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      1 /* $Id: tif_fax3.c,v 1.75 2015-08-30 20:49:55 erouault Exp $ */
      2 
      3 /*
      4  * Copyright (c) 1990-1997 Sam Leffler
      5  * Copyright (c) 1991-1997 Silicon Graphics, Inc.
      6  *
      7  * Permission to use, copy, modify, distribute, and sell this software and
      8  * its documentation for any purpose is hereby granted without fee, provided
      9  * that (i) the above copyright notices and this permission notice appear in
     10  * all copies of the software and related documentation, and (ii) the names of
     11  * Sam Leffler and Silicon Graphics may not be used in any advertising or
     12  * publicity relating to the software without the specific, prior written
     13  * permission of Sam Leffler and Silicon Graphics.
     14  *
     15  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
     16  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
     17  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
     18  *
     19  * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
     20  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
     21  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
     22  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
     23  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
     24  * OF THIS SOFTWARE.
     25  */
     26 
     27 #include "tiffiop.h"
     28 #ifdef CCITT_SUPPORT
     29 /*
     30  * TIFF Library.
     31  *
     32  * CCITT Group 3 (T.4) and Group 4 (T.6) Compression Support.
     33  *
     34  * This file contains support for decoding and encoding TIFF
     35  * compression algorithms 2, 3, 4, and 32771.
     36  *
     37  * Decoder support is derived, with permission, from the code
     38  * in Frank Cringle's viewfax program;
     39  *      Copyright (C) 1990, 1995  Frank D. Cringle.
     40  */
     41 #include "tif_fax3.h"
     42 #define	G3CODES
     43 #include "t4.h"
     44 #include <stdio.h>
     45 
     46 /*
     47  * Compression+decompression state blocks are
     48  * derived from this ``base state'' block.
     49  */
     50 typedef struct {
     51 	int      rw_mode;                /* O_RDONLY for decode, else encode */
     52 	int      mode;                   /* operating mode */
     53 	tmsize_t rowbytes;               /* bytes in a decoded scanline */
     54 	uint32   rowpixels;              /* pixels in a scanline */
     55 
     56 	uint16   cleanfaxdata;           /* CleanFaxData tag */
     57 	uint32   badfaxrun;              /* BadFaxRun tag */
     58 	uint32   badfaxlines;            /* BadFaxLines tag */
     59 	uint32   groupoptions;           /* Group 3/4 options tag */
     60 
     61 	TIFFVGetMethod  vgetparent;      /* super-class method */
     62 	TIFFVSetMethod  vsetparent;      /* super-class method */
     63 	TIFFPrintMethod printdir;        /* super-class method */
     64 } Fax3BaseState;
     65 #define	Fax3State(tif)		((Fax3BaseState*) (tif)->tif_data)
     66 
     67 typedef enum { G3_1D, G3_2D } Ttag;
     68 typedef struct {
     69 	Fax3BaseState b;
     70 
     71 	/* Decoder state info */
     72 	const unsigned char* bitmap;	/* bit reversal table */
     73 	uint32	data;			/* current i/o byte/word */
     74 	int	bit;			/* current i/o bit in byte */
     75 	int	EOLcnt;			/* count of EOL codes recognized */
     76 	TIFFFaxFillFunc fill;		/* fill routine */
     77 	uint32*	runs;			/* b&w runs for current/previous row */
     78 	uint32*	refruns;		/* runs for reference line */
     79 	uint32*	curruns;		/* runs for current line */
     80 
     81 	/* Encoder state info */
     82 	Ttag    tag;			/* encoding state */
     83 	unsigned char*	refline;	/* reference line for 2d decoding */
     84 	int	k;			/* #rows left that can be 2d encoded */
     85 	int	maxk;			/* max #rows that can be 2d encoded */
     86 
     87 	int line;
     88 } Fax3CodecState;
     89 #define DecoderState(tif) ((Fax3CodecState*) Fax3State(tif))
     90 #define EncoderState(tif) ((Fax3CodecState*) Fax3State(tif))
     91 
     92 #define is2DEncoding(sp) (sp->b.groupoptions & GROUP3OPT_2DENCODING)
     93 #define isAligned(p,t) ((((size_t)(p)) & (sizeof (t)-1)) == 0)
     94 
     95 /*
     96  * Group 3 and Group 4 Decoding.
     97  */
     98 
     99 /*
    100  * These macros glue the TIFF library state to
    101  * the state expected by Frank's decoder.
    102  */
    103 #define	DECLARE_STATE(tif, sp, mod)					\
    104     static const char module[] = mod;					\
    105     Fax3CodecState* sp = DecoderState(tif);				\
    106     int a0;				/* reference element */		\
    107     int lastx = sp->b.rowpixels;	/* last element in row */	\
    108     uint32 BitAcc;			/* bit accumulator */		\
    109     int BitsAvail;			/* # valid bits in BitAcc */	\
    110     int RunLength;			/* length of current run */	\
    111     unsigned char* cp;			/* next byte of input data */	\
    112     unsigned char* ep;			/* end of input data */		\
    113     uint32* pa;				/* place to stuff next run */	\
    114     uint32* thisrun;			/* current row's run array */	\
    115     int EOLcnt;				/* # EOL codes recognized */	\
    116     const unsigned char* bitmap = sp->bitmap;	/* input data bit reverser */	\
    117     const TIFFFaxTabEnt* TabEnt
    118 #define	DECLARE_STATE_2D(tif, sp, mod)					\
    119     DECLARE_STATE(tif, sp, mod);					\
    120     int b1;				/* next change on prev line */	\
    121     uint32* pb				/* next run in reference line */\
    122 /*
    123  * Load any state that may be changed during decoding.
    124  */
    125 #define	CACHE_STATE(tif, sp) do {					\
    126     BitAcc = sp->data;							\
    127     BitsAvail = sp->bit;						\
    128     EOLcnt = sp->EOLcnt;						\
    129     cp = (unsigned char*) tif->tif_rawcp;				\
    130     ep = cp + tif->tif_rawcc;						\
    131 } while (0)
    132 /*
    133  * Save state possibly changed during decoding.
    134  */
    135 #define	UNCACHE_STATE(tif, sp) do {					\
    136     sp->bit = BitsAvail;						\
    137     sp->data = BitAcc;							\
    138     sp->EOLcnt = EOLcnt;						\
    139     tif->tif_rawcc -= (tmsize_t)((uint8*) cp - tif->tif_rawcp);		\
    140     tif->tif_rawcp = (uint8*) cp;					\
    141 } while (0)
    142 
    143 /*
    144  * Setup state for decoding a strip.
    145  */
    146 static int
    147 Fax3PreDecode(TIFF* tif, uint16 s)
    148 {
    149 	Fax3CodecState* sp = DecoderState(tif);
    150 
    151 	(void) s;
    152 	assert(sp != NULL);
    153 	sp->bit = 0;			/* force initial read */
    154 	sp->data = 0;
    155 	sp->EOLcnt = 0;			/* force initial scan for EOL */
    156 	/*
    157 	 * Decoder assumes lsb-to-msb bit order.  Note that we select
    158 	 * this here rather than in Fax3SetupState so that viewers can
    159 	 * hold the image open, fiddle with the FillOrder tag value,
    160 	 * and then re-decode the image.  Otherwise they'd need to close
    161 	 * and open the image to get the state reset.
    162 	 */
    163 	sp->bitmap =
    164 	    TIFFGetBitRevTable(tif->tif_dir.td_fillorder != FILLORDER_LSB2MSB);
    165 	if (sp->refruns) {		/* init reference line to white */
    166 		sp->refruns[0] = (uint32) sp->b.rowpixels;
    167 		sp->refruns[1] = 0;
    168 	}
    169 	sp->line = 0;
    170 	return (1);
    171 }
    172 
    173 /*
    174  * Routine for handling various errors/conditions.
    175  * Note how they are "glued into the decoder" by
    176  * overriding the definitions used by the decoder.
