apps/codecs/libwmapro/bitstream.c

   1 /*
   2  * Common bit i/o utils
   3  * Copyright (c) 2000, 2001 Fabrice Bellard
   4  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
   5  * Copyright (c) 2010 Loren Merritt
   6  *
   7  * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
   8  *
   9  * This file is part of FFmpeg.
  10  *
  11  * FFmpeg is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; either
  14  * version 2.1 of the License, or (at your option) any later version.
  15  *
  16  * FFmpeg is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with FFmpeg; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 /**
  27  * @file libavcodec/bitstream.c
  28  * bitstream api.
  29  */
  30
  31 #include "get_bits.h"
  32 #include "put_bits.h"
  33 #include <string.h>
  34
  35 #define av_log(...)
  36
  37 /* Taken from libavutil/common.h */
  38 #define FFMIN(a,b) ((a) > (b) ? (b) : (a))
  39 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
  40
  41 /* av_reverse - taken from libavutil/mathematics.c*/
  42 const uint8_t av_reverse[256]={
  43 0x00,0x80,0x40,0xC0,0x20,0xA0,0x60,0xE0,0x10,0x90,0x50,0xD0,0x30,0xB0,0x70,0xF0,
  44 0x08,0x88,0x48,0xC8,0x28,0xA8,0x68,0xE8,0x18,0x98,0x58,0xD8,0x38,0xB8,0x78,0xF8,
  45 0x04,0x84,0x44,0xC4,0x24,0xA4,0x64,0xE4,0x14,0x94,0x54,0xD4,0x34,0xB4,0x74,0xF4,
  46 0x0C,0x8C,0x4C,0xCC,0x2C,0xAC,0x6C,0xEC,0x1C,0x9C,0x5C,0xDC,0x3C,0xBC,0x7C,0xFC,
  47 0x02,0x82,0x42,0xC2,0x22,0xA2,0x62,0xE2,0x12,0x92,0x52,0xD2,0x32,0xB2,0x72,0xF2,
  48 0x0A,0x8A,0x4A,0xCA,0x2A,0xAA,0x6A,0xEA,0x1A,0x9A,0x5A,0xDA,0x3A,0xBA,0x7A,0xFA,
  49 0x06,0x86,0x46,0xC6,0x26,0xA6,0x66,0xE6,0x16,0x96,0x56,0xD6,0x36,0xB6,0x76,0xF6,
  50 0x0E,0x8E,0x4E,0xCE,0x2E,0xAE,0x6E,0xEE,0x1E,0x9E,0x5E,0xDE,0x3E,0xBE,0x7E,0xFE,
  51 0x01,0x81,0x41,0xC1,0x21,0xA1,0x61,0xE1,0x11,0x91,0x51,0xD1,0x31,0xB1,0x71,0xF1,
  52 0x09,0x89,0x49,0xC9,0x29,0xA9,0x69,0xE9,0x19,0x99,0x59,0xD9,0x39,0xB9,0x79,0xF9,
  53 0x05,0x85,0x45,0xC5,0x25,0xA5,0x65,0xE5,0x15,0x95,0x55,0xD5,0x35,0xB5,0x75,0xF5,
  54 0x0D,0x8D,0x4D,0xCD,0x2D,0xAD,0x6D,0xED,0x1D,0x9D,0x5D,0xDD,0x3D,0xBD,0x7D,0xFD,
  55 0x03,0x83,0x43,0xC3,0x23,0xA3,0x63,0xE3,0x13,0x93,0x53,0xD3,0x33,0xB3,0x73,0xF3,
  56 0x0B,0x8B,0x4B,0xCB,0x2B,0xAB,0x6B,0xEB,0x1B,0x9B,0x5B,0xDB,0x3B,0xBB,0x7B,0xFB,
  57 0x07,0x87,0x47,0xC7,0x27,0xA7,0x67,0xE7,0x17,0x97,0x57,0xD7,0x37,0xB7,0x77,0xF7,
  58 0x0F,0x8F,0x4F,0xCF,0x2F,0xAF,0x6F,0xEF,0x1F,0x9F,0x5F,0xDF,0x3F,0xBF,0x7F,0xFF,
  59 };
  60
  61
  62 const uint8_t ff_log2_run[32]={
  63  0, 0, 0, 0, 1, 1, 1, 1,
  64  2, 2, 2, 2, 3, 3, 3, 3,
  65  4, 4, 5, 5, 6, 6, 7, 7,
  66  8, 9,10,11,12,13,14,15
  67 };
  68
  69 void align_put_bits(PutBitContext *s)
  70 {
  71 #ifdef ALT_BITSTREAM_WRITER
  72     put_bits(s,(  - s->index) & 7,0);
  73 #else
  74     put_bits(s,s->bit_left & 7,0);
  75 #endif
  76 }
  77
