text: /*
   * 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.
   */
  
  #include "tiffiop.h"
  #ifdef CCITT_SUPPORT
  /*
   * TIFF Library.
   *
   * CCITT Group 3 (T.4) and Group 4 (T.6) Compression Support.
   *
   * This file contains support for decoding and encoding TIFF
   * compression algorithms 2, 3, 4, and 32771.
   *
   * Decoder support is derived, with permission, from the code
   * in Frank Cringle's viewfax program;
   *      Copyright (C) 1990, 1995  Frank D. Cringle.
   */
  #include "tif_fax3.h"
  #define	G3CODES
  #include "t4.h"
  #include <stdio.h>
  
  /*
   * Compression+decompression state blocks are
   * derived from this ``base state'' block.
   */
  typedef struct {
  	int      rw_mode;                /* O_RDONLY for decode, else encode */
  	int      mode;                   /* operating mode */
  	tmsize_t rowbytes;               /* bytes in a decoded scanline */
  	uint32   rowpixels;              /* pixels in a scanline */
  
  	uint16   cleanfaxdata;           /* CleanFaxData tag */
  	uint32   badfaxrun;              /* BadFaxRun tag */
  	uint32   badfaxlines;            /* BadFaxLines tag */
  	uint32   groupoptions;           /* Group 3/4 options tag */
  
  	TIFFVGetMethod  vgetparent;      /* super-class method */
  	TIFFVSetMethod  vsetparent;      /* super-class method */
  	TIFFPrintMethod printdir;        /* super-class method */
  } Fax3BaseState;
  #define	Fax3State(tif)		((Fax3BaseState*) (tif)->tif_data)
  
  typedef enum { G3_1D, G3_2D } Ttag;
  typedef struct {
  	Fax3BaseState b;
  
  	/* Decoder state info */
  	const unsigned char* bitmap;	/* bit reversal table */
  	uint32	data;			/* current i/o byte/word */
  	int	bit;			/* current i/o bit in byte */
  	int	EOLcnt;			/* count of EOL codes recognized */
  	TIFFFaxFillFunc fill;		/* fill routine */
  	uint32*	runs;			/* b&w runs for current/previous row */
  	uint32	nruns;			/* size of the refruns / curruns arrays */
  	uint32*	refruns;		/* runs for reference line */
  	uint32*	curruns;		/* runs for current line */
  
  	/* Encoder state info */
  	Ttag    tag;			/* encoding state */
  	unsigned char*	refline;	/* reference line for 2d decoding */
  	int	k;			/* #rows left that can be 2d encoded */
  	int	maxk;			/* max #rows that can be 2d encoded */
  
  	int line;
  } Fax3CodecState;
  #define DecoderState(tif) ((Fax3CodecState*) Fax3State(tif))
  #define EncoderState(tif) ((Fax3CodecState*) Fax3State(tif))
  
  #define is2DEncoding(sp) (sp->b.groupoptions & GROUP3OPT_2DENCODING)
  #define isAligned(p,t) ((((size_t)(p)) & (sizeof (t)-1)) == 0)
  
  /*
   * Group 3 and Group 4 Decoding.
   */
  
  /*
   * These macros glue the TIFF library state to
   * the state expected by Frank's decoder.
   */
  #define	DECLARE_STATE(tif, sp, mod)					\
      static const char module[] = mod;					\
      Fax3CodecState* sp = DecoderState(tif);				\
      int a0;				/* reference element */		\
      int lastx = sp->b.rowpixels;	/* last element in row */	\
      uint32 BitAcc;			/* bit accumulator */		\
      int BitsAvail;			/* # valid bits in BitAcc */	\
      int RunLength;			/* length of current run */	\
      unsigned char* cp;			/* next byte of input data */	\
      unsigned char* ep;			/* end of input data */		\
      uint32* pa;				/* place to stuff next run */	\
      uint32* thisrun;			/* current row's run array */	\
      int EOLcnt;				/* # EOL codes recognized */	\
      const unsigned char* bitmap = sp->bitmap;	/* input data bit reverser */	\
      const TIFFFaxTabEnt* TabEnt
  #define	DECLARE_STATE_2D(tif, sp, mod)					\
      DECLARE_STATE(tif, sp, mod);					\
      int b1;				/* next change on prev line */	\
      uint32* pb				/* next run in reference line */\
  /*
   * Load any state that may be changed during decoding.
   */
  #define	CACHE_STATE(tif, sp) do {					\
      BitAcc = sp->data;							\
      BitsAvail = sp->bit;						\
      EOLcnt = sp->EOLcnt;						\
      cp = (unsigned char*) tif->tif_rawcp;				\
      ep = cp + tif->tif_rawcc;						\
  } while (0)
  /*
   * Save state possibly changed during decoding.
   */
  #define	UNCACHE_STATE(tif, sp) do {					\
      sp->bit = BitsAvail;						\
      sp->data = BitAcc;							\
      sp->EOLcnt = EOLcnt;						\
      tif->tif_rawcc -= (tmsize_t)((uint8*) cp - tif->tif_rawcp);		\
      tif->tif_rawcp = (uint8*) cp;					\
  } while (0)
  
  /*
   * Setup state for decoding a strip.
   */
  static int
  Fax3PreDecode(TIFF* tif, uint16 s)
  {
  	Fax3CodecState* sp = DecoderState(tif);
  
  	(void) s;
  	assert(sp != NULL);
  	sp->bit = 0;			/* force initial read */
  	sp->data = 0;
  	sp->EOLcnt = 0;			/* force initial scan for EOL */
  	/*
  	 * Decoder assumes lsb-to-msb bit order.  Note that we select
  	 * this here rather than in Fax3SetupState so that viewers can
  	 * hold the image open, fiddle with the FillOrder tag value,
  	 * and then re-decode the image.  Otherwise they'd need to close
  	 * and open the image to get the state reset.
  	 */
  	sp->bitmap =
  	    TIFFGetBitRevTable(tif->tif_dir.td_fillorder != FILLORDER_LSB2MSB);
  	sp->curruns = sp->runs;
  	if (sp->refruns) {		/* init reference line to white */
  		sp->refruns = sp->runs + sp->nruns;
  		sp->refruns[0] = (uint32) sp->b.rowpixels;
  		sp->refruns[1] = 0;
  	}
  	sp->line = 0;
  	return (1);
  }
  
  /*
   * Routine for handling various errors/conditions.
   * Note how they are "glued into the decoder" by
   * overriding the definitions used by the decoder.
   */
  
  static void
  Fax3Unexpected(const char* module, TIFF* tif, uint32 line, uint32 a0)
  {
  	TIFFErrorExt(tif->tif_clientdata, module, "Bad code word at line %u of %s %u (x %u)",
  	    line, isTiled(tif) ? "tile" : "strip",
  	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
  	    a0);
  }
  #define	unexpected(table, a0)	Fax3Unexpected(module, tif, sp->line, a0)
  
  static void
  Fax3Extension(const char* module, TIFF* tif, uint32 line, uint32 a0)
  {
  	TIFFErrorExt(tif->tif_clientdata, module,
  	    "Uncompressed data (not supported) at line %u of %s %u (x %u)",
  	    line, isTiled(tif) ? "tile" : "strip",
  	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
  	    a0);
  }
  #define	extension(a0)	Fax3Extension(module, tif, sp->line, a0)
  
  static void
  Fax3BadLength(const char* module, TIFF* tif, uint32 line, uint32 a0, uint32 lastx)
  {
  	TIFFWarningExt(tif->tif_clientdata, module, "%s at line %u of %s %u (got %u, expected %u)",
  	    a0 < lastx ? "Premature EOL" : "Line length mismatch",
  	    line, isTiled(tif) ? "tile" : "strip",
  	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
  	    a0, lastx);
  }
  #define	badlength(a0,lastx)	Fax3BadLength(module, tif, sp->line, a0, lastx)
  
  static void
  Fax3PrematureEOF(const char* module, TIFF* tif, uint32 line, uint32 a0)
  {
  	TIFFWarningExt(tif->tif_clientdata, module, "Premature EOF at line %u of %s %u (x %u)",
  	    line, isTiled(tif) ? "tile" : "strip",
  	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
  	    a0);
  }
  #define	prematureEOF(a0)	Fax3PrematureEOF(module, tif, sp->line, a0)
  
