+++ /dev/null
-/* $Id: tif_packbits.c,v 1.1 2005/06/17 13:54:52 vp153 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 PACKBITS_SUPPORT
-/*
- * TIFF Library.
- *
- * PackBits Compression Algorithm Support
- */
-#include <stdio.h>
-
-static int
-PackBitsPreEncode(TIFF* tif, tsample_t s)
-{
- (void) s;
-
- if (!(tif->tif_data = _TIFFmalloc(sizeof(tsize_t))))
- return (0);
- /*
- * Calculate the scanline/tile-width size in bytes.
- */
- if (isTiled(tif))
- *(tsize_t*)tif->tif_data = TIFFTileRowSize(tif);
- else
- *(tsize_t*)tif->tif_data = TIFFScanlineSize(tif);
- return (1);
-}
-
-static int
-PackBitsPostEncode(TIFF* tif)
-{
- if (tif->tif_data)
- _TIFFfree(tif->tif_data);
- return (1);
-}
-
-/*
- * NB: tidata is the type representing *(tidata_t);
- * if tidata_t is made signed then this type must
- * be adjusted accordingly.
- */
-typedef unsigned char tidata;
-
-/*
- * Encode a run of pixels.
- */
-static int
-PackBitsEncode(TIFF* tif, tidata_t buf, tsize_t cc, tsample_t s)
-{
- unsigned char* bp = (unsigned char*) buf;
- tidata_t op, ep, lastliteral;
- long n, slop;
- int b;
- enum { BASE, LITERAL, RUN, LITERAL_RUN } state;
-
- (void) s;
- op = tif->tif_rawcp;
- ep = tif->tif_rawdata + tif->tif_rawdatasize;
- state = BASE;
- lastliteral = 0;
- while (cc > 0) {
- /*
- * Find the longest string of identical bytes.
- */
- b = *bp++, cc--, n = 1;
- for (; cc > 0 && b == *bp; cc--, bp++)
- n++;
- again:
- if (op + 2 >= ep) { /* insure space for new data */
- /*
- * Be careful about writing the last
- * literal. Must write up to that point
- * and then copy the remainder to the
- * front of the buffer.
- */
- if (state == LITERAL || state == LITERAL_RUN) {
- slop = op - lastliteral;
- tif->tif_rawcc += lastliteral - tif->tif_rawcp;
- if (!TIFFFlushData1(tif))
- return (-1);
- op = tif->tif_rawcp;
- while (slop-- > 0)
- *op++ = *lastliteral++;
- lastliteral = tif->tif_rawcp;
- } else {
- tif->tif_rawcc += op - tif->tif_rawcp;
- if (!TIFFFlushData1(tif))
- return (-1);
- op = tif->tif_rawcp;
- }
- }
- switch (state) {
- case BASE: /* initial state, set run/literal */
- if (n > 1) {
- state = RUN;
- if (n > 128) {
- *op++ = (tidata) -127;
- *op++ = (tidataval_t) b;
- n -= 128;
- goto again;
- }
- *op++ = (tidataval_t)(-(n-1));
- *op++ = (tidataval_t) b;
- } else {
- lastliteral = op;
- *op++ = 0;
- *op++ = (tidataval_t) b;
- state = LITERAL;
- }
- break;
- case LITERAL: /* last object was literal string */
- if (n > 1) {
- state = LITERAL_RUN;
- if (n > 128) {
- *op++ = (tidata) -127;
- *op++ = (tidataval_t) b;
- n -= 128;
- goto again;
- }
- *op++ = (tidataval_t)(-(n-1)); /* encode run */
- *op++ = (tidataval_t) b;
- } else { /* extend literal */
- if (++(*lastliteral) == 127)
- state = BASE;
- *op++ = (tidataval_t) b;
- }
- break;
- case RUN: /* last object was run */
- if (n > 1) {
- if (n > 128) {
- *op++ = (tidata) -127;
- *op++ = (tidataval_t) b;
- n -= 128;
- goto again;
- }
- *op++ = (tidataval_t)(-(n-1));
- *op++ = (tidataval_t) b;
- } else {
- lastliteral = op;
- *op++ = 0;
- *op++ = (tidataval_t) b;
- state = LITERAL;
- }
- break;
- case LITERAL_RUN: /* literal followed by a run */
- /*
- * Check to see if previous run should
- * be converted to a literal, in which
- * case we convert literal-run-literal
- * to a single literal.
