/* $Id: tif_fax3.h,v 1.9 2011-03-10 20:23:07 fwarmerdam Exp $ */
/*
* Copyright (c) 1990-1997 Sam Leffler
* Copyright (c) 1991-1997 Silicon Graphics, Inc.
*
* 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.
*/
#ifndef _FAX3_
#define _FAX3_
/*
* TIFF Library.
*
* CCITT Group 3 (T.4) and Group 4 (T.6) Decompression Support.
*
* Decoder support is derived, with permission, from the code
* in Frank Cringle's viewfax program;
* Copyright (C) 1990, 1995 Frank D. Cringle.
*/
#include "tiff.h"
/*
* To override the default routine used to image decoded
* spans one can use the pseduo tag TIFFTAG_FAXFILLFUNC.
* The routine must have the type signature given below;
* for example:
*
* fillruns(unsigned char* buf, uint32* runs, uint32* erun, uint32 lastx)
*
* where buf is place to set the bits, runs is the array of b&w run
* lengths (white then black), erun is the last run in the array, and
* lastx is the width of the row in pixels. Fill routines can assume
* the run array has room for at least lastx runs and can overwrite
* data in the run array as needed (e.g. to append zero runs to bring
* the count up to a nice multiple).
*/
typedef void (*TIFFFaxFillFunc)(unsigned char*, uint32*, uint32*, uint32);
/*
* The default run filler; made external for other decoders.
*/
#if defined(__cplusplus)
extern "C" {
#endif
extern void _TIFFFax3fillruns(unsigned char*, uint32*, uint32*, uint32);
#if defined(__cplusplus)
}
#endif
/* finite state machine codes */
#define S_Null 0
#define S_Pass 1
#define S_Horiz 2
#define S_V0 3
#define S_VR 4
#define S_VL 5
#define S_Ext 6
#define S_TermW 7
#define S_TermB 8
#define S_MakeUpW 9
#define S_MakeUpB 10
#define S_MakeUp 11
#define S_EOL 12
typedef struct { /* state table entry */
unsigned char State; /* see above */
unsigned char Width; /* width of code in bits */
uint32 Param; /* unsigned 32-bit run length in bits */
} TIFFFaxTabEnt;
extern const TIFFFaxTabEnt TIFFFaxMainTable[];
extern const TIFFFaxTabEnt TIFFFaxWhiteTable[];
extern const TIFFFaxTabEnt TIFFFaxBlackTable[];
/*
* The following macros define the majority of the G3/G4 decoder
* algorithm using the state tables defined elsewhere. To build
* a decoder you need some setup code and some glue code. Note
* that you may also need/want to change the way the NeedBits*
* macros get input data if, for example, you know the data to be
* decoded is properly aligned and oriented (doing so before running
* the decoder can be a big performance win).
*
* Consult the decoder in the TIFF library for an idea of what you
* need to define and setup to make use of these definitions.
*
* NB: to enable a debugging version of these macros define FAX3_DEBUG
* before including this file. Trace output goes to stdout.
*/
#ifndef EndOfData
#define EndOfData() (cp >= ep)
#endif
/*
* Need <=8 or <=16 bits of input data. Unlike viewfax we
* cannot use/assume a word-aligned, properly bit swizzled
* input data set because data may come from an arbitrarily
* aligned, read-only source such as a memory-mapped file.
* Note also that the viewfax decoder does not check for
* running off the end of the input data buffer. This is
* possible for G3-encoded data because it prescans the input
* data to count EOL markers, but can cause problems for G4
* data. In any event, we don't prescan and must watch for
* running out of data since we can't permit the library to
* scan past the end of the input data buffer.
*
* Finally, note that we must handle remaindered data at the end
* of a strip specially. The coder asks for a fixed number of
* bits when scanning for the next code. This may be more bits
* than are actually present in the data stream. If we appear
* to run out of data but still have some number of valid bits
* remaining then we makeup the requested amount with zeros and
* return successfully. If the returned data is incorrect then
* we should be called again and get a premature EOF error;
* otherwise we should get the right answer.
