libfaad2/bits.h

   1 /*
   2 ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
   3 ** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
   4 **
   5 ** This program is free software; you can redistribute it and/or modify
   6 ** it under the terms of the GNU General Public License as published by
   7 ** the Free Software Foundation; either version 2 of the License, or
   8 ** (at your option) any later version.
   9 **
  10 ** This program is distributed in the hope that it will be useful,
  11 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 ** GNU General Public License for more details.
  14 **
  15 ** You should have received a copy of the GNU General Public License
  16 ** along with this program; if not, write to the Free Software
  17 ** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18 **
  19 ** Any non-GPL usage of this software or parts of this software is strictly
  20 ** forbidden.
  21 **
  22 ** Commercial non-GPL licensing of this software is possible.
  23 ** For more info contact Ahead Software through Mpeg4AAClicense@nero.com.
  24 **
  25 ** Initially modified for use with MPlayer by Arpad Gereöffy on 2003/08/30
  26 ** $Id$
  27 ** detailed CVS changelog at http://www.mplayerhq.hu/cgi-bin/cvsweb.cgi/main/
  28 ** local_changes.diff contains the exact changes to this file.
  29 **/
  30
  31 #ifndef __BITS_H__
  32 #define __BITS_H__
  33
  34 #ifdef __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 #include "analysis.h"
  39 #ifdef ANALYSIS
  40 #include <stdio.h>
  41 #endif
  42
  43 #define BYTE_NUMBIT 8
  44 #define bit2byte(a) ((a+7)/BYTE_NUMBIT)
  45
  46 typedef struct _bitfile
  47 {
  48     /* bit input */
  49     uint32_t bufa;
  50     uint32_t bufb;
  51     uint32_t bits_left;
  52     uint32_t buffer_size; /* size of the buffer in bytes */
  53     uint32_t bytes_used;
  54     uint8_t no_more_reading;
  55     uint8_t error;
  56     uint32_t *tail;
  57     uint32_t *start;
  58     void *buffer;
  59 } bitfile;
  60
  61
  62 #if defined (_WIN32) && !defined(_WIN32_WCE) && !defined(__MINGW32__)
  63 #define BSWAP(a) __asm mov eax,a __asm bswap eax __asm mov a, eax
  64 #elif defined(LINUX) || defined(DJGPP)
  65 #define BSWAP(a) __asm__ ( "bswapl %0\n" : "=r" (a) : "0" (a) )
  66 #else
  67 #define BSWAP(a) \
  68     ((a) = ( ((a)&0xff)<<24) | (((a)&0xff00)<<8) | (((a)>>8)&0xff00) | (((a)>>24)&0xff))
  69 #endif
  70
  71 static uint32_t bitmask[] = {
  72     0x0, 0x1, 0x3, 0x7, 0xF, 0x1F, 0x3F, 0x7F, 0xFF, 0x1FF,
  73     0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF,
  74     0x1FFFF, 0x3FFFF, 0x7FFFF, 0xFFFFF, 0x1FFFFF, 0x3FFFFF,
  75     0x7FFFFF, 0xFFFFFF, 0x1FFFFFF, 0x3FFFFFF, 0x7FFFFFF,
  76     0xFFFFFFF, 0x1FFFFFFF, 0x3FFFFFFF, 0x7FFFFFFF
  77     /* added bitmask 32, correct?!?!?! */
  78     , 0xFFFFFFFF
  79 };
  80
  81 void faad_initbits(bitfile *ld, const void *buffer, const uint32_t buffer_size);
  82 void faad_endbits(bitfile *ld);
  83 void faad_initbits_rev(bitfile *ld, void *buffer,
  84                        uint32_t bits_in_buffer);
  85 uint8_t faad_byte_align(bitfile *ld);
  86 uint32_t faad_get_processed_bits(bitfile *ld);
  87 void faad_flushbits_ex(bitfile *ld, uint32_t bits);
  88 void faad_rewindbits(bitfile *ld);
  89 uint8_t *faad_getbitbuffer(bitfile *ld, uint32_t bits
  90                        DEBUGDEC);
  91 #ifdef DRM
  92 void *faad_origbitbuffer(bitfile *ld);
  93 uint32_t faad_origbitbuffer_size(bitfile *ld);
  94 #endif
  95
  96 /* circumvent memory alignment errors on ARM */
  97 static INLINE uint32_t getdword(void *mem)
  98 {
  99 #ifdef ARM
 100     uint32_t tmp;
 101 #ifndef ARCH_IS_BIG_ENDIAN
 102     ((uint8_t*)&tmp)[0] = ((uint8_t*)mem)[3];
 103     ((uint8_t*)&tmp)[1] = ((uint8_t*)mem)[2];
 104     ((uint8_t*)&tmp)[2] = ((uint8_t*)mem)[1];
 105     ((uint8_t*)&tmp)[3] = ((uint8_t*)mem)[0];
 106 #else
 107     ((uint8_t*)&tmp)[0] = ((uint8_t*)mem)[0];
 108     ((uint8_t*)&tmp)[1] = ((uint8_t*)mem)[1];
