firstEOL = false; // should not be aligned
else if (bit != 4)
putBits(0, (bit < 4) ? bit+4 : bit-4); // byte-align other EOLs
if (is2D)
if (rp)
putBits((EOL<<1)|0, 12+1); // T.4 4.2.2
else
putBits((EOL<<1)|1, 12+1);
else
putBits(EOL, 12);
}
if (rp) { // 2-D line
uint32 a0 = 0;
uint32 a1 = (PIXEL(bp, 0) != 0 ? 0 : finddiff(bp, 0, w, 0));
uint32 b1 = (PIXEL(rp, 0) != 0 ? 0 : finddiff(rp, 0, w, 0));
uint32 a2, b2;
for (;;) {
b2 = finddiff2(rp, b1, w, PIXEL(rp,b1));
if (b2 >= a1) {
int32 d = b1 - a1;
if (!(-3 <= d && d <= 3)) { /* horizontal mode */
a2 = finddiff2(bp, a1, w, PIXEL(bp,a1));
putcode(horizcode);
if (a0+a1 == 0 || PIXEL(bp, a0) == 0) {
putspan(a1-a0, TIFFFaxWhiteCodes);
putspan(a2-a1, TIFFFaxBlackCodes);
} else {
putspan(a1-a0, TIFFFaxBlackCodes);
putspan(a2-a1, TIFFFaxWhiteCodes);
}
a0 = a2;
} else { /* vertical mode */
putcode(vcodes[d+3]);
a0 = a1;
}
} else { /* pass mode */
putcode(passcode);
a0 = b2;
}
if (a0 >= w)
break;
a1 = finddiff(bp, a0, w, PIXEL(bp,a0));
b1 = finddiff(rp, a0, w, !PIXEL(bp,a0));
b1 = finddiff(rp, b1, w, PIXEL(bp,a0));
}
memcpy(rp, bp, rowbytes);
bp += rowbytes; // advance raster row
} else { // 1-D line
int bs = 0, span;
for (;;) {
span = findspan(&bp, bs, w, zeroruns); // white span
putspan(span, TIFFFaxWhiteCodes);
bs += span;
if ((u_int) bs >= w)
break;
span = findspan(&bp, bs, w, oneruns); // black span
putspan(span, TIFFFaxBlackCodes);
bs += span;
if ((u_int) bs >= w)
break;
}
}
}
#undef PIXEL
}
void
G3Encoder::encoderCleanup()
{
if (isG4) {
putBits(EOL, 12);
putBits(EOL, 12);
}
if (bit != 8) // flush partial byte
flushBits();
}
/*
* Write the sequence of codes that describes
* the specified span of zero's or one's. The
* appropriate table that holds the make-up and
* terminating codes is supplied.
*/
void
G3Encoder::putspan(int span, const tableentry* tab)
{
while (span >= 2624) {
const tableentry& te = tab[63 + (2560>>6)];
putcode(te);
span -= te.runlen;
}
if (span >= 64) {
const tableentry& te = tab[63 + (span>>6)];
putcode(te);
span -= te.runlen;
}
putcode(tab[span]);
}
/*
* Write a variable-length bit-value to the output
* stream. Values are assumed to be at most 16 bits.
*/
void
G3Encoder::putBits(u_int bits, u_int length)
{
static const u_int mask[9] =
{ 0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff };
while (length > (u_short) bit) {
data |= bits >> (length - bit);
length -= bit;
flushBits();
}
data |= (bits & mask[length]) << (bit - length);
bit -= length;
if (bit == 0)
flushBits();
}
const u_char G3Encoder::zeroruns[256] = {
8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, /* 0x00 - 0x0f */
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, /* 0x10 - 0x1f */
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* 0x20 - 0x2f */
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* 0x30 - 0x3f */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x40 - 0x4f */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x50 - 0x5f */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x60 - 0x6f */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x70 - 0x7f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x80 - 0x8f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x90 - 0x9f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xa0 - 0xaf */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xb0 - 0xbf */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xc0 - 0xcf */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xd0 - 0xdf */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xe0 - 0xef */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0xf0 - 0xff */
};
const u_char G3Encoder::oneruns[256] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x00 - 0x0f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x10 - 0x1f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x20 - 0x2f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x30 - 0x3f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x40 - 0x4f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x50 - 0x5f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x60 - 0x6f */
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x70 - 0x7f */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x80 - 0x8f */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0x90 - 0x9f */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0xa0 - 0xaf */
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 0xb0 - 0xbf */
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* 0xc0 - 0xcf */
2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, /* 0xd0 - 0xdf */
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, /* 0xe0 - 0xef */
4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8, /* 0xf0 - 0xff */
};
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