    177  */
    178 
    179 static void
    180 Fax3Unexpected(const char* module, TIFF* tif, uint32 line, uint32 a0)
    181 {
    182 	TIFFErrorExt(tif->tif_clientdata, module, "Bad code word at line %u of %s %u (x %u)",
    183 	    line, isTiled(tif) ? "tile" : "strip",
    184 	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
    185 	    a0);
    186 }
    187 #define	unexpected(table, a0)	Fax3Unexpected(module, tif, sp->line, a0)
    188 
    189 static void
    190 Fax3Extension(const char* module, TIFF* tif, uint32 line, uint32 a0)
    191 {
    192 	TIFFErrorExt(tif->tif_clientdata, module,
    193 	    "Uncompressed data (not supported) at line %u of %s %u (x %u)",
    194 	    line, isTiled(tif) ? "tile" : "strip",
    195 	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
    196 	    a0);
    197 }
    198 #define	extension(a0)	Fax3Extension(module, tif, sp->line, a0)
    199 
    200 static void
    201 Fax3BadLength(const char* module, TIFF* tif, uint32 line, uint32 a0, uint32 lastx)
    202 {
    203 	TIFFWarningExt(tif->tif_clientdata, module, "%s at line %u of %s %u (got %u, expected %u)",
    204 	    a0 < lastx ? "Premature EOL" : "Line length mismatch",
    205 	    line, isTiled(tif) ? "tile" : "strip",
    206 	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
    207 	    a0, lastx);
    208 }
    209 #define	badlength(a0,lastx)	Fax3BadLength(module, tif, sp->line, a0, lastx)
    210 
    211 static void
    212 Fax3PrematureEOF(const char* module, TIFF* tif, uint32 line, uint32 a0)
    213 {
    214 	TIFFWarningExt(tif->tif_clientdata, module, "Premature EOF at line %u of %s %u (x %u)",
    215 	    line, isTiled(tif) ? "tile" : "strip",
    216 	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
    217 	    a0);
    218 }
    219 #define	prematureEOF(a0)	Fax3PrematureEOF(module, tif, sp->line, a0)
    220 
    221 #define	Nop
    222 
    223 /*
    224  * Decode the requested amount of G3 1D-encoded data.
    225  */
    226 static int
    227 Fax3Decode1D(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
    228 {
    229 	DECLARE_STATE(tif, sp, "Fax3Decode1D");
    230 	(void) s;
    231 	if (occ % sp->b.rowbytes)
    232 	{
    233 		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
    234 		return (-1);
    235 	}
    236 	CACHE_STATE(tif, sp);
    237 	thisrun = sp->curruns;
    238 	while (occ > 0) {
    239 		a0 = 0;
    240 		RunLength = 0;
    241 		pa = thisrun;
    242 #ifdef FAX3_DEBUG
    243 		printf("\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail);
    244 		printf("-------------------- %d\n", tif->tif_row);
    245 		fflush(stdout);
    246 #endif
    247 		SYNC_EOL(EOF1D);
    248 		EXPAND1D(EOF1Da);
    249 		(*sp->fill)(buf, thisrun, pa, lastx);
    250 		buf += sp->b.rowbytes;
    251 		occ -= sp->b.rowbytes;
    252 		sp->line++;
    253 		continue;
    254 	EOF1D:				/* premature EOF */
    255 		CLEANUP_RUNS();
    256 	EOF1Da:				/* premature EOF */
    257 		(*sp->fill)(buf, thisrun, pa, lastx);
    258 		UNCACHE_STATE(tif, sp);
    259 		return (-1);
    260 	}
    261 	UNCACHE_STATE(tif, sp);
    262 	return (1);
    263 }
    264 
    265 #define	SWAP(t,a,b)	{ t x; x = (a); (a) = (b); (b) = x; }
    266 /*
    267  * Decode the requested amount of G3 2D-encoded data.
    268  */
    269 static int
    270 Fax3Decode2D(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
    271 {
    272 	DECLARE_STATE_2D(tif, sp, "Fax3Decode2D");
    273 	int is1D;			/* current line is 1d/2d-encoded */
    274 	(void) s;
    275 	if (occ % sp->b.rowbytes)
    276 	{
    277 		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
    278 		return (-1);
    279 	}
    280 	CACHE_STATE(tif, sp);
    281 	while (occ > 0) {
    282 		a0 = 0;
    283 		RunLength = 0;
    284 		pa = thisrun = sp->curruns;
    285 #ifdef FAX3_DEBUG
    286 		printf("\nBitAcc=%08X, BitsAvail = %d EOLcnt = %d",
    287 		    BitAcc, BitsAvail, EOLcnt);
    288 #endif
    289 		SYNC_EOL(EOF2D);
    290 		NeedBits8(1, EOF2D);
    291 		is1D = GetBits(1);	/* 1D/2D-encoding tag bit */
    292 		ClrBits(1);
    293 #ifdef FAX3_DEBUG
    294 		printf(" %s\n-------------------- %d\n",
    295 		    is1D ? "1D" : "2D", tif->tif_row);
    296 		fflush(stdout);
    297 #endif
    298 		pb = sp->refruns;
    299 		b1 = *pb++;
    300 		if (is1D)
    301 			EXPAND1D(EOF2Da);
    302 		else
    303 			EXPAND2D(EOF2Da);
    304 		(*sp->fill)(buf, thisrun, pa, lastx);
    305 		SETVALUE(0);		/* imaginary change for reference */
    306 		SWAP(uint32*, sp->curruns, sp->refruns);
    307 		buf += sp->b.rowbytes;
    308 		occ -= sp->b.rowbytes;
    309 		sp->line++;
    310 		continue;
    311 	EOF2D:				/* premature EOF */
    312 		CLEANUP_RUNS();
    313 	EOF2Da:				/* premature EOF */
    314 		(*sp->fill)(buf, thisrun, pa, lastx);
    315 		UNCACHE_STATE(tif, sp);
    316 		return (-1);
    317 	}
    318 	UNCACHE_STATE(tif, sp);
    319 	return (1);
    320 }
    321 #undef SWAP
    322 
    323 /*
    324  * The ZERO & FILL macros must handle spans < 2*sizeof(long) bytes.
    325  * For machines with 64-bit longs this is <16 bytes; otherwise
    326  * this is <8 bytes.  We optimize the code here to reflect the
    327  * machine characteristics.
    328  */
    329 #if SIZEOF_UNSIGNED_LONG == 8
    330 # define FILL(n, cp)							    \
    331     switch (n) {							    \
    332     case 15:(cp)[14] = 0xff; case 14:(cp)[13] = 0xff; case 13: (cp)[12] = 0xff;\
    333     case 12:(cp)[11] = 0xff; case 11:(cp)[10] = 0xff; case 10: (cp)[9] = 0xff;\
    334     case  9: (cp)[8] = 0xff; case  8: (cp)[7] = 0xff; case  7: (cp)[6] = 0xff;\
    335     case  6: (cp)[5] = 0xff; case  5: (cp)[4] = 0xff; case  4: (cp)[3] = 0xff;\
    336     case  3: (cp)[2] = 0xff; case  2: (cp)[1] = 0xff;			      \
    337     case  1: (cp)[0] = 0xff; (cp) += (n); case 0:  ;			      \
    338     }
    339 # define ZERO(n, cp)							\
    340     switch (n) {							\
    341     case 15:(cp)[14] = 0; case 14:(cp)[13] = 0; case 13: (cp)[12] = 0;	\
    342     case 12:(cp)[11] = 0; case 11:(cp)[10] = 0; case 10: (cp)[9] = 0;	\
    343     case  9: (cp)[8] = 0; case  8: (cp)[7] = 0; case  7: (cp)[6] = 0;	\
    344     case  6: (cp)[5] = 0; case  5: (cp)[4] = 0; case  4: (cp)[3] = 0;	\
    345     case  3: (cp)[2] = 0; case  2: (cp)[1] = 0;				\
    346     case  1: (cp)[0] = 0; (cp) += (n); case 0:  ;			\
    347     }
    348 #else
    349 # define FILL(n, cp)							    \
    350     switch (n) {							    \
    351     case 7: (cp)[6] = 0xff; case 6: (cp)[5] = 0xff; case 5: (cp)[4] = 0xff; \
    352     case 4: (cp)[3] = 0xff; case 3: (cp)[2] = 0xff; case 2: (cp)[1] = 0xff; \
    353     case 1: (cp)[0] = 0xff; (cp) += (n); case 0:  ;			    \
    354     }
    355 # define ZERO(n, cp)							\
    356     switch (n) {							\
    357     case 7: (cp)[6] = 0; case 6: (cp)[5] = 0; case 5: (cp)[4] = 0;	\
    358     case 4: (cp)[3] = 0; case 3: (cp)[2] = 0; case 2: (cp)[1] = 0;	\
    359     case 1: (cp)[0] = 0; (cp) += (n); case 0:  ;			\
    360     }
    361 #endif
    362 
    363 /*
    364  * Bit-fill a row according to the white/black
    365  * runs generated during G3/G4 decoding.
