First commit - moving from LuaForge to SourceForge

1 files changed, 1084 insertions, 0 deletions

diff --git a/src/libtiff/tif_lzw.c b/src/libtiff/tif_lzw.c
new file mode 100644
index 0000000..79d4091
--- /dev/null
+++ b/src/libtiff/tif_lzw.c
@@ -0,0 +1,1084 @@
+/* $Id: tif_lzw.c,v 1.1 2008/10/17 06:16:07 scuri Exp $ */
+
+/*
+ * Copyright (c) 1988-1997 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 LZW_SUPPORT
+/*
+ * TIFF Library.
+ * Rev 5.0 Lempel-Ziv & Welch Compression Support
+ *
+ * This code is derived from the compress program whose code is
+ * derived from software contributed to Berkeley by James A. Woods,
+ * derived from original work by Spencer Thomas and Joseph Orost.
+ *
+ * The original Berkeley copyright notice appears below in its entirety.
+ */
+#include "tif_predict.h"
+
+#include <stdio.h>
+
+/*
+ * NB: The 5.0 spec describes a different algorithm than Aldus
+ *     implements.  Specifically, Aldus does code length transitions
+ *     one code earlier than should be done (for real LZW).
+ *     Earlier versions of this library implemented the correct
+ *     LZW algorithm, but emitted codes in a bit order opposite
+ *     to the TIFF spec.  Thus, to maintain compatibility w/ Aldus
+ *     we interpret MSB-LSB ordered codes to be images written w/
+ *     old versions of this library, but otherwise adhere to the
+ *     Aldus "off by one" algorithm.
+ *
+ * Future revisions to the TIFF spec are expected to "clarify this issue".
+ */
+#define	LZW_COMPAT		/* include backwards compatibility code */
+/*
+ * Each strip of data is supposed to be terminated by a CODE_EOI.
+ * If the following #define is included, the decoder will also
+ * check for end-of-strip w/o seeing this code.  This makes the
+ * library more robust, but also slower.
+ */
+#define	LZW_CHECKEOS		/* include checks for strips w/o EOI code */
+
+#define MAXCODE(n)	((1L<<(n))-1)
+/*
+ * The TIFF spec specifies that encoded bit
+ * strings range from 9 to 12 bits.
+ */
+#define	BITS_MIN	9		/* start with 9 bits */
+#define	BITS_MAX	12		/* max of 12 bit strings */
+/* predefined codes */
+#define	CODE_CLEAR	256		/* code to clear string table */
+#define	CODE_EOI	257		/* end-of-information code */
+#define CODE_FIRST	258		/* first free code entry */
+#define	CODE_MAX	MAXCODE(BITS_MAX)
+#define	HSIZE		9001L		/* 91% occupancy */
+#define	HSHIFT		(13-8)
+#ifdef LZW_COMPAT
+/* NB: +1024 is for compatibility with old files */
+#define	CSIZE		(MAXCODE(BITS_MAX)+1024L)
+#else
+#define	CSIZE		(MAXCODE(BITS_MAX)+1L)
+#endif
+
+/*
+ * State block for each open TIFF file using LZW
+ * compression/decompression.  Note that the predictor
+ * state block must be first in this data structure.
+ */
+typedef	struct {
+	TIFFPredictorState predict;	/* predictor super class */
+
+	unsigned short	nbits;		/* # of bits/code */
+	unsigned short	maxcode;	/* maximum code for lzw_nbits */
+	unsigned short	free_ent;	/* next free entry in hash table */
+	long		nextdata;	/* next bits of i/o */
+	long		nextbits;	/* # of valid bits in lzw_nextdata */
+
+        int             rw_mode;        /* preserve rw_mode from init */
+} LZWBaseState;
+
+#define	lzw_nbits	base.nbits
+#define	lzw_maxcode	base.maxcode
+#define	lzw_free_ent	base.free_ent
+#define	lzw_nextdata	base.nextdata
+#define	lzw_nextbits	base.nextbits
+
+/*
+ * Encoding-specific state.
+ */
+typedef uint16 hcode_t;			/* codes fit in 16 bits */
+typedef struct {
+	long	hash;
+	hcode_t	code;
+} hash_t;
+
+/*
+ * Decoding-specific state.