*/
#ifndef NeedBits8
#define NeedBits8(n,eoflab) do { \
if (BitsAvail < (n)) { \
if (EndOfData()) { \
if (BitsAvail == 0) /* no valid bits */ \
goto eoflab; \
BitsAvail = (n); /* pad with zeros */ \
} else { \
BitAcc |= ((uint32) bitmap[*cp++])<<BitsAvail; \
BitsAvail += 8; \
} \
} \
} while (0)
#endif
#ifndef NeedBits16
#define NeedBits16(n,eoflab) do { \
if (BitsAvail < (n)) { \
if (EndOfData()) { \
if (BitsAvail == 0) /* no valid bits */ \
goto eoflab; \
BitsAvail = (n); /* pad with zeros */ \
} else { \
BitAcc |= ((uint32) bitmap[*cp++])<<BitsAvail; \
if ((BitsAvail += 8) < (n)) { \
if (EndOfData()) { \
/* NB: we know BitsAvail is non-zero here */ \
BitsAvail = (n); /* pad with zeros */ \
} else { \
BitAcc |= ((uint32) bitmap[*cp++])<<BitsAvail; \
BitsAvail += 8; \
} \
} \
} \
} \
} while (0)
#endif
#define GetBits(n) (BitAcc & ((1<<(n))-1))
#define ClrBits(n) do { \
BitsAvail -= (n); \
BitAcc >>= (n); \
} while (0)
#ifdef FAX3_DEBUG
static const char* StateNames[] = {
"Null ",
"Pass ",
"Horiz ",
"V0 ",
"VR ",
"VL ",
"Ext ",
"TermW ",
"TermB ",
"MakeUpW",
"MakeUpB",
"MakeUp ",
"EOL ",
};
#define DEBUG_SHOW putchar(BitAcc & (1 << t) ? '1' : '0')
#define LOOKUP8(wid,tab,eoflab) do { \
int t; \
NeedBits8(wid,eoflab); \
TabEnt = tab + GetBits(wid); \
printf("%08lX/%d: %s%5d\t", (long) BitAcc, BitsAvail, \
StateNames[TabEnt->State], TabEnt->Param); \
for (t = 0; t < TabEnt->Width; t++) \
DEBUG_SHOW; \
putchar('\n'); \
fflush(stdout); \
ClrBits(TabEnt->Width); \
} while (0)
#define LOOKUP16(wid,tab,eoflab) do { \
int t; \
NeedBits16(wid,eoflab); \
TabEnt = tab + GetBits(wid); \
printf("%08lX/%d: %s%5d\t", (long) BitAcc, BitsAvail, \
StateNames[TabEnt->State], TabEnt->Param); \
for (t = 0; t < TabEnt->Width; t++) \
DEBUG_SHOW; \
putchar('\n'); \
fflush(stdout); \
ClrBits(TabEnt->Width); \
} while (0)
#define SETVALUE(x) do { \
*pa++ = RunLength + (x); \
printf("SETVALUE: %d\t%d\n", RunLength + (x), a0); \
a0 += x; \
RunLength = 0; \
} while (0)
#else
#define LOOKUP8(wid,tab,eoflab) do { \
NeedBits8(wid,eoflab); \
TabEnt = tab + GetBits(wid); \
ClrBits(TabEnt->Width); \
} while (0)
#define LOOKUP16(wid,tab,eoflab) do { \
NeedBits16(wid,eoflab); \
TabEnt = tab + GetBits(wid); \
ClrBits(TabEnt->Width); \
} while (0)
/*
* Append a run to the run length array for the
* current row and reset decoding state.
*/
#define SETVALUE(x) do { \
*pa++ = RunLength + (x); \
a0 += (x); \
RunLength = 0; \
} while (0)
#endif
/*
* Synchronize input decoding at the start of each
* row by scanning for an EOL (if appropriate) and
* skipping any trash data that might be present
* after a decoding error. Note that the decoding
* done elsewhere that recognizes an EOL only consumes
* 11 consecutive zero bits. This means that if EOLcnt
* is non-zero then we still need to scan for the final flag
* bit that is part of the EOL code.