    366  */
    367 void
    368 _TIFFFax3fillruns(unsigned char* buf, uint32* runs, uint32* erun, uint32 lastx)
    369 {
    370 	static const unsigned char _fillmasks[] =
    371 	    { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff };
    372 	unsigned char* cp;
    373 	uint32 x, bx, run;
    374 	int32 n, nw;
    375 	long* lp;
    376 
    377 	if ((erun-runs)&1)
    378 	    *erun++ = 0;
    379 	x = 0;
    380 	for (; runs < erun; runs += 2) {
    381 	    run = runs[0];
    382 	    if (x+run > lastx || run > lastx )
    383 		run = runs[0] = (uint32) (lastx - x);
    384 	    if (run) {
    385 		cp = buf + (x>>3);
    386 		bx = x&7;
    387 		if (run > 8-bx) {
    388 		    if (bx) {			/* align to byte boundary */
    389 			*cp++ &= 0xff << (8-bx);
    390 			run -= 8-bx;
    391 		    }
    392 		    if( (n = run >> 3) != 0 ) {	/* multiple bytes to fill */
    393 			if ((n/sizeof (long)) > 1) {
    394 			    /*
    395 			     * Align to longword boundary and fill.
    396 			     */
    397 			    for (; n && !isAligned(cp, long); n--)
    398 				    *cp++ = 0x00;
    399 			    lp = (long*) cp;
    400 			    nw = (int32)(n / sizeof (long));
    401 			    n -= nw * sizeof (long);
    402 			    do {
    403 				    *lp++ = 0L;
    404 			    } while (--nw);
    405 			    cp = (unsigned char*) lp;
    406 			}
    407 			ZERO(n, cp);
    408 			run &= 7;
    409 		    }
    410 		    if (run)
    411 			cp[0] &= 0xff >> run;
    412 		} else
    413 		    cp[0] &= ~(_fillmasks[run]>>bx);
    414 		x += runs[0];
    415 	    }
    416 	    run = runs[1];
    417 	    if (x+run > lastx || run > lastx )
    418 		run = runs[1] = lastx - x;
    419 	    if (run) {
    420 		cp = buf + (x>>3);
    421 		bx = x&7;
    422 		if (run > 8-bx) {
    423 		    if (bx) {			/* align to byte boundary */
    424 			*cp++ |= 0xff >> bx;
    425 			run -= 8-bx;
    426 		    }
    427 		    if( (n = run>>3) != 0 ) {	/* multiple bytes to fill */
    428 			if ((n/sizeof (long)) > 1) {
    429 			    /*
    430 			     * Align to longword boundary and fill.
    431 			     */
    432 			    for (; n && !isAligned(cp, long); n--)
    433 				*cp++ = 0xff;
    434 			    lp = (long*) cp;
    435 			    nw = (int32)(n / sizeof (long));
    436 			    n -= nw * sizeof (long);
    437 			    do {
    438 				*lp++ = -1L;
    439 			    } while (--nw);
    440 			    cp = (unsigned char*) lp;
    441 			}
    442 			FILL(n, cp);
    443 			run &= 7;
    444 		    }
    445                     /* Explicit 0xff masking to make icc -check=conversions happy */
    446 		    if (run)
    447 			cp[0] = (unsigned char)((cp[0] | (0xff00 >> run))&0xff);
    448 		} else
    449 		    cp[0] |= _fillmasks[run]>>bx;
    450 		x += runs[1];
    451 	    }
    452 	}
    453 	assert(x == lastx);
    454 }
    455 #undef	ZERO
    456 #undef	FILL
    457 
    458 static int
    459 Fax3FixupTags(TIFF* tif)
    460 {
    461 	(void) tif;
    462 	return (1);
    463 }
    464 
    465 /*
    466  * Setup G3/G4-related compression/decompression state
    467  * before data is processed.  This routine is called once
    468  * per image -- it sets up different state based on whether
    469  * or not decoding or encoding is being done and whether
    470  * 1D- or 2D-encoded data is involved.
    471  */
    472 static int
    473 Fax3SetupState(TIFF* tif)
    474 {
    475 	static const char module[] = "Fax3SetupState";
    476 	TIFFDirectory* td = &tif->tif_dir;
    477 	Fax3BaseState* sp = Fax3State(tif);
    478 	int needsRefLine;
    479 	Fax3CodecState* dsp = (Fax3CodecState*) Fax3State(tif);
    480 	tmsize_t rowbytes;
    481 	uint32 rowpixels, nruns;
    482 
    483 	if (td->td_bitspersample != 1) {
    484 		TIFFErrorExt(tif->tif_clientdata, module,
    485 		    "Bits/sample must be 1 for Group 3/4 encoding/decoding");
    486 		return (0);
    487 	}
    488 	/*
    489 	 * Calculate the scanline/tile widths.
    490 	 */
    491 	if (isTiled(tif)) {
    492 		rowbytes = TIFFTileRowSize(tif);
    493 		rowpixels = td->td_tilewidth;
    494 	} else {
    495 		rowbytes = TIFFScanlineSize(tif);
    496 		rowpixels = td->td_imagewidth;
    497 	}
    498 	sp->rowbytes = rowbytes;
    499 	sp->rowpixels = rowpixels;
    500 	/*
    501 	 * Allocate any additional space required for decoding/encoding.
    502 	 */
    503 	needsRefLine = (
    504 	    (sp->groupoptions & GROUP3OPT_2DENCODING) ||
    505 	    td->td_compression == COMPRESSION_CCITTFAX4
    506 	);
    507 
    508 	/*
    509 	  Assure that allocation computations do not overflow.
    510 
    511 	  TIFFroundup and TIFFSafeMultiply return zero on integer overflow
    512 	*/
    513 	dsp->runs=(uint32*) NULL;
    514 	nruns = TIFFroundup_32(rowpixels,32);
    515 	if (needsRefLine) {
    516 		nruns = TIFFSafeMultiply(uint32,nruns,2);
    517 	}
    518 	if ((nruns == 0) || (TIFFSafeMultiply(uint32,nruns,2) == 0)) {
    519 		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
    520 			     "Row pixels integer overflow (rowpixels %u)",
    521 			     rowpixels);
    522 		return (0);
    523 	}
    524 	dsp->runs = (uint32*) _TIFFCheckMalloc(tif,
    525 					       TIFFSafeMultiply(uint32,nruns,2),
    526 					       sizeof (uint32),
    527 					       "for Group 3/4 run arrays");
    528 	if (dsp->runs == NULL)
    529 		return (0);
    530 	memset( dsp->runs, 0, TIFFSafeMultiply(uint32,nruns,2)*sizeof(uint32));
    531 	dsp->curruns = dsp->runs;
    532 	if (needsRefLine)
    533 		dsp->refruns = dsp->runs + nruns;
    534 	else
    535 		dsp->refruns = NULL;
    536 	if (td->td_compression == COMPRESSION_CCITTFAX3
    537 	    && is2DEncoding(dsp)) {	/* NB: default is 1D routine */
    538 		tif->tif_decoderow = Fax3Decode2D;
    539 		tif->tif_decodestrip = Fax3Decode2D;
    540 		tif->tif_decodetile = Fax3Decode2D;
    541 	}
    542 
    543 	if (needsRefLine) {		/* 2d encoding */
    544 		Fax3CodecState* esp = EncoderState(tif);
    545 		/*
    546 		 * 2d encoding requires a scanline
    547 		 * buffer for the ``reference line''; the
    548 		 * scanline against which delta encoding
    549 		 * is referenced.  The reference line must
    550 		 * be initialized to be ``white'' (done elsewhere).
    551 		 */
    552 		esp->refline = (unsigned char*) _TIFFmalloc(rowbytes);
    553 		if (esp->refline == NULL) {
    554 			TIFFErrorExt(tif->tif_clientdata, module,
    555 			    "No space for Group 3/4 reference line");
    556 			return (0);
    557 		}
    558 	} else					/* 1d encoding */
    559 		EncoderState(tif)->refline = NULL;
    560 
    561 	return (1);
    562 }
    563 
    564 /*
    565  * CCITT Group 3 FAX Encoding.
    566  */
    567 
    568 #define	Fax3FlushBits(tif, sp) {				\
    569 	if ((tif)->tif_rawcc >= (tif)->tif_rawdatasize)		\
    570 		(void) TIFFFlushData1(tif);			\
    571 	*(tif)->tif_rawcp++ = (uint8) (sp)->data;		\
    572 	(tif)->tif_rawcc++;					\
    573 	(sp)->data = 0, (sp)->bit = 8;				\
    574 }
    575 #define	_FlushBits(tif) {					\
    576 	if ((tif)->tif_rawcc >= (tif)->tif_rawdatasize)		\
    577 		(void) TIFFFlushData1(tif);			\
    578 	*(tif)->tif_rawcp++ = (uint8) data;		\
    579 	(tif)->tif_rawcc++;					\
    580 	data = 0, bit = 8;					\
    581 }
    582 static const int _msbmask[9] =
    583     { 0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff };
    584 #define	_PutBits(tif, bits, length) {				\
    585 	while (length > bit) {					\
    586 		data |= bits >> (length - bit);			\
    587 		length -= bit;					\
    588 		_FlushBits(tif);				\
    589 	}							\
    590         assert( length < 9 );                                   \
    591 	data |= (bits & _msbmask[length]) << (bit - length);	\
    592 	bit -= length;						\
    593 	if (bit == 0)						\
    594 		_FlushBits(tif);				\
    595 }
    596 
    597 /*
    598  * Write a variable-length bit-value to
    599  * the output stream.  Values are
    600  * assumed to be at most 16 bits.