  #define	Nop
  
  /**
   * Decode the requested amount of G3 1D-encoded data.
   * @param buf destination buffer
   * @param occ available bytes in destination buffer
   * @param s number of planes (ignored)
   * @returns 1 for success, -1 in case of error
   */
  static int
  Fax3Decode1D(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
  {
  	DECLARE_STATE(tif, sp, "Fax3Decode1D");
  	(void) s;
  	if (occ % sp->b.rowbytes)
  	{
  		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
  		return (-1);
  	}
  	CACHE_STATE(tif, sp);
  	thisrun = sp->curruns;
  	while (occ > 0) {
  		a0 = 0;
  		RunLength = 0;
  		pa = thisrun;
  #ifdef FAX3_DEBUG
  		printf("\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail);
  		printf("-------------------- %d\n", tif->tif_row);
  		fflush(stdout);
  #endif
  		SYNC_EOL(EOF1D);
  		EXPAND1D(EOF1Da);
  		(*sp->fill)(buf, thisrun, pa, lastx);
  		buf += sp->b.rowbytes;
  		occ -= sp->b.rowbytes;
  		sp->line++;
  		continue;
  	EOF1D:				/* premature EOF */
  		CLEANUP_RUNS();
  	EOF1Da:				/* premature EOF */
  		(*sp->fill)(buf, thisrun, pa, lastx);
  		UNCACHE_STATE(tif, sp);
  		return (-1);
  	}
  	UNCACHE_STATE(tif, sp);
  	return (1);
  }
  
  #define	SWAP(t,a,b)	{ t x; x = (a); (a) = (b); (b) = x; }
  /*
   * Decode the requested amount of G3 2D-encoded data.
   */
  static int
  Fax3Decode2D(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
  {
  	DECLARE_STATE_2D(tif, sp, "Fax3Decode2D");
  	int is1D;			/* current line is 1d/2d-encoded */
  	(void) s;
  	if (occ % sp->b.rowbytes)
  	{
  		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
  		return (-1);
  	}
  	CACHE_STATE(tif, sp);
  	while (occ > 0) {
  		a0 = 0;
  		RunLength = 0;
  		pa = thisrun = sp->curruns;
  #ifdef FAX3_DEBUG
  		printf("\nBitAcc=%08X, BitsAvail = %d EOLcnt = %d",
  		    BitAcc, BitsAvail, EOLcnt);
  #endif
  		SYNC_EOL(EOF2D);
  		NeedBits8(1, EOF2D);
  		is1D = GetBits(1);	/* 1D/2D-encoding tag bit */
  		ClrBits(1);
  #ifdef FAX3_DEBUG
  		printf(" %s\n-------------------- %d\n",
  		    is1D ? "1D" : "2D", tif->tif_row);
  		fflush(stdout);
  #endif
  		pb = sp->refruns;
  		b1 = *pb++;
  		if (is1D)
  			EXPAND1D(EOF2Da);
  		else
  			EXPAND2D(EOF2Da);
  		(*sp->fill)(buf, thisrun, pa, lastx);
  		if (pa < thisrun + sp->nruns) {
  			SETVALUE(0);	/* imaginary change for reference */
  		}
  		SWAP(uint32*, sp->curruns, sp->refruns);
  		buf += sp->b.rowbytes;
  		occ -= sp->b.rowbytes;
  		sp->line++;
  		continue;
  	EOF2D:				/* premature EOF */
  		CLEANUP_RUNS();
  	EOF2Da:				/* premature EOF */
  		(*sp->fill)(buf, thisrun, pa, lastx);
  		UNCACHE_STATE(tif, sp);
  		return (-1);
  	}
  	UNCACHE_STATE(tif, sp);
  	return (1);
  }
  #undef SWAP
  
  /*
   * The ZERO & FILL macros must handle spans < 2*sizeof(long) bytes.
   * For machines with 64-bit longs this is <16 bytes; otherwise
   * this is <8 bytes.  We optimize the code here to reflect the
   * machine characteristics.
   */
  #if SIZEOF_UNSIGNED_LONG == 8
  # define FILL(n, cp)							    \
      switch (n) {							    \
      case 15:(cp)[14] = 0xff; /*-fallthrough*/ \
      case 14:(cp)[13] = 0xff; /*-fallthrough*/ \
      case 13:(cp)[12] = 0xff; /*-fallthrough*/ \
      case 12:(cp)[11] = 0xff; /*-fallthrough*/ \
      case 11:(cp)[10] = 0xff; /*-fallthrough*/ \
      case 10: (cp)[9] = 0xff; /*-fallthrough*/ \
      case  9: (cp)[8] = 0xff; /*-fallthrough*/ \
      case  8: (cp)[7] = 0xff; /*-fallthrough*/ \
      case  7: (cp)[6] = 0xff; /*-fallthrough*/ \
      case  6: (cp)[5] = 0xff; /*-fallthrough*/ \
      case  5: (cp)[4] = 0xff; /*-fallthrough*/ \
      case  4: (cp)[3] = 0xff; /*-fallthrough*/ \
      case  3: (cp)[2] = 0xff; /*-fallthrough*/ \
      case  2: (cp)[1] = 0xff; /*-fallthrough*/ \
      case  1: (cp)[0] = 0xff; (cp) += (n); /*-fallthrough*/ \
      case 0:  ;			      \
      }
  # define ZERO(n, cp)							\
      switch (n) {							\
      case 15:(cp)[14] = 0; /*-fallthrough*/ \
      case 14:(cp)[13] = 0; /*-fallthrough*/ \
      case 13:(cp)[12] = 0; /*-fallthrough*/ \
      case 12:(cp)[11] = 0; /*-fallthrough*/ \
      case 11:(cp)[10] = 0; /*-fallthrough*/ \
      case 10: (cp)[9] = 0; /*-fallthrough*/ \
      case  9: (cp)[8] = 0; /*-fallthrough*/ \
      case  8: (cp)[7] = 0; /*-fallthrough*/ \
      case  7: (cp)[6] = 0; /*-fallthrough*/ \
      case  6: (cp)[5] = 0; /*-fallthrough*/ \
      case  5: (cp)[4] = 0; /*-fallthrough*/ \
      case  4: (cp)[3] = 0; /*-fallthrough*/ \
      case  3: (cp)[2] = 0; /*-fallthrough*/ \
      case  2: (cp)[1] = 0; /*-fallthrough*/ \
      case  1: (cp)[0] = 0; (cp) += (n); /*-fallthrough*/ \
      case 0:  ;			\
      }
  #else
  # define FILL(n, cp)							    \
      switch (n) {							    \
      case 7: (cp)[6] = 0xff; /*-fallthrough*/ \
      case 6: (cp)[5] = 0xff; /*-fallthrough*/ \
      case 5: (cp)[4] = 0xff; /*-fallthrough*/ \
      case 4: (cp)[3] = 0xff; /*-fallthrough*/ \
      case 3: (cp)[2] = 0xff; /*-fallthrough*/ \
      case 2: (cp)[1] = 0xff; /*-fallthrough*/ \
      case 1: (cp)[0] = 0xff; (cp) += (n);  /*-fallthrough*/ \
      case 0:  ;			    \
      }
  # define ZERO(n, cp)							\
      switch (n) {							\
      case 7: (cp)[6] = 0; /*-fallthrough*/ \
      case 6: (cp)[5] = 0; /*-fallthrough*/ \
      case 5: (cp)[4] = 0; /*-fallthrough*/ \
      case 4: (cp)[3] = 0; /*-fallthrough*/ \
      case 3: (cp)[2] = 0; /*-fallthrough*/ \
      case 2: (cp)[1] = 0; /*-fallthrough*/ \
      case 1: (cp)[0] = 0; (cp) += (n); /*-fallthrough*/ \
      case 0:  ;			\
      }
  #endif
  