  78 void ff_put_string(PutBitContext *pb, const char *string, int terminate_string)
  79 {
  80     while(*string){
  81         put_bits(pb, 8, *string);
  82         string++;
  83     }
  84     if(terminate_string)
  85         put_bits(pb, 8, 0);
  86 }
  87
  88 void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
  89 {
  90     int words= length>>4;
  91     int bits= length&15;
  92     int i;
  93
  94     if(length==0) return;
  95 /* The following define was just added to make the codec (wma pro) compile */
  96 #define CONFIG_SMALL 0
  97     if(CONFIG_SMALL || words < 16 || put_bits_count(pb)&7){
  98         for(i=0; i<words; i++) put_bits(pb, 16, AV_RB16(src + 2*i));
  99     }else{
 100         for(i=0; put_bits_count(pb)&31; i++)
 101             put_bits(pb, 8, src[i]);
 102         flush_put_bits(pb);
 103         memcpy(put_bits_ptr(pb), src+i, 2*words-i);
 104         skip_put_bytes(pb, 2*words-i);
 105     }
 106
 107     put_bits(pb, bits, AV_RB16(src + 2*words)>>(16-bits));
 108 }
 109
 110 /* VLC decoding */
 111
 112 //#define DEBUG_VLC
 113
 114 #define GET_DATA(v, table, i, wrap, size) \
 115 {\
 116     const uint8_t *ptr = (const uint8_t *)table + i * wrap;\
 117     switch(size) {\
 118     case 1:\
 119         v = *(const uint8_t *)ptr;\
 120         break;\
 121     case 2:\
 122         v = *(const uint16_t *)ptr;\
 123         break;\
 124     default:\
 125         v = *(const uint32_t *)ptr;\
 126         break;\
 127     }\
 128 }
 129
 130
 131 static int alloc_table(VLC *vlc, int size, int use_static)
 132 {
 133     int index;
 134     index = vlc->table_size;
 135     vlc->table_size += size;
 136     if (vlc->table_size > vlc->table_allocated) {
 137         if(use_static)
 138             return -1; //cant do anything, init_vlc() is used with too little memory
 139         vlc->table_allocated += (1 << vlc->bits);
 140         //vlc->table = av_realloc(vlc->table,
 141         //                        sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
 142         if (!vlc->table)
 143             return -1;
 144     }
 145     return index;
 146 }
 147
 148 static inline uint32_t bitswap_32(uint32_t x) {
 149     return av_reverse[x&0xFF]<<24
 150          | av_reverse[(x>>8)&0xFF]<<16
 151          | av_reverse[(x>>16)&0xFF]<<8
 152          | av_reverse[x>>24];
 153 }
 154
 155 typedef struct {
 156     uint8_t bits;
 157     uint16_t symbol;
 158     /** codeword, with the first bit-to-be-read in the msb
 159      * (even if intended for a little-endian bitstream reader) */
 160     uint32_t code;
 161 } VLCcode;
 162
 163 static int compare_vlcspec(const void *a, const void *b)
 164 {
 165     const VLCcode *sa=a, *sb=b;
 166     return (sa->code >> 1) - (sb->code >> 1);
 167 }
 168
 169 /**
 170  * Build VLC decoding tables suitable for use with get_vlc().