    601  */
    602 static void
    603 Fax3PutBits(TIFF* tif, unsigned int bits, unsigned int length)
    604 {
    605 	Fax3CodecState* sp = EncoderState(tif);
    606 	unsigned int bit = sp->bit;
    607 	int data = sp->data;
    608 
    609 	_PutBits(tif, bits, length);
    610 
    611 	sp->data = data;
    612 	sp->bit = bit;
    613 }
    614 
    615 /*
    616  * Write a code to the output stream.
    617  */
    618 #define putcode(tif, te)	Fax3PutBits(tif, (te)->code, (te)->length)
    619 
    620 #ifdef FAX3_DEBUG
    621 #define	DEBUG_COLOR(w) (tab == TIFFFaxWhiteCodes ? w "W" : w "B")
    622 #define	DEBUG_PRINT(what,len) {						\
    623     int t;								\
    624     printf("%08X/%-2d: %s%5d\t", data, bit, DEBUG_COLOR(what), len);	\
    625     for (t = length-1; t >= 0; t--)					\
    626 	putchar(code & (1<<t) ? '1' : '0');				\
    627     putchar('\n');							\
    628 }
    629 #endif
    630 
    631 /*
    632  * Write the sequence of codes that describes
    633  * the specified span of zero's or one's.  The
    634  * appropriate table that holds the make-up and
    635  * terminating codes is supplied.
    636  */
    637 static void
    638 putspan(TIFF* tif, int32 span, const tableentry* tab)
    639 {
    640 	Fax3CodecState* sp = EncoderState(tif);
    641 	unsigned int bit = sp->bit;
    642 	int data = sp->data;
    643 	unsigned int code, length;
    644 
    645 	while (span >= 2624) {
    646 		const tableentry* te = &tab[63 + (2560>>6)];
    647 		code = te->code, length = te->length;
    648 #ifdef FAX3_DEBUG
    649 		DEBUG_PRINT("MakeUp", te->runlen);
    650 #endif
    651 		_PutBits(tif, code, length);
    652 		span -= te->runlen;
    653 	}
    654 	if (span >= 64) {
    655 		const tableentry* te = &tab[63 + (span>>6)];
    656 		assert(te->runlen == 64*(span>>6));
    657 		code = te->code, length = te->length;
    658 #ifdef FAX3_DEBUG
    659 		DEBUG_PRINT("MakeUp", te->runlen);
    660 #endif
    661 		_PutBits(tif, code, length);
    662 		span -= te->runlen;
    663 	}
    664 	code = tab[span].code, length = tab[span].length;
    665 #ifdef FAX3_DEBUG
    666 	DEBUG_PRINT("  Term", tab[span].runlen);
    667 #endif
    668 	_PutBits(tif, code, length);
    669 
    670 	sp->data = data;
    671 	sp->bit = bit;
    672 }
    673 
    674 /*
    675  * Write an EOL code to the output stream.  The zero-fill
    676  * logic for byte-aligning encoded scanlines is handled
    677  * here.  We also handle writing the tag bit for the next
    678  * scanline when doing 2d encoding.
    679  */
    680 static void
    681 Fax3PutEOL(TIFF* tif)
    682 {
    683 	Fax3CodecState* sp = EncoderState(tif);
    684 	unsigned int bit = sp->bit;
    685 	int data = sp->data;
    686 	unsigned int code, length, tparm;
    687 
    688 	if (sp->b.groupoptions & GROUP3OPT_FILLBITS) {
    689 		/*
    690 		 * Force bit alignment so EOL will terminate on
    691 		 * a byte boundary.  That is, force the bit alignment
    692 		 * to 16-12 = 4 before putting out the EOL code.
    693 		 */
    694 		int align = 8 - 4;
    695 		if (align != sp->bit) {
    696 			if (align > sp->bit)
    697 				align = sp->bit + (8 - align);
    698 			else
    699 				align = sp->bit - align;
    700 			code = 0;
    701 			tparm=align;
    702 			_PutBits(tif, 0, tparm);
    703 		}
    704 	}
    705 	code = EOL, length = 12;
    706 	if (is2DEncoding(sp))
    707 		code = (code<<1) | (sp->tag == G3_1D), length++;
    708 	_PutBits(tif, code, length);
    709 
    710 	sp->data = data;
    711 	sp->bit = bit;
    712 }
    713 
    714 /*
    715  * Reset encoding state at the start of a strip.
    716  */
    717 static int
    718 Fax3PreEncode(TIFF* tif, uint16 s)
    719 {
    720 	Fax3CodecState* sp = EncoderState(tif);
    721 
    722 	(void) s;
    723 	assert(sp != NULL);
    724 	sp->bit = 8;
    725 	sp->data = 0;
    726 	sp->tag = G3_1D;
    727 	/*
    728 	 * This is necessary for Group 4; otherwise it isn't
    729 	 * needed because the first scanline of each strip ends
    730 	 * up being copied into the refline.
    731 	 */
    732 	if (sp->refline)
    733 		_TIFFmemset(sp->refline, 0x00, sp->b.rowbytes);
    734 	if (is2DEncoding(sp)) {
    735 		float res = tif->tif_dir.td_yresolution;
    736 		/*
    737 		 * The CCITT spec says that when doing 2d encoding, you
    738 		 * should only do it on K consecutive scanlines, where K
    739 		 * depends on the resolution of the image being encoded
    740 		 * (2 for <= 200 lpi, 4 for > 200 lpi).  Since the directory
    741 		 * code initializes td_yresolution to 0, this code will
    742 		 * select a K of 2 unless the YResolution tag is set
    743 		 * appropriately.  (Note also that we fudge a little here
    744 		 * and use 150 lpi to avoid problems with units conversion.)
    745 		 */
    746 		if (tif->tif_dir.td_resolutionunit == RESUNIT_CENTIMETER)
    747 			res *= 2.54f;		/* convert to inches */
    748 		sp->maxk = (res > 150 ? 4 : 2);
    749 		sp->k = sp->maxk-1;
    750 	} else
    751 		sp->k = sp->maxk = 0;
    752 	sp->line = 0;
    753 	return (1);
    754 }
    755 
    756 static const unsigned char zeroruns[256] = {
    757     8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,	/* 0x00 - 0x0f */
    758     3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,	/* 0x10 - 0x1f */
    759     2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,	/* 0x20 - 0x2f */
    760     2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,	/* 0x30 - 0x3f */
    761     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x40 - 0x4f */
    762     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x50 - 0x5f */
    763     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x60 - 0x6f */
    764     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x70 - 0x7f */
    765     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x80 - 0x8f */
    766     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x90 - 0x9f */
    767     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xa0 - 0xaf */
    768     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xb0 - 0xbf */
    769     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xc0 - 0xcf */
    770     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xd0 - 0xdf */
    771     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xe0 - 0xef */
    772     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xf0 - 0xff */
    773 };
    774 static const unsigned char oneruns[256] = {
    775     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x00 - 0x0f */
    776     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x10 - 0x1f */
    777     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x20 - 0x2f */
    778     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x30 - 0x3f */
    779     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x40 - 0x4f */
    780     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x50 - 0x5f */
    781     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x60 - 0x6f */
    782     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x70 - 0x7f */
    783     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x80 - 0x8f */
    784     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x90 - 0x9f */
    785     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0xa0 - 0xaf */
    786     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0xb0 - 0xbf */
    787     2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,	/* 0xc0 - 0xcf */
    788     2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,	/* 0xd0 - 0xdf */
    789     3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,	/* 0xe0 - 0xef */
    790     4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8,	/* 0xf0 - 0xff */
    791 };
    792 
    793 /*
    794  * On certain systems it pays to inline
    795  * the routines that find pixel spans.
    796  */
    797 #ifdef VAXC
    798 static	int32 find0span(unsigned char*, int32, int32);
    799 static	int32 find1span(unsigned char*, int32, int32);
    800 #pragma inline(find0span,find1span)
    801 #endif
    802 
    803 /*
    804  * Find a span of ones or zeros using the supplied
    805  * table.  The ``base'' of the bit string is supplied
    806  * along with the start+end bit indices.
    807  */
    808 inline static int32
    809 find0span(unsigned char* bp, int32 bs, int32 be)
    810 {
    811 	int32 bits = be - bs;
    812 	int32 n, span;
    813 
    814 	bp += bs>>3;
    815 	/*
    816 	 * Check partial byte on lhs.