  /*
   * Bit-fill a row according to the white/black
   * runs generated during G3/G4 decoding.
   */
  void
  _TIFFFax3fillruns(unsigned char* buf, uint32* runs, uint32* erun, uint32 lastx)
  {
  	static const unsigned char _fillmasks[] =
  	    { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff };
  	unsigned char* cp;
  	uint32 x, bx, run;
  	int32 n, nw;
  	long* lp;
  
  	if ((erun-runs)&1)
  	    *erun++ = 0;
  	x = 0;
  	for (; runs < erun; runs += 2) {
  	    run = runs[0];
  	    if (x+run > lastx || run > lastx )
  		run = runs[0] = (uint32) (lastx - x);
  	    if (run) {
  		cp = buf + (x>>3);
  		bx = x&7;
  		if (run > 8-bx) {
  		    if (bx) {			/* align to byte boundary */
  			*cp++ &= 0xff << (8-bx);
  			run -= 8-bx;
  		    }
  		    if( (n = run >> 3) != 0 ) {	/* multiple bytes to fill */
  			if ((n/sizeof (long)) > 1) {
  			    /*
  			     * Align to longword boundary and fill.
  			     */
  			    for (; n && !isAligned(cp, long); n--)
  				    *cp++ = 0x00;
  			    lp = (long*) cp;
  			    nw = (int32)(n / sizeof (long));
  			    n -= nw * sizeof (long);
  			    do {
  				    *lp++ = 0L;
  			    } while (--nw);
  			    cp = (unsigned char*) lp;
  			}
  			ZERO(n, cp);
  			run &= 7;
  		    }
  		    if (run)
  			cp[0] &= 0xff >> run;
  		} else
  		    cp[0] &= ~(_fillmasks[run]>>bx);
  		x += runs[0];
  	    }
  	    run = runs[1];
  	    if (x+run > lastx || run > lastx )
  		run = runs[1] = lastx - x;
  	    if (run) {
  		cp = buf + (x>>3);
  		bx = x&7;
  		if (run > 8-bx) {
  		    if (bx) {			/* align to byte boundary */
  			*cp++ |= 0xff >> bx;
  			run -= 8-bx;
  		    }
  		    if( (n = run>>3) != 0 ) {	/* multiple bytes to fill */
  			if ((n/sizeof (long)) > 1) {
  			    /*
  			     * Align to longword boundary and fill.
  			     */
  			    for (; n && !isAligned(cp, long); n--)
  				*cp++ = 0xff;
  			    lp = (long*) cp;
  			    nw = (int32)(n / sizeof (long));
  			    n -= nw * sizeof (long);
  			    do {
  				*lp++ = -1L;
  			    } while (--nw);
  			    cp = (unsigned char*) lp;
  			}
  			FILL(n, cp);
  			run &= 7;
  		    }
                      /* Explicit 0xff masking to make icc -check=conversions happy */
  		    if (run)
  			cp[0] = (unsigned char)((cp[0] | (0xff00 >> run))&0xff);
  		} else
  		    cp[0] |= _fillmasks[run]>>bx;
  		x += runs[1];
  	    }
  	}
  	assert(x == lastx);
  }
  #undef	ZERO
  #undef	FILL
  
  static int
  Fax3FixupTags(TIFF* tif)
  {
  	(void) tif;
  	return (1);
  }
  
  /*
   * Setup G3/G4-related compression/decompression state
   * before data is processed.  This routine is called once
   * per image -- it sets up different state based on whether
   * or not decoding or encoding is being done and whether
   * 1D- or 2D-encoded data is involved.
   */
  static int
  Fax3SetupState(TIFF* tif)
  {
  	static const char module[] = "Fax3SetupState";
  	TIFFDirectory* td = &tif->tif_dir;
  	Fax3BaseState* sp = Fax3State(tif);
  	int needsRefLine;
  	Fax3CodecState* dsp = (Fax3CodecState*) Fax3State(tif);
  	tmsize_t rowbytes;
  	uint32 rowpixels;
  
  	if (td->td_bitspersample != 1) {
  		TIFFErrorExt(tif->tif_clientdata, module,
  		    "Bits/sample must be 1 for Group 3/4 encoding/decoding");
  		return (0);
  	}
  	/*
  	 * Calculate the scanline/tile widths.
  	 */
  	if (isTiled(tif)) {
  		rowbytes = TIFFTileRowSize(tif);
  		rowpixels = td->td_tilewidth;
  	} else {
  		rowbytes = TIFFScanlineSize(tif);
  		rowpixels = td->td_imagewidth;
  	}
  	if ((uint64)rowbytes < ((uint64)rowpixels + 7) / 8)
  	{
  		TIFFErrorExt(tif->tif_clientdata, module,
  			"Inconsistent number of bytes per row : rowbytes=%lu rowpixels=%lu",
  			(unsigned long)(rowbytes), (unsigned long)(rowpixels));
  		return (0);
  	}
  	sp->rowbytes = rowbytes;
  	sp->rowpixels = rowpixels;
  	/*
  	 * Allocate any additional space required for decoding/encoding.
  	 */
  	needsRefLine = (
  	    (sp->groupoptions & GROUP3OPT_2DENCODING) ||
  	    td->td_compression == COMPRESSION_CCITTFAX4
  	);
  
  	/*
  	  Assure that allocation computations do not overflow.
  	  