+ */
+typedef struct code_ent {
+	struct code_ent *next;
+	unsigned short	length;		/* string len, including this token */
+	unsigned char	value;		/* data value */
+	unsigned char	firstchar;	/* first token of string */
+} code_t;
+
+typedef	int (*decodeFunc)(TIFF*, tidata_t, tsize_t, tsample_t);
+
+typedef struct {
+	LZWBaseState base;
+
+	/* Decoding specific data */
+	long	dec_nbitsmask;		/* lzw_nbits 1 bits, right adjusted */
+	long	dec_restart;		/* restart count */
+#ifdef LZW_CHECKEOS
+	long	dec_bitsleft;		/* available bits in raw data */
+#endif
+	decodeFunc dec_decode;		/* regular or backwards compatible */
+	code_t*	dec_codep;		/* current recognized code */
+	code_t*	dec_oldcodep;		/* previously recognized code */
+	code_t*	dec_free_entp;		/* next free entry */
+	code_t*	dec_maxcodep;		/* max available entry */
+	code_t*	dec_codetab;		/* kept separate for small machines */
+
+	/* Encoding specific data */
+	int	enc_oldcode;		/* last code encountered */
+	long	enc_checkpoint;		/* point at which to clear table */
+#define CHECK_GAP	10000		/* enc_ratio check interval */
+	long	enc_ratio;		/* current compression ratio */
+	long	enc_incount;		/* (input) data bytes encoded */
+	long	enc_outcount;		/* encoded (output) bytes */
+	tidata_t enc_rawlimit;		/* bound on tif_rawdata buffer */
+	hash_t*	enc_hashtab;		/* kept separate for small machines */
+} LZWCodecState;
+
+#define	LZWState(tif)		((LZWBaseState*) (tif)->tif_data)
+#define	DecoderState(tif)	((LZWCodecState*) LZWState(tif))
+#define	EncoderState(tif)	((LZWCodecState*) LZWState(tif))
+
+static	int LZWDecode(TIFF*, tidata_t, tsize_t, tsample_t);
+#ifdef LZW_COMPAT
+static	int LZWDecodeCompat(TIFF*, tidata_t, tsize_t, tsample_t);
+#endif
+static  void cl_hash(LZWCodecState*);
+
+/*
+ * LZW Decoder.
+ */
+
+#ifdef LZW_CHECKEOS
+/*
+ * This check shouldn't be necessary because each
+ * strip is suppose to be terminated with CODE_EOI.
+ */
+#define	NextCode(_tif, _sp, _bp, _code, _get) {				\
+	if ((_sp)->dec_bitsleft < nbits) {				\
+		TIFFWarningExt(_tif->tif_clientdata, _tif->tif_name,				\
+		    "LZWDecode: Strip %d not terminated with EOI code", \
+		    _tif->tif_curstrip);				\
+		_code = CODE_EOI;					\
+	} else {							\
+		_get(_sp,_bp,_code);					\
+		(_sp)->dec_bitsleft -= nbits;				\
+	}								\
+}
+#else
+#define	NextCode(tif, sp, bp, code, get) get(sp, bp, code)
+#endif
+
+static int
+LZWSetupDecode(TIFF* tif)
+{
+	LZWCodecState* sp = DecoderState(tif);
+	static const char module[] = " LZWSetupDecode";
+	int code;
+
+        if( sp == NULL )
+        {
+            /*
+             * Allocate state block so tag methods have storage to record 
+			 * values.
+             */
+            tif->tif_data = (tidata_t) _TIFFmalloc(sizeof(LZWCodecState));
+            if (tif->tif_data == NULL)
+            {
+				TIFFErrorExt(tif->tif_clientdata, "LZWPreDecode", "No space for LZW state block");
+                return (0);
+            }
+
+            DecoderState(tif)->dec_codetab = NULL;
+            DecoderState(tif)->dec_decode = NULL;
+            
+            /*
+             * Setup predictor setup.
+             */
+            (void) TIFFPredictorInit(tif);
+
+            sp = DecoderState(tif);
+        }
+            
+	assert(sp != NULL);
+
+	if (sp->dec_codetab == NULL) {
+		sp->dec_codetab = (code_t*)_TIFFmalloc(CSIZE*sizeof (code_t));
+		if (sp->dec_codetab == NULL) {
+			TIFFErrorExt(tif->tif_clientdata, module, "No space for LZW code table");
+			return (0);
+		}
+		/*
+		 * Pre-load the table.
+		 */
+                code = 255;
+                do {
+                    sp->dec_codetab[code].value = code;
+                    sp->dec_codetab[code].firstchar = code;
+                    sp->dec_codetab[code].length = 1;
+                    sp->dec_codetab[code].next = NULL;
+                } while (code--);
+	}
+	return (1);
+}
+
+/*
+ * Setup state for decoding a strip.
+ */
+static int
+LZWPreDecode(TIFF* tif, tsample_t s)
+{
+	LZWCodecState *sp = DecoderState(tif);
+
+	(void) s;
+	assert(sp != NULL);
+	/*
+	 * Check for old bit-reversed codes.