    817 	 */
    818 	if (bits > 0 && (n = (bs & 7))) {
    819 		span = zeroruns[(*bp << n) & 0xff];
    820 		if (span > 8-n)		/* table value too generous */
    821 			span = 8-n;
    822 		if (span > bits)	/* constrain span to bit range */
    823 			span = bits;
    824 		if (n+span < 8)		/* doesn't extend to edge of byte */
    825 			return (span);
    826 		bits -= span;
    827 		bp++;
    828 	} else
    829 		span = 0;
    830 	if (bits >= (int32)(2 * 8 * sizeof(long))) {
    831 		long* lp;
    832 		/*
    833 		 * Align to longword boundary and check longwords.
    834 		 */
    835 		while (!isAligned(bp, long)) {
    836 			if (*bp != 0x00)
    837 				return (span + zeroruns[*bp]);
    838 			span += 8, bits -= 8;
    839 			bp++;
    840 		}
    841 		lp = (long*) bp;
    842 		while ((bits >= (int32)(8 * sizeof(long))) && (0 == *lp)) {
    843 			span += 8*sizeof (long), bits -= 8*sizeof (long);
    844 			lp++;
    845 		}
    846 		bp = (unsigned char*) lp;
    847 	}
    848 	/*
    849 	 * Scan full bytes for all 0's.
    850 	 */
    851 	while (bits >= 8) {
    852 		if (*bp != 0x00)	/* end of run */
    853 			return (span + zeroruns[*bp]);
    854 		span += 8, bits -= 8;
    855 		bp++;
    856 	}
    857 	/*
    858 	 * Check partial byte on rhs.
    859 	 */
    860 	if (bits > 0) {
    861 		n = zeroruns[*bp];
    862 		span += (n > bits ? bits : n);
    863 	}
    864 	return (span);
    865 }
    866 
    867 inline static int32
    868 find1span(unsigned char* bp, int32 bs, int32 be)
    869 {
    870 	int32 bits = be - bs;
    871 	int32 n, span;
    872 
    873 	bp += bs>>3;
    874 	/*
    875 	 * Check partial byte on lhs.
    876 	 */
    877 	if (bits > 0 && (n = (bs & 7))) {
    878 		span = oneruns[(*bp << n) & 0xff];
    879 		if (span > 8-n)		/* table value too generous */
    880 			span = 8-n;
    881 		if (span > bits)	/* constrain span to bit range */
    882 			span = bits;
    883 		if (n+span < 8)		/* doesn't extend to edge of byte */
    884 			return (span);
    885 		bits -= span;
    886 		bp++;
    887 	} else
    888 		span = 0;
    889 	if (bits >= (int32)(2 * 8 * sizeof(long))) {
    890 		long* lp;
    891 		/*
    892 		 * Align to longword boundary and check longwords.
    893 		 */
    894 		while (!isAligned(bp, long)) {
    895 			if (*bp != 0xff)
    896 				return (span + oneruns[*bp]);
    897 			span += 8, bits -= 8;
    898 			bp++;
    899 		}
    900 		lp = (long*) bp;
    901 		while ((bits >= (int32)(8 * sizeof(long))) && (~0 == *lp)) {
    902 			span += 8*sizeof (long), bits -= 8*sizeof (long);
    903 			lp++;
    904 		}
    905 		bp = (unsigned char*) lp;
    906 	}
    907 	/*
    908 	 * Scan full bytes for all 1's.
    909 	 */
    910 	while (bits >= 8) {
    911 		if (*bp != 0xff)	/* end of run */
    912 			return (span + oneruns[*bp]);
    913 		span += 8, bits -= 8;
    914 		bp++;
    915 	}
    916 	/*
    917 	 * Check partial byte on rhs.
    918 	 */
    919 	if (bits > 0) {
    920 		n = oneruns[*bp];
    921 		span += (n > bits ? bits : n);
    922 	}
    923 	return (span);
    924 }
    925 
    926 /*
    927  * Return the offset of the next bit in the range
    928  * [bs..be] that is different from the specified
    929  * color.  The end, be, is returned if no such bit
    930  * exists.
    931  */
    932 #define	finddiff(_cp, _bs, _be, _color)	\
    933 	(_bs + (_color ? find1span(_cp,_bs,_be) : find0span(_cp,_bs,_be)))
    934 /*
    935  * Like finddiff, but also check the starting bit
    936  * against the end in case start > end.
    937  */
    938 #define	finddiff2(_cp, _bs, _be, _color) \
    939 	(_bs < _be ? finddiff(_cp,_bs,_be,_color) : _be)
    940 
    941 /*
    942  * 1d-encode a row of pixels.  The encoding is
    943  * a sequence of all-white or all-black spans
    944  * of pixels encoded with Huffman codes.
    945  */
    946 static int
    947 Fax3Encode1DRow(TIFF* tif, unsigned char* bp, uint32 bits)
    948 {
    949 	Fax3CodecState* sp = EncoderState(tif);
    950 	int32 span;
    951         uint32 bs = 0;
    952 
    953 	for (;;) {
    954 		span = find0span(bp, bs, bits);		/* white span */
    955 		putspan(tif, span, TIFFFaxWhiteCodes);
    956 		bs += span;
    957 		if (bs >= bits)
    958 			break;
    959 		span = find1span(bp, bs, bits);		/* black span */
    960 		putspan(tif, span, TIFFFaxBlackCodes);
    961 		bs += span;
    962 		if (bs >= bits)
    963 			break;
    964 	}
    965 	if (sp->b.mode & (FAXMODE_BYTEALIGN|FAXMODE_WORDALIGN)) {
    966 		if (sp->bit != 8)			/* byte-align */
    967 			Fax3FlushBits(tif, sp);
    968 		if ((sp->b.mode&FAXMODE_WORDALIGN) &&
    969 		    !isAligned(tif->tif_rawcp, uint16))
    970 			Fax3FlushBits(tif, sp);
    971 	}
    972 	return (1);
    973 }
    974 
    975 static const tableentry horizcode =
    976     { 3, 0x1, 0 };	/* 001 */
    977 static const tableentry passcode =
    978     { 4, 0x1, 0 };	/* 0001 */
    979 static const tableentry vcodes[7] = {
    980     { 7, 0x03, 0 },	/* 0000 011 */
    981     { 6, 0x03, 0 },	/* 0000 11 */
    982     { 3, 0x03, 0 },	/* 011 */
    983     { 1, 0x1, 0 },	/* 1 */
    984     { 3, 0x2, 0 },	/* 010 */
    985     { 6, 0x02, 0 },	/* 0000 10 */
    986     { 7, 0x02, 0 }	/* 0000 010 */
    987 };
    988 
    989 /*
    990  * 2d-encode a row of pixels.  Consult the CCITT
    991  * documentation for the algorithm.
    992  */
    993 static int
    994 Fax3Encode2DRow(TIFF* tif, unsigned char* bp, unsigned char* rp, uint32 bits)
    995 {
    996 #define	PIXEL(buf,ix)	((((buf)[(ix)>>3]) >> (7-((ix)&7))) & 1)
    997         uint32 a0 = 0;
    998 	uint32 a1 = (PIXEL(bp, 0) != 0 ? 0 : finddiff(bp, 0, bits, 0));
    999 	uint32 b1 = (PIXEL(rp, 0) != 0 ? 0 : finddiff(rp, 0, bits, 0));
   1000 	uint32 a2, b2;
   1001 
   1002 	for (;;) {
   1003 		b2 = finddiff2(rp, b1, bits, PIXEL(rp,b1));
   1004 		if (b2 >= a1) {
   1005 			int32 d = b1 - a1;
   1006 			if (!(-3 <= d && d <= 3)) {	/* horizontal mode */
   1007 				a2 = finddiff2(bp, a1, bits, PIXEL(bp,a1));
   1008 				putcode(tif, &horizcode);
   1009 				if (a0+a1 == 0 || PIXEL(bp, a0) == 0) {
   1010 					putspan(tif, a1-a0, TIFFFaxWhiteCodes);
   1011 					putspan(tif, a2-a1, TIFFFaxBlackCodes);
   1012 				} else {
   1013 					putspan(tif, a1-a0, TIFFFaxBlackCodes);
   1014 					putspan(tif, a2-a1, TIFFFaxWhiteCodes);
   1015 				}
   1016 				a0 = a2;
   1017 			} else {			/* vertical mode */
   1018 				putcode(tif, &vcodes[d+3]);
   1019 				a0 = a1;
   1020 			}
   1021 		} else {				/* pass mode */
   1022 			putcode(tif, &passcode);
   1023 			a0 = b2;
   1024 		}
   1025 		if (a0 >= bits)
   1026 			break;
   1027 		a1 = finddiff(bp, a0, bits, PIXEL(bp,a0));
   1028 		b1 = finddiff(rp, a0, bits, !PIXEL(bp,a0));
   1029 		b1 = finddiff(rp, b1, bits, PIXEL(bp,a0));
   1030 	}
   1031 	return (1);
   1032 #undef PIXEL
   1033 }
   1034 
   1035 /*
   1036  * Encode a buffer of pixels.
