/* $Id: tif_fax3.c,v 1.81 2017-06-18 10:31:50 erouault 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 */

	tmsize_t rowbytes;               /* bytes in a decoded scanline */

	uint32   rowpixels;              /* pixels in a scanline */

	uint16   cleanfaxdata;           /* CleanFaxData tag */

	uint32   badfaxrun;              /* BadFaxRun tag */

	uint32   badfaxlines;            /* BadFaxLines tag */

	uint32   groupoptions;           /* Group 3/4 options tag */

	TIFFVGetMethod  vgetparent;      /* super-class method */

	TIFFVSetMethod  vsetparent;      /* super-class method */

	TIFFPrintMethod printdir;        /* super-class method */

} Fax3BaseState;

#define	Fax3State(tif)		((Fax3BaseState*) (tif)->tif_data)

typedef enum { G3_1D, G3_2D } Ttag;

typedef struct {

	Fax3BaseState b;

	/* Decoder state info */

	const unsigned char* bitmap;	/* bit reversal table */

	uint32	data;			/* current i/o byte/word */

	int	bit;			/* current i/o bit in byte */

	int	EOLcnt;			/* count of EOL codes recognized */

	TIFFFaxFillFunc fill;		/* fill routine */

	uint32*	runs;			/* b&w runs for current/previous row */

	uint32*	refruns;		/* runs for reference line */

	uint32*	curruns;		/* runs for current line */

	/* Encoder state info */

	Ttag    tag;			/* encoding state */

	unsigned char*	refline;	/* reference line for 2d decoding */

	int	k;			/* #rows left that can be 2d encoded */

	int	maxk;			/* max #rows that can be 2d encoded */

	int line;

} Fax3CodecState;

#define DecoderState(tif) ((Fax3CodecState*) Fax3State(tif))

#define EncoderState(tif) ((Fax3CodecState*) Fax3State(tif))

#define is2DEncoding(sp) (sp->b.groupoptions & GROUP3OPT_2DENCODING)

#define isAligned(p,t) ((((size_t)(p)) & (sizeof (t)-1)) == 0)

/*

 * Group 3 and Group 4 Decoding.

 */

/*

 * These macros glue the TIFF library state to

 * the state expected by Frank's decoder.

 */

#define	DECLARE_STATE(tif, sp, mod)					\

    static const char module[] = mod;					\

    Fax3CodecState* sp = DecoderState(tif);				\

    int a0;				/* reference element */		\

    int lastx = sp->b.rowpixels;	/* last element in row */	\

    uint32 BitAcc;			/* bit accumulator */		\

    int BitsAvail;			/* # valid bits in BitAcc */	\

    int RunLength;			/* length of current run */	\

    unsigned char* cp;			/* next byte of input data */	\

    unsigned char* ep;			/* end of input data */		\

    uint32* pa;				/* place to stuff next run */	\

    uint32* thisrun;			/* current row's run array */	\

    int EOLcnt;				/* # EOL codes recognized */	\

    const unsigned char* bitmap = sp->bitmap;	/* input data bit reverser */	\

    const TIFFFaxTabEnt* TabEnt

#define	DECLARE_STATE_2D(tif, sp, mod)					\

    DECLARE_STATE(tif, sp, mod);					\

    int b1;				/* next change on prev line */	\

    uint32* pb				/* next run in reference line */\

/*

 * Load any state that may be changed during decoding.

 */

#define	CACHE_STATE(tif, sp) do {					\

    BitAcc = sp->data;							\

    BitsAvail = sp->bit;						\

    EOLcnt = sp->EOLcnt;						\

    cp = (unsigned char*) tif->tif_rawcp;				\

    ep = cp + tif->tif_rawcc;						\

} while (0)

/*

 * Save state possibly changed during decoding.

 */

#define	UNCACHE_STATE(tif, sp) do {					\

    sp->bit = BitsAvail;						\

    sp->data = BitAcc;							\

    sp->EOLcnt = EOLcnt;						\

    tif->tif_rawcc -= (tmsize_t)((uint8*) cp - tif->tif_rawcp);		\

    tif->tif_rawcp = (uint8*) cp;					\

} while (0)

/*

 * Setup state for decoding a strip.