  	  TIFFroundup and TIFFSafeMultiply return zero on integer overflow
  	*/
  	dsp->runs=(uint32*) NULL;
  	dsp->nruns = TIFFroundup_32(rowpixels,32);
  	if (needsRefLine) {
  		dsp->nruns = TIFFSafeMultiply(uint32,dsp->nruns,2);
  	}
  	if ((dsp->nruns == 0) || (TIFFSafeMultiply(uint32,dsp->nruns,2) == 0)) {
  		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
  			     "Row pixels integer overflow (rowpixels %u)",
  			     rowpixels);
  		return (0);
  	}
  	dsp->runs = (uint32*) _TIFFCheckMalloc(tif,
  					       TIFFSafeMultiply(uint32,dsp->nruns,2),
  					       sizeof (uint32),
  					       "for Group 3/4 run arrays");
  	if (dsp->runs == NULL)
  		return (0);
  	memset( dsp->runs, 0, TIFFSafeMultiply(uint32,dsp->nruns,2)*sizeof(uint32));
  	dsp->curruns = dsp->runs;
  	if (needsRefLine)
  		dsp->refruns = dsp->runs + dsp->nruns;
  	else
  		dsp->refruns = NULL;
  	if (td->td_compression == COMPRESSION_CCITTFAX3
  	    && is2DEncoding(dsp)) {	/* NB: default is 1D routine */
  		tif->tif_decoderow = Fax3Decode2D;
  		tif->tif_decodestrip = Fax3Decode2D;
  		tif->tif_decodetile = Fax3Decode2D;
  	}
  
  	if (needsRefLine) {		/* 2d encoding */
  		Fax3CodecState* esp = EncoderState(tif);
  		/*
  		 * 2d encoding requires a scanline
  		 * buffer for the ``reference line''; the
  		 * scanline against which delta encoding
  		 * is referenced.  The reference line must
  		 * be initialized to be ``white'' (done elsewhere).
  		 */
  		esp->refline = (unsigned char*) _TIFFmalloc(rowbytes);
  		if (esp->refline == NULL) {
  			TIFFErrorExt(tif->tif_clientdata, module,
  			    "No space for Group 3/4 reference line");
  			return (0);
  		}
  	} else					/* 1d encoding */
  		EncoderState(tif)->refline = NULL;
  
  	return (1);
  }
  
  /*
   * CCITT Group 3 FAX Encoding.
   */
  
  #define	Fax3FlushBits(tif, sp) {				\
  	if ((tif)->tif_rawcc >= (tif)->tif_rawdatasize)		\
  		(void) TIFFFlushData1(tif);			\
  	*(tif)->tif_rawcp++ = (uint8) (sp)->data;		\
  	(tif)->tif_rawcc++;					\
  	(sp)->data = 0, (sp)->bit = 8;				\
  }
  #define	_FlushBits(tif) {					\
  	if ((tif)->tif_rawcc >= (tif)->tif_rawdatasize)		\
  		(void) TIFFFlushData1(tif);			\
  	*(tif)->tif_rawcp++ = (uint8) data;		\
  	(tif)->tif_rawcc++;					\
  	data = 0, bit = 8;					\
  }
  static const int _msbmask[9] =
      { 0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff };
  #define	_PutBits(tif, bits, length) {				\
  	while (length > bit) {					\
  		data |= bits >> (length - bit);			\
  		length -= bit;					\
  		_FlushBits(tif);				\
  	}							\
          assert( length < 9 );                                   \
  	data |= (bits & _msbmask[length]) << (bit - length);	\
  	bit -= length;						\
  	if (bit == 0)						\
  		_FlushBits(tif);				\
  }
  	
  /*
   * Write a variable-length bit-value to
   * the output stream.  Values are
   * assumed to be at most 16 bits.
   */
  static void
  Fax3PutBits(TIFF* tif, unsigned int bits, unsigned int length)
  {
  	Fax3CodecState* sp = EncoderState(tif);
  	unsigned int bit = sp->bit;
  	int data = sp->data;
  
  	_PutBits(tif, bits, length);
  
  	sp->data = data;
  	sp->bit = bit;
  }
  
  /*
   * Write a code to the output stream.
   */
  #define putcode(tif, te)	Fax3PutBits(tif, (te)->code, (te)->length)
  
  #ifdef FAX3_DEBUG
  #define	DEBUG_COLOR(w) (tab == TIFFFaxWhiteCodes ? w "W" : w "B")
  #define	DEBUG_PRINT(what,len) {						\
      int t;								\
      printf("%08X/%-2d: %s%5d\t", data, bit, DEBUG_COLOR(what), len);	\
      for (t = length-1; t >= 0; t--)					\
  	putchar(code & (1<<t) ? '1' : '0');				\
      putchar('\n');							\
  }
  #endif
  
  /*
   * 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.
   */
  static void
  putspan(TIFF* tif, int32 span, const tableentry* tab)
  {
  	Fax3CodecState* sp = EncoderState(tif);
  	unsigned int bit = sp->bit;
  	int data = sp->data;
  	unsigned int code, length;
  
  	while (span >= 2624) {
  		const tableentry* te = &tab[63 + (2560>>6)];
  		code = te->code;
  		length = te->length;
  #ifdef FAX3_DEBUG
  		DEBUG_PRINT("MakeUp", te->runlen);
  #endif
  		_PutBits(tif, code, length);
  		span -= te->runlen;
  	}
  	if (span >= 64) {
  		const tableentry* te = &tab[63 + (span>>6)];
  		assert(te->runlen == 64*(span>>6));
  		code = te->code;
  		length = te->length;
  #ifdef FAX3_DEBUG
  		DEBUG_PRINT("MakeUp", te->runlen);
  #endif
  		_PutBits(tif, code, length);
  		span -= te->runlen;
  	}
  	code = tab[span].code;
  	length = tab[span].length;
  #ifdef FAX3_DEBUG
  	DEBUG_PRINT("  Term", tab[span].runlen);
  #endif
  	_PutBits(tif, code, length);
  
  	sp->data = data;
  	sp->bit = bit;
  }
  
  /*
   * Write an EOL code to the output stream.  The zero-fill
   * logic for byte-aligning encoded scanlines is handled
   * here.  We also handle writing the tag bit for the next
   * scanline when doing 2d encoding.
   */
  static void
  Fax3PutEOL(TIFF* tif)
  {
  	Fax3CodecState* sp = EncoderState(tif);
  	unsigned int bit = sp->bit;
  	int data = sp->data;
  	unsigned int code, length, tparm;
  
  	if (sp->b.groupoptions & GROUP3OPT_FILLBITS) {
  		/*
  		 * Force bit alignment so EOL will terminate on
  		 * a byte boundary.  That is, force the bit alignment
  		 * to 16-12 = 4 before putting out the EOL code.
  		 */
  		int align = 8 - 4;
  		if (align != sp->bit) {
  			if (align > sp->bit)
  				align = sp->bit + (8 - align);
  			else
  				align = sp->bit - align;
  			tparm=align; 
  			_PutBits(tif, 0, tparm);
  		}
  	}
  	code = EOL;
  	length = 12;
  	if (is2DEncoding(sp)) {
  		code = (code<<1) | (sp->tag == G3_1D);
  		length++;
  	}
  	_PutBits(tif, code, length);
  
  	sp->data = data;
  	sp->bit = bit;
  }
  
  /*
   * Reset encoding state at the start of a strip.
   */
  static int
  Fax3PreEncode(TIFF* tif, uint16 s)
  {
  	Fax3CodecState* sp = EncoderState(tif);
  
