| /* |
| * Common bit i/o utils |
| * Copyright (c) 2000, 2001 Fabrice Bellard |
| * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> |
| * |
| * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at> |
| * |
| * 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 libavcodec/bitstream.c |
| * bitstream api. |
| */ |
| |
| #include "avcodec.h" |
| #include "bitstream.h" |
| |
| const uint8_t ff_log2_run[32]={ |
| 0, 0, 0, 0, 1, 1, 1, 1, |
| 2, 2, 2, 2, 3, 3, 3, 3, |
| 4, 4, 5, 5, 6, 6, 7, 7, |
| 8, 9,10,11,12,13,14,15 |
| }; |
| |
| /** |
| * Same as av_mallocz_static(), but does a realloc. |
| * |
| * @param[in] ptr The block of memory to reallocate. |
| * @param[in] size The requested size. |
| * @return Block of memory of requested size. |
| * @deprecated. Code which uses ff_realloc_static is broken/misdesigned |
| * and should correctly use static arrays |
| */ |
| attribute_deprecated av_alloc_size(2) |
| static void *ff_realloc_static(void *ptr, unsigned int size); |
| |
| static void *ff_realloc_static(void *ptr, unsigned int size) |
| { |
| return av_realloc(ptr, size); |
| } |
| |
| void align_put_bits(PutBitContext *s) |
| { |
| #ifdef ALT_BITSTREAM_WRITER |
| put_bits(s,( - s->index) & 7,0); |
| #else |
| put_bits(s,s->bit_left & 7,0); |
| #endif |
| } |
| |
| void ff_put_string(PutBitContext * pbc, const char *s, int put_zero) |
| { |
| while(*s){ |
| put_bits(pbc, 8, *s); |
| s++; |
| } |
| if(put_zero) |
| put_bits(pbc, 8, 0); |
| } |
| |
| void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length) |
| { |
| const uint16_t *srcw= (const uint16_t*)src; |
| int words= length>>4; |
| int bits= length&15; |
| int i; |
| |
| if(length==0) return; |
| |
| if(CONFIG_SMALL || words < 16 || put_bits_count(pb)&7){ |
| for(i=0; i<words; i++) put_bits(pb, 16, be2me_16(srcw[i])); |
| }else{ |
| for(i=0; put_bits_count(pb)&31; i++) |
| put_bits(pb, 8, src[i]); |
| flush_put_bits(pb); |
| memcpy(pbBufPtr(pb), src+i, 2*words-i); |
| skip_put_bytes(pb, 2*words-i); |
| } |
| |
| put_bits(pb, bits, be2me_16(srcw[words])>>(16-bits)); |
| } |
| |
| /* VLC decoding */ |
| |
| //#define DEBUG_VLC |
| |
| #define GET_DATA(v, table, i, wrap, size) \ |
| {\ |
| const uint8_t *ptr = (const uint8_t *)table + i * wrap;\ |
| switch(size) {\ |
| case 1:\ |
| v = *(const uint8_t *)ptr;\ |
| break;\ |
| case 2:\ |
| v = *(const uint16_t *)ptr;\ |
| break;\ |
| default:\ |
| v = *(const uint32_t *)ptr;\ |
| break;\ |
| }\ |
| } |
| |
| |
| static int alloc_table(VLC *vlc, int size, int use_static) |
| { |
| int index; |
| index = vlc->table_size; |
| vlc->table_size += size; |
| if (vlc->table_size > vlc->table_allocated) { |
| if(use_static>1) |
| abort(); //cant do anything, init_vlc() is used with too little memory |
| vlc->table_allocated += (1 << vlc->bits); |
| if(use_static) |
| vlc->table = ff_realloc_static(vlc->table, |
| sizeof(VLC_TYPE) * 2 * vlc->table_allocated); |
| else |
| vlc->table = av_realloc(vlc->table, |
| sizeof(VLC_TYPE) * 2 * vlc->table_allocated); |
| if (!vlc->table) |
| return -1; |
| } |
| return index; |
| } |
| |
| static int build_table(VLC *vlc, int table_nb_bits, |
| int nb_codes, |
| const void *bits, int bits_wrap, int bits_size, |
| const void *codes, int codes_wrap, int codes_size, |
| const void *symbols, int symbols_wrap, int symbols_size, |
| uint32_t code_prefix, int n_prefix, int flags) |
| { |
| int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2, symbol; |
| uint32_t code; |
| VLC_TYPE (*table)[2]; |
| |
| table_size = 1 << table_nb_bits; |
| table_index = alloc_table(vlc, table_size, flags & (INIT_VLC_USE_STATIC|INIT_VLC_USE_NEW_STATIC)); |
| #ifdef DEBUG_VLC |
| av_log(NULL,AV_LOG_DEBUG,"new table index=%d size=%d code_prefix=%x n=%d\n", |
| table_index, table_size, code_prefix, n_prefix); |
| #endif |
| if (table_index < 0) |
| return -1; |
| table = &vlc->table[table_index]; |
| |
| for(i=0;i<table_size;i++) { |
| table[i][1] = 0; //bits |
| table[i][0] = -1; //codes |
| } |
| |
| /* first pass: map codes and compute auxillary table sizes */ |
| for(i=0;i<nb_codes;i++) { |
| GET_DATA(n, bits, i, bits_wrap, bits_size); |
| GET_DATA(code, codes, i, codes_wrap, codes_size); |
| /* we accept tables with holes */ |
| if (n <= 0) |
| continue; |
| if (!symbols) |
| symbol = i; |
| else |
| GET_DATA(symbol, symbols, i, symbols_wrap, symbols_size); |
| #if defined(DEBUG_VLC) && 0 |