 */

static int

Fax3PreDecode(TIFF* tif, uint16 s)

{

	Fax3CodecState* sp = DecoderState(tif);

	(void) s;

	assert(sp != NULL);

	sp->bit = 0;			/* force initial read */

	sp->data = 0;

	sp->EOLcnt = 0;			/* force initial scan for EOL */

	/*

	 * Decoder assumes lsb-to-msb bit order.  Note that we select

	 * this here rather than in Fax3SetupState so that viewers can

	 * hold the image open, fiddle with the FillOrder tag value,

	 * and then re-decode the image.  Otherwise they'd need to close

	 * and open the image to get the state reset.

	 */

	sp->bitmap =

	    TIFFGetBitRevTable(tif->tif_dir.td_fillorder != FILLORDER_LSB2MSB);

	if (sp->refruns) {		/* init reference line to white */

		sp->refruns[0] = (uint32) sp->b.rowpixels;

		sp->refruns[1] = 0;

	}

	sp->line = 0;

	return (1);

}

/*

 * Routine for handling various errors/conditions.

 * Note how they are "glued into the decoder" by

 * overriding the definitions used by the decoder.

 */

static void

Fax3Unexpected(const char* module, TIFF* tif, uint32 line, uint32 a0)

{

	TIFFErrorExt(tif->tif_clientdata, module, "Bad code word at line %u of %s %u (x %u)",

	    line, isTiled(tif) ? "tile" : "strip",

	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),

	    a0);

}

#define	unexpected(table, a0)	Fax3Unexpected(module, tif, sp->line, a0)

static void

Fax3Extension(const char* module, TIFF* tif, uint32 line, uint32 a0)

{

	TIFFErrorExt(tif->tif_clientdata, module,

	    "Uncompressed data (not supported) at line %u of %s %u (x %u)",

	    line, isTiled(tif) ? "tile" : "strip",

	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),

	    a0);

}

#define	extension(a0)	Fax3Extension(module, tif, sp->line, a0)

static void

Fax3BadLength(const char* module, TIFF* tif, uint32 line, uint32 a0, uint32 lastx)

{

	TIFFWarningExt(tif->tif_clientdata, module, "%s at line %u of %s %u (got %u, expected %u)",

	    a0 < lastx ? "Premature EOL" : "Line length mismatch",

	    line, isTiled(tif) ? "tile" : "strip",

	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),

	    a0, lastx);

}

#define	badlength(a0,lastx)	Fax3BadLength(module, tif, sp->line, a0, lastx)

static void

Fax3PrematureEOF(const char* module, TIFF* tif, uint32 line, uint32 a0)

{

	TIFFWarningExt(tif->tif_clientdata, module, "Premature EOF at line %u of %s %u (x %u)",

	    line, isTiled(tif) ? "tile" : "strip",

	    (isTiled(tif) ? tif->tif_curtile : tif->tif_curstrip),

	    a0);

}

#define	prematureEOF(a0)	Fax3PrematureEOF(module, tif, sp->line, a0)

#define	Nop

/*

 * Decode the requested amount of G3 1D-encoded data.

 */

static int

Fax3Decode1D(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)

{

	DECLARE_STATE(tif, sp, "Fax3Decode1D");

	(void) s;

	if (occ % sp->b.rowbytes)

	{

		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");

		return (-1);

	}

	CACHE_STATE(tif, sp);

	thisrun = sp->curruns;

	while (occ > 0) {

		a0 = 0;

		RunLength = 0;

		pa = thisrun;

#ifdef FAX3_DEBUG

		printf("\nBitAcc=%08X, BitsAvail = %d\n", BitAcc, BitsAvail);

		printf("-------------------- %d\n", tif->tif_row);

		fflush(stdout);

#endif

		SYNC_EOL(EOF1D);

		EXPAND1D(EOF1Da);

		(*sp->fill)(buf, thisrun, pa, lastx);

		buf += sp->b.rowbytes;

		occ -= sp->b.rowbytes;

		sp->line++;

		continue;

	EOF1D:				/* premature EOF */

		CLEANUP_RUNS();

	EOF1Da:				/* premature EOF */

		(*sp->fill)(buf, thisrun, pa, lastx);

		UNCACHE_STATE(tif, sp);

		return (-1);

	}

	UNCACHE_STATE(tif, sp);

	return (1);

}

#define	SWAP(t,a,b)	{ t x; x = (a); (a) = (b); (b) = x; }

/*

 * Decode the requested amount of G3 2D-encoded data.

