/* $Id: tif_fax3.c,v 1.5 2005/11/19 16:02:59 malaterre Exp $ */

/*
 * Copyright (c) 1990-1997 Sam Leffler
 * Copyright (c) 1991-1997 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and 
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the names of
 * Sam Leffler and Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Sam Leffler and Silicon Graphics.
 * 
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
 * 
 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 */

#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 */
  uint32  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 */
  uint32  recvparams;    /* encoded Class 2 session params */
  char*  subaddress;    /* subaddress string */
  uint32  recvtime;    /* time spent receiving (secs) */
  char*  faxdcs;      /* Table 2/T.30 encoded session params */
  TIFFVGetMethod vgetparent;  /* super-class method */
  TIFFVSetMethod vsetparent;  /* 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*  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 */
} 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)  ((((unsigned long)(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 -= (tidata_t) cp - tif->tif_rawcp;      \
    tif->tif_rawcp = (tidata_t) cp;          \
} while (0)

/*
 * Setup state for decoding a strip.
 */
static int
Fax3PreDecode(TIFF* tif, tsample_t 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);
  if (sp->refruns) {    /* init reference line to white */
    sp->refruns[0] = (uint32) sp->b.rowpixels;
    sp->refruns[1] = 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 a0)
{
  TIFFError(module, "%s: Bad code word at scanline %d (x %lu)",
      tif->tif_name, tif->tif_row, (unsigned long) a0);
}
#define  unexpected(table, a0)  Fax3Unexpected(module, tif, a0)

static void
Fax3Extension(const char* module, TIFF* tif, uint32 a0)
{
  TIFFError(module,
      "%s: Uncompressed data (not supported) at scanline %d (x %lu)",
      tif->tif_name, tif->tif_row, (unsigned long) a0);
}
#define  extension(a0)  Fax3Extension(module, tif, a0)

static void
Fax3BadLength(const char* module, TIFF* tif, uint32 a0, uint32 lastx)
{
  TIFFWarning(module, "%s: %s at scanline %d (got %lu, expected %lu)",
      tif->tif_name,
      a0 < lastx ? "Premature EOL" : "Line length mismatch",
      tif->tif_row, (unsigned long) a0, (unsigned long) lastx);
}
#define  badlength(a0,lastx)  Fax3BadLength(module, tif, a0, lastx)

static void
Fax3PrematureEOF(const char* module, TIFF* tif, uint32 a0)
{
  TIFFWarning(module, "%s: Premature EOF at scanline %d (x %lu)",
      tif->tif_name, tif->tif_row, (unsigned long) a0);
}
#define  prematureEOF(a0)  Fax3PrematureEOF(module, tif, a0)

#define  Nop

/*
 * Decode the requested amount of G3 1D-encoded data.
 */
static int
Fax3Decode1D(TIFF* tif, tidata_t buf, tsize_t occ, tsample_t s)
{
  DECLARE_STATE(tif, sp, "Fax3Decode1D");

  (void) s;
  CACHE_STATE(tif, sp);
  thisrun = sp->curruns;
  while ((long)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;
    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, tidata_t buf, tsize_t occ, tsample_t s)
{
  DECLARE_STATE_2D(tif, sp, "Fax3Decode2D");
  int is1D;      /* current line is 1d/2d-encoded */