- */
- if (n == 1 && op[-2] == (tidata) -1 &&
- *lastliteral < 126) {
- state = (((*lastliteral) += 2) == 127 ?
- BASE : LITERAL);
- op[-2] = op[-1]; /* replicate */
- } else
- state = RUN;
- goto again;
- }
- }
- tif->tif_rawcc += op - tif->tif_rawcp;
- tif->tif_rawcp = op;
- return (1);
-}
-
-/*
- * Encode a rectangular chunk of pixels. We break it up
- * into row-sized pieces to insure that encoded runs do
- * not span rows. Otherwise, there can be problems with
- * the decoder if data is read, for example, by scanlines
- * when it was encoded by strips.
- */
-static int
-PackBitsEncodeChunk(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
-{
- tsize_t rowsize = *(tsize_t*)tif->tif_data;
-
- while ((long)cc > 0) {
- int chunk = rowsize;
-
- if( cc < chunk )
- chunk = cc;
-
- if (PackBitsEncode(tif, bp, chunk, s) < 0)
- return (-1);
- bp += chunk;
- cc -= chunk;
- }
- return (1);
-}
-
-static int
-PackBitsDecode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
-{
- char *bp;
- tsize_t cc;
- long n;
- int b;
-
- (void) s;
- bp = (char*) tif->tif_rawcp;
- cc = tif->tif_rawcc;
- while (cc > 0 && (long)occ > 0) {
- n = (long) *bp++, cc--;
- /*
- * Watch out for compilers that
- * don't sign extend chars...
- */
- if (n >= 128)
- n -= 256;
- if (n < 0) { /* replicate next byte -n+1 times */
- if (n == -128) /* nop */
- continue;
- n = -n + 1;
- if( occ < n )
- {
- TIFFWarning(tif->tif_name,
- "PackBitsDecode: discarding %d bytes "
- "to avoid buffer overrun",
- n - occ);
- n = occ;
- }
- occ -= n;
- b = *bp++, cc--;
- while (n-- > 0)
- *op++ = (tidataval_t) b;
- } else { /* copy next n+1 bytes literally */
- if (occ < n + 1)
- {
- TIFFWarning(tif->tif_name,
- "PackBitsDecode: discarding %d bytes "
- "to avoid buffer overrun",
- n - occ + 1);
- n = occ - 1;
- }
- _TIFFmemcpy(op, bp, ++n);
- op += n; occ -= n;
- bp += n; cc -= n;
- }
- }
- tif->tif_rawcp = (tidata_t) bp;
- tif->tif_rawcc = cc;
- if (occ > 0) {
- TIFFError(tif->tif_name,
- "PackBitsDecode: Not enough data for scanline %ld",
- (long) tif->tif_row);
- return (0);
- }
- return (1);
-}
-
-int
-TIFFInitPackBits(TIFF* tif, int scheme)
-{
- (void) scheme;
- tif->tif_decoderow = PackBitsDecode;
- tif->tif_decodestrip = PackBitsDecode;
- tif->tif_decodetile = PackBitsDecode;
- tif->tif_preencode = PackBitsPreEncode;
- tif->tif_postencode = PackBitsPostEncode;
- tif->tif_encoderow = PackBitsEncode;
- tif->tif_encodestrip = PackBitsEncodeChunk;
- tif->tif_encodetile = PackBitsEncodeChunk;
- return (1);
-}
-#endif /* PACKBITS_SUPPORT */
-
-/* vim: set ts=8 sts=8 sw=8 noet: */
projects / opencv / blobdiff