 */

static int

Fax3Decode2D(TIFF* tif, uint8* buf, tmsize_t occ, uint16 s)

{

	DECLARE_STATE_2D(tif, sp, "Fax3Decode2D");

	int is1D;			/* current line is 1d/2d-encoded */

	(void) s;

	if (occ % sp->b.rowbytes)

	{

		TIFFErrorExt(tif->tif_clientdata, module, "Fractional scanlines cannot be read");

		return (-1);

	}

	CACHE_STATE(tif, sp);

	while (occ > 0) {

		a0 = 0;

		RunLength = 0;

		pa = thisrun = sp->curruns;

#ifdef FAX3_DEBUG

		printf("\nBitAcc=%08X, BitsAvail = %d EOLcnt = %d",

		    BitAcc, BitsAvail, EOLcnt);

#endif

		SYNC_EOL(EOF2D);

		NeedBits8(1, EOF2D);

		is1D = GetBits(1);	/* 1D/2D-encoding tag bit */

		ClrBits(1);

#ifdef FAX3_DEBUG

		printf(" %s\n-------------------- %d\n",

		    is1D ? "1D" : "2D", tif->tif_row);

		fflush(stdout);

#endif

		pb = sp->refruns;

		b1 = *pb++;

		if (is1D)

			EXPAND1D(EOF2Da);

		else

			EXPAND2D(EOF2Da);

		(*sp->fill)(buf, thisrun, pa, lastx);

		SETVALUE(0);		/* imaginary change for reference */

		SWAP(uint32*, sp->curruns, sp->refruns);

		buf += sp->b.rowbytes;

		occ -= sp->b.rowbytes;

		sp->line++;

		continue;

	EOF2D:				/* premature EOF */

		CLEANUP_RUNS();

	EOF2Da:				/* premature EOF */

		(*sp->fill)(buf, thisrun, pa, lastx);

		UNCACHE_STATE(tif, sp);

		return (-1);

	}

	UNCACHE_STATE(tif, sp);

	return (1);

}

#undef SWAP

/*

 * The ZERO & FILL macros must handle spans < 2*sizeof(long) bytes.

 * For machines with 64-bit longs this is <16 bytes; otherwise

 * this is <8 bytes.  We optimize the code here to reflect the

 * machine characteristics.

