--- /dev/null
+/* $Header$ */
+
+/*
+ * 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 <assert.h>
+#include <stdio.h>
+
+static int
+PackBitsPreEncode(TIFF* tif, tsample_t s)
+{
+ (void) s;
+ /*
+ * Calculate the scanline/tile-width size in bytes.
+ */
+ if (isTiled(tif))
+ tif->tif_data = (tidata_t) TIFFTileRowSize(tif);
+ else
+ tif->tif_data = (tidata_t) TIFFScanlineSize(tif);
+ 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)
+{
+ u_char* bp = (u_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++ = b;
+ n -= 128;
+ goto again;
+ }
+ *op++ = (tidataval_t)(-(n-1));
+ *op++ = b;
+ } else {
+ lastliteral = op;
+ *op++ = 0;
+ *op++ = b;
+ state = LITERAL;
+ }
+ break;
+ case LITERAL: /* last object was literal string */
+ if (n > 1) {
+ state = LITERAL_RUN;
+ if (n > 128) {
+ *op++ = (tidata) -127;
+ *op++ = b;
+ n -= 128;
+ goto again;
+ }
+ *op++ = (tidataval_t)(-(n-1)); /* encode run */
+ *op++ = b;
+ } else { /* extend literal */
+ if (++(*lastliteral) == 127)
+ state = BASE;
+ *op++ = b;
+ }
+ break;
+ case RUN: /* last object was run */
+ if (n > 1) {
+ if (n > 128) {
+ *op++ = (tidata) -127;
+ *op++ = b;
+ n -= 128;
+ goto again;
+ }
+ *op++ = (tidataval_t)(-(n-1));
+ *op++ = b;
+ } else {
+ lastliteral = op;
+ *op++ = 0;
+ *op++ = 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;
+
+ assert(rowsize > 0);
+ while ((long)cc > 0) {
+ if (PackBitsEncode(tif, bp, rowsize, s) < 0)
+ return (-1);
+ bp += rowsize;
+ cc -= rowsize;
+ }
+ 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;
+ occ -= n;
+ b = *bp++, cc--;
+ while (n-- > 0)
+ *op++ = b;
+ } else { /* copy next n+1 bytes literally */
+ _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);
+ }
+ /* check for buffer overruns? */
+ 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_encoderow = PackBitsEncode;
+ tif->tif_encodestrip = PackBitsEncodeChunk;
+ tif->tif_encodetile = PackBitsEncodeChunk;
+ return (1);
+}
+#endif /* PACKBITS_SUPPORT */
projects / wxWidgets.git / blobdiff