apps/codecs/libfaad/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 ** $Id$
  26 **/
  27
  28 #ifndef __BITS_H__
  29 #define __BITS_H__
  30
  31 #ifdef __cplusplus
  32 extern "C" {
  33 #endif
  34
  35 #include "analysis.h"
  36 #ifdef ANALYSIS
  37 #include <stdio.h>
  38 #endif
  39
  40 #define BYTE_NUMBIT 8
  41 #define bit2byte(a) ((a+7)/BYTE_NUMBIT)
  42
  43 typedef struct _bitfile
  44 {
  45     /* bit input */
  46     uint32_t bufa;
  47     uint32_t bufb;
  48     uint32_t bits_left;
  49     uint32_t buffer_size; /* size of the buffer in bytes */
  50     uint32_t bytes_used;
  51     uint8_t no_more_reading;
  52     uint8_t error;
  53     uint32_t *tail;
  54     uint32_t *start;
  55     void *buffer;
  56 } bitfile;
  57
  58 /* rockbox: use asm optimized swap32()
  59 #define BSWAP(a) \
  60     ((a) = ( ((a)&0xff)<<24) | (((a)&0xff00)<<8) | (((a)>>8)&0xff00) | (((a)>>24)&0xff))
  61 */
  62 #define BSWAP(a) swap32(a)
  63
  64 static uint32_t bitmask[] = {
  65     0x0, 0x1, 0x3, 0x7, 0xF, 0x1F, 0x3F, 0x7F, 0xFF, 0x1FF,
  66     0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF,
  67     0x1FFFF, 0x3FFFF, 0x7FFFF, 0xFFFFF, 0x1FFFFF, 0x3FFFFF,
  68     0x7FFFFF, 0xFFFFFF, 0x1FFFFFF, 0x3FFFFFF, 0x7FFFFFF,
  69     0xFFFFFFF, 0x1FFFFFFF, 0x3FFFFFFF, 0x7FFFFFFF
  70     /* added bitmask 32, correct?!?!?! */
  71     , 0xFFFFFFFF
  72 };
  73
  74 void faad_initbits(bitfile *ld, const void *buffer, const uint32_t buffer_size);
  75 void faad_endbits(bitfile *ld);
  76 /* not used
  77 void faad_initbits_rev(bitfile *ld, void *buffer,
  78                        uint32_t bits_in_buffer);
  79 */
  80 uint8_t faad_byte_align(bitfile *ld);
  81 uint32_t faad_get_processed_bits(bitfile *ld);
  82 void faad_rewindbits(bitfile *ld);
  83 uint8_t *faad_getbitbuffer(bitfile *ld, uint32_t bits
  84                        DEBUGDEC);
  85 #ifdef DRM
  86 void *faad_origbitbuffer(bitfile *ld);
  87 uint32_t faad_origbitbuffer_size(bitfile *ld);
  88 #endif
  89
  90 static INLINE uint32_t getdword(void *mem)
  91 {
  92 #ifndef ARCH_IS_BIG_ENDIAN
  93     return BSWAP(*(uint32_t*)mem);
  94 #else
  95     return *(uint32_t*)mem;
  96 #endif
  97 }
  98
  99 static INLINE void faad_flushbits_ex(bitfile *ld, uint32_t bits)
 100 {
 101     uint32_t tmp;
 102
 103     ld->bufa = ld->bufb;
 104     if (ld->no_more_reading == 0)
 105     {
 106         tmp = getdword(ld->tail);
 107         ld->tail++;
 108     } else {
 109         tmp = 0;
 110     }
 111     ld->bufb = tmp;
 112     ld->bits_left += (32 - bits);
 113     ld->bytes_used += 4;
 114     if (ld->bytes_used == ld->buffer_size)
 115         ld->no_more_reading = 1;
 116     if (ld->bytes_used > ld->buffer_size)
 117         ld->error = 1;
 118 }
 119
 120 static INLINE uint32_t faad_showbits(bitfile *ld, uint32_t bits)
 121 {
 122     if (bits <= ld->bits_left)
 123     {
 124         return (ld->bufa >> (ld->bits_left - bits)) & bitmask[bits];
 125     }
 126
 127     bits -= ld->bits_left;
 128     return ((ld->bufa & bitmask[ld->bits_left]) << bits) | (ld->bufb >> (32 - bits));
 129 }
 130
 131 static INLINE void faad_flushbits(bitfile *ld, uint32_t bits)
 132 {
 133     /* do nothing if error */
 134     if (ld->error != 0)
 135         return;
 136
 137     if (bits < ld->bits_left)
 138     {
 139         ld->bits_left -= bits;
 140     } else {
 141         faad_flushbits_ex(ld, bits);
 142     }
 143 }
 144
 145 /* return next n bits (right adjusted) */
 146 static uint32_t faad_getbits(bitfile *ld, uint32_t n DEBUGDEC)
 147 {
 148     uint32_t ret;
 149
 150     if (ld->no_more_reading || n == 0)
 151         return 0;
 152
 153     ret = faad_showbits(ld, n);
 154     faad_flushbits(ld, n);
 155
 156 #ifdef ANALYSIS
 157     if (print)
 158         fprintf(stdout, "%4d %2d bits, val: %4d, variable: %d %s\n", dbg_count++, n, ret, var, dbg);
 159 #endif
 160
 161     return ret;
 162 }
 163
 164 static INLINE uint8_t faad_get1bit(bitfile *ld DEBUGDEC)
 165 {
 166     uint8_t r;
 167
 168     if (ld->bits_left > 0)
 169     {
 170         ld->bits_left--;
 171         r = (uint8_t)((ld->bufa >> ld->bits_left) & 1);
 172         return r;
 173     }
 174
 175     /* bits_left == 0 */
 176 #if 0
 177     r = (uint8_t)(ld->bufb >> 31);
 178     faad_flushbits_ex(ld, 1);
