| /* |
| * 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, uint16_t s) |
| { |
| (void)s; |
| |
| tif->tif_data = (uint8_t *)_TIFFmallocExt(tif, sizeof(tmsize_t)); |
| if (tif->tif_data == NULL) |
| return (0); |
| /* |
| * Calculate the scanline/tile-width size in bytes. |
| */ |
| if (isTiled(tif)) |
| *(tmsize_t *)tif->tif_data = TIFFTileRowSize(tif); |
| else |
| *(tmsize_t *)tif->tif_data = TIFFScanlineSize(tif); |
| return (1); |
| } |
| |
| static int PackBitsPostEncode(TIFF *tif) |
| { |
| if (tif->tif_data) |
| _TIFFfreeExt(tif, tif->tif_data); |
| return (1); |
| } |
| |
| /* |
| * Encode a run of pixels. |
| */ |
| static int PackBitsEncode(TIFF *tif, uint8_t *buf, tmsize_t cc, uint16_t s) |
| { |
| unsigned char *bp = (unsigned char *)buf; |
| uint8_t *op; |
| uint8_t *ep; |
| uint8_t *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 = (long)(op - lastliteral); |
| tif->tif_rawcc += (tmsize_t)(lastliteral - tif->tif_rawcp); |
| if (!TIFFFlushData1(tif)) |
| return (0); |
| op = tif->tif_rawcp; |
| while (slop-- > 0) |
| *op++ = *lastliteral++; |
| lastliteral = tif->tif_rawcp; |
| } |
| else |
| { |
| tif->tif_rawcc += (tmsize_t)(op - tif->tif_rawcp); |
| if (!TIFFFlushData1(tif)) |
| return (0); |
| op = tif->tif_rawcp; |
| } |
| } |
| switch (state) |
| { |
| case BASE: /* initial state, set run/literal */ |
| if (n > 1) |
| { |
| state = RUN; |
| if (n > 128) |
| { |
| *op++ = (uint8_t)-127; |
| *op++ = (uint8_t)b; |
| n -= 128; |
| goto again; |
| } |
| *op++ = (uint8_t)(-(n - 1)); |
| *op++ = (uint8_t)b; |
| } |
| else |
| { |
| lastliteral = op; |
| *op++ = 0; |
| *op++ = (uint8_t)b; |
| state = LITERAL; |
| } |
| break; |
| case LITERAL: /* last object was literal string */ |
| if (n > 1) |
| { |
| state = LITERAL_RUN; |
| if (n > 128) |
| { |
| *op++ = (uint8_t)-127; |
| *op++ = (uint8_t)b; |
| n -= 128; |
| goto again; |
| } |
| *op++ = (uint8_t)(-(n - 1)); /* encode run */ |
| *op++ = (uint8_t)b; |
| } |
| else |
| { /* extend literal */ |
| if (++(*lastliteral) == 127) |
| state = BASE; |
| *op++ = (uint8_t)b; |
| } |
| break; |
| case RUN: /* last object was run */ |
| if (n > 1) |
| { |
| if (n > 128) |
| { |
| *op++ = (uint8_t)-127; |
| *op++ = (uint8_t)b; |
| n -= 128; |
| goto again; |
| } |
| *op++ = (uint8_t)(-(n - 1)); |
| *op++ = (uint8_t)b; |
| } |
| else |
| { |
| lastliteral = op; |
| *op++ = 0; |
| *op++ = (uint8_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] == (uint8_t)-1 && *lastliteral < 126) |
| { |
| state = (((*lastliteral) += 2) == 127 ? BASE : LITERAL); |
| op[-2] = op[-1]; /* replicate */ |
| } |
| else |
| state = RUN; |
| goto again; |
| } |
| } |
| tif->tif_rawcc += (tmsize_t)(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, uint8_t *bp, tmsize_t cc, uint16_t s) |
| { |
| tmsize_t rowsize = *(tmsize_t *)tif->tif_data; |
| |
| while (cc > 0) |
| { |
| tmsize_t 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, uint8_t *op, tmsize_t occ, uint16_t s) |
| { |
| static const char module[] = "PackBitsDecode"; |
| int8_t *bp; |
| tmsize_t cc; |
| long n; |
| int b; |
| |
| (void)s; |
| bp = (int8_t *)tif->tif_rawcp; |
| cc = tif->tif_rawcc; |
| while (cc > 0 && occ > 0) |
| { |
| n = (long)*bp++; |
| cc--; |
| if (n < 0) |
| { /* replicate next byte -n+1 times */ |
| if (n == -128) /* nop */ |
| continue; |
| n = -n + 1; |
| if (occ < (tmsize_t)n) |
| { |
| TIFFWarningExtR(tif, module, |
| "Discarding %" TIFF_SSIZE_FORMAT |
| " bytes to avoid buffer overrun", |
| (tmsize_t)n - occ); |
| n = (long)occ; |
| } |
| if (cc == 0) |
| { |
| TIFFWarningExtR( |
| tif, module, |
| "Terminating PackBitsDecode due to lack of data."); |
| break; |
| } |
| occ -= n; |
| b = *bp++; |
| cc--; |
| while (n-- > 0) |
| *op++ = (uint8_t)b; |
| } |
| else |
| { /* copy next n+1 bytes literally */ |
| if (occ < (tmsize_t)(n + 1)) |
| { |
| TIFFWarningExtR(tif, module, |
| "Discarding %" TIFF_SSIZE_FORMAT |
| " bytes to avoid buffer overrun", |
| (tmsize_t)n - occ + 1); |
| n = (long)occ - 1; |
| } |
| if (cc < (tmsize_t)(n + 1)) |
| { |
| TIFFWarningExtR( |
| tif, module, |
| "Terminating PackBitsDecode due to lack of data."); |
| break; |
| } |
| _TIFFmemcpy(op, bp, ++n); |
| op += n; |
| occ -= n; |
| bp += n; |
| cc -= n; |
| } |
| } |
| tif->tif_rawcp = (uint8_t *)bp; |
| tif->tif_rawcc = cc; |
| if (occ > 0) |
| { |
| TIFFErrorExtR(tif, module, "Not enough data for scanline %" PRIu32, |
| 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 */ |