+	 */
+	if (tif->tif_rawdata[0] == 0 && (tif->tif_rawdata[1] & 0x1)) {
+#ifdef LZW_COMPAT
+		if (!sp->dec_decode) {
+			TIFFWarningExt(tif->tif_clientdata, tif->tif_name,
+			    "Old-style LZW codes, convert file");
+			/*
+			 * Override default decoding methods with
+			 * ones that deal with the old coding.
+			 * Otherwise the predictor versions set
+			 * above will call the compatibility routines
+			 * through the dec_decode method.
+			 */
+			tif->tif_decoderow = LZWDecodeCompat;
+			tif->tif_decodestrip = LZWDecodeCompat;
+			tif->tif_decodetile = LZWDecodeCompat;
+			/*
+			 * If doing horizontal differencing, must
+			 * re-setup the predictor logic since we
+			 * switched the basic decoder methods...
+			 */
+			(*tif->tif_setupdecode)(tif);
+			sp->dec_decode = LZWDecodeCompat;
+		}
+		sp->lzw_maxcode = MAXCODE(BITS_MIN);
+#else /* !LZW_COMPAT */
+		if (!sp->dec_decode) {
+			TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+			    "Old-style LZW codes not supported");
+			sp->dec_decode = LZWDecode;
+		}
+		return (0);
+#endif/* !LZW_COMPAT */
+	} else {
+		sp->lzw_maxcode = MAXCODE(BITS_MIN)-1;
+		sp->dec_decode = LZWDecode;
+	}
+	sp->lzw_nbits = BITS_MIN;
+	sp->lzw_nextbits = 0;
+	sp->lzw_nextdata = 0;
+
+	sp->dec_restart = 0;
+	sp->dec_nbitsmask = MAXCODE(BITS_MIN);
+#ifdef LZW_CHECKEOS
+	sp->dec_bitsleft = tif->tif_rawcc << 3;
+#endif
+	sp->dec_free_entp = sp->dec_codetab + CODE_FIRST;
+	/*
+	 * Zero entries that are not yet filled in.  We do
+	 * this to guard against bogus input data that causes
+	 * us to index into undefined entries.  If you can
+	 * come up with a way to safely bounds-check input codes
+	 * while decoding then you can remove this operation.
+	 */
+	_TIFFmemset(sp->dec_free_entp, 0, (CSIZE-CODE_FIRST)*sizeof (code_t));
+	sp->dec_oldcodep = &sp->dec_codetab[-1];
+	sp->dec_maxcodep = &sp->dec_codetab[sp->dec_nbitsmask-1];
+	return (1);
+}
+
+/*
+ * Decode a "hunk of data".
+ */
+#define	GetNextCode(sp, bp, code) {				\
+	nextdata = (nextdata<<8) | *(bp)++;			\
+	nextbits += 8;						\
+	if (nextbits < nbits) {					\
+		nextdata = (nextdata<<8) | *(bp)++;		\
+		nextbits += 8;					\
+	}							\
+	code = (hcode_t)((nextdata >> (nextbits-nbits)) & nbitsmask);	\
+	nextbits -= nbits;					\
+}
+
+static void
+codeLoop(TIFF* tif)
+{
+	TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+	    "LZWDecode: Bogus encoding, loop in the code table; scanline %d",
+	    tif->tif_row);
+}
+
+static int
+LZWDecode(TIFF* tif, tidata_t op0, tsize_t occ0, tsample_t s)
+{
+	LZWCodecState *sp = DecoderState(tif);
+	char *op = (char*) op0;
+	long occ = (long) occ0;
+	char *tp;
+	unsigned char *bp;
+	hcode_t code;
+	int len;
+	long nbits, nextbits, nextdata, nbitsmask;
+	code_t *codep, *free_entp, *maxcodep, *oldcodep;
+
+	(void) s;
+	assert(sp != NULL);
+	/*
+	 * Restart interrupted output operation.
+	 */
+	if (sp->dec_restart) {
+		long residue;
+
+		codep = sp->dec_codep;
+		residue = codep->length - sp->dec_restart;
+		if (residue > occ) {
+			/*
+			 * Residue from previous decode is sufficient
+			 * to satisfy decode request.  Skip to the
+			 * start of the decoded string, place decoded
+			 * values in the output buffer, and return.
+			 */
+			sp->dec_restart += occ;
+			do {
+				codep = codep->next;
+			} while (--residue > occ && codep);
+			if (codep) {
+				tp = op + occ;
+				do {
+					*--tp = codep->value;
+					codep = codep->next;
+				} while (--occ && codep);
+			}
+			return (1);
+		}
+		/*
+		 * Residue satisfies only part of the decode request.