  (void) s;
  CACHE_STATE(tif, sp);
  while ((long)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);
    SETVAL(0);    /* imaginary change for reference */
    SWAP(uint32*, sp->curruns, sp->refruns);
    buf += sp->b.rowbytes;
    occ -= sp->b.rowbytes;
    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_LONG == 8
# define FILL(n, cp)                  \
    switch (n) {                  \
    case 15:(cp)[14] = 0xff; case 14:(cp)[13] = 0xff; case 13: (cp)[12] = 0xff;\
    case 12:(cp)[11] = 0xff; case 11:(cp)[10] = 0xff; case 10: (cp)[9] = 0xff;\
    case  9: (cp)[8] = 0xff; case  8: (cp)[7] = 0xff; case  7: (cp)[6] = 0xff;\
    case  6: (cp)[5] = 0xff; case  5: (cp)[4] = 0xff; case  4: (cp)[3] = 0xff;\
    case  3: (cp)[2] = 0xff; case  2: (cp)[1] = 0xff;            \
    case  1: (cp)[0] = 0xff; (cp) += (n); case 0:  ;            \
    }
# define ZERO(n, cp)              \
    switch (n) {              \
    case 15:(cp)[14] = 0; case 14:(cp)[13] = 0; case 13: (cp)[12] = 0;  \
    case 12:(cp)[11] = 0; case 11:(cp)[10] = 0; case 10: (cp)[9] = 0;  \
    case  9: (cp)[8] = 0; case  8: (cp)[7] = 0; case  7: (cp)[6] = 0;  \
    case  6: (cp)[5] = 0; case  5: (cp)[4] = 0; case  4: (cp)[3] = 0;  \
    case  3: (cp)[2] = 0; case  2: (cp)[1] = 0;        \
    case  1: (cp)[0] = 0; (cp) += (n); case 0:  ;      \
    }
#else
# define FILL(n, cp)                  \
    switch (n) {                  \
    case 7: (cp)[6] = 0xff; case 6: (cp)[5] = 0xff; case 5: (cp)[4] = 0xff; \
    case 4: (cp)[3] = 0xff; case 3: (cp)[2] = 0xff; case 2: (cp)[1] = 0xff; \
    case 1: (cp)[0] = 0xff; (cp) += (n); case 0:  ;          \
    }
# define ZERO(n, cp)              \
    switch (n) {              \
    case 7: (cp)[6] = 0; case 6: (cp)[5] = 0; case 5: (cp)[4] = 0;  \
    case 4: (cp)[3] = 0; case 3: (cp)[2] = 0; case 2: (cp)[1] = 0;  \
    case 1: (cp)[0] = 0; (cp) += (n); 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;
        }
        if (run)
      cp[0] |= 0xff00 >> run;
    } else
        cp[0] |= _fillmasks[run]>>bx;
    x += runs[1];
      }
  }
  assert(x == lastx);
}
#undef  ZERO
#undef  FILL

static char *
CheckMalloc(TIFF* tif, size_t nmemb, size_t elem_size, const char* what)
{
  char  *cp = NULL;
  tsize_t  bytes = nmemb * elem_size;

  if (nmemb && elem_size && bytes / elem_size == nmemb)
    cp = (char*) _TIFFmalloc(bytes);

  if (cp == NULL)
    TIFFError(tif->tif_name, "No space %s", what);
  
  return (cp);
}

/*
 * 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)
{
  TIFFDirectory* td = &tif->tif_dir;
  Fax3BaseState* sp = Fax3State(tif);
  long rowbytes, rowpixels;
  int needsRefLine;
  Fax3CodecState* dsp = (Fax3CodecState*) Fax3State(tif);
  uint32 nruns;

  if (td->td_bitspersample != 1) {
    TIFFError(tif->tif_name,
        "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;
  }
  sp->rowbytes = (uint32) rowbytes;
  sp->rowpixels = (uint32) rowpixels;
  /*
   * Allocate any additional space required for decoding/encoding.
   */
  needsRefLine = (
      (sp->groupoptions & GROUP3OPT_2DENCODING) ||
      td->td_compression == COMPRESSION_CCITTFAX4
  );

  nruns = needsRefLine ? 2*TIFFroundup(rowpixels,32) : (uint32)rowpixels;

  dsp->runs = (uint32*) CheckMalloc(tif, 2*nruns+3, sizeof (uint32),
            "for Group 3/4 run arrays");
  if (dsp->runs == NULL)
    return (0);
  dsp->curruns = dsp->runs;
  if (needsRefLine)
    dsp->refruns = dsp->runs + (nruns>>1);
  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) {
      TIFFError("Fax3SetupState",
          "%s: No space for Group 3/4 reference line",
          tif->tif_name);
      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++ = (tidataval_t) (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++ = (tidataval_t) 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);        \
  }              \
  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;
      code = 0;
      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, tsample_t 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;
  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))) {
    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)) && *lp == 0) {
      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))) {
    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)) && *lp == ~0) {
      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) {
      int32 d = b1 - a1;
      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, tidata_t bp, tsize_t cc, tsample_t s)
{
  Fax3CodecState* sp = EncoderState(tif);

  (void) s;
  while ((long)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) {
    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)
{
  if (tif->tif_data) {
    Fax3CodecState* sp = DecoderState(tif);

    if (sp->runs)
      _TIFFfree(sp->runs);
    if (sp->refline)
      _TIFFfree(sp->refline);

    if (Fax3State(tif)->subaddress)
      _TIFFfree(Fax3State(tif)->subaddress);
    _TIFFfree(tif->tif_data);
    tif->tif_data = NULL;
  }
}

#define  FIELD_BADFAXLINES  (FIELD_CODEC+0)
#define  FIELD_CLEANFAXDATA  (FIELD_CODEC+1)
#define  FIELD_BADFAXRUN    (FIELD_CODEC+2)
#define  FIELD_RECVPARAMS  (FIELD_CODEC+3)
#define  FIELD_SUBADDRESS  (FIELD_CODEC+4)
#define  FIELD_RECVTIME    (FIELD_CODEC+5)
#define  FIELD_FAXDCS    (FIELD_CODEC+6)

