tif_fax3.c

一个国人自己实现图像库的程序（有参考价值）

/* $Header: /cvsroot/osrs/libtiff/libtiff/tif_fax3.c,v 1.15 2001/09/09 16:10:37 warmerda 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 <assert.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) */
	TIFFVGetMethod vgetparent;	/* super-class method */
	TIFFVSetMethod vsetparent;	/* super-class method */
} Fax3BaseState;
#define	Fax3State(tif)		((Fax3BaseState*) (tif)->tif_data)

typedef struct {
	Fax3BaseState b;
	const u_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 */
} Fax3DecodeState;
#define	DecoderState(tif)	((Fax3DecodeState*) Fax3State(tif))

typedef enum { G3_1D, G3_2D } Ttag;
typedef struct {
	Fax3BaseState b;
	int	data;			/* current i/o byte */
	int	bit;			/* current i/o bit in byte */
	Ttag    tag;	                /* encoding state */
	u_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 */
} Fax3EncodeState;
#define	EncoderState(tif)	((Fax3EncodeState*) Fax3State(tif))

#define	is2DEncoding(sp) \
	(sp->b.groupoptions & GROUP3OPT_2DENCODING)
#define	isAligned(p,t)	((((u_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;					\
    Fax3DecodeState* 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 */	\
    u_char* cp;				/* next byte of input data */	\
    u_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 u_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)
{
	Fax3DecodeState* 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, (u_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, (u_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, (u_long) a0, (u_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, (u_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;
		if (occ != 0)
			tif->tif_row++;
		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;
		if (occ != 0)
			tif->tif_row++;
		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 defined(__alpha) || _MIPS_SZLONG == 64 || defined(__LP64__)
#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(u_char* buf, uint32* runs, uint32* erun, uint32 lastx)
{
	static const unsigned char _fillmasks[] =
	    { 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff };
	u_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 = (u_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 = (u_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);
	long rowbytes, rowpixels;
	int needsRefLine;

	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
	);
	if (sp->rw_mode == O_RDONLY) {	/* 1d/2d decoding */
		Fax3DecodeState* dsp = DecoderState(tif);
		uint32 nruns = needsRefLine ?
		     2*TIFFroundup(rowpixels,32) : rowpixels;

		dsp->runs = (uint32*) _TIFFmalloc((2*nruns+3)*sizeof (uint32));
		if (dsp->runs == NULL) {
			TIFFError("Fax3SetupState",
			    "%s: No space for Group 3/4 run arrays",
			    tif->tif_name);
			return (0);
		}
		dsp->curruns = dsp->runs;
		if (needsRefLine)
			dsp->refruns = dsp->runs + (nruns>>1);
		else
			dsp->refruns = NULL;
		if (is2DEncoding(dsp)) {	/* NB: default is 1D routine */
			tif->tif_decoderow = Fax3Decode2D;
			tif->tif_decodestrip = Fax3Decode2D;
			tif->tif_decodetile = Fax3Decode2D;
		}
	} else if (needsRefLine) {		/* 2d encoding */
		Fax3EncodeState* 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