+		 */
+		op += residue, occ -= residue;
+		tp = op;
+		do {
+			int t;
+			--tp;
+			t = codep->value;
+			codep = codep->next;
+			*tp = t;
+		} while (--residue && codep);
+		sp->dec_restart = 0;
+	}
+
+	bp = (unsigned char *)tif->tif_rawcp;
+	nbits = sp->lzw_nbits;
+	nextdata = sp->lzw_nextdata;
+	nextbits = sp->lzw_nextbits;
+	nbitsmask = sp->dec_nbitsmask;
+	oldcodep = sp->dec_oldcodep;
+	free_entp = sp->dec_free_entp;
+	maxcodep = sp->dec_maxcodep;
+
+	while (occ > 0) {
+		NextCode(tif, sp, bp, code, GetNextCode);
+		if (code == CODE_EOI)
+			break;
+		if (code == CODE_CLEAR) {
+			free_entp = sp->dec_codetab + CODE_FIRST;
+			nbits = BITS_MIN;
+			nbitsmask = MAXCODE(BITS_MIN);
+			maxcodep = sp->dec_codetab + nbitsmask-1;
+			NextCode(tif, sp, bp, code, GetNextCode);
+			if (code == CODE_EOI)
+				break;
+			*op++ = (char)code, occ--;
+			oldcodep = sp->dec_codetab + code;
+			continue;
+		}
+		codep = sp->dec_codetab + code;
+
+		/*
+	 	 * Add the new entry to the code table.
+	 	 */
+		if (free_entp < &sp->dec_codetab[0] ||
+			free_entp >= &sp->dec_codetab[CSIZE]) {
+			TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+			"LZWDecode: Corrupted LZW table at scanline %d",
+			tif->tif_row);
+			return (0);
+		}
+
+		free_entp->next = oldcodep;
+		if (free_entp->next < &sp->dec_codetab[0] ||
+			free_entp->next >= &sp->dec_codetab[CSIZE]) {
+			TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+			"LZWDecode: Corrupted LZW table at scanline %d",
+			tif->tif_row);
+			return (0);
+		}
+		free_entp->firstchar = free_entp->next->firstchar;
+		free_entp->length = free_entp->next->length+1;
+		free_entp->value = (codep < free_entp) ?
+		    codep->firstchar : free_entp->firstchar;
+		if (++free_entp > maxcodep) {
+			if (++nbits > BITS_MAX)		/* should not happen */
+				nbits = BITS_MAX;
+			nbitsmask = MAXCODE(nbits);
+			maxcodep = sp->dec_codetab + nbitsmask-1;
+		}
+		oldcodep = codep;
+		if (code >= 256) {
+			/*
+		 	 * Code maps to a string, copy string
+			 * value to output (written in reverse).
+		 	 */
+			if(codep->length == 0) {
+				TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+	    		    "LZWDecode: Wrong length of decoded string: "
+			    "data probably corrupted at scanline %d",
+			    tif->tif_row);	
+			    return (0);
+			}
+			if (codep->length > occ) {
+				/*
+				 * String is too long for decode buffer,
+				 * locate portion that will fit, copy to
+				 * the decode buffer, and setup restart
+				 * logic for the next decoding call.
+				 */
+				sp->dec_codep = codep;
+				do {
+					codep = codep->next;
+				} while (codep && codep->length > occ);
+				if (codep) {
+					sp->dec_restart = occ;
+					tp = op + occ;
+					do  {
+						*--tp = codep->value;
+						codep = codep->next;
+					}  while (--occ && codep);
+					if (codep)
+						codeLoop(tif);
+				}
+				break;
+			}
+			len = codep->length;
+			tp = op + len;
+			do {
+				int t;
+				--tp;
+				t = codep->value;
+				codep = codep->next;
+				*tp = t;
+			} while (codep && tp > op);
+			if (codep) {
+			    codeLoop(tif);
+			    break;
+			}
+			op += len, occ -= len;
+		} else
+			*op++ = (char)code, occ--;
+	}
+
+	tif->tif_rawcp = (tidata_t) bp;
+	sp->lzw_nbits = (unsigned short) nbits;
+	sp->lzw_nextdata = nextdata;
+	sp->lzw_nextbits = nextbits;
+	sp->dec_nbitsmask = nbitsmask;
+	sp->dec_oldcodep = oldcodep;
+	sp->dec_free_entp = free_entp;
+	sp->dec_maxcodep = maxcodep;
+
+	if (occ > 0) {
+		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+		"LZWDecode: Not enough data at scanline %d (short %d bytes)",
+		    tif->tif_row, occ);
+		return (0);
+	}
+	return (1);
+}
+
+#ifdef LZW_COMPAT
+/*
+ * Decode a "hunk of data" for old images.
