static int
LZWDecode(TIFF* tif, uint8* op0, tmsize_t occ0, uint16 s)
{
static const char module[] = "LZWDecode";
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, nbitsmask;
unsigned long nextdata;
code_t *codep, *free_entp, *maxcodep, *oldcodep;
(void) s;
assert(sp != NULL);
assert(sp->dec_codetab != NULL);
/*
Fail if value does not fit in long.
*/
if ((tmsize_t) occ != occ0)
return (0);
/*
* 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 = (char)t;
} while (--residue && codep);
sp->dec_restart = 0;
}
bp = (unsigned char *)tif->tif_rawcp;
#ifdef LZW_CHECKEOS
sp->dec_bitsleft = (((uint64)tif->tif_rawcc) << 3);
#endif
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) {
do {
free_entp = sp->dec_codetab + CODE_FIRST;
_TIFFmemset(free_entp, 0,
(CSIZE - CODE_FIRST) * sizeof (code_t));
nbits = BITS_MIN;
nbitsmask = MAXCODE(BITS_MIN);
maxcodep = sp->dec_codetab + nbitsmask-1;
NextCode(tif, sp, bp, code, GetNextCode);
} while (code == CODE_CLEAR); /* consecutive CODE_CLEAR codes */
if (code == CODE_EOI)
break;
if (code > CODE_CLEAR) {
TIFFErrorExt(tif->tif_clientdata, tif->tif_name,
"LZWDecode: Corrupted LZW table at scanline %d",
tif->tif_row);
return (0);
}
*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, module,
"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, module,
"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, module,
"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 = (long)occ;
tp = op + occ;
do {
*--tp = codep->value;
codep = codep->next;
} while (--occ && codep);
if (codep)
codeLoop(tif, module);
}
break;
}
len = codep->length;
tp = op + len;
do {
int t;
--tp;
t = codep->value;
codep = codep->next;
*tp = (char)t;
} while (codep && tp > op);
if (codep) {
codeLoop(tif, module);
break;
}
assert(occ >= len);
op += len;
occ -= len;
} else {
*op++ = (char)code;
occ--;
}
}
tif->tif_rawcc -= (tmsize_t)( (uint8*) bp - tif->tif_rawcp );
tif->tif_rawcp = (uint8*) 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) {
#if defined(__WIN32__) && (defined(_MSC_VER) || defined(__MINGW32__))
TIFFErrorExt(tif->tif_clientdata, module,
"Not enough data at scanline %d (short %I64d bytes)",
tif->tif_row, (unsigned __int64) occ);
#else
TIFFErrorExt(tif->tif_clientdata, module,
"Not enough data at scanline %d (short %llu bytes)",
tif->tif_row, (unsigned long long) occ);
#endif
return (0);
}
return (1);
}
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;
u_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 = (char) t;
} while (--residue && codep);
sp->dec_restart = 0;
}
bp = (u_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]) {
TIFFError(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]) {
TIFFError(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) {
TIFFError(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 = (char) 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 = (u_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) {
TIFFError(tif->tif_name,
"LZWDecode: Not enough data at scanline %d (short %d bytes)",
tif->tif_row, occ);
return (0);
}
return (1);
}