diff options
Diffstat (limited to 'contrib/ffmpeg/libavcodec/lzw.c')
| -rw-r--r-- | contrib/ffmpeg/libavcodec/lzw.c | 229 |
1 files changed, 0 insertions, 229 deletions
diff --git a/contrib/ffmpeg/libavcodec/lzw.c b/contrib/ffmpeg/libavcodec/lzw.c deleted file mode 100644 index 6bc0b9a48..000000000 --- a/contrib/ffmpeg/libavcodec/lzw.c +++ /dev/null @@ -1,229 +0,0 @@ -/* - * LZW decoder - * Copyright (c) 2003 Fabrice Bellard. - * Copyright (c) 2006 Konstantin Shishkov. - * - * This file is part of FFmpeg. - * - * FFmpeg is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * FFmpeg is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with FFmpeg; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - */ - -/** - * @file lzw.c - * @brief LZW decoding routines - * @author Fabrice Bellard - * Modified for use in TIFF by Konstantin Shishkov - */ - -#include "avcodec.h" -#include "lzw.h" - -#define LZW_MAXBITS 12 -#define LZW_SIZTABLE (1<<LZW_MAXBITS) - -static const uint16_t mask[17] = -{ - 0x0000, 0x0001, 0x0003, 0x0007, - 0x000F, 0x001F, 0x003F, 0x007F, - 0x00FF, 0x01FF, 0x03FF, 0x07FF, - 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF -}; - -struct LZWState { - uint8_t *pbuf, *ebuf; - int bbits; - unsigned int bbuf; - - int mode; ///< Decoder mode - int cursize; ///< The current code size - int curmask; - int codesize; - int clear_code; - int end_code; - int newcodes; ///< First available code - int top_slot; ///< Highest code for current size - int extra_slot; - int slot; ///< Last read code - int fc, oc; - uint8_t *sp; - uint8_t stack[LZW_SIZTABLE]; - uint8_t suffix[LZW_SIZTABLE]; - uint16_t prefix[LZW_SIZTABLE]; - int bs; ///< current buffer size for GIF -}; - -/* get one code from stream */ -static int lzw_get_code(struct LZWState * s) -{ - int c; - - if(s->mode == FF_LZW_GIF) { - while (s->bbits < s->cursize) { - if (!s->bs) { - s->bs = *s->pbuf++; - } - s->bbuf |= (*s->pbuf++) << s->bbits; - s->bbits += 8; - s->bs--; - } - c = s->bbuf; - s->bbuf >>= s->cursize; - } else { // TIFF - while (s->bbits < s->cursize) { - s->bbuf = (s->bbuf << 8) | (*s->pbuf++); - s->bbits += 8; - } - c = s->bbuf >> (s->bbits - s->cursize); - } - s->bbits -= s->cursize; - return c & s->curmask; -} - -uint8_t* ff_lzw_cur_ptr(LZWState *p) -{ - return ((struct LZWState*)p)->pbuf; -} - -void ff_lzw_decode_tail(LZWState *p) -{ - struct LZWState *s = (struct LZWState *)p; - - if(s->mode == FF_LZW_GIF) { - while(s->pbuf < s->ebuf && s->bs>0){ - s->pbuf += s->bs; - s->bs = *s->pbuf++; - } - }else - s->pbuf= s->ebuf; -} - -void ff_lzw_decode_open(LZWState **p) -{ - *p = av_mallocz(sizeof(struct LZWState)); -} - -void ff_lzw_decode_close(LZWState **p) -{ - av_freep(p); -} - -/** - * Initialize LZW decoder - * @param s LZW context - * @param csize initial code size in bits - * @param buf input data - * @param buf_size input data size - * @param mode decoder working mode - either GIF or TIFF - */ -int ff_lzw_decode_init(LZWState *p, int csize, uint8_t *buf, int buf_size, int mode) -{ - struct LZWState *s = (struct LZWState *)p; - - if(csize < 1 || csize > LZW_MAXBITS) - return -1; - /* read buffer */ - s->pbuf = buf; - s->ebuf = s->pbuf + buf_size; - s->bbuf = 0; - s->bbits = 0; - s->bs = 0; - - /* decoder */ - s->codesize = csize; - s->cursize = s->codesize + 1; - s->curmask = mask[s->cursize]; - s->top_slot = 1 << s->cursize; - s->clear_code = 1 << s->codesize; - s->end_code = s->clear_code + 1; - s->slot = s->newcodes = s->clear_code + 2; - s->oc = s->fc = -1; - s->sp = s->stack; - - s->mode = mode; - s->extra_slot = s->mode == FF_LZW_TIFF; - return 0; -} - -/** - * Decode given number of bytes - * NOTE: the algorithm here is inspired from the LZW GIF decoder - * written by Steven A. Bennett in 1987. - * - * @param s LZW context - * @param buf output buffer - * @param len number of bytes to decode - * @return number of bytes decoded - */ -int ff_lzw_decode(LZWState *p, uint8_t *buf, int len){ - int l, c, code, oc, fc; - uint8_t *sp; - struct LZWState *s = (struct LZWState *)p; - - if (s->end_code < 0) - return 0; - - l = len; - sp = s->sp; - oc = s->oc; - fc = s->fc; - - for (;;) { - while (sp > s->stack) { - *buf++ = *(--sp); - if ((--l) == 0) - goto the_end; - } - c = lzw_get_code(s); - if (c == s->end_code) { - break; - } else if (c == s->clear_code) { - s->cursize = s->codesize + 1; - s->curmask = mask[s->cursize]; - s->slot = s->newcodes; - s->top_slot = 1 << s->cursize; - fc= oc= -1; - } else { - code = c; - if (code == s->slot && fc>=0) { - *sp++ = fc; - code = oc; - }else if(code >= s->slot) - break; - while (code >= s->newcodes) { - *sp++ = s->suffix[code]; - code = s->prefix[code]; - } - *sp++ = code; - if (s->slot < s->top_slot && oc>=0) { - s->suffix[s->slot] = code; - s->prefix[s->slot++] = oc; - } - fc = code; - oc = c; - if (s->slot >= s->top_slot - s->extra_slot) { - if (s->cursize < LZW_MAXBITS) { - s->top_slot <<= 1; - s->curmask = mask[++s->cursize]; - } - } - } - } - s->end_code = -1; - the_end: - s->sp = sp; - s->oc = oc; - s->fc = fc; - return len - l; -} |