+ */
+#define	GetNextCodeCompat(sp, bp, code) {			\
+	nextdata |= (unsigned long) *(bp)++ << nextbits;	\
+	nextbits += 8;						\
+	if (nextbits < nbits) {					\
+		nextdata |= (unsigned long) *(bp)++ << nextbits;\
+		nextbits += 8;					\
+	}							\
+	code = (hcode_t)(nextdata & nbitsmask);			\
+	nextdata >>= nbits;					\
+	nextbits -= nbits;					\
+}
+
+static int
+LZWDecodeCompat(TIFF* tif, tidata_t op0, tsize_t occ0, tsample_t s)
+{
+	LZWCodecState *sp = DecoderState(tif);
+	char *op = (char*) op0;
+	long occ = (long) occ0;
+	char *tp;
+	unsigned char *bp;
+	int code, nbits;
+	long nextbits, nextdata, nbitsmask;
+	code_t *codep, *free_entp, *maxcodep, *oldcodep;
+
+	(void) s;
+	assert(sp != NULL);
+	/*
+	 * Restart interrupted output operation.
+	 */
+	if (sp->dec_restart) {
+		long residue;
+
+		codep = sp->dec_codep;
+		residue = codep->length - sp->dec_restart;
+		if (residue > occ) {
+			/*
+			 * Residue from previous decode is sufficient
+			 * to satisfy decode request.  Skip to the
+			 * start of the decoded string, place decoded
+			 * values in the output buffer, and return.
+			 */
+			sp->dec_restart += occ;
+			do {
+				codep = codep->next;
+			} while (--residue > occ);
+			tp = op + occ;
+			do {
+				*--tp = codep->value;
+				codep = codep->next;
+			} while (--occ);
+			return (1);
+		}
+		/*
+		 * Residue satisfies only part of the decode request.
+		 */
+		op += residue, occ -= residue;
+		tp = op;
+		do {
+			*--tp = codep->value;
+			codep = codep->next;
+		} while (--residue);
+		sp->dec_restart = 0;
+	}
+
+	bp = (unsigned char *)tif->tif_rawcp;
+	nbits = sp->lzw_nbits;
+	nextdata = sp->lzw_nextdata;
+	nextbits = sp->lzw_nextbits;
+	nbitsmask = sp->dec_nbitsmask;
+	oldcodep = sp->dec_oldcodep;
+	free_entp = sp->dec_free_entp;
+	maxcodep = sp->dec_maxcodep;
+
+	while (occ > 0) {
+		NextCode(tif, sp, bp, code, GetNextCodeCompat);
+		if (code == CODE_EOI)
+			break;
+		if (code == CODE_CLEAR) {
+			free_entp = sp->dec_codetab + CODE_FIRST;
+			nbits = BITS_MIN;
+			nbitsmask = MAXCODE(BITS_MIN);
+			maxcodep = sp->dec_codetab + nbitsmask;
+			NextCode(tif, sp, bp, code, GetNextCodeCompat);
+			if (code == CODE_EOI)
+				break;
+			*op++ = code, occ--;
+			oldcodep = sp->dec_codetab + code;
+			continue;
+		}
+		codep = sp->dec_codetab + code;
+
+		/*
+	 	 * Add the new entry to the code table.
+	 	 */
+		if (free_entp < &sp->dec_codetab[0] ||
+			free_entp >= &sp->dec_codetab[CSIZE]) {
+			TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+			"LZWDecodeCompat: Corrupted LZW table at scanline %d",
+			tif->tif_row);
+			return (0);
+		}
+
+		free_entp->next = oldcodep;
+		if (free_entp->next < &sp->dec_codetab[0] ||
+			free_entp->next >= &sp->dec_codetab[CSIZE]) {
+			TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+			"LZWDecodeCompat: Corrupted LZW table at scanline %d",
+			tif->tif_row);
+			return (0);
+		}
+		free_entp->firstchar = free_entp->next->firstchar;
+		free_entp->length = free_entp->next->length+1;
+		free_entp->value = (codep < free_entp) ?
+		    codep->firstchar : free_entp->firstchar;
+		if (++free_entp > maxcodep) {
+			if (++nbits > BITS_MAX)		/* should not happen */
+				nbits = BITS_MAX;
+			nbitsmask = MAXCODE(nbits);
+			maxcodep = sp->dec_codetab + nbitsmask;
+		}
+		oldcodep = codep;
+		if (code >= 256) {
+			/*
+		 	 * Code maps to a string, copy string
+			 * value to output (written in reverse).
+		 	 */
+			if(codep->length == 0) {
+				TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+	    		    "LZWDecodeCompat: Wrong length of decoded "
+			    "string: data probably corrupted at scanline %d",
+			    tif->tif_row);	
+			    return (0);
+			}
+			if (codep->length > occ) {
+				/*
+				 * String is too long for decode buffer,
+				 * locate portion that will fit, copy to
+				 * the decode buffer, and setup restart
+				 * logic for the next decoding call.