 109     ((uint8_t*)&tmp)[2] = ((uint8_t*)mem)[2];
 110     ((uint8_t*)&tmp)[3] = ((uint8_t*)mem)[3];
 111 #endif
 112
 113     return tmp;
 114 #else
 115     uint32_t tmp;
 116     tmp = *(uint32_t*)mem;
 117 #ifndef ARCH_IS_BIG_ENDIAN
 118     BSWAP(tmp);
 119 #endif
 120     return tmp;
 121 #endif
 122 }
 123
 124 static INLINE uint32_t faad_showbits(bitfile *ld, uint32_t bits)
 125 {
 126     if (bits <= ld->bits_left)
 127     {
 128         return (ld->bufa >> (ld->bits_left - bits)) & bitmask[bits];
 129     }
 130
 131     bits -= ld->bits_left;
 132     return ((ld->bufa & bitmask[ld->bits_left]) << bits) | (ld->bufb >> (32 - bits));
 133 }
 134
 135 static INLINE void faad_flushbits(bitfile *ld, uint32_t bits)
 136 {
 137     /* do nothing if error */
 138     if (ld->error != 0)
 139         return;
 140
 141     if (bits < ld->bits_left)
 142     {
 143         ld->bits_left -= bits;
 144     } else {
 145         faad_flushbits_ex(ld, bits);
 146     }
 147 }
 148
 149 /* return next n bits (right adjusted) */
 150 static INLINE uint32_t faad_getbits(bitfile *ld, uint32_t n DEBUGDEC)
 151 {
 152     uint32_t ret;
 153
 154     if (ld->no_more_reading || n == 0)
 155         return 0;
 156
 157     ret = faad_showbits(ld, n);
 158     faad_flushbits(ld, n);
 159
 160 #ifdef ANALYSIS
 161     if (print)
 162         fprintf(stdout, "%4d %2d bits, val: %4d, variable: %d %s\n", dbg_count++, n, ret, var, dbg);
 163 #endif
 164
 165     return ret;
 166 }
 167
 168 static INLINE uint8_t faad_get1bit(bitfile *ld DEBUGDEC)
 169 {
 170     uint8_t r;
 171
 172     if (ld->bits_left > 0)
 173     {
 174         ld->bits_left--;
 175         r = (uint8_t)((ld->bufa >> ld->bits_left) & 1);
 176         return r;
 177     }
 178
 179     /* bits_left == 0 */
 180 #if 0
 181     r = (uint8_t)(ld->bufb >> 31);
 182     faad_flushbits_ex(ld, 1);
 183 #else
 184     r = (uint8_t)faad_getbits(ld, 1);
 185 #endif
 186     return r;
 187 }
 188
 189 /* reversed bitreading routines */
 190 static INLINE uint32_t faad_showbits_rev(bitfile *ld, uint32_t bits)
 191 {
 192     uint8_t i;
 193     uint32_t B = 0;
 194
 195     if (bits <= ld->bits_left)
 196     {
 197         for (i = 0; i < bits; i++)
 198         {
 199             if (ld->bufa & (1 << (i + (32 - ld->bits_left))))
 200                 B |= (1 << (bits - i - 1));
 201         }
 202         return B;
 203     } else {
 204         for (i = 0; i < ld->bits_left; i++)
 205         {
 206             if (ld->bufa & (1 << (i + (32 - ld->bits_left))))
 207                 B |= (1 << (bits - i - 1));
 208         }
 209         for (i = 0; i < bits - ld->bits_left; i++)
 210         {
 211             if (ld->bufb & (1 << (i + (32-ld->bits_left))))
 212                 B |= (1 << (bits - ld->bits_left - i - 1));
 213         }
 214         return B;
 215     }
 216 }
 217
 218 static INLINE void faad_flushbits_rev(bitfile *ld, uint32_t bits)
 219 {
 220     /* do nothing if error */
 221     if (ld->error != 0)
 222         return;
 223
 224     if (bits < ld->bits_left)
 225     {
 226         ld->bits_left -= bits;
 227     } else {
 228         uint32_t tmp;
 229
 230         ld->bufa = ld->bufb;
 231         tmp = getdword(ld->start);
 232         ld->bufb = tmp;
 233         ld->start--;
 234         ld->bits_left += (32 - bits);
 235
 236         ld->bytes_used += 4;
 237         if (ld->bytes_used == ld->buffer_size)
 238             ld->no_more_reading = 1;
 239         if (ld->bytes_used > ld->buffer_size)
 240             ld->error = 1;
 241     }
 242 }
 243
 244 static INLINE uint32_t faad_getbits_rev(bitfile *ld, uint32_t n
 245                                         DEBUGDEC)
 246 {
 247     uint32_t ret;
 248
 249     if (ld->no_more_reading)
 250         return 0;
 251
 252     if (n == 0)
 253         return 0;
 254
 255     ret = faad_showbits_rev(ld, n);
 256     faad_flushbits_rev(ld, n);
 257
 258 #ifdef ANALYSIS