   1037  */
   1038 static int
   1039 Fax3Encode(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s)
   1040 {
   1041 	static const char module[] = "Fax3Encode";
   1042 	Fax3CodecState* sp = EncoderState(tif);
   1043 	(void) s;
   1044 	if (cc % sp->b.rowbytes)
   1045 	{
   1046 		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be written");
   1047 		return (0);
   1048 	}
   1049 	while (cc > 0) {
   1050 		if ((sp->b.mode & FAXMODE_NOEOL) == 0)
   1051 			Fax3PutEOL(tif);
   1052 		if (is2DEncoding(sp)) {
   1053 			if (sp->tag == G3_1D) {
   1054 				if (!Fax3Encode1DRow(tif, bp, sp->b.rowpixels))
   1055 					return (0);
   1056 				sp->tag = G3_2D;
   1057 			} else {
   1058 				if (!Fax3Encode2DRow(tif, bp, sp->refline,
   1059 				    sp->b.rowpixels))
   1060 					return (0);
   1061 				sp->k--;
   1062 			}
   1063 			if (sp->k == 0) {
   1064 				sp->tag = G3_1D;
   1065 				sp->k = sp->maxk-1;
   1066 			} else
   1067 				_TIFFmemcpy(sp->refline, bp, sp->b.rowbytes);
   1068 		} else {
   1069 			if (!Fax3Encode1DRow(tif, bp, sp->b.rowpixels))
   1070 				return (0);
   1071 		}
   1072 		bp += sp->b.rowbytes;
   1073 		cc -= sp->b.rowbytes;
   1074 	}
   1075 	return (1);
   1076 }
   1077 
   1078 static int
   1079 Fax3PostEncode(TIFF* tif)
   1080 {
   1081 	Fax3CodecState* sp = EncoderState(tif);
   1082 
   1083 	if (sp->bit != 8)
   1084 		Fax3FlushBits(tif, sp);
   1085 	return (1);
   1086 }
   1087 
   1088 static void
   1089 Fax3Close(TIFF* tif)
   1090 {
   1091 	if ((Fax3State(tif)->mode & FAXMODE_NORTC) == 0) {
   1092 		Fax3CodecState* sp = EncoderState(tif);
   1093 		unsigned int code = EOL;
   1094 		unsigned int length = 12;
   1095 		int i;
   1096 
   1097 		if (is2DEncoding(sp))
   1098 			code = (code<<1) | (sp->tag == G3_1D), length++;
   1099 		for (i = 0; i < 6; i++)
   1100 			Fax3PutBits(tif, code, length);
   1101 		Fax3FlushBits(tif, sp);
   1102 	}
   1103 }
   1104 
   1105 static void
   1106 Fax3Cleanup(TIFF* tif)
   1107 {
   1108 	Fax3CodecState* sp = DecoderState(tif);
   1109 
   1110 	assert(sp != 0);
   1111 
   1112 	tif->tif_tagmethods.vgetfield = sp->b.vgetparent;
   1113 	tif->tif_tagmethods.vsetfield = sp->b.vsetparent;
   1114 	tif->tif_tagmethods.printdir = sp->b.printdir;
   1115 
   1116 	if (sp->runs)
   1117 		_TIFFfree(sp->runs);
   1118 	if (sp->refline)
   1119 		_TIFFfree(sp->refline);
   1120 
   1121 	_TIFFfree(tif->tif_data);
   1122 	tif->tif_data = NULL;
   1123 
   1124 	_TIFFSetDefaultCompressionState(tif);
   1125 }
   1126 
   1127 #define	FIELD_BADFAXLINES	(FIELD_CODEC+0)
   1128 #define	FIELD_CLEANFAXDATA	(FIELD_CODEC+1)
   1129 #define	FIELD_BADFAXRUN		(FIELD_CODEC+2)
   1130 
   1131 #define	FIELD_OPTIONS		(FIELD_CODEC+7)
   1132 
   1133 static const TIFFField faxFields[] = {
   1134     { TIFFTAG_FAXMODE, 0, 0, TIFF_ANY, 0, TIFF_SETGET_INT, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, FALSE, FALSE, "FaxMode", NULL },
   1135     { TIFFTAG_FAXFILLFUNC, 0, 0, TIFF_ANY, 0, TIFF_SETGET_OTHER, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, FALSE, FALSE, "FaxFillFunc", NULL },
   1136     { TIFFTAG_BADFAXLINES, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_BADFAXLINES, TRUE, FALSE, "BadFaxLines", NULL },
   1137     { TIFFTAG_CLEANFAXDATA, 1, 1, TIFF_SHORT, 0, TIFF_SETGET_UINT16, TIFF_SETGET_UINT16, FIELD_CLEANFAXDATA, TRUE, FALSE, "CleanFaxData", NULL },
   1138     { TIFFTAG_CONSECUTIVEBADFAXLINES, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_BADFAXRUN, TRUE, FALSE, "ConsecutiveBadFaxLines", NULL }};
   1139 static const TIFFField fax3Fields[] = {
   1140     { TIFFTAG_GROUP3OPTIONS, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_OPTIONS, FALSE, FALSE, "Group3Options", NULL },
   1141 };
   1142 static const TIFFField fax4Fields[] = {
   1143     { TIFFTAG_GROUP4OPTIONS, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_OPTIONS, FALSE, FALSE, "Group4Options", NULL },
   1144 };
   1145 
   1146 static int
   1147 Fax3VSetField(TIFF* tif, uint32 tag, va_list ap)
   1148 {
   1149 	Fax3BaseState* sp = Fax3State(tif);
   1150 	const TIFFField* fip;
   1151 
   1152 	assert(sp != 0);
   1153 	assert(sp->vsetparent != 0);
   1154 
   1155 	switch (tag) {
   1156 	case TIFFTAG_FAXMODE:
   1157 		sp->mode = (int) va_arg(ap, int);
   1158 		return 1;			/* NB: pseudo tag */
   1159 	case TIFFTAG_FAXFILLFUNC:
   1160 		DecoderState(tif)->fill = va_arg(ap, TIFFFaxFillFunc);
   1161 		return 1;			/* NB: pseudo tag */
   1162 	case TIFFTAG_GROUP3OPTIONS:
   1163 		/* XXX: avoid reading options if compression mismatches. */
   1164 		if (tif->tif_dir.td_compression == COMPRESSION_CCITTFAX3)
   1165 			sp->groupoptions = (uint32) va_arg(ap, uint32);
   1166 		break;
   1167 	case TIFFTAG_GROUP4OPTIONS:
   1168 		/* XXX: avoid reading options if compression mismatches. */
   1169 		if (tif->tif_dir.td_compression == COMPRESSION_CCITTFAX4)
   1170 			sp->groupoptions = (uint32) va_arg(ap, uint32);
   1171 		break;
   1172 	case TIFFTAG_BADFAXLINES:
   1173 		sp->badfaxlines = (uint32) va_arg(ap, uint32);
   1174 		break;
   1175 	case TIFFTAG_CLEANFAXDATA:
   1176 		sp->cleanfaxdata = (uint16) va_arg(ap, uint16_vap);
   1177 		break;
   1178 	case TIFFTAG_CONSECUTIVEBADFAXLINES:
   1179 		sp->badfaxrun = (uint32) va_arg(ap, uint32);
   1180 		break;
   1181 	default:
   1182 		return (*sp->vsetparent)(tif, tag, ap);
   1183 	}
   1184 
   1185 	if ((fip = TIFFFieldWithTag(tif, tag)))
   1186 		TIFFSetFieldBit(tif, fip->field_bit);
   1187 	else
   1188 		return 0;
   1189 
   1190 	tif->tif_flags |= TIFF_DIRTYDIRECT;
   1191 	return 1;
   1192 }
   1193 
   1194 static int
   1195 Fax3VGetField(TIFF* tif, uint32 tag, va_list ap)
   1196 {
   1197 	Fax3BaseState* sp = Fax3State(tif);
   1198 
   1199 	assert(sp != 0);
   1200 
   1201 	switch (tag) {
   1202 	case TIFFTAG_FAXMODE:
   1203 		*va_arg(ap, int*) = sp->mode;
   1204 		break;
   1205 	case TIFFTAG_FAXFILLFUNC:
   1206 		*va_arg(ap, TIFFFaxFillFunc*) = DecoderState(tif)->fill;
   1207 		break;