  	(void) s;
  	assert(sp != NULL);
  	sp->bit = 8;
  	sp->data = 0;
  	sp->tag = G3_1D;
  	/*
  	 * This is necessary for Group 4; otherwise it isn't
  	 * needed because the first scanline of each strip ends
  	 * up being copied into the refline.
  	 */
  	if (sp->refline)
  		_TIFFmemset(sp->refline, 0x00, sp->b.rowbytes);
  	if (is2DEncoding(sp)) {
  		float res = tif->tif_dir.td_yresolution;
  		/*
  		 * The CCITT spec says that when doing 2d encoding, you
  		 * should only do it on K consecutive scanlines, where K
  		 * depends on the resolution of the image being encoded
  		 * (2 for <= 200 lpi, 4 for > 200 lpi).  Since the directory
  		 * code initializes td_yresolution to 0, this code will
  		 * select a K of 2 unless the YResolution tag is set
  		 * appropriately.  (Note also that we fudge a little here
  		 * and use 150 lpi to avoid problems with units conversion.)
  		 */
  		if (tif->tif_dir.td_resolutionunit == RESUNIT_CENTIMETER)
  			res *= 2.54f;		/* convert to inches */
  		sp->maxk = (res > 150 ? 4 : 2);
  		sp->k = sp->maxk-1;
  	} else
  		sp->k = sp->maxk = 0;
  	sp->line = 0;
  	return (1);
  }
  
  static const unsigned char 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 */
  };
  static const unsigned char 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 */
  };
  
  /*
   * On certain systems it pays to inline
   * the routines that find pixel spans.
   */
  #ifdef VAXC
  static	int32 find0span(unsigned char*, int32, int32);
  static	int32 find1span(unsigned char*, int32, int32);
  #pragma inline(find0span,find1span)
  #endif
  
  /*
   * 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.
   */
  inline static int32
  find0span(unsigned char* bp, int32 bs, int32 be)
  {
  	int32 bits = be - bs;
  	int32 n, span;
  
  	bp += bs>>3;
  	/*
  	 * Check partial byte on lhs.
  	 */
  	if (bits > 0 && (n = (bs & 7)) != 0) {
  		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 (bits >= (int32)(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 ((bits >= (int32)(8 * sizeof(long))) && (0 == *lp)) {
  			span += 8*sizeof (long);
  			bits -= 8*sizeof (long);
  			lp++;
  		}
  		bp = (unsigned 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);
  }
  
  inline static int32
  find1span(unsigned char* bp, int32 bs, int32 be)
  {
  	int32 bits = be - bs;
  	int32 n, span;
  
  	bp += bs>>3;
  	/*
  	 * Check partial byte on lhs.
  	 */
  	if (bits > 0 && (n = (bs & 7)) != 0) {
  		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 (bits >= (int32)(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 ((bits >= (int32)(8 * sizeof(long))) && (~0 == *lp)) {
  			span += 8*sizeof (long);
  			bits -= 8*sizeof (long);
  			lp++;
  		}
  		bp = (unsigned 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);
  }
  
  /*
   * 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)
  
  /*
   * 1d-encode a row of pixels.  The encoding is
   * a sequence of all-white or all-black spans
   * of pixels encoded with Huffman codes.
   */
  static int
  Fax3Encode1DRow(TIFF* tif, unsigned char* bp, uint32 bits)
  {
  	Fax3CodecState* sp = EncoderState(tif);
  	int32 span;
          uint32 bs = 0;
  
  	for (;;) {
  		span = find0span(bp, bs, bits);		/* white span */
  		putspan(tif, span, TIFFFaxWhiteCodes);
  		bs += span;
  		if (bs >= bits)
  			break;
  		span = find1span(bp, bs, bits);		/* black span */
  		putspan(tif, span, TIFFFaxBlackCodes);
  		bs += span;
  		if (bs >= bits)
  			break;
  	}
  	if (sp->b.mode & (FAXMODE_BYTEALIGN|FAXMODE_WORDALIGN)) {
  		if (sp->bit != 8)			/* byte-align */
  			Fax3FlushBits(tif, sp);
  		if ((sp->b.mode&FAXMODE_WORDALIGN) &&
  		    !isAligned(tif->tif_rawcp, uint16))
  			Fax3FlushBits(tif, sp);
  	}
  	return (1);
  }
  
  static const tableentry horizcode =
      { 3, 0x1, 0 };	/* 001 */
  static const tableentry passcode =
      { 4, 0x1, 0 };	/* 0001 */
  static const tableentry vcodes[7] = {
      { 7, 0x03, 0 },	/* 0000 011 */
      { 6, 0x03, 0 },	/* 0000 11 */
      { 3, 0x03, 0 },	/* 011 */
      { 1, 0x1, 0 },	/* 1 */
      { 3, 0x2, 0 },	/* 010 */
      { 6, 0x02, 0 },	/* 0000 10 */
      { 7, 0x02, 0 }	/* 0000 010 */
  };
  
  /*
   * 2d-encode a row of pixels.  Consult the CCITT
   * documentation for the algorithm.
   */
  static int
  Fax3Encode2DRow(TIFF* tif, unsigned char* bp, unsigned char* rp, uint32 bits)
  {
  #define	PIXEL(buf,ix)	((((buf)[(ix)>>3]) >> (7-((ix)&7))) & 1)
          uint32 a0 = 0;
  	uint32 a1 = (PIXEL(bp, 0) != 0 ? 0 : finddiff(bp, 0, bits, 0));
  	uint32 b1 = (PIXEL(rp, 0) != 0 ? 0 : finddiff(rp, 0, bits, 0));
  	uint32 a2, b2;
  
  	for (;;) {
  		b2 = finddiff2(rp, b1, bits, PIXEL(rp,b1));
  		if (b2 >= a1) {
  			/* Naive computation triggers -fsanitize=undefined,unsigned-integer-overflow */
  			/* although it is correct unless the difference between both is < 31 bit */
  			/* int32 d = b1 - a1; */
  			int32 d = (b1 >= a1 && b1 - a1 <= 3U) ? (int32)(b1 - a1):
  			          (b1 < a1 && a1 - b1 <= 3U) ? -(int32)(a1 - b1) : 0x7FFFFFFF;
  			if (!(-3 <= d && d <= 3)) {	/* horizontal mode */
  				a2 = finddiff2(bp, a1, bits, PIXEL(bp,a1));
  				putcode(tif, &horizcode);
  				if (a0+a1 == 0 || PIXEL(bp, a0) == 0) {
  					putspan(tif, a1-a0, TIFFFaxWhiteCodes);
  					putspan(tif, a2-a1, TIFFFaxBlackCodes);
  				} else {
  					putspan(tif, a1-a0, TIFFFaxBlackCodes);
  					putspan(tif, a2-a1, TIFFFaxWhiteCodes);
  				}
  				a0 = a2;
  			} else {			/* vertical mode */
  				putcode(tif, &vcodes[d+3]);
  				a0 = a1;
  			}
  		} else {				/* pass mode */
  			putcode(tif, &passcode);
  			a0 = b2;
  		}
  		if (a0 >= bits)
  			break;
  		a1 = finddiff(bp, a0, bits, PIXEL(bp,a0));
  		b1 = finddiff(rp, a0, bits, !PIXEL(bp,a0));
  		b1 = finddiff(rp, b1, bits, PIXEL(bp,a0));
  	}
  	return (1);
  #undef PIXEL
  }
  
