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tif_fax3.c

/* $Id: tif_fax3.c,v 1.40 2006/03/16 12:38:24 dron 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 line, uint32 a0)
{
      TIFFErrorExt(tif->tif_clientdata, module, "%s: Bad code word at line %lu of %s %lu (x %lu)",
            tif->tif_name, (unsigned long) line, isTiled(tif) ? "tile" : "strip",
         (unsigned long) (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
         (unsigned long) a0);
}
#define     unexpected(table, a0)   Fax3Unexpected(module, tif, line, a0)

static void
Fax3Extension(const char* module, TIFF* tif, uint32 line, uint32 a0)
{
      TIFFErrorExt(tif->tif_clientdata, module,
          "%s: Uncompressed data (not supported) at line %lu of %s %lu (x %lu)",
          tif->tif_name, (unsigned long) line, isTiled(tif) ? "tile" : "strip",
       (unsigned long) (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
       (unsigned long) a0);
}
#define     extension(a0)     Fax3Extension(module, tif, line, a0)

static void
Fax3BadLength(const char* module, TIFF* tif, uint32 line, uint32 a0, uint32 lastx)
{
      TIFFWarningExt(tif->tif_clientdata, module, "%s: %s at line %lu of %s %lu (got %lu, expected %lu)",
          tif->tif_name,
          a0 < lastx ? "Premature EOL" : "Line length mismatch",
          (unsigned long) line, isTiled(tif) ? "tile" : "strip",
        (unsigned long) (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
        (unsigned long) a0, lastx);
}
#define     badlength(a0,lastx)     Fax3BadLength(module, tif, line, a0, lastx)

static void
Fax3PrematureEOF(const char* module, TIFF* tif, uint32 line, uint32 a0)
{
      TIFFWarningExt(tif->tif_clientdata, module, "%s: Premature EOF at line %lu of %s %lu (x %lu)",
          tif->tif_name,
          (unsigned long) line, isTiled(tif) ? "tile" : "strip",
        (unsigned long) (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),
        (unsigned long) a0);
}
#define     prematureEOF(a0)  Fax3PrematureEOF(module, tif, line, 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");
        int line = 0;

      (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;
                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, tidata_t buf, tsize_t occ, tsample_t s)
{
      DECLARE_STATE_2D(tif, sp, "Fax3Decode2D");
        int line = 0;
      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);
            SETVALUE(0);            /* imaginary change for reference */
            SWAP(uint32*, sp->curruns, sp->refruns);
            buf += sp->b.rowbytes;
            occ -= sp->b.rowbytes;
                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_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

/*
 * 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);
      int needsRefLine;
      Fax3CodecState* dsp = (Fax3CodecState*) Fax3State(tif);
      uint32 rowbytes, rowpixels, nruns;

      if (td->td_bitspersample != 1) {
            TIFFErrorExt(tif->tif_clientdata, 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) : rowpixels;

      dsp->runs = (uint32*) _TIFFCheckMalloc(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) {
                  TIFFErrorExt(tif->tif_clientdata, "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))) && (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))) {
            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) {
                  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)
{
      Fax3CodecState* sp = DecoderState(tif);
      
      assert(sp != 0);

      tif->tif_tagmethods.vgetfield = sp->b.vgetparent;
      tif->tif_tagmethods.vsetfield = sp->b.vsetparent;

      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;

      _TIFFSetDefaultCompressionState(tif);
}

#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);

      assert(sp != 0);
      assert(sp->vsetparent != 0);

      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) {
            TIFFErrorExt(tif->tif_clientdata, "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");
        int line = 0;

      (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);
            SETVALUE(0);            /* imaginary change for reference */
            SWAP(uint32*, sp->curruns, sp->refruns);
            buf += sp->b.rowbytes;
            occ -= sp->b.rowbytes;
                line++;
            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;
        int line = 0;

      (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;
                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 */

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