| av_log(NULL,AV_LOG_DEBUG,"i=%d n=%d code=0x%x\n", i, n, code); |
| #endif |
| /* if code matches the prefix, it is in the table */ |
| n -= n_prefix; |
| if(flags & INIT_VLC_LE) |
| code_prefix2= code & (n_prefix>=32 ? 0xffffffff : (1 << n_prefix)-1); |
| else |
| code_prefix2= code >> n; |
| if (n > 0 && code_prefix2 == code_prefix) { |
| if (n <= table_nb_bits) { |
| /* no need to add another table */ |
| j = (code << (table_nb_bits - n)) & (table_size - 1); |
| nb = 1 << (table_nb_bits - n); |
| for(k=0;k<nb;k++) { |
| if(flags & INIT_VLC_LE) |
| j = (code >> n_prefix) + (k<<n); |
| #ifdef DEBUG_VLC |
| av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n", |
| j, i, n); |
| #endif |
| if (table[j][1] /*bits*/ != 0) { |
| av_log(NULL, AV_LOG_ERROR, "incorrect codes\n"); |
| return -1; |
| } |
| table[j][1] = n; //bits |
| table[j][0] = symbol; |
| j++; |
| } |
| } else { |
| n -= table_nb_bits; |
| j = (code >> ((flags & INIT_VLC_LE) ? n_prefix : n)) & ((1 << table_nb_bits) - 1); |
| #ifdef DEBUG_VLC |
| av_log(NULL,AV_LOG_DEBUG,"%4x: n=%d (subtable)\n", |
| j, n); |
| #endif |
| /* compute table size */ |
| n1 = -table[j][1]; //bits |
| if (n > n1) |
| n1 = n; |
| table[j][1] = -n1; //bits |
| } |
| } |
| } |
| |
| /* second pass : fill auxillary tables recursively */ |
| for(i=0;i<table_size;i++) { |
| n = table[i][1]; //bits |
| if (n < 0) { |
| n = -n; |
| if (n > table_nb_bits) { |
| n = table_nb_bits; |
| table[i][1] = -n; //bits |
| } |
| index = build_table(vlc, n, nb_codes, |
| bits, bits_wrap, bits_size, |
| codes, codes_wrap, codes_size, |
| symbols, symbols_wrap, symbols_size, |
| (flags & INIT_VLC_LE) ? (code_prefix | (i << n_prefix)) : ((code_prefix << table_nb_bits) | i), |
| n_prefix + table_nb_bits, flags); |
| if (index < 0) |
| return -1; |
| /* note: realloc has been done, so reload tables */ |
| table = &vlc->table[table_index]; |
| table[i][0] = index; //code |
| } |
| } |
| return table_index; |
| } |
| |
| |
| /* Build VLC decoding tables suitable for use with get_vlc(). |
| |
| 'nb_bits' set thee decoding table size (2^nb_bits) entries. The |
| bigger it is, the faster is the decoding. But it should not be too |
| big to save memory and L1 cache. '9' is a good compromise. |
| |
| 'nb_codes' : number of vlcs codes |
| |
| 'bits' : table which gives the size (in bits) of each vlc code. |
| |
| 'codes' : table which gives the bit pattern of of each vlc code. |
| |
| 'symbols' : table which gives the values to be returned from get_vlc(). |
| |
| 'xxx_wrap' : give the number of bytes between each entry of the |
| 'bits' or 'codes' tables. |
| |
| 'xxx_size' : gives the number of bytes of each entry of the 'bits' |
| or 'codes' tables. |
| |
| 'wrap' and 'size' allows to use any memory configuration and types |
| (byte/word/long) to store the 'bits', 'codes', and 'symbols' tables. |
| |
| 'use_static' should be set to 1 for tables, which should be freed |
| with av_free_static(), 0 if free_vlc() will be used. |
| */ |
| int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, |
| const void *bits, int bits_wrap, int bits_size, |
| const void *codes, int codes_wrap, int codes_size, |
| const void *symbols, int symbols_wrap, int symbols_size, |
| int flags) |
| { |
| vlc->bits = nb_bits; |
| if(flags & INIT_VLC_USE_NEW_STATIC){ |
| if(vlc->table_size && vlc->table_size == vlc->table_allocated){ |
| return 0; |
| }else if(vlc->table_size){ |
| abort(); // fatal error, we are called on a partially initialized table |
| } |
| }else if(!(flags & INIT_VLC_USE_STATIC)) { |
| vlc->table = NULL; |
| vlc->table_allocated = 0; |
| vlc->table_size = 0; |
| } else { |
| /* Static tables are initially always NULL, return |
| if vlc->table != NULL to avoid double allocation */ |
| if(vlc->table) |
| return 0; |
| } |
| |
| #ifdef DEBUG_VLC |
| av_log(NULL,AV_LOG_DEBUG,"build table nb_codes=%d\n", nb_codes); |
| #endif |
| |
| if (build_table(vlc, nb_bits, nb_codes, |
| bits, bits_wrap, bits_size, |
| codes, codes_wrap, codes_size, |
| symbols, symbols_wrap, symbols_size, |
| 0, 0, flags) < 0) { |
| av_freep(&vlc->table); |
| return -1; |
| } |
| if((flags & INIT_VLC_USE_NEW_STATIC) && vlc->table_size != vlc->table_allocated) |
| av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated); |
| return 0; |
| } |
| |
| |
| void free_vlc(VLC *vlc) |
| { |
| av_freep(&vlc->table); |
| } |
| |