 */

#if SIZEOF_UNSIGNED_LONG == 8

# define FILL(n, cp)							    \

    switch (n) {							    \

    case 15:(cp)[14] = 0xff; /*-fallthrough*/ \

    case 14:(cp)[13] = 0xff; /*-fallthrough*/ \

    case 13:(cp)[12] = 0xff; /*-fallthrough*/ \

    case 12:(cp)[11] = 0xff; /*-fallthrough*/ \

    case 11:(cp)[10] = 0xff; /*-fallthrough*/ \

    case 10: (cp)[9] = 0xff; /*-fallthrough*/ \

    case  9: (cp)[8] = 0xff; /*-fallthrough*/ \

    case  8: (cp)[7] = 0xff; /*-fallthrough*/ \

    case  7: (cp)[6] = 0xff; /*-fallthrough*/ \

    case  6: (cp)[5] = 0xff; /*-fallthrough*/ \

    case  5: (cp)[4] = 0xff; /*-fallthrough*/ \

    case  4: (cp)[3] = 0xff; /*-fallthrough*/ \

    case  3: (cp)[2] = 0xff; /*-fallthrough*/ \

    case  2: (cp)[1] = 0xff; /*-fallthrough*/ \

    case  1: (cp)[0] = 0xff; (cp) += (n); /*-fallthrough*/ \

    case 0:  ;			      \

    }

# define ZERO(n, cp)							\

    switch (n) {							\

    case 15:(cp)[14] = 0; /*-fallthrough*/ \

    case 14:(cp)[13] = 0; /*-fallthrough*/ \

    case 13:(cp)[12] = 0; /*-fallthrough*/ \

    case 12:(cp)[11] = 0; /*-fallthrough*/ \

    case 11:(cp)[10] = 0; /*-fallthrough*/ \

    case 10: (cp)[9] = 0; /*-fallthrough*/ \

    case  9: (cp)[8] = 0; /*-fallthrough*/ \

    case  8: (cp)[7] = 0; /*-fallthrough*/ \

    case  7: (cp)[6] = 0; /*-fallthrough*/ \

    case  6: (cp)[5] = 0; /*-fallthrough*/ \

    case  5: (cp)[4] = 0; /*-fallthrough*/ \

    case  4: (cp)[3] = 0; /*-fallthrough*/ \

    case  3: (cp)[2] = 0; /*-fallthrough*/ \

    case  2: (cp)[1] = 0; /*-fallthrough*/ \

    case  1: (cp)[0] = 0; (cp) += (n); /*-fallthrough*/ \

    case 0:  ;			\

    }

#else

# define FILL(n, cp)							    \

    switch (n) {							    \

    case 7: (cp)[6] = 0xff; /*-fallthrough*/ \

    case 6: (cp)[5] = 0xff; /*-fallthrough*/ \

    case 5: (cp)[4] = 0xff; /*-fallthrough*/ \

    case 4: (cp)[3] = 0xff; /*-fallthrough*/ \

    case 3: (cp)[2] = 0xff; /*-fallthrough*/ \

    case 2: (cp)[1] = 0xff; /*-fallthrough*/ \

    case 1: (cp)[0] = 0xff; (cp) += (n);  /*-fallthrough*/ \

    case 0:  ;			    \

    }

# define ZERO(n, cp)							\

    switch (n) {							\

    case 7: (cp)[6] = 0; /*-fallthrough*/ \

    case 6: (cp)[5] = 0; /*-fallthrough*/ \

    case 5: (cp)[4] = 0; /*-fallthrough*/ \

    case 4: (cp)[3] = 0; /*-fallthrough*/ \

    case 3: (cp)[2] = 0; /*-fallthrough*/ \

    case 2: (cp)[1] = 0; /*-fallthrough*/ \

    case 1: (cp)[0] = 0; (cp) += (n); /*-fallthrough*/ \

    case 0:  ;			\

    }

#endif

/*

 * Bit-fill a row according to the white/black

 * runs generated during G3/G4 decoding.

 */

void

_TIFFFax3fillruns(unsigned char* buf, uint32* runs, uint32* erun, uint32 lastx)

{

	static const unsigned char _fillmasks[] =

	    { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff };

	unsigned char* cp;

	uint32 x, bx, run;

	int32 n, nw;

	long* lp;

	if ((erun-runs)&1)

	    *erun++ = 0;

	x = 0;

	for (; runs < erun; runs += 2) {

	    run = runs[0];

	    if (x+run > lastx || run > lastx )

		run = runs[0] = (uint32) (lastx - x);

	    if (run) {

		cp = buf + (x>>3);

		bx = x&7;

		if (run > 8-bx) {

		    if (bx) {			/* align to byte boundary */

			*cp++ &= 0xff << (8-bx);

			run -= 8-bx;

		    }

		    if( (n = run >> 3) != 0 ) {	/* multiple bytes to fill */

			if ((n/sizeof (long)) > 1) {

			    /*

			     * Align to longword boundary and fill.

			     */

			    for (; n && !isAligned(cp, long); n--)

				    *cp++ = 0x00;

			    lp = (long*) cp;

			    nw = (int32)(n / sizeof (long));

			    n -= nw * sizeof (long);

			    do {

				    *lp++ = 0L;

			    } while (--nw);

			    cp = (unsigned char*) lp;

			}

			ZERO(n, cp);

			run &= 7;

		    }

		    if (run)

			cp[0] &= 0xff >> run;

		} else

		    cp[0] &= ~(_fillmasks[run]>>bx);

		x += runs[0];

	    }

	    run = runs[1];

	    if (x+run > lastx || run > lastx )

		run = runs[1] = lastx - x;

	    if (run) {

		cp = buf + (x>>3);

		bx = x&7;

		if (run > 8-bx) {

		    if (bx) {			/* align to byte boundary */

			*cp++ |= 0xff >> bx;

			run -= 8-bx;

		    }

		    if( (n = run>>3) != 0 ) {	/* multiple bytes to fill */

			if ((n/sizeof (long)) > 1) {

			    /*

			     * Align to longword boundary and fill.

			     */

			    for (; n && !isAligned(cp, long); n--)

				*cp++ = 0xff;

			    lp = (long*) cp;

			    nw = (int32)(n / sizeof (long));

			    n -= nw * sizeof (long);

			    do {

				*lp++ = -1L;

			    } while (--nw);

			    cp = (unsigned char*) lp;

			}

			FILL(n, cp);

			run &= 7;

		    }

                    /* Explicit 0xff masking to make icc -check=conversions happy */

		    if (run)

			cp[0] = (unsigned char)((cp[0] | (0xff00 >> run))&0xff);

		} else

		    cp[0] |= _fillmasks[run]>>bx;

		x += runs[1];

	    }

	}

	assert(x == lastx);

}

#undef	ZERO

#undef	FILL

static int

Fax3FixupTags(TIFF* tif)

{

	(void) tif;

	return (1);

}

/*

 * Setup G3/G4-related compression/decompression state

 * before data is processed.  This routine is called once

 * per image -- it sets up different state based on whether

 * or not decoding or encoding is being done and whether

 * 1D- or 2D-encoded data is involved.