*/
#define SYNC_EOL(eoflab) do { \
if (EOLcnt == 0) { \
for (;;) { \
NeedBits16(11,eoflab); \
if (GetBits(11) == 0) \
break; \
ClrBits(1); \
} \
} \
for (;;) { \
NeedBits8(8,eoflab); \
if (GetBits(8)) \
break; \
ClrBits(8); \
} \
while (GetBits(1) == 0) \
ClrBits(1); \
ClrBits(1); /* EOL bit */ \
EOLcnt = 0; /* reset EOL counter/flag */ \
} while (0)
/*
* Cleanup the array of runs after decoding a row.
* We adjust final runs to insure the user buffer is not
* overwritten and/or undecoded area is white filled.
*/
#define CLEANUP_RUNS() do { \
if (RunLength) \
SETVALUE(0); \
if (a0 != lastx) { \
badlength(a0, lastx); \
while (a0 > lastx && pa > thisrun) \
a0 -= *--pa; \
if (a0 < lastx) { \
if (a0 < 0) \
a0 = 0; \
if ((pa-thisrun)&1) \
SETVALUE(0); \
SETVALUE(lastx - a0); \
} else if (a0 > lastx) { \
SETVALUE(lastx); \
SETVALUE(0); \
} \
} \
} while (0)
/*
* Decode a line of 1D-encoded data.
*
* The line expanders are written as macros so that they can be reused
* but still have direct access to the local variables of the "calling"
* function.
*
* Note that unlike the original version we have to explicitly test for
* a0 >= lastx after each black/white run is decoded. This is because
* the original code depended on the input data being zero-padded to
* insure the decoder recognized an EOL before running out of data.
*/
#define EXPAND1D(eoflab) do { \
for (;;) { \
for (;;) { \
LOOKUP16(12, TIFFFaxWhiteTable, eof1d); \
switch (TabEnt->State) { \
case S_EOL: \
EOLcnt = 1; \
goto done1d; \
case S_TermW: \
SETVALUE(TabEnt->Param); \
goto doneWhite1d; \
case S_MakeUpW: \
case S_MakeUp: \
a0 += TabEnt->Param; \
RunLength += TabEnt->Param; \
break; \
default: \
unexpected("WhiteTable", a0); \
goto done1d; \
} \
} \
doneWhite1d: \
if (a0 >= lastx) \
goto done1d; \
for (;;) { \
LOOKUP16(13, TIFFFaxBlackTable, eof1d); \
switch (TabEnt->State) { \
case S_EOL: \
EOLcnt = 1; \
goto done1d; \
case S_TermB: \
SETVALUE(TabEnt->Param); \
goto doneBlack1d; \
case S_MakeUpB: \
case S_MakeUp: \
a0 += TabEnt->Param; \
RunLength += TabEnt->Param; \
break; \
default: \
unexpected("BlackTable", a0); \
goto done1d; \
} \
} \
doneBlack1d: \
if (a0 >= lastx) \
goto done1d; \
if( *(pa-1) == 0 && *(pa-2) == 0 ) \
pa -= 2; \
} \
eof1d: \
prematureEOF(a0); \
CLEANUP_RUNS(); \
goto eoflab; \
done1d: \
CLEANUP_RUNS(); \
} while (0)
/*
* Update the value of b1 using the array
* of runs for the reference line.
*/
#define CHECK_b1 do { \
if (pa != thisrun) while (b1 <= a0 && b1 < lastx) { \
b1 += pb[0] + pb[1]; \
pb += 2; \
} \
} while (0)
/*
* Expand a row of 2D-encoded data.