   1208 	case TIFFTAG_GROUP3OPTIONS:
   1209 	case TIFFTAG_GROUP4OPTIONS:
   1210 		*va_arg(ap, uint32*) = sp->groupoptions;
   1211 		break;
   1212 	case TIFFTAG_BADFAXLINES:
   1213 		*va_arg(ap, uint32*) = sp->badfaxlines;
   1214 		break;
   1215 	case TIFFTAG_CLEANFAXDATA:
   1216 		*va_arg(ap, uint16*) = sp->cleanfaxdata;
   1217 		break;
   1218 	case TIFFTAG_CONSECUTIVEBADFAXLINES:
   1219 		*va_arg(ap, uint32*) = sp->badfaxrun;
   1220 		break;
   1221 	default:
   1222 		return (*sp->vgetparent)(tif, tag, ap);
   1223 	}
   1224 	return (1);
   1225 }
   1226 
   1227 static void
   1228 Fax3PrintDir(TIFF* tif, FILE* fd, long flags)
   1229 {
   1230 	Fax3BaseState* sp = Fax3State(tif);
   1231 
   1232 	assert(sp != 0);
   1233 
   1234 	(void) flags;
   1235 	if (TIFFFieldSet(tif,FIELD_OPTIONS)) {
   1236 		const char* sep = " ";
   1237 		if (tif->tif_dir.td_compression == COMPRESSION_CCITTFAX4) {
   1238 			fprintf(fd, "  Group 4 Options:");
   1239 			if (sp->groupoptions & GROUP4OPT_UNCOMPRESSED)
   1240 				fprintf(fd, "%suncompressed data", sep);
   1241 		} else {
   1242 
   1243 			fprintf(fd, "  Group 3 Options:");
   1244 			if (sp->groupoptions & GROUP3OPT_2DENCODING)
   1245 				fprintf(fd, "%s2-d encoding", sep), sep = "+";
   1246 			if (sp->groupoptions & GROUP3OPT_FILLBITS)
   1247 				fprintf(fd, "%sEOL padding", sep), sep = "+";
   1248 			if (sp->groupoptions & GROUP3OPT_UNCOMPRESSED)
   1249 				fprintf(fd, "%suncompressed data", sep);
   1250 		}
   1251 		fprintf(fd, " (%lu = 0x%lx)\n",
   1252                         (unsigned long) sp->groupoptions,
   1253                         (unsigned long) sp->groupoptions);
   1254 	}
   1255 	if (TIFFFieldSet(tif,FIELD_CLEANFAXDATA)) {
   1256 		fprintf(fd, "  Fax Data:");
   1257 		switch (sp->cleanfaxdata) {
   1258 		case CLEANFAXDATA_CLEAN:
   1259 			fprintf(fd, " clean");
   1260 			break;
   1261 		case CLEANFAXDATA_REGENERATED:
   1262 			fprintf(fd, " receiver regenerated");
   1263 			break;
   1264 		case CLEANFAXDATA_UNCLEAN:
   1265 			fprintf(fd, " uncorrected errors");
   1266 			break;
   1267 		}
   1268 		fprintf(fd, " (%u = 0x%x)\n",
   1269 		    sp->cleanfaxdata, sp->cleanfaxdata);
   1270 	}
   1271 	if (TIFFFieldSet(tif,FIELD_BADFAXLINES))
   1272 		fprintf(fd, "  Bad Fax Lines: %lu\n",
   1273                         (unsigned long) sp->badfaxlines);
   1274 	if (TIFFFieldSet(tif,FIELD_BADFAXRUN))
   1275 		fprintf(fd, "  Consecutive Bad Fax Lines: %lu\n",
   1276 		    (unsigned long) sp->badfaxrun);
   1277 	if (sp->printdir)
   1278 		(*sp->printdir)(tif, fd, flags);
   1279 }
   1280 
   1281 static int
   1282 InitCCITTFax3(TIFF* tif)
   1283 {
   1284 	static const char module[] = "InitCCITTFax3";
   1285 	Fax3BaseState* sp;
   1286 
   1287 	/*
   1288 	 * Merge codec-specific tag information.
   1289 	 */
   1290 	if (!_TIFFMergeFields(tif, faxFields, TIFFArrayCount(faxFields))) {
   1291 		TIFFErrorExt(tif->tif_clientdata, "InitCCITTFax3",
   1292 			"Merging common CCITT Fax codec-specific tags failed");
   1293 		return 0;
   1294 	}
   1295 
   1296 	/*
   1297 	 * Allocate state block so tag methods have storage to record values.
   1298 	 */
   1299 	tif->tif_data = (uint8*)
   1300 		_TIFFmalloc(sizeof (Fax3CodecState));
   1301 
   1302 	if (tif->tif_data == NULL) {
   1303 		TIFFErrorExt(tif->tif_clientdata, module,
   1304 		    "No space for state block");
   1305 		return (0);
   1306 	}
   1307 
   1308 	sp = Fax3State(tif);
   1309         sp->rw_mode = tif->tif_mode;
   1310 
   1311 	/*
   1312 	 * Override parent get/set field methods.
   1313 	 */
   1314 	sp->vgetparent = tif->tif_tagmethods.vgetfield;
   1315 	tif->tif_tagmethods.vgetfield = Fax3VGetField; /* hook for codec tags */
   1316 	sp->vsetparent = tif->tif_tagmethods.vsetfield;
   1317 	tif->tif_tagmethods.vsetfield = Fax3VSetField; /* hook for codec tags */
   1318 	sp->printdir = tif->tif_tagmethods.printdir;
   1319 	tif->tif_tagmethods.printdir = Fax3PrintDir;   /* hook for codec tags */
   1320 	sp->groupoptions = 0;
   1321 
   1322 	if (sp->rw_mode == O_RDONLY) /* FIXME: improve for in place update */
   1323 		tif->tif_flags |= TIFF_NOBITREV; /* decoder does bit reversal */
   1324 	DecoderState(tif)->runs = NULL;
   1325 	TIFFSetField(tif, TIFFTAG_FAXFILLFUNC, _TIFFFax3fillruns);
   1326 	EncoderState(tif)->refline = NULL;
   1327 
   1328 	/*
   1329 	 * Install codec methods.
   1330 	 */
   1331 	tif->tif_fixuptags = Fax3FixupTags;
   1332 	tif->tif_setupdecode = Fax3SetupState;
   1333 	tif->tif_predecode = Fax3PreDecode;
   1334 	tif->tif_decoderow = Fax3Decode1D;
   1335 	tif->tif_decodestrip = Fax3Decode1D;
   1336 	tif->tif_decodetile = Fax3Decode1D;
   1337 	tif->tif_setupencode = Fax3SetupState;
   1338 	tif->tif_preencode = Fax3PreEncode;
   1339 	tif->tif_postencode = Fax3PostEncode;
   1340 	tif->tif_encoderow = Fax3Encode;
   1341 	tif->tif_encodestrip = Fax3Encode;
   1342 	tif->tif_encodetile = Fax3Encode;
   1343 	tif->tif_close = Fax3Close;
   1344 	tif->tif_cleanup = Fax3Cleanup;
   1345 
   1346 	return (1);
   1347 }
   1348 
   1349 int
   1350 TIFFInitCCITTFax3(TIFF* tif, int scheme)
   1351 {
   1352 	(void) scheme;
   1353 	if (InitCCITTFax3(tif)) {
   1354 		/*
   1355 		 * Merge codec-specific tag information.
   1356 		 */
   1357 		if (!_TIFFMergeFields(tif, fax3Fields,
   1358 				      TIFFArrayCount(fax3Fields))) {
   1359 			TIFFErrorExt(tif->tif_clientdata, "TIFFInitCCITTFax3",
   1360 			"Merging CCITT Fax 3 codec-specific tags failed");
   1361 			return 0;
   1362 		}
   1363 
   1364 		/*
   1365 		 * The default format is Class/F-style w/o RTC.
   1366 		 */
   1367 		return TIFFSetField(tif, TIFFTAG_FAXMODE, FAXMODE_CLASSF);
   1368 	} else
   1369 		return 01;
   1370 }
   1371 
   1372 /*
   1373  * CCITT Group 4 (T.6) Facsimile-compatible
   1374  * Compression Scheme Support.
   1375  */
   1376 
   1377 #define SWAP(t,a,b) { t x; x = (a); (a) = (b); (b) = x; }
   1378 /*
   1379  * Decode the requested amount of G4-encoded data.