  /*
   * Encode a buffer of pixels.
   */
  static int
  Fax3Encode(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s)
  {
  	static const char module[] = "Fax3Encode";
  	Fax3CodecState* sp = EncoderState(tif);
  	(void) s;
  	if (cc % sp->b.rowbytes)
  	{
  		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be written");
  		return (0);
  	}
  	while (cc > 0) {
  		if ((sp->b.mode & FAXMODE_NOEOL) == 0)
  			Fax3PutEOL(tif);
  		if (is2DEncoding(sp)) {
  			if (sp->tag == G3_1D) {
  				if (!Fax3Encode1DRow(tif, bp, sp->b.rowpixels))
  					return (0);
  				sp->tag = G3_2D;
  			} else {
  				if (!Fax3Encode2DRow(tif, bp, sp->refline,
  				    sp->b.rowpixels))
  					return (0);
  				sp->k--;
  			}
  			if (sp->k == 0) {
  				sp->tag = G3_1D;
  				sp->k = sp->maxk-1;
  			} else
  				_TIFFmemcpy(sp->refline, bp, sp->b.rowbytes);
  		} else {
  			if (!Fax3Encode1DRow(tif, bp, sp->b.rowpixels))
  				return (0);
  		}
  		bp += sp->b.rowbytes;
  		cc -= sp->b.rowbytes;
  	}
  	return (1);
  }
  
  static int
  Fax3PostEncode(TIFF* tif)
  {
  	Fax3CodecState* sp = EncoderState(tif);
  
  	if (sp->bit != 8)
  		Fax3FlushBits(tif, sp);
  	return (1);
  }
  
  static void
  Fax3Close(TIFF* tif)
  {
  	if ((Fax3State(tif)->mode & FAXMODE_NORTC) == 0 && tif->tif_rawcp) {
  		Fax3CodecState* sp = EncoderState(tif);
  		unsigned int code = EOL;
  		unsigned int length = 12;
  		int i;
  
  		if (is2DEncoding(sp)) {
  			code = (code<<1) | (sp->tag == G3_1D);
  			length++;
  		}
  		for (i = 0; i < 6; i++)
  			Fax3PutBits(tif, code, length);
  		Fax3FlushBits(tif, sp);
  	}
  }
  
  static void
  Fax3Cleanup(TIFF* tif)
  {
  	Fax3CodecState* sp = DecoderState(tif);
  	
  	assert(sp != 0);
  
  	tif->tif_tagmethods.vgetfield = sp->b.vgetparent;
  	tif->tif_tagmethods.vsetfield = sp->b.vsetparent;
  	tif->tif_tagmethods.printdir = sp->b.printdir;
  
  	if (sp->runs)
  		_TIFFfree(sp->runs);
  	if (sp->refline)
  		_TIFFfree(sp->refline);
  
  	_TIFFfree(tif->tif_data);
  	tif->tif_data = NULL;
  
  	_TIFFSetDefaultCompressionState(tif);
  }
  
  #define	FIELD_BADFAXLINES	(FIELD_CODEC+0)
  #define	FIELD_CLEANFAXDATA	(FIELD_CODEC+1)
  #define	FIELD_BADFAXRUN		(FIELD_CODEC+2)
  
  #define	FIELD_OPTIONS		(FIELD_CODEC+7)
  
  static const TIFFField faxFields[] = {
      { TIFFTAG_FAXMODE, 0, 0, TIFF_ANY, 0, TIFF_SETGET_INT, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, FALSE, FALSE, "FaxMode", NULL },
      { TIFFTAG_FAXFILLFUNC, 0, 0, TIFF_ANY, 0, TIFF_SETGET_OTHER, TIFF_SETGET_UNDEFINED, FIELD_PSEUDO, FALSE, FALSE, "FaxFillFunc", NULL },
      { TIFFTAG_BADFAXLINES, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_BADFAXLINES, TRUE, FALSE, "BadFaxLines", NULL },
      { TIFFTAG_CLEANFAXDATA, 1, 1, TIFF_SHORT, 0, TIFF_SETGET_UINT16, TIFF_SETGET_UINT16, FIELD_CLEANFAXDATA, TRUE, FALSE, "CleanFaxData", NULL },
      { TIFFTAG_CONSECUTIVEBADFAXLINES, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_BADFAXRUN, TRUE, FALSE, "ConsecutiveBadFaxLines", NULL }};
  static const TIFFField fax3Fields[] = {
      { TIFFTAG_GROUP3OPTIONS, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_OPTIONS, FALSE, FALSE, "Group3Options", NULL },
  };
  static const TIFFField fax4Fields[] = {
      { TIFFTAG_GROUP4OPTIONS, 1, 1, TIFF_LONG, 0, TIFF_SETGET_UINT32, TIFF_SETGET_UINT32, FIELD_OPTIONS, FALSE, FALSE, "Group4Options", NULL },
  };
  
  static int
  Fax3VSetField(TIFF* tif, uint32 tag, va_list ap)
  {
  	Fax3BaseState* sp = Fax3State(tif);
  	const TIFFField* fip;
  
  	assert(sp != 0);
  	assert(sp->vsetparent != 0);
  
  	switch (tag) {
  	case TIFFTAG_FAXMODE:
  		sp->mode = (int) va_arg(ap, int);
  		return 1;			/* NB: pseudo tag */
  	case TIFFTAG_FAXFILLFUNC:
  		DecoderState(tif)->fill = va_arg(ap, TIFFFaxFillFunc);
  		return 1;			/* NB: pseudo tag */
  	case TIFFTAG_GROUP3OPTIONS:
  		/* XXX: avoid reading options if compression mismatches. */
  		if (tif->tif_dir.td_compression == COMPRESSION_CCITTFAX3)
  			sp->groupoptions = (uint32) va_arg(ap, uint32);
  		break;
  	case TIFFTAG_GROUP4OPTIONS:
  		/* XXX: avoid reading options if compression mismatches. */
  		if (tif->tif_dir.td_compression == COMPRESSION_CCITTFAX4)
  			sp->groupoptions = (uint32) va_arg(ap, uint32);
  		break;
  	case TIFFTAG_BADFAXLINES:
  		sp->badfaxlines = (uint32) va_arg(ap, uint32);
  		break;
  	case TIFFTAG_CLEANFAXDATA:
  		sp->cleanfaxdata = (uint16) va_arg(ap, uint16_vap);
  		break;
  	case TIFFTAG_CONSECUTIVEBADFAXLINES:
  		sp->badfaxrun = (uint32) va_arg(ap, uint32);
  		break;
  	default:
  		return (*sp->vsetparent)(tif, tag, ap);
  	}
  	
  	if ((fip = TIFFFieldWithTag(tif, tag)) != NULL)
  		TIFFSetFieldBit(tif, fip->field_bit);
  	else
  		return 0;
  
  	tif->tif_flags |= TIFF_DIRTYDIRECT;
  	return 1;
  }
  
  static int
  Fax3VGetField(TIFF* tif, uint32 tag, va_list ap)
  {
  	Fax3BaseState* sp = Fax3State(tif);
  
  	assert(sp != 0);
  
  	switch (tag) {
  	case TIFFTAG_FAXMODE:
  		*va_arg(ap, int*) = sp->mode;
  		break;
  	case TIFFTAG_FAXFILLFUNC:
  		*va_arg(ap, TIFFFaxFillFunc*) = DecoderState(tif)->fill;
  		break;
  	case TIFFTAG_GROUP3OPTIONS:
  	case TIFFTAG_GROUP4OPTIONS:
  		*va_arg(ap, uint32*) = sp->groupoptions;
  		break;
  	case TIFFTAG_BADFAXLINES:
  		*va_arg(ap, uint32*) = sp->badfaxlines;
  		break;
  	case TIFFTAG_CLEANFAXDATA:
  		*va_arg(ap, uint16*) = sp->cleanfaxdata;
  		break;
  	case TIFFTAG_CONSECUTIVEBADFAXLINES:
  		*va_arg(ap, uint32*) = sp->badfaxrun;
  		break;
  	default:
  		return (*sp->vgetparent)(tif, tag, ap);
  	}
  	return (1);
  }
  
  static void
  Fax3PrintDir(TIFF* tif, FILE* fd, long flags)
  {
  	Fax3BaseState* sp = Fax3State(tif);
  
  	assert(sp != 0);
  