 171  *
 172  * @param vlc            the context to be initted
 173  *
 174  * @param table_nb_bits  max length of vlc codes to store directly in this table
 175  *                       (Longer codes are delegated to subtables.)
 176  *
 177  * @param nb_codes       number of elements in codes[]
 178  *
 179  * @param codes          descriptions of the vlc codes
 180  *                       These must be ordered such that codes going into the same subtable are contiguous.
 181  *                       Sorting by VLCcode.code is sufficient, though not necessary.
 182  */
 183 static int build_table(VLC *vlc, int table_nb_bits, int nb_codes,
 184                        VLCcode *codes, int flags)
 185 {
 186     int table_size, table_index, index, code_prefix, symbol, subtable_bits;
 187     int i, j, k, n, nb, inc;
 188     uint32_t code;
 189     VLC_TYPE (*table)[2];
 190
 191     table_size = 1 << table_nb_bits;
 192     table_index = alloc_table(vlc, table_size, flags & INIT_VLC_USE_NEW_STATIC);
 193 #ifdef DEBUG_VLC
 194     av_log(NULL,AV_LOG_DEBUG,"new table index=%d size=%d\n",
 195            table_index, table_size);
 196 #endif
 197     if (table_index < 0)
 198         return -1;
 199     table = &vlc->table[table_index];
 200
 201     for (i = 0; i < table_size; i++) {
 202         table[i][1] = 0; //bits
 203         table[i][0] = -1; //codes
 204     }
 205
 206     /* first pass: map codes and compute auxillary table sizes */
 207     for (i = 0; i < nb_codes; i++) {
 208         n = codes[i].bits;
 209         code = codes[i].code;
 210         symbol = codes[i].symbol;
 211 #if defined(DEBUG_VLC) && 0
 212         av_log(NULL,AV_LOG_DEBUG,"i=%d n=%d code=0x%x\n", i, n, code);
 213 #endif
 214         if (n <= table_nb_bits) {
 215             /* no need to add another table */
 216             j = code >> (32 - table_nb_bits);
 217             nb = 1 << (table_nb_bits - n);
 218             inc = 1;
 219             if (flags & INIT_VLC_LE) {
 220                 j = bitswap_32(code);
 221                 inc = 1 << n;
 222             }
 223             for (k = 0; k < nb; k++) {
 224 #ifdef DEBUG_VLC
 225                 av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n",
 226                        j, i, n);
 227 #endif
 228                 if (table[j][1] /*bits*/ != 0) {
 229                     av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
 230                     return -1;
 231                 }
 232                 table[j][1] = n; //bits
 233                 table[j][0] = symbol;
 234                 j += inc;
 235             }
 236         } else {
 237             /* fill auxiliary table recursively */
 238             n -= table_nb_bits;
 239             code_prefix = code >> (32 - table_nb_bits);
 240             subtable_bits = n;
 241             codes[i].bits = n;
 242             codes[i].code = code << table_nb_bits;
 243             for (k = i+1; k < nb_codes; k++) {
 244                 n = codes[k].bits - table_nb_bits;
 245                 if (n <= 0)
 246                     break;
 247                 code = codes[k].code;
 248                 if (code >> (32 - table_nb_bits) != (unsigned)code_prefix)
 249                     break;
 250                 codes[k].bits = n;
 251                 codes[k].code = code << table_nb_bits;
 252                 subtable_bits = FFMAX(subtable_bits, n);
 253             }
 254             subtable_bits = FFMIN(subtable_bits, table_nb_bits);
 255             j = (flags & INIT_VLC_LE) ? bitswap_32(code_prefix) >> (32 - table_nb_bits) : (unsigned)code_prefix;
 256             table[j][1] = -subtable_bits;
 257 #ifdef DEBUG_VLC
 258             av_log(NULL,AV_LOG_DEBUG,"%4x: n=%d (subtable)\n",
 259                    j, codes[i].bits + table_nb_bits);
 260 #endif
 261             index = build_table(vlc, subtable_bits, k-i, codes+i, flags);
 262             if (index < 0)
 263                 return -1;
 264             /* note: realloc has been done, so reload tables */
 265             table = &vlc->table[table_index];
 266             table[j][0] = index; //code
 267             i = k-1;
 268         }
 269     }
 270     return table_index;
 271 }
 272
 273
 274 /* Build VLC decoding tables suitable for use with get_vlc().