+				 */
+				sp->dec_codep = codep;
+				do {
+					codep = codep->next;
+				} while (codep->length > occ);
+				sp->dec_restart = occ;
+				tp = op + occ;
+				do  {
+					*--tp = codep->value;
+					codep = codep->next;
+				}  while (--occ);
+				break;
+			}
+			op += codep->length, occ -= codep->length;
+			tp = op;
+			do {
+				*--tp = codep->value;
+			} while( (codep = codep->next) != NULL);
+		} else
+			*op++ = code, occ--;
+	}
+
+	tif->tif_rawcp = (tidata_t) bp;
+	sp->lzw_nbits = nbits;
+	sp->lzw_nextdata = nextdata;
+	sp->lzw_nextbits = nextbits;
+	sp->dec_nbitsmask = nbitsmask;
+	sp->dec_oldcodep = oldcodep;
+	sp->dec_free_entp = free_entp;
+	sp->dec_maxcodep = maxcodep;
+
+	if (occ > 0) {
+		TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
+	    "LZWDecodeCompat: Not enough data at scanline %d (short %d bytes)",
+		    tif->tif_row, occ);
+		return (0);
+	}
+	return (1);
+}
+#endif /* LZW_COMPAT */
+
+/*
+ * LZW Encoding.
+ */
+
+static int
+LZWSetupEncode(TIFF* tif)
+{
+	LZWCodecState* sp = EncoderState(tif);
+	static const char module[] = "LZWSetupEncode";
+
+	assert(sp != NULL);
+	sp->enc_hashtab = (hash_t*) _TIFFmalloc(HSIZE*sizeof (hash_t));
+	if (sp->enc_hashtab == NULL) {
+		TIFFErrorExt(tif->tif_clientdata, module, "No space for LZW hash table");
+		return (0);
+	}
+	return (1);
+}
+
+/*
+ * Reset encoding state at the start of a strip.
+ */
+static int
+LZWPreEncode(TIFF* tif, tsample_t s)
+{
+	LZWCodecState *sp = EncoderState(tif);
+
+	(void) s;
+	assert(sp != NULL);
+	sp->lzw_nbits = BITS_MIN;
+	sp->lzw_maxcode = MAXCODE(BITS_MIN);
+	sp->lzw_free_ent = CODE_FIRST;
+	sp->lzw_nextbits = 0;
+	sp->lzw_nextdata = 0;
+	sp->enc_checkpoint = CHECK_GAP;
+	sp->enc_ratio = 0;
+	sp->enc_incount = 0;
+	sp->enc_outcount = 0;
+	/*
+	 * The 4 here insures there is space for 2 max-sized
+	 * codes in LZWEncode and LZWPostDecode.
+	 */
+	sp->enc_rawlimit = tif->tif_rawdata + tif->tif_rawdatasize-1 - 4;
+	cl_hash(sp);		/* clear hash table */
+	sp->enc_oldcode = (hcode_t) -1;	/* generates CODE_CLEAR in LZWEncode */
+	return (1);
+}
+
+#define	CALCRATIO(sp, rat) {					\
+	if (incount > 0x007fffff) { /* NB: shift will overflow */\
+		rat = outcount >> 8;				\
+		rat = (rat == 0 ? 0x7fffffff : incount/rat);	\
+	} else							\
+		rat = (incount<<8) / outcount;			\
+}
+#define	PutNextCode(op, c) {					\
+	nextdata = (nextdata << nbits) | c;			\
+	nextbits += nbits;					\
+	*op++ = (unsigned char)(nextdata >> (nextbits-8));		\
+	nextbits -= 8;						\
+	if (nextbits >= 8) {					\
+		*op++ = (unsigned char)(nextdata >> (nextbits-8));	\
+		nextbits -= 8;					\
+	}							\
+	outcount += nbits;					\
+}
+
+/*
+ * Encode a chunk of pixels.
+ *
+ * Uses an open addressing double hashing (no chaining) on the 
+ * prefix code/next character combination.  We do a variant of
+ * Knuth's algorithm D (vol. 3, sec. 6.4) along with G. Knott's
+ * relatively-prime secondary probe.  Here, the modular division
+ * first probe is gives way to a faster exclusive-or manipulation. 
+ * Also do block compression with an adaptive reset, whereby the
+ * code table is cleared when the compression ratio decreases,
+ * but after the table fills.  The variable-length output codes
+ * are re-sized at this point, and a CODE_CLEAR is generated
+ * for the decoder. 