*/
#define EXPAND2D(eoflab) do { \
while (a0 < lastx) { \
LOOKUP8(7, TIFFFaxMainTable, eof2d); \
switch (TabEnt->State) { \
case S_Pass: \
CHECK_b1; \
b1 += *pb++; \
RunLength += b1 - a0; \
a0 = b1; \
b1 += *pb++; \
break; \
case S_Horiz: \
if ((pa-thisrun)&1) { \
for (;;) { /* black first */ \
LOOKUP16(13, TIFFFaxBlackTable, eof2d); \
switch (TabEnt->State) { \
case S_TermB: \
SETVALUE(TabEnt->Param); \
goto doneWhite2da; \
case S_MakeUpB: \
case S_MakeUp: \
a0 += TabEnt->Param; \
RunLength += TabEnt->Param; \
break; \
default: \
goto badBlack2d; \
} \
} \
doneWhite2da:; \
for (;;) { /* then white */ \
LOOKUP16(12, TIFFFaxWhiteTable, eof2d); \
switch (TabEnt->State) { \
case S_TermW: \
SETVALUE(TabEnt->Param); \
goto doneBlack2da; \
case S_MakeUpW: \
case S_MakeUp: \
a0 += TabEnt->Param; \
RunLength += TabEnt->Param; \
break; \
default: \
goto badWhite2d; \
} \
} \
doneBlack2da:; \
} else { \
for (;;) { /* white first */ \
LOOKUP16(12, TIFFFaxWhiteTable, eof2d); \
switch (TabEnt->State) { \
case S_TermW: \
SETVALUE(TabEnt->Param); \
goto doneWhite2db; \
case S_MakeUpW: \
case S_MakeUp: \
a0 += TabEnt->Param; \
RunLength += TabEnt->Param; \
break; \
default: \
goto badWhite2d; \
} \
} \
doneWhite2db:; \
for (;;) { /* then black */ \
LOOKUP16(13, TIFFFaxBlackTable, eof2d); \
switch (TabEnt->State) { \
case S_TermB: \
SETVALUE(TabEnt->Param); \
goto doneBlack2db; \
case S_MakeUpB: \
case S_MakeUp: \
a0 += TabEnt->Param; \
RunLength += TabEnt->Param; \
break; \
default: \
goto badBlack2d; \
} \
} \
doneBlack2db:; \
} \
CHECK_b1; \
break; \
case S_V0: \
CHECK_b1; \
SETVALUE(b1 - a0); \
b1 += *pb++; \
break; \
case S_VR: \
CHECK_b1; \
SETVALUE(b1 - a0 + TabEnt->Param); \
b1 += *pb++; \
break; \
case S_VL: \
CHECK_b1; \
if (b1 <= (int) (a0 + TabEnt->Param)) { \
if (b1 < (int) (a0 + TabEnt->Param) || pa != thisrun) { \
unexpected("VL", a0); \
goto eol2d; \
} \
} \
SETVALUE(b1 - a0 - TabEnt->Param); \
b1 -= *--pb; \
break; \
case S_Ext: \
*pa++ = lastx - a0; \
extension(a0); \
goto eol2d; \
case S_EOL: \
*pa++ = lastx - a0; \
NeedBits8(4,eof2d); \
if (GetBits(4)) \
unexpected("EOL", a0); \
ClrBits(4); \
EOLcnt = 1; \
goto eol2d; \
default: \
badMain2d: \
unexpected("MainTable", a0); \
goto eol2d; \
badBlack2d: \
unexpected("BlackTable", a0); \
goto eol2d; \
badWhite2d: \
unexpected("WhiteTable", a0); \
goto eol2d; \
eof2d: \
prematureEOF(a0); \
CLEANUP_RUNS(); \
goto eoflab; \
} \
} \
if (RunLength) { \
if (RunLength + a0 < lastx) { \
/* expect a final V0 */ \
NeedBits8(1,eof2d); \
if (!GetBits(1)) \
goto badMain2d; \
ClrBits(1); \
} \
SETVALUE(0); \
} \
eol2d: \
CLEANUP_RUNS(); \
} while (0)
#endif /* _FAX3_ */
/*
* Local Variables:
* mode: c
* c-basic-offset: 8
* fill-column: 78
* End:
*/