 275
 276    'nb_bits' set thee decoding table size (2^nb_bits) entries. The
 277    bigger it is, the faster is the decoding. But it should not be too
 278    big to save memory and L1 cache. '9' is a good compromise.
 279
 280    'nb_codes' : number of vlcs codes
 281
 282    'bits' : table which gives the size (in bits) of each vlc code.
 283
 284    'codes' : table which gives the bit pattern of of each vlc code.
 285
 286    'symbols' : table which gives the values to be returned from get_vlc().
 287
 288    'xxx_wrap' : give the number of bytes between each entry of the
 289    'bits' or 'codes' tables.
 290
 291    'xxx_size' : gives the number of bytes of each entry of the 'bits'
 292    or 'codes' tables.
 293
 294    'wrap' and 'size' allows to use any memory configuration and types
 295    (byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
 296
 297    'use_static' should be set to 1 for tables, which should be freed
 298    with av_free_static(), 0 if free_vlc() will be used.
 299 */
 300 int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
 301              const void *bits, int bits_wrap, int bits_size,
 302              const void *codes, int codes_wrap, int codes_size,
 303              const void *symbols, int symbols_wrap, int symbols_size,
 304              int flags)
 305 {
 306     VLCcode buf[nb_codes];
 307     int i, j;
 308
 309     vlc->bits = nb_bits;
 310     if(flags & INIT_VLC_USE_NEW_STATIC){
 311         if(vlc->table_size && vlc->table_size == vlc->table_allocated){
 312             return 0;
 313         }else if(vlc->table_size){
 314             return -1; // fatal error, we are called on a partially initialized table
 315         }
 316     }else {
 317         vlc->table = NULL;
 318         vlc->table_allocated = 0;
 319         vlc->table_size = 0;
 320     }
 321
 322 #ifdef DEBUG_VLC
 323     av_log(NULL,AV_LOG_DEBUG,"build table nb_codes=%d\n", nb_codes);
 324 #endif
 325
 326     //assert(symbols_size <= 2 || !symbols);
 327     j = 0;
 328 #define COPY(condition)\
 329     for (i = 0; i < nb_codes; i++) {\
 330         GET_DATA(buf[j].bits, bits, i, bits_wrap, bits_size);\
 331         if (!(condition))\
 332             continue;\
 333         GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size);\
 334         if (flags & INIT_VLC_LE)\
 335             buf[j].code = bitswap_32(buf[j].code);\
 336         else\
 337             buf[j].code <<= 32 - buf[j].bits;\
 338         if (symbols)\
 339             GET_DATA(buf[j].symbol, symbols, i, symbols_wrap, symbols_size)\
 340         else\
 341             buf[j].symbol = i;\
 342         j++;\
 343     }
 344     COPY(buf[j].bits > nb_bits);
 345     // qsort is the slowest part of init_vlc, and could probably be improved or avoided
 346     qsort(buf, j, sizeof(VLCcode), compare_vlcspec);
 347     COPY(buf[j].bits && buf[j].bits <= nb_bits);
 348     nb_codes = j;
 349
 350     if (build_table(vlc, nb_bits, nb_codes, buf, flags) < 0) {
 351         //av_freep(&vlc->table);
 352         return -1;
 353     }
 354     //if((flags & INIT_VLC_USE_NEW_STATIC) && vlc->table_size != vlc->table_allocated)
 355      //   av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
 356     return 0;
 357 }
 358