 */

static int

Fax3SetupState(TIFF* tif)

{

	static const char module[] = "Fax3SetupState";

	TIFFDirectory* td = &tif->tif_dir;

	Fax3BaseState* sp = Fax3State(tif);

	int needsRefLine;

	Fax3CodecState* dsp = (Fax3CodecState*) Fax3State(tif);

	tmsize_t rowbytes;

	uint32 rowpixels, nruns;

	if (td->td_bitspersample != 1) {

		TIFFErrorExt(tif->tif_clientdata, module,

		    "Bits/sample must be 1 for Group 3/4 encoding/decoding");

		return (0);

	}

	/*

	 * Calculate the scanline/tile widths.

	 */

	if (isTiled(tif)) {

		rowbytes = TIFFTileRowSize(tif);

		rowpixels = td->td_tilewidth;

	} else {

		rowbytes = TIFFScanlineSize(tif);

		rowpixels = td->td_imagewidth;

	}

	sp->rowbytes = rowbytes;

	sp->rowpixels = rowpixels;

	/*

	 * Allocate any additional space required for decoding/encoding.

	 */

	needsRefLine = (

	    (sp->groupoptions & GROUP3OPT_2DENCODING) ||

	    td->td_compression == COMPRESSION_CCITTFAX4

	);

	/*

	  Assure that allocation computations do not overflow.

	  TIFFroundup and TIFFSafeMultiply return zero on integer overflow

	*/

	dsp->runs=(uint32*) NULL;

	nruns = TIFFroundup_32(rowpixels,32);

	if (needsRefLine) {

		nruns = TIFFSafeMultiply(uint32,nruns,2);

	}

	if ((nruns == 0) || (TIFFSafeMultiply(uint32,nruns,2) == 0)) {

		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,

			     "Row pixels integer overflow (rowpixels %u)",

			     rowpixels);

		return (0);

	}

	dsp->runs = (uint32*) _TIFFCheckMalloc(tif,

					       TIFFSafeMultiply(uint32,nruns,2),

					       sizeof (uint32),

					       "for Group 3/4 run arrays");

	if (dsp->runs == NULL)

		return (0);

	memset( dsp->runs, 0, TIFFSafeMultiply(uint32,nruns,2)*sizeof(uint32));

	dsp->curruns = dsp->runs;

	if (needsRefLine)

		dsp->refruns = dsp->runs + nruns;

	else

		dsp->refruns = NULL;

	if (td->td_compression == COMPRESSION_CCITTFAX3

	    && is2DEncoding(dsp)) {	/* NB: default is 1D routine */

		tif->tif_decoderow = Fax3Decode2D;

		tif->tif_decodestrip = Fax3Decode2D;

		tif->tif_decodetile = Fax3Decode2D;

	}

	if (needsRefLine) {		/* 2d encoding */

		Fax3CodecState* esp = EncoderState(tif);

		/*

		 * 2d encoding requires a scanline

		 * buffer for the ``reference line''; the

		 * scanline against which delta encoding

		 * is referenced.  The reference line must

		 * be initialized to be ``white'' (done elsewhere).

		 */

		esp->refline = (unsigned char*) _TIFFmalloc(rowbytes);

		if (esp->refline == NULL) {

			TIFFErrorExt(tif->tif_clientdata, module,

			    "No space for Group 3/4 reference line");

			return (0);

		}

	} else					/* 1d encoding */

		EncoderState(tif)->refline = NULL;

	return (1);

}

/*

 * CCITT Group 3 FAX Encoding.

