/* * 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 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(ENABLE_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);}