#define  FIELD_OPTIONS    (FIELD_CODEC+7)

static const TIFFFieldInfo faxFieldInfo[] = {
    { TIFFTAG_FAXMODE,     0, 0,  TIFF_ANY,  FIELD_PSEUDO,
      FALSE,  FALSE,  "FaxMode" },
    { TIFFTAG_FAXFILLFUNC,   0, 0,  TIFF_ANY,  FIELD_PSEUDO,
      FALSE,  FALSE,  "FaxFillFunc" },
    { TIFFTAG_BADFAXLINES,   1, 1,  TIFF_LONG,  FIELD_BADFAXLINES,
      TRUE,  FALSE,  "BadFaxLines" },
    { TIFFTAG_BADFAXLINES,   1, 1,  TIFF_SHORT,  FIELD_BADFAXLINES,
      TRUE,  FALSE,  "BadFaxLines" },
    { TIFFTAG_CLEANFAXDATA,   1, 1,  TIFF_SHORT,  FIELD_CLEANFAXDATA,
      TRUE,  FALSE,  "CleanFaxData" },
    { TIFFTAG_CONSECUTIVEBADFAXLINES,1,1, TIFF_LONG,  FIELD_BADFAXRUN,
      TRUE,  FALSE,  "ConsecutiveBadFaxLines" },
    { TIFFTAG_CONSECUTIVEBADFAXLINES,1,1, TIFF_SHORT,  FIELD_BADFAXRUN,
      TRUE,  FALSE,  "ConsecutiveBadFaxLines" },
    { TIFFTAG_FAXRECVPARAMS,   1, 1, TIFF_LONG,  FIELD_RECVPARAMS,
      TRUE,  FALSE,  "FaxRecvParams" },
    { TIFFTAG_FAXSUBADDRESS,  -1,-1, TIFF_ASCII,  FIELD_SUBADDRESS,
      TRUE,  FALSE,  "FaxSubAddress" },
    { TIFFTAG_FAXRECVTIME,   1, 1, TIFF_LONG,  FIELD_RECVTIME,
      TRUE,  FALSE,  "FaxRecvTime" },
    { TIFFTAG_FAXDCS,    -1,-1, TIFF_ASCII,  FIELD_FAXDCS,
      TRUE,  FALSE,  "FaxDcs" },
};
static const TIFFFieldInfo fax3FieldInfo[] = {
    { TIFFTAG_GROUP3OPTIONS,   1, 1,  TIFF_LONG,  FIELD_OPTIONS,
      FALSE,  FALSE,  "Group3Options" },
};
static const TIFFFieldInfo fax4FieldInfo[] = {
    { TIFFTAG_GROUP4OPTIONS,   1, 1,  TIFF_LONG,  FIELD_OPTIONS,
      FALSE,  FALSE,  "Group4Options" },
};
#define  N(a)  (sizeof (a) / sizeof (a[0]))

static int
Fax3VSetField(TIFF* tif, ttag_t tag, va_list ap)
{
  Fax3BaseState* sp = Fax3State(tif);

  switch (tag) {
  case TIFFTAG_FAXMODE:
    sp->mode = 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 = 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 = va_arg(ap, uint32);
    break;
  case TIFFTAG_BADFAXLINES:
    sp->badfaxlines = va_arg(ap, uint32);
    break;
  case TIFFTAG_CLEANFAXDATA:
    sp->cleanfaxdata = (uint16) va_arg(ap, int);
    break;
  case TIFFTAG_CONSECUTIVEBADFAXLINES:
    sp->badfaxrun = va_arg(ap, uint32);
    break;
  case TIFFTAG_FAXRECVPARAMS:
    sp->recvparams = va_arg(ap, uint32);
    break;
  case TIFFTAG_FAXSUBADDRESS:
    _TIFFsetString(&sp->subaddress, va_arg(ap, char*));
    break;
  case TIFFTAG_FAXRECVTIME:
    sp->recvtime = va_arg(ap, uint32);
    break;
  case TIFFTAG_FAXDCS:
    _TIFFsetString(&sp->faxdcs, va_arg(ap, char*));
    break;
  default:
    return (*sp->vsetparent)(tif, tag, ap);
  }
  TIFFSetFieldBit(tif, _TIFFFieldWithTag(tif, tag)->field_bit);
  tif->tif_flags |= TIFF_DIRTYDIRECT;
  return (1);
}

static int
Fax3VGetField(TIFF* tif, ttag_t tag, va_list ap)
{
  Fax3BaseState* sp = Fax3State(tif);