 */

#define	Fax3FlushBits(tif, sp) {				\

	if ((tif)->tif_rawcc >= (tif)->tif_rawdatasize)		\

		(void) TIFFFlushData1(tif);			\

	*(tif)->tif_rawcp++ = (uint8) (sp)->data;		\

	(tif)->tif_rawcc++;					\

	(sp)->data = 0, (sp)->bit = 8;				\

}

#define	_FlushBits(tif) {					\

	if ((tif)->tif_rawcc >= (tif)->tif_rawdatasize)		\

		(void) TIFFFlushData1(tif);			\

	*(tif)->tif_rawcp++ = (uint8) data;		\

	(tif)->tif_rawcc++;					\

	data = 0, bit = 8;					\

}

static const int _msbmask[9] =

    { 0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff };

#define	_PutBits(tif, bits, length) {				\

	while (length > bit) {					\

		data |= bits >> (length - bit);			\

		length -= bit;					\

		_FlushBits(tif);				\

	}							\

        assert( length < 9 );                                   \

	data |= (bits & _msbmask[length]) << (bit - length);	\

	bit -= length;						\

	if (bit == 0)						\

		_FlushBits(tif);				\

}

/*

 * Write a variable-length bit-value to

 * the output stream.  Values are

 * assumed to be at most 16 bits.

 */

static void

Fax3PutBits(TIFF* tif, unsigned int bits, unsigned int length)

{

	Fax3CodecState* sp = EncoderState(tif);

	unsigned int bit = sp->bit;

	int data = sp->data;

	_PutBits(tif, bits, length);

	sp->data = data;

	sp->bit = bit;

}

/*

 * Write a code to the output stream.

 */

#define putcode(tif, te)	Fax3PutBits(tif, (te)->code, (te)->length)

#ifdef FAX3_DEBUG

#define	DEBUG_COLOR(w) (tab == TIFFFaxWhiteCodes ? w "W" : w "B")

#define	DEBUG_PRINT(what,len) {						\

    int t;								\

    printf("%08X/%-2d: %s%5d\t", data, bit, DEBUG_COLOR(what), len);	\

    for (t = length-1; t >= 0; t--)					\

	putchar(code & (1<

    putchar('\n');							\

}

#endif

/*

 * Write the sequence of codes that describes

 * the specified span of zero's or one's.  The

 * appropriate table that holds the make-up and

 * terminating codes is supplied.

 */

static void

putspan(TIFF* tif, int32 span, const tableentry* tab)

{

	Fax3CodecState* sp = EncoderState(tif);

	unsigned int bit = sp->bit;

	int data = sp->data;

	unsigned int code, length;

	while (span >= 2624) {

		const tableentry* te = &tab[63 + (2560>>6)];

		code = te->code;

		length = te->length;

#ifdef FAX3_DEBUG

		DEBUG_PRINT("MakeUp", te->runlen);

#endif

		_PutBits(tif, code, length);

		span -= te->runlen;

	}

	if (span >= 64) {

		const tableentry* te = &tab[63 + (span>>6)];

		assert(te->runlen == 64*(span>>6));

		code = te->code;

		length = te->length;

#ifdef FAX3_DEBUG

		DEBUG_PRINT("MakeUp", te->runlen);

#endif

		_PutBits(tif, code, length);

		span -= te->runlen;

	}

	code = tab[span].code;

	length = tab[span].length;

#ifdef FAX3_DEBUG

	DEBUG_PRINT("  Term", tab[span].runlen);

#endif

	_PutBits(tif, code, length);

	sp->data = data;

	sp->bit = bit;

}

/*

 * Write an EOL code to the output stream.  The zero-fill

 * logic for byte-aligning encoded scanlines is handled

 * here.  We also handle writing the tag bit for the next

 * scanline when doing 2d encoding.

 */

static void

Fax3PutEOL(TIFF* tif)

{

	Fax3CodecState* sp = EncoderState(tif);

	unsigned int bit = sp->bit;

	int data = sp->data;

	unsigned int code, length, tparm;

	if (sp->b.groupoptions & GROUP3OPT_FILLBITS) {

		/*

		 * Force bit alignment so EOL will terminate on

		 * a byte boundary.  That is, force the bit alignment

		 * to 16-12 = 4 before putting out the EOL code.

		 */

		int align = 8 - 4;

		if (align != sp->bit) {

			if (align > sp->bit)

				align = sp->bit + (8 - align);

			else

				align = sp->bit - align;

			tparm=align; 

			_PutBits(tif, 0, tparm);

		}

	}

	code = EOL;

	length = 12;

	if (is2DEncoding(sp)) {

		code = (code<<1) | (sp->tag == G3_1D);

		length++;

	}

	_PutBits(tif, code, length);

	sp->data = data;

	sp->bit = bit;

}

/*

 * Reset encoding state at the start of a strip.