   1380  */
   1381 static int
   1382 Fax4Decode(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
   1383 {
   1384 	DECLARE_STATE_2D(tif, sp, "Fax4Decode");
   1385 	(void) s;
   1386 	if (occ % sp->b.rowbytes)
   1387 	{
   1388 		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
   1389 		return (-1);
   1390 	}
   1391 	CACHE_STATE(tif, sp);
   1392 	while (occ > 0) {
   1393 		a0 = 0;
   1394 		RunLength = 0;
   1395 		pa = thisrun = sp->curruns;
   1396 		pb = sp->refruns;
   1397 		b1 = *pb++;
   1398 #ifdef FAX3_DEBUG
   1399 		printf("\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail);
   1400 		printf("-------------------- %d\n", tif->tif_row);
   1401 		fflush(stdout);
   1402 #endif
   1403 		EXPAND2D(EOFG4);
   1404                 if (EOLcnt)
   1405                     goto EOFG4;
   1406 		(*sp->fill)(buf, thisrun, pa, lastx);
   1407 		SETVALUE(0);		/* imaginary change for reference */
   1408 		SWAP(uint32*, sp->curruns, sp->refruns);
   1409 		buf += sp->b.rowbytes;
   1410 		occ -= sp->b.rowbytes;
   1411 		sp->line++;
   1412 		continue;
   1413 	EOFG4:
   1414                 NeedBits16( 13, BADG4 );
   1415         BADG4:
   1416 #ifdef FAX3_DEBUG
   1417                 if( GetBits(13) != 0x1001 )
   1418                     fputs( "Bad EOFB\n", stderr );
   1419 #endif
   1420                 ClrBits( 13 );
   1421 		(*sp->fill)(buf, thisrun, pa, lastx);
   1422 		UNCACHE_STATE(tif, sp);
   1423 		return ( sp->line ? 1 : -1);	/* don't error on badly-terminated strips */
   1424 	}
   1425 	UNCACHE_STATE(tif, sp);
   1426 	return (1);
   1427 }
   1428 #undef	SWAP
   1429 
   1430 /*
   1431  * Encode the requested amount of data.
   1432  */
   1433 static int
   1434 Fax4Encode(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s)
   1435 {
   1436 	static const char module[] = "Fax4Encode";
   1437 	Fax3CodecState *sp = EncoderState(tif);
   1438 	(void) s;
   1439 	if (cc % sp->b.rowbytes)
   1440 	{
   1441 		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be written");
   1442 		return (0);
   1443 	}
   1444 	while (cc > 0) {
   1445 		if (!Fax3Encode2DRow(tif, bp, sp->refline, sp->b.rowpixels))
   1446 			return (0);
   1447 		_TIFFmemcpy(sp->refline, bp, sp->b.rowbytes);
   1448 		bp += sp->b.rowbytes;
   1449 		cc -= sp->b.rowbytes;
   1450 	}
   1451 	return (1);
   1452 }
   1453 
   1454 static int
   1455 Fax4PostEncode(TIFF* tif)
   1456 {
   1457 	Fax3CodecState *sp = EncoderState(tif);
   1458 
   1459 	/* terminate strip w/ EOFB */
   1460 	Fax3PutBits(tif, EOL, 12);
   1461 	Fax3PutBits(tif, EOL, 12);
   1462 	if (sp->bit != 8)
   1463 		Fax3FlushBits(tif, sp);
   1464 	return (1);
   1465 }
   1466 
   1467 int
   1468 TIFFInitCCITTFax4(TIFF* tif, int scheme)
   1469 {
   1470 	(void) scheme;
   1471 	if (InitCCITTFax3(tif)) {		/* reuse G3 support */
   1472 		/*
   1473 		 * Merge codec-specific tag information.
   1474 		 */
   1475 		if (!_TIFFMergeFields(tif, fax4Fields,
   1476 				      TIFFArrayCount(fax4Fields))) {
   1477 			TIFFErrorExt(tif->tif_clientdata, "TIFFInitCCITTFax4",
   1478 			"Merging CCITT Fax 4 codec-specific tags failed");
   1479 			return 0;
   1480 		}
   1481 
   1482 		tif->tif_decoderow = Fax4Decode;
   1483 		tif->tif_decodestrip = Fax4Decode;
   1484 		tif->tif_decodetile = Fax4Decode;
   1485 		tif->tif_encoderow = Fax4Encode;
   1486 		tif->tif_encodestrip = Fax4Encode;
   1487 		tif->tif_encodetile = Fax4Encode;
   1488 		tif->tif_postencode = Fax4PostEncode;
   1489 		/*
   1490 		 * Suppress RTC at the end of each strip.
   1491 		 */
   1492 		return TIFFSetField(tif, TIFFTAG_FAXMODE, FAXMODE_NORTC);
   1493 	} else
   1494 		return (0);
   1495 }
   1496 
   1497 /*
   1498  * CCITT Group 3 1-D Modified Huffman RLE Compression Support.
   1499  * (Compression algorithms 2 and 32771)
   1500  */
   1501 
   1502 /*
   1503  * Decode the requested amount of RLE-encoded data.
   1504  */
   1505 static int
   1506 Fax3DecodeRLE(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
   1507 {
   1508 	DECLARE_STATE(tif, sp, "Fax3DecodeRLE");
   1509 	int mode = sp->b.mode;
   1510 	(void) s;
   1511 	if (occ % sp->b.rowbytes)
   1512 	{
   1513 		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
   1514 		return (-1);
   1515 	}
   1516 	CACHE_STATE(tif, sp);
   1517 	thisrun = sp->curruns;
   1518 	while (occ > 0) {
   1519 		a0 = 0;
   1520 		RunLength = 0;
   1521 		pa = thisrun;
   1522 #ifdef FAX3_DEBUG
   1523 		printf("\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail);
   1524 		printf("-------------------- %d\n", tif->tif_row);
   1525 		fflush(stdout);
   1526 #endif
   1527 		EXPAND1D(EOFRLE);
   1528 		(*sp->fill)(buf, thisrun, pa, lastx);
   1529 		/*
   1530 		 * Cleanup at the end of the row.
   1531 		 */
   1532 		if (mode & FAXMODE_BYTEALIGN) {
   1533 			int n = BitsAvail - (BitsAvail &~ 7);
   1534 			ClrBits(n);
   1535 		} else if (mode & FAXMODE_WORDALIGN) {
   1536 			int n = BitsAvail - (BitsAvail &~ 15);
   1537 			ClrBits(n);
   1538 			if (BitsAvail == 0 && !isAligned(cp, uint16))
   1539 			    cp++;
   1540 		}
   1541 		buf += sp->b.rowbytes;
   1542 		occ -= sp->b.rowbytes;
   1543 		sp->line++;
   1544 		continue;
   1545 	EOFRLE:				/* premature EOF */
   1546 		(*sp->fill)(buf, thisrun, pa, lastx);
   1547 		UNCACHE_STATE(tif, sp);
   1548 		return (-1);
   1549 	}
   1550 	UNCACHE_STATE(tif, sp);
   1551 	return (1);
   1552 }
   1553 
   1554 int
   1555 TIFFInitCCITTRLE(TIFF* tif, int scheme)
   1556 {
   1557 	(void) scheme;
   1558 	if (InitCCITTFax3(tif)) {		/* reuse G3 support */
   1559 		tif->tif_decoderow = Fax3DecodeRLE;
   1560 		tif->tif_decodestrip = Fax3DecodeRLE;
   1561 		tif->tif_decodetile = Fax3DecodeRLE;
   1562 		/*
   1563 		 * Suppress RTC+EOLs when encoding and byte-align data.
   1564 		 */
   1565 		return TIFFSetField(tif, TIFFTAG_FAXMODE,
   1566 		    FAXMODE_NORTC|FAXMODE_NOEOL|FAXMODE_BYTEALIGN);
   1567 	} else
   1568 		return (0);
   1569 }
   1570 
   1571 int
   1572 TIFFInitCCITTRLEW(TIFF* tif, int scheme)
   1573 {
   1574 	(void) scheme;
   1575 	if (InitCCITTFax3(tif)) {		/* reuse G3 support */
   1576 		tif->tif_decoderow = Fax3DecodeRLE;
   1577 		tif->tif_decodestrip = Fax3DecodeRLE;
   1578 		tif->tif_decodetile = Fax3DecodeRLE;
   1579 		/*
   1580 		 * Suppress RTC+EOLs when encoding and word-align data.
   1581 		 */
   1582 		return TIFFSetField(tif, TIFFTAG_FAXMODE,
   1583 		    FAXMODE_NORTC|FAXMODE_NOEOL|FAXMODE_WORDALIGN);
   1584 	} else
   1585 		return (0);
   1586 }
   1587 #endif /* CCITT_SUPPORT */
   1588 
   1589 /* vim: set ts=8 sts=8 sw=8 noet: */
   1590 /*
   1591  * Local Variables:
   1592  * mode: c
   1593  * c-basic-offset: 8
   1594  * fill-column: 78
   1595  * End:
   1596  */
   1597