  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;
  case TIFFTAG_FAXRECVPARAMS:
    *va_arg(ap, uint32*) = sp->recvparams;
    break;
  case TIFFTAG_FAXSUBADDRESS:
    *va_arg(ap, char**) = sp->subaddress;
    break;
  case TIFFTAG_FAXRECVTIME:
    *va_arg(ap, uint32*) = sp->recvtime;
    break;
  case TIFFTAG_FAXDCS:
    *va_arg(ap, char**) = sp->faxdcs;
    break;
  default:
    return (*sp->vgetparent)(tif, tag, ap);
  }
  return (1);
}

static void
Fax3PrintDir(TIFF* tif, FILE* fd, long flags)
{
  Fax3BaseState* sp = Fax3State(tif);

  (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 (TIFFFieldSet(tif,FIELD_RECVPARAMS))
    fprintf(fd, "  Fax Receive Parameters: %08lx\n",
       (unsigned long) sp->recvparams);
  if (TIFFFieldSet(tif,FIELD_SUBADDRESS))
    fprintf(fd, "  Fax SubAddress: %s\n", sp->subaddress);
  if (TIFFFieldSet(tif,FIELD_RECVTIME))
    fprintf(fd, "  Fax Receive Time: %lu secs\n",
        (unsigned long) sp->recvtime);
  if (TIFFFieldSet(tif,FIELD_FAXDCS))
    fprintf(fd, "  Fax DCS: %s\n", sp->faxdcs);
}

static int
InitCCITTFax3(TIFF* tif)
{
  Fax3BaseState* sp;

  /*
   * Allocate state block so tag methods have storage to record values.
   */
  tif->tif_data = (tidata_t)
    _TIFFmalloc(sizeof (Fax3CodecState));

  if (tif->tif_data == NULL) {
    TIFFError("TIFFInitCCITTFax3",
        "%s: No space for state block", tif->tif_name);
    return (0);
  }

  sp = Fax3State(tif);
        sp->rw_mode = tif->tif_mode;

  /*
   * Merge codec-specific tag information and
   * override parent get/set field methods.
   */
  _TIFFMergeFieldInfo(tif, faxFieldInfo, N(faxFieldInfo));
  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 */
  tif->tif_tagmethods.printdir = Fax3PrintDir;   /* hook for codec tags */
  sp->groupoptions = 0;  
  sp->recvparams = 0;
  sp->subaddress = NULL;
  sp->faxdcs = NULL;

  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_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)) {
    _TIFFMergeFieldInfo(tif, fax3FieldInfo, N(fax3FieldInfo));

    /*
     * The default format is Class/F-style w/o RTC.
     */
    return TIFFSetField(tif, TIFFTAG_FAXMODE, FAXMODE_CLASSF);
  } else
    return (0);
}

/*
 * 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, tidata_t buf, tsize_t occ, tsample_t s)
{
  DECLARE_STATE_2D(tif, sp, "Fax4Decode");

  (void) s;
  CACHE_STATE(tif, sp);
  while ((long)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;
    (*sp->fill)(buf, thisrun, pa, lastx);
    SETVAL(0);    /* imaginary change for reference */
    SWAP(uint32*, sp->curruns, sp->refruns);
    buf += sp->b.rowbytes;
    occ -= sp->b.rowbytes;
    continue;
  EOFG4:
                NeedBits16( 13, BADG4 );
        BADG4:
#ifdef FAX3_DEBUG
                if( GetBits(13) != 0x1001 )
                    fputs( "Bad RTC\n", stderr );
#endif                
                ClrBits( 13 );
    (*sp->fill)(buf, thisrun, pa, lastx);
    UNCACHE_STATE(tif, sp);
    return (-1);
  }
  UNCACHE_STATE(tif, sp);
  return (1);
}
#undef  SWAP

/*
 * Encode the requested amount of data.
 */
static int
Fax4Encode(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
{
  Fax3CodecState *sp = EncoderState(tif);

  (void) s;
  while ((long)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 */
    _TIFFMergeFieldInfo(tif, fax4FieldInfo, N(fax4FieldInfo));

    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, tidata_t buf, tsize_t occ, tsample_t s)
{
  DECLARE_STATE(tif, sp, "Fax3DecodeRLE");
  int mode = sp->b.mode;

  (void) s;
  CACHE_STATE(tif, sp);
  thisrun = sp->curruns;
  while ((long)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;
    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 */