 259     if (print)
 260         fprintf(stdout, "%4d %2d bits, val: %4d, variable: %d %s\n", dbg_count++, n, ret, var, dbg);
 261 #endif
 262
 263     return ret;
 264 }
 265
 266 #ifdef DRM
 267 static uint8_t faad_check_CRC(bitfile *ld, uint16_t len)
 268 {
 269     uint8_t CRC;
 270     uint16_t r=255;  /* Initialize to all ones */
 271
 272     /* CRC polynome used x^8 + x^4 + x^3 + x^2 +1 */
 273 #define GPOLY 0435
 274
 275     faad_rewindbits(ld);
 276
 277     CRC = (uint8_t) ~faad_getbits(ld, 8
 278         DEBUGVAR(1,999,"faad_check_CRC(): CRC"));          /* CRC is stored inverted */
 279
 280     for (; len>0; len--)
 281     {
 282         r = ( (r << 1) ^ (( ( faad_get1bit(ld
 283             DEBUGVAR(1,998,""))  & 1) ^ ((r >> 7) & 1)) * GPOLY )) & 0xFF;
 284     }
 285
 286     if (r != CRC)
 287     {
 288         return 8;
 289     } else {
 290         return 0;
 291     }
 292 }
 293
 294 static uint8_t tabFlipbits[256] = {
 295     0,128,64,192,32,160,96,224,16,144,80,208,48,176,112,240,
 296     8,136,72,200,40,168,104,232,24,152,88,216,56,184,120,248,
 297     4,132,68,196,36,164,100,228,20,148,84,212,52,180,116,244,
 298     12,140,76,204,44,172,108,236,28,156,92,220,60,188,124,252,
 299     2,130,66,194,34,162,98,226,18,146,82,210,50,178,114,242,
 300     10,138,74,202,42,170,106,234,26,154,90,218,58,186,122,250,
 301     6,134,70,198,38,166,102,230,22,150,86,214,54,182,118,246,
 302     14,142,78,206,46,174,110,238,30,158,94,222,62,190,126,254,
 303     1,129,65,193,33,161,97,225,17,145,81,209,49,177,113,241,
 304     9,137,73,201,41,169,105,233,25,153,89,217,57,185,121,249,
 305     5,133,69,197,37,165,101,229,21,149,85,213,53,181,117,245,
 306     13,141,77,205,45,173,109,237,29,157,93,221,61,189,125,253,
 307     3,131,67,195,35,163,99,227,19,147,83,211,51,179,115,243,
 308     11,139,75,203,43,171,107,235,27,155,91,219,59,187,123,251,
 309     7,135,71,199,39,167,103,231,23,151,87,215,55,183,119,247,
 310     15,143,79,207,47,175,111,239,31,159,95,223,63,191,127,255
 311 };
 312 #endif
 313
 314 #ifdef ERROR_RESILIENCE
 315
 316 /* Modified bit reading functions for HCR */
 317
 318 typedef struct
 319 {
 320     /* bit input */
 321     uint32_t bufa;
 322     uint32_t bufb;
 323     int8_t len;
 324 } bits_t;
 325
 326
 327 static INLINE uint32_t showbits_hcr(bits_t *ld, uint8_t bits)
 328 {
 329     if (bits == 0) return 0;
 330     if (ld->len <= 32)
 331     {
 332         /* huffman_spectral_data_2 needs to read more than may be available, bits maybe
 333            > ld->len, deliver 0 than */
 334         if (ld->len >= bits)
 335             return ((ld->bufa >> (ld->len - bits)) & (0xFFFFFFFF >> (32 - bits)));
 336         else
 337             return ((ld->bufa << (bits - ld->len)) & (0xFFFFFFFF >> (32 - bits)));
 338     } else {
 339         if ((ld->len - bits) < 32)
 340         {
 341             return ( (ld->bufb & (0xFFFFFFFF >> (64 - ld->len))) << (bits - ld->len + 32)) |
 342                 (ld->bufa >> (ld->len - bits));
 343         } else {
 344             return ((ld->bufb >> (ld->len - bits - 32)) & (0xFFFFFFFF >> (32 - bits)));
 345         }
 346     }
 347 }
 348
 349 /* return 1 if position is outside of buffer, 0 otherwise */
 350 static INLINE int8_t flushbits_hcr( bits_t *ld, uint8_t bits)
 351 {
 352     ld->len -= bits;
 353
 354     if (ld->len <0)
 355     {
 356         ld->len = 0;
 357         return 1;
 358     } else {
 359         return 0;
 360     }
 361 }
 362
 363 static INLINE int8_t getbits_hcr(bits_t *ld, uint8_t n, uint32_t *result)
 364 {
 365     *result = showbits_hcr(ld, n);
 366     return flushbits_hcr(ld, n);
 367 }
 368
 369 static INLINE int8_t get1bit_hcr(bits_t *ld, uint8_t *result)
 370 {
 371     uint32_t res;
 372     int8_t ret;
 373
 374     ret = getbits_hcr(ld, 1, &res);
 375     *result = (int8_t)(res & 1);
 376     return ret;
 377 }
 378
 379 #endif
 380
 381
 382 #ifdef __cplusplus
 383 }
 384 #endif
 385 #endif