 */

static int

Fax3PreEncode(TIFF* tif, uint16 s)

{

	Fax3CodecState* sp = EncoderState(tif);

	(void) s;

	assert(sp != NULL);

	sp->bit = 8;

	sp->data = 0;

	sp->tag = G3_1D;

	/*

	 * This is necessary for Group 4; otherwise it isn't

	 * needed because the first scanline of each strip ends

	 * up being copied into the refline.

	 */

	if (sp->refline)

		_TIFFmemset(sp->refline, 0x00, sp->b.rowbytes);

	if (is2DEncoding(sp)) {

		float res = tif->tif_dir.td_yresolution;

		/*

		 * The CCITT spec says that when doing 2d encoding, you

		 * should only do it on K consecutive scanlines, where K

		 * depends on the resolution of the image being encoded

		 * (2 for <= 200 lpi, 4 for > 200 lpi).  Since the directory

		 * code initializes td_yresolution to 0, this code will

		 * select a K of 2 unless the YResolution tag is set

		 * appropriately.  (Note also that we fudge a little here

		 * and use 150 lpi to avoid problems with units conversion.)

		 */

		if (tif->tif_dir.td_resolutionunit == RESUNIT_CENTIMETER)

			res *= 2.54f;		/* convert to inches */

		sp->maxk = (res > 150 ? 4 : 2);

		sp->k = sp->maxk-1;

	} else

		sp->k = sp->maxk = 0;

	sp->line = 0;

	return (1);

}

static const unsigned char zeroruns[256] = {

    8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,	/* 0x00 - 0x0f */

    3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,	/* 0x10 - 0x1f */

    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,	/* 0x20 - 0x2f */

    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,	/* 0x30 - 0x3f */

    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x40 - 0x4f */

    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x50 - 0x5f */

    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x60 - 0x6f */

    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x70 - 0x7f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x80 - 0x8f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x90 - 0x9f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xa0 - 0xaf */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xb0 - 0xbf */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xc0 - 0xcf */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xd0 - 0xdf */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xe0 - 0xef */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0xf0 - 0xff */

};

static const unsigned char oneruns[256] = {

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x00 - 0x0f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x10 - 0x1f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x20 - 0x2f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x30 - 0x3f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x40 - 0x4f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x50 - 0x5f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x60 - 0x6f */

    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,	/* 0x70 - 0x7f */

    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x80 - 0x8f */

    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0x90 - 0x9f */

    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0xa0 - 0xaf */

    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,	/* 0xb0 - 0xbf */

    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,	/* 0xc0 - 0xcf */

    2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,	/* 0xd0 - 0xdf */

    3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,	/* 0xe0 - 0xef */

    4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 7, 8,	/* 0xf0 - 0xff */

};

/*

 * On certain systems it pays to inline

 * the routines that find pixel spans.

 */

#ifdef VAXC

static	int32 find0span(unsigned char*, int32, int32);

static	int32 find1span(unsigned char*, int32, int32);

#pragma inline(find0span,find1span)

#endif

/*

 * Find a span of ones or zeros using the supplied

 * table.  The ``base'' of the bit string is supplied

 * along with the start+end bit indices.

 */

inline static int32

find0span(unsigned char* bp, int32 bs, int32 be)

{

	int32 bits = be - bs;

	int32 n, span;

	bp += bs>>3;

	/*

	 * Check partial byte on lhs.

	 */

	if (bits > 0 && (n = (bs & 7)) != 0) {

		span = zeroruns[(*bp << n) & 0xff];

		if (span > 8-n)		/* table value too generous */

			span = 8-n;

		if (span > bits)	/* constrain span to bit range */

			span = bits;

		if (n+span < 8)		/* doesn't extend to edge of byte */

			return (span);

		bits -= span;

		bp++;

	} else

		span = 0;

	if (bits >= (int32)(2 * 8 * sizeof(long))) {

		long* lp;

		/*

		 * Align to longword boundary and check longwords.

		 */

		while (!isAligned(bp, long)) {

			if (*bp != 0x00)

				return (span + zeroruns[*bp]);

			span += 8;

			bits -= 8;

			bp++;

		}

		lp = (long*) bp;

		while ((bits >= (int32)(8 * sizeof(long))) && (0 == *lp)) {

			span += 8*sizeof (long);

			bits -= 8*sizeof (long);