  	(void) flags;
  	if (TIFFFieldSet(tif,FIELD_OPTIONS)) {
  		const char* sep = " ";
  		if (tif->tif_dir.td_compression == COMPRESSION_CCITTFAX4) {
  			fprintf(fd, "  Group 4 Options:");
  			if (sp->groupoptions & GROUP4OPT_UNCOMPRESSED)
  				fprintf(fd, "%suncompressed data", sep);
  		} else {
  
  			fprintf(fd, "  Group 3 Options:");
  			if (sp->groupoptions & GROUP3OPT_2DENCODING) {
  				fprintf(fd, "%s2-d encoding", sep);
  				sep = "+";
  			}
  			if (sp->groupoptions & GROUP3OPT_FILLBITS) {
  				fprintf(fd, "%sEOL padding", sep);
  				sep = "+";
  			}
  			if (sp->groupoptions & GROUP3OPT_UNCOMPRESSED)
  				fprintf(fd, "%suncompressed data", sep);
  		}
  		fprintf(fd, " (%lu = 0x%lx)\n",
                          (unsigned long) sp->groupoptions,
                          (unsigned long) sp->groupoptions);
  	}
  	if (TIFFFieldSet(tif,FIELD_CLEANFAXDATA)) {
  		fprintf(fd, "  Fax Data:");
  		switch (sp->cleanfaxdata) {
  		case CLEANFAXDATA_CLEAN:
  			fprintf(fd, " clean");
  			break;
  		case CLEANFAXDATA_REGENERATED:
  			fprintf(fd, " receiver regenerated");
  			break;
  		case CLEANFAXDATA_UNCLEAN:
  			fprintf(fd, " uncorrected errors");
  			break;
  		}
  		fprintf(fd, " (%u = 0x%x)\n",
  		    sp->cleanfaxdata, sp->cleanfaxdata);
  	}
  	if (TIFFFieldSet(tif,FIELD_BADFAXLINES))
  		fprintf(fd, "  Bad Fax Lines: %lu\n",
                          (unsigned long) sp->badfaxlines);
  	if (TIFFFieldSet(tif,FIELD_BADFAXRUN))
  		fprintf(fd, "  Consecutive Bad Fax Lines: %lu\n",
  		    (unsigned long) sp->badfaxrun);
  	if (sp->printdir)
  		(*sp->printdir)(tif, fd, flags);
  }
  
  static int
  InitCCITTFax3(TIFF* tif)
  {
  	static const char module[] = "InitCCITTFax3";
  	Fax3BaseState* sp;
  
  	/*
  	 * Merge codec-specific tag information.
  	 */
  	if (!_TIFFMergeFields(tif, faxFields, TIFFArrayCount(faxFields))) {
  		TIFFErrorExt(tif->tif_clientdata, "InitCCITTFax3",
  			"Merging common CCITT Fax codec-specific tags failed");
  		return 0;
  	}
  
  	/*
  	 * Allocate state block so tag methods have storage to record values.
  	 */
  	tif->tif_data = (uint8*)
  		_TIFFmalloc(sizeof (Fax3CodecState));
  
  	if (tif->tif_data == NULL) {
  		TIFFErrorExt(tif->tif_clientdata, module,
  		    "No space for state block");
  		return (0);
  	}
  	_TIFFmemset(tif->tif_data, 0, sizeof (Fax3CodecState));
  
  	sp = Fax3State(tif);
          sp->rw_mode = tif->tif_mode;
  
  	/*
  	 * Override parent get/set field methods.
  	 */
  	sp->vgetparent = tif->tif_tagmethods.vgetfield;
  	tif->tif_tagmethods.vgetfield = Fax3VGetField; /* hook for codec tags */
  	sp->vsetparent = tif->tif_tagmethods.vsetfield;
  	tif->tif_tagmethods.vsetfield = Fax3VSetField; /* hook for codec tags */
  	sp->printdir = tif->tif_tagmethods.printdir;
  	tif->tif_tagmethods.printdir = Fax3PrintDir;   /* hook for codec tags */
  	sp->groupoptions = 0;	
  
  	if (sp->rw_mode == O_RDONLY) /* FIXME: improve for in place update */
  		tif->tif_flags |= TIFF_NOBITREV; /* decoder does bit reversal */
  	DecoderState(tif)->runs = NULL;
  	TIFFSetField(tif, TIFFTAG_FAXFILLFUNC, _TIFFFax3fillruns);
  	EncoderState(tif)->refline = NULL;
  
  	/*
  	 * Install codec methods.
  	 */
  	tif->tif_fixuptags = Fax3FixupTags;
  	tif->tif_setupdecode = Fax3SetupState;
  	tif->tif_predecode = Fax3PreDecode;
  	tif->tif_decoderow = Fax3Decode1D;
  	tif->tif_decodestrip = Fax3Decode1D;
  	tif->tif_decodetile = Fax3Decode1D;
  	tif->tif_setupencode = Fax3SetupState;
  	tif->tif_preencode = Fax3PreEncode;
  	tif->tif_postencode = Fax3PostEncode;
  	tif->tif_encoderow = Fax3Encode;
  	tif->tif_encodestrip = Fax3Encode;
  	tif->tif_encodetile = Fax3Encode;
  	tif->tif_close = Fax3Close;
  	tif->tif_cleanup = Fax3Cleanup;
  
  	return (1);
  }
  
  int
  TIFFInitCCITTFax3(TIFF* tif, int scheme)
  {
  	(void) scheme;
  	if (InitCCITTFax3(tif)) {
  		/*
  		 * Merge codec-specific tag information.
  		 */
  		if (!_TIFFMergeFields(tif, fax3Fields,
  				      TIFFArrayCount(fax3Fields))) {
  			TIFFErrorExt(tif->tif_clientdata, "TIFFInitCCITTFax3",
  			"Merging CCITT Fax 3 codec-specific tags failed");
  			return 0;
  		}
  
  		/*
  		 * The default format is Class/F-style w/o RTC.
  		 */
  		return TIFFSetField(tif, TIFFTAG_FAXMODE, FAXMODE_CLASSF);
  	} else
  		return 01;
  }
  
  /*
   * CCITT Group 4 (T.6) Facsimile-compatible
   * Compression Scheme Support.
   */
  
