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- /*
- * 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 pseudo tag TIFFTAG_FAXFILLFUNC.
- * The routine must have the type signature given below;
- * for example:
- *
- * fillruns(unsigned char* buf, uint32_t* runs, uint32_t* erun, uint32_t 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_t *, uint32_t *,
- uint32_t);
- /*
- * The default run filler; made external for other decoders.
- */
- #if defined(__cplusplus)
- extern "C"
- {
- #endif
- extern void _TIFFFax3fillruns(unsigned char *, uint32_t *, uint32_t *,
- uint32_t);
- #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
- /* WARNING: do not change the layout of this structure as the HylaFAX software
- */
- /* really depends on it. See http://bugzilla.maptools.org/show_bug.cgi?id=2636
- */
- typedef struct
- { /* state table entry */
- unsigned char State; /* see above */
- unsigned char Width; /* width of code in bits */
- uint32_t Param; /* unsigned 32-bit run length in bits (holds on 16 bit
- actually, but cannot be changed. See above warning) */
- } 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_t)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_t)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_t)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 \
- { \
- if (pa >= thisrun + sp->nruns) \
- { \
- TIFFErrorExtR(tif, module, "Buffer overflow at line %u of %s %u", \
- sp->line, isTiled(tif) ? "tile" : "strip", \
- isTiled(tif) ? tif->tif_curtile \
- : tif->tif_curstrip); \
- return (-1); \
- } \
- *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) \
- { \
- if (pb + 1 >= sp->refruns + sp->nruns) \
- { \
- TIFFErrorExtR( \
- tif, module, "Buffer overflow at line %u of %s %u", \
- sp->line, isTiled(tif) ? "tile" : "strip", \
- isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip); \
- return (-1); \
- } \
- b1 += pb[0] + pb[1]; \
- pb += 2; \
- } \
- } while (0)
- /*
- * Expand a row of 2D-encoded data.
- */
- #define EXPAND2D(eoflab) \
- do \
- { \
- while (a0 < lastx) \
- { \
- if (pa >= thisrun + sp->nruns) \
- { \
- TIFFErrorExtR( \
- tif, module, "Buffer overflow at line %u of %s %u", \
- sp->line, isTiled(tif) ? "tile" : "strip", \
- isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip); \
- return (-1); \
- } \
- LOOKUP8(7, TIFFFaxMainTable, eof2d); \
- switch (TabEnt->State) \
- { \
- case S_Pass: \
- CHECK_b1; \
- if (pb + 1 >= sp->refruns + sp->nruns) \
- { \
- TIFFErrorExtR(tif, module, \
- "Buffer overflow at line %u of %s %u", \
- sp->line, \
- isTiled(tif) ? "tile" : "strip", \
- isTiled(tif) ? tif->tif_curtile \
- : tif->tif_curstrip); \
- return (-1); \
- } \
- 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); \
- if (pb >= sp->refruns + sp->nruns) \
- { \
- TIFFErrorExtR(tif, module, \
- "Buffer overflow at line %u of %s %u", \
- sp->line, \
- isTiled(tif) ? "tile" : "strip", \
- isTiled(tif) ? tif->tif_curtile \
- : tif->tif_curstrip); \
- return (-1); \
- } \
- b1 += *pb++; \
- break; \
- case S_VR: \
- CHECK_b1; \
- SETVALUE(b1 - a0 + TabEnt->Param); \
- if (pb >= sp->refruns + sp->nruns) \
- { \
- TIFFErrorExtR(tif, module, \
- "Buffer overflow at line %u of %s %u", \
- sp->line, \
- isTiled(tif) ? "tile" : "strip", \
- isTiled(tif) ? tif->tif_curtile \
- : tif->tif_curstrip); \
- return (-1); \
- } \
- b1 += *pb++; \
- break; \
- case S_VL: \
- CHECK_b1; \
- if (b1 < (int)(a0 + TabEnt->Param)) \
- { \
- 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_ */
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