+ */
+static int
+LZWEncode(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
+{
+	register LZWCodecState *sp = EncoderState(tif);
+	register long fcode;
+	register hash_t *hp;
+	register int h, c;
+	hcode_t ent;
+	long disp;
+	long incount, outcount, checkpoint;
+	long nextdata, nextbits;
+	int free_ent, maxcode, nbits;
+	tidata_t op, limit;
+
+	(void) s;
+	if (sp == NULL)
+		return (0);
+	/*
+	 * Load local state.
+	 */
+	incount = sp->enc_incount;
+	outcount = sp->enc_outcount;
+	checkpoint = sp->enc_checkpoint;
+	nextdata = sp->lzw_nextdata;
+	nextbits = sp->lzw_nextbits;
+	free_ent = sp->lzw_free_ent;
+	maxcode = sp->lzw_maxcode;
+	nbits = sp->lzw_nbits;
+	op = tif->tif_rawcp;
+	limit = sp->enc_rawlimit;
+	ent = sp->enc_oldcode;
+
+	if (ent == (hcode_t) -1 && cc > 0) {
+		/*
+		 * NB: This is safe because it can only happen
+		 *     at the start of a strip where we know there
+		 *     is space in the data buffer.
+		 */
+		PutNextCode(op, CODE_CLEAR);
+		ent = *bp++; cc--; incount++;
+	}
+	while (cc > 0) {
+		c = *bp++; cc--; incount++;
+		fcode = ((long)c << BITS_MAX) + ent;
+		h = (c << HSHIFT) ^ ent;	/* xor hashing */
+#ifdef _WINDOWS
+		/*
+		 * Check hash index for an overflow.
+		 */
+		if (h >= HSIZE)
+			h -= HSIZE;
+#endif
+		hp = &sp->enc_hashtab[h];
+		if (hp->hash == fcode) {
+			ent = hp->code;
+			continue;
+		}
+		if (hp->hash >= 0) {
+			/*
+			 * Primary hash failed, check secondary hash.
+			 */
+			disp = HSIZE - h;
+			if (h == 0)
+				disp = 1;
+			do {
+				/*
+				 * Avoid pointer arithmetic 'cuz of
+				 * wraparound problems with segments.
+				 */
+				if ((h -= disp) < 0)
+					h += HSIZE;
+				hp = &sp->enc_hashtab[h];
+				if (hp->hash == fcode) {
+					ent = hp->code;
+					goto hit;
+				}
+			} while (hp->hash >= 0);
+		}
+		/*
+		 * New entry, emit code and add to table.
+		 */
+		/*
+		 * Verify there is space in the buffer for the code
+		 * and any potential Clear code that might be emitted
+		 * below.  The value of limit is setup so that there
+		 * are at least 4 bytes free--room for 2 codes.
+		 */
+		if (op > limit) {
+			tif->tif_rawcc = (tsize_t)(op - tif->tif_rawdata);
+			TIFFFlushData1(tif);
+			op = tif->tif_rawdata;
+		}
+		PutNextCode(op, ent);
+		ent = c;
+		hp->code = free_ent++;
+		hp->hash = fcode;
+		if (free_ent == CODE_MAX-1) {
+			/* table is full, emit clear code and reset */
+			cl_hash(sp);
+			sp->enc_ratio = 0;
+			incount = 0;
+			outcount = 0;
+			free_ent = CODE_FIRST;
+			PutNextCode(op, CODE_CLEAR);
+			nbits = BITS_MIN;
+			maxcode = MAXCODE(BITS_MIN);
+		} else {
+			/*
+			 * If the next entry is going to be too big for
+			 * the code size, then increase it, if possible.
+			 */
+			if (free_ent > maxcode) {
+				nbits++;
+				assert(nbits <= BITS_MAX);
+				maxcode = (int) MAXCODE(nbits);
+			} else if (incount >= checkpoint) {
+				long rat;
+				/*
+				 * Check compression ratio and, if things seem
+				 * to be slipping, clear the hash table and
+				 * reset state.  The compression ratio is a
+				 * 24+8-bit fractional number.
+				 */
+				checkpoint = incount+CHECK_GAP;
+				CALCRATIO(sp, rat);
+				if (rat <= sp->enc_ratio) {
+					cl_hash(sp);
+					sp->enc_ratio = 0;
+					incount = 0;
+					outcount = 0;
+					free_ent = CODE_FIRST;
+					PutNextCode(op, CODE_CLEAR);
+					nbits = BITS_MIN;
+					maxcode = MAXCODE(BITS_MIN);
+				} else
+					sp->enc_ratio = rat;
+			}
+		}
+	hit:
+		;
+	}
+
+	/*
+	 * Restore global state.