  #define SWAP(t,a,b) { t x; x = (a); (a) = (b); (b) = x; }
  /*
   * Decode the requested amount of G4-encoded data.
   */
  static int
  Fax4Decode(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
  {
  	DECLARE_STATE_2D(tif, sp, "Fax4Decode");
  	(void) s;
  	if (occ % sp->b.rowbytes)
  	{
  		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
  		return (-1);
  	}
  	CACHE_STATE(tif, sp);
  	while (occ > 0) {
  		a0 = 0;
  		RunLength = 0;
  		pa = thisrun = sp->curruns;
  		pb = sp->refruns;
  		b1 = *pb++;
  #ifdef FAX3_DEBUG
  		printf("\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail);
  		printf("-------------------- %d\n", tif->tif_row);
  		fflush(stdout);
  #endif
  		EXPAND2D(EOFG4);
                  if (EOLcnt)
                      goto EOFG4;
  		if (((lastx + 7) >> 3) > (int)occ)	/* check for buffer overrun */
  		{
  			TIFFErrorExt(tif->tif_clientdata, module,
  			             "Buffer overrun detected : %d bytes available, %d bits needed",
  			             (int)occ, lastx);
  			return -1;
  		}
  		(*sp->fill)(buf, thisrun, pa, lastx);
  		SETVALUE(0);		/* imaginary change for reference */
  		SWAP(uint32*, sp->curruns, sp->refruns);
  		buf += sp->b.rowbytes;
  		occ -= sp->b.rowbytes;
  		sp->line++;
  		continue;
  	EOFG4:
                  NeedBits16( 13, BADG4 );
          BADG4:
  #ifdef FAX3_DEBUG
                  if( GetBits(13) != 0x1001 )
                      fputs( "Bad EOFB\n", stderr );
  #endif                
                  ClrBits( 13 );
  		if (((lastx + 7) >> 3) > (int)occ)	/* check for buffer overrun */
  		{
  			TIFFErrorExt(tif->tif_clientdata, module,
  			             "Buffer overrun detected : %d bytes available, %d bits needed",
  			             (int)occ, lastx);
  			return -1;
  		}
  		(*sp->fill)(buf, thisrun, pa, lastx);
  		UNCACHE_STATE(tif, sp);
  		return ( sp->line ? 1 : -1);	/* don't error on badly-terminated strips */
  	}
  	UNCACHE_STATE(tif, sp);
  	return (1);
  }
  #undef	SWAP
  
  /*
   * Encode the requested amount of data.
   */
  static int
  Fax4Encode(TIFF* tif, uint8* bp, tmsize_t cc, uint16 s)
  {
  	static const char module[] = "Fax4Encode";
  	Fax3CodecState *sp = EncoderState(tif);
  	(void) s;
  	if (cc % sp->b.rowbytes)
  	{
  		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be written");
  		return (0);
  	}
  	while (cc > 0) {
  		if (!Fax3Encode2DRow(tif, bp, sp->refline, sp->b.rowpixels))
  			return (0);
  		_TIFFmemcpy(sp->refline, bp, sp->b.rowbytes);
  		bp += sp->b.rowbytes;
  		cc -= sp->b.rowbytes;
  	}
  	return (1);
  }
  
  static int
  Fax4PostEncode(TIFF* tif)
  {
  	Fax3CodecState *sp = EncoderState(tif);
  
  	/* terminate strip w/ EOFB */
  	Fax3PutBits(tif, EOL, 12);
  	Fax3PutBits(tif, EOL, 12);
  	if (sp->bit != 8)
  		Fax3FlushBits(tif, sp);
  	return (1);
  }
  
  int
  TIFFInitCCITTFax4(TIFF* tif, int scheme)
  {
  	(void) scheme;
  	if (InitCCITTFax3(tif)) {		/* reuse G3 support */
  		/*
  		 * Merge codec-specific tag information.
  		 */
  		if (!_TIFFMergeFields(tif, fax4Fields,
  				      TIFFArrayCount(fax4Fields))) {
  			TIFFErrorExt(tif->tif_clientdata, "TIFFInitCCITTFax4",
  			"Merging CCITT Fax 4 codec-specific tags failed");
  			return 0;
  		}
  
  		tif->tif_decoderow = Fax4Decode;
  		tif->tif_decodestrip = Fax4Decode;
  		tif->tif_decodetile = Fax4Decode;
  		tif->tif_encoderow = Fax4Encode;
  		tif->tif_encodestrip = Fax4Encode;
  		tif->tif_encodetile = Fax4Encode;
  		tif->tif_postencode = Fax4PostEncode;
  		/*
  		 * Suppress RTC at the end of each strip.
  		 */
  		return TIFFSetField(tif, TIFFTAG_FAXMODE, FAXMODE_NORTC);
  	} else
  		return (0);
  }
  
  /*
   * CCITT Group 3 1-D Modified Huffman RLE Compression Support.
   * (Compression algorithms 2 and 32771)
   */
  
  /*
   * Decode the requested amount of RLE-encoded data.
   */
  static int
  Fax3DecodeRLE(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)
  {
  	DECLARE_STATE(tif, sp, "Fax3DecodeRLE");
  	int mode = sp->b.mode;
  	(void) s;
  	if (occ % sp->b.rowbytes)
  	{
  		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");
  		return (-1);
  	}
  	CACHE_STATE(tif, sp);
  	thisrun = sp->curruns;
  	while (occ > 0) {
  		a0 = 0;
  		RunLength = 0;
  		pa = thisrun;
  #ifdef FAX3_DEBUG
  		printf("\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail);
  		printf("-------------------- %d\n", tif->tif_row);
  		fflush(stdout);
  #endif
  		EXPAND1D(EOFRLE);
  		(*sp->fill)(buf, thisrun, pa, lastx);
  		/*
  		 * Cleanup at the end of the row.
  		 */
  		if (mode & FAXMODE_BYTEALIGN) {
  			int n = BitsAvail - (BitsAvail &~ 7);
  			ClrBits(n);
  		} else if (mode & FAXMODE_WORDALIGN) {
  			int n = BitsAvail - (BitsAvail &~ 15);
  			ClrBits(n);
  			if (BitsAvail == 0 && !isAligned(cp, uint16))
  			    cp++;
  		}
  		buf += sp->b.rowbytes;
  		occ -= sp->b.rowbytes;
  		sp->line++;
  		continue;
  	EOFRLE:				/* premature EOF */
  		(*sp->fill)(buf, thisrun, pa, lastx);
  		UNCACHE_STATE(tif, sp);
  		return (-1);
  	}
  	UNCACHE_STATE(tif, sp);
  	return (1);
  }
  
  int
  TIFFInitCCITTRLE(TIFF* tif, int scheme)
  {
  	(void) scheme;
  	if (InitCCITTFax3(tif)) {		/* reuse G3 support */
  		tif->tif_decoderow = Fax3DecodeRLE;
  		tif->tif_decodestrip = Fax3DecodeRLE;
  		tif->tif_decodetile = Fax3DecodeRLE;
  		/*
  		 * Suppress RTC+EOLs when encoding and byte-align data.
  		 */
  		return TIFFSetField(tif, TIFFTAG_FAXMODE,
  		    FAXMODE_NORTC|FAXMODE_NOEOL|FAXMODE_BYTEALIGN);
  	} else
  		return (0);
  }
  
  int
  TIFFInitCCITTRLEW(TIFF* tif, int scheme)
  {
  	(void) scheme;
  	if (InitCCITTFax3(tif)) {		/* reuse G3 support */
  		tif->tif_decoderow = Fax3DecodeRLE;
  		tif->tif_decodestrip = Fax3DecodeRLE;
  		tif->tif_decodetile = Fax3DecodeRLE;  
  		/*
  		 * Suppress RTC+EOLs when encoding and word-align data.
  		 */
  		return TIFFSetField(tif, TIFFTAG_FAXMODE,
  		    FAXMODE_NORTC|FAXMODE_NOEOL|FAXMODE_WORDALIGN);
  	} else
  		return (0);
  }
  #endif /* CCITT_SUPPORT */
  
  /* vim: set ts=8 sts=8 sw=8 noet: */
  /*
   * Local Variables:
   * mode: c
   * c-basic-offset: 8
   * fill-column: 78
   * End:
   */
  