+	 */
+	sp->enc_incount = incount;
+	sp->enc_outcount = outcount;
+	sp->enc_checkpoint = checkpoint;
+	sp->enc_oldcode = ent;
+	sp->lzw_nextdata = nextdata;
+	sp->lzw_nextbits = nextbits;
+	sp->lzw_free_ent = free_ent;
+	sp->lzw_maxcode = maxcode;
+	sp->lzw_nbits = nbits;
+	tif->tif_rawcp = op;
+	return (1);
+}
+
+/*
+ * Finish off an encoded strip by flushing the last
+ * string and tacking on an End Of Information code.
+ */
+static int
+LZWPostEncode(TIFF* tif)
+{
+	register LZWCodecState *sp = EncoderState(tif);
+	tidata_t op = tif->tif_rawcp;
+	long nextbits = sp->lzw_nextbits;
+	long nextdata = sp->lzw_nextdata;
+	long outcount = sp->enc_outcount;
+	int nbits = sp->lzw_nbits;
+
+	if (op > sp->enc_rawlimit) {
+		tif->tif_rawcc = (tsize_t)(op - tif->tif_rawdata);
+		TIFFFlushData1(tif);
+		op = tif->tif_rawdata;
+	}
+	if (sp->enc_oldcode != (hcode_t) -1) {
+		PutNextCode(op, sp->enc_oldcode);
+		sp->enc_oldcode = (hcode_t) -1;
+	}
+	PutNextCode(op, CODE_EOI);
+	if (nextbits > 0) 
+		*op++ = (unsigned char)(nextdata << (8-nextbits));
+	tif->tif_rawcc = (tsize_t)(op - tif->tif_rawdata);
+	return (1);
+}
+
+/*
+ * Reset encoding hash table.
+ */
+static void
+cl_hash(LZWCodecState* sp)
+{
+	register hash_t *hp = &sp->enc_hashtab[HSIZE-1];
+	register long i = HSIZE-8;
+
+ 	do {
+		i -= 8;
+		hp[-7].hash = -1;
+		hp[-6].hash = -1;
+		hp[-5].hash = -1;
+		hp[-4].hash = -1;
+		hp[-3].hash = -1;
+		hp[-2].hash = -1;
+		hp[-1].hash = -1;
+		hp[ 0].hash = -1;
+		hp -= 8;
+	} while (i >= 0);
+    	for (i += 8; i > 0; i--, hp--)
+		hp->hash = -1;
+}
+
+static void
+LZWCleanup(TIFF* tif)
+{
+	(void)TIFFPredictorCleanup(tif);
+
+	assert(tif->tif_data != 0);
+
+	if (DecoderState(tif)->dec_codetab)
+		_TIFFfree(DecoderState(tif)->dec_codetab);
+
+	if (EncoderState(tif)->enc_hashtab)
+		_TIFFfree(EncoderState(tif)->enc_hashtab);
+
+	_TIFFfree(tif->tif_data);
+	tif->tif_data = NULL;
+
+	_TIFFSetDefaultCompressionState(tif);
+}
+
+int
+TIFFInitLZW(TIFF* tif, int scheme)
+{
+	assert(scheme == COMPRESSION_LZW);
+	/*
+	 * Allocate state block so tag methods have storage to record values.
+	 */
+	tif->tif_data = (tidata_t) _TIFFmalloc(sizeof (LZWCodecState));
+	if (tif->tif_data == NULL)
+		goto bad;
+	DecoderState(tif)->dec_codetab = NULL;
+	DecoderState(tif)->dec_decode = NULL;
+	EncoderState(tif)->enc_hashtab = NULL;
+        LZWState(tif)->rw_mode = tif->tif_mode;
+
+	/*
+	 * Install codec methods.
+	 */
+	tif->tif_setupdecode = LZWSetupDecode;
+	tif->tif_predecode = LZWPreDecode;
+	tif->tif_decoderow = LZWDecode;
+	tif->tif_decodestrip = LZWDecode;
+	tif->tif_decodetile = LZWDecode;
+	tif->tif_setupencode = LZWSetupEncode;
+	tif->tif_preencode = LZWPreEncode;
+	tif->tif_postencode = LZWPostEncode;
+	tif->tif_encoderow = LZWEncode;
+	tif->tif_encodestrip = LZWEncode;
+	tif->tif_encodetile = LZWEncode;
+	tif->tif_cleanup = LZWCleanup;
+	/*
+	 * Setup predictor setup.
+	 */
+	(void) TIFFPredictorInit(tif);
+	return (1);
+bad:
+	TIFFErrorExt(tif->tif_clientdata, "TIFFInitLZW", 
+		     "No space for LZW state block");
+	return (0);
+}
+
+/*
+ * Copyright (c) 1985, 1986 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * James A. Woods, derived from original work by Spencer Thomas
+ * and Joseph Orost.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+#endif /* LZW_SUPPORT */
+
+/* vim: set ts=8 sts=8 sw=8 noet: */