 179 #else
 180     r = (uint8_t)faad_getbits(ld, 1);
 181 #endif
 182     return r;
 183 }
 184
 185 /* reversed bitreading routines */
 186 static INLINE uint32_t faad_showbits_rev(bitfile *ld, uint32_t bits)
 187 {
 188     uint8_t i;
 189     uint32_t B = 0;
 190
 191     if (bits <= ld->bits_left)
 192     {
 193         for (i = 0; i < bits; i++)
 194         {
 195             if (ld->bufa & (1 << (i + (32 - ld->bits_left))))
 196                 B |= (1 << (bits - i - 1));
 197         }
 198         return B;
 199     } else {
 200         for (i = 0; i < ld->bits_left; i++)
 201         {
 202             if (ld->bufa & (1 << (i + (32 - ld->bits_left))))
 203                 B |= (1 << (bits - i - 1));
 204         }
 205         for (i = 0; i < bits - ld->bits_left; i++)
 206         {
 207             if (ld->bufb & (1 << (i + (32-ld->bits_left))))
 208                 B |= (1 << (bits - ld->bits_left - i - 1));
 209         }
 210         return B;
 211     }
 212 }
 213
 214 static INLINE void faad_flushbits_rev(bitfile *ld, uint32_t bits)
 215 {
 216     /* do nothing if error */
 217     if (ld->error != 0)
 218         return;
 219
 220     if (bits < ld->bits_left)
 221     {
 222         ld->bits_left -= bits;
 223     } else {
 224         uint32_t tmp;
 225
 226         ld->bufa = ld->bufb;
 227         tmp = getdword(ld->start);
 228         ld->bufb = tmp;
 229         ld->start--;
 230         ld->bits_left += (32 - bits);
 231
 232         ld->bytes_used += 4;
 233         if (ld->bytes_used == ld->buffer_size)
 234             ld->no_more_reading = 1;
 235         if (ld->bytes_used > ld->buffer_size)
 236             ld->error = 1;
 237     }
 238 }
 239
 240 static INLINE uint32_t faad_getbits_rev(bitfile *ld, uint32_t n
 241                                         DEBUGDEC)
 242 {
 243     uint32_t ret;
 244
 245     if (ld->no_more_reading)
 246         return 0;
 247
 248     if (n == 0)
 249         return 0;
 250
 251     ret = faad_showbits_rev(ld, n);
 252     faad_flushbits_rev(ld, n);
 253
 254 #ifdef ANALYSIS
 255     if (print)
 256         fprintf(stdout, "%4d %2d bits, val: %4d, variable: %d %s\n", dbg_count++, n, ret, var, dbg);
 257 #endif
 258
 259     return ret;
 260 }
 261
 262 #ifdef DRM
 263 static uint8_t faad_check_CRC(bitfile *ld, uint16_t len)
 264 {
 265     uint8_t CRC;
 266     uint16_t r=255;  /* Initialize to all ones */
 267
 268     /* CRC polynome used x^8 + x^4 + x^3 + x^2 +1 */
 269 #define GPOLY 0435
 270
 271     faad_rewindbits(ld);
 272
 273     CRC = (uint8_t) ~faad_getbits(ld, 8
 274         DEBUGVAR(1,999,"faad_check_CRC(): CRC"));          /* CRC is stored inverted */
 275
 276     for (; len>0; len--)
 277     {
 278         r = ( (r << 1) ^ (( ( faad_get1bit(ld
 279             DEBUGVAR(1,998,""))  & 1) ^ ((r >> 7) & 1)) * GPOLY )) & 0xFF;
 280     }
 281
 282     if (r != CRC)
 283     {
 284         return 8;
 285     } else {
 286         return 0;
 287     }
 288 }
 289
 290 static uint8_t tabFlipbits[256] = {
 291     0,128,64,192,32,160,96,224,16,144,80,208,48,176,112,240,
 292     8,136,72,200,40,168,104,232,24,152,88,216,56,184,120,248,
 293     4,132,68,196,36,164,100,228,20,148,84,212,52,180,116,244,
 294     12,140,76,204,44,172,108,236,28,156,92,220,60,188,124,252,
 295     2,130,66,194,34,162,98,226,18,146,82,210,50,178,114,242,
 296     10,138,74,202,42,170,106,234,26,154,90,218,58,186,122,250,
 297     6,134,70,198,38,166,102,230,22,150,86,214,54,182,118,246,
 298     14,142,78,206,46,174,110,238,30,158,94,222,62,190,126,254,
 299     1,129,65,193,33,161,97,225,17,145,81,209,49,177,113,241,
 300     9,137,73,201,41,169,105,233,25,153,89,217,57,185,121,249,
 301     5,133,69,197,37,165,101,229,21,149,85,213,53,181,117,245,
 302     13,141,77,205,45,173,109,237,29,157,93,221,61,189,125,253,
 303     3,131,67,195,35,163,99,227,19,147,83,211,51,179,115,243,
 304     11,139,75,203,43,171,107,235,27,155,91,219,59,187,123,251,
 305     7,135,71,199,39,167,103,231,23,151,87,215,55,183,119,247,
 306     15,143,79,207,47,175,111,239,31,159,95,223,63,191,127,255
 307 };
 308 #endif
 309
 310 #ifdef ERROR_RESILIENCE
 311
 312 /* Modified bit reading functions for HCR */
 313
 314 typedef struct
 315 {
 316     /* bit input */
 317     uint32_t bufa;
 318     uint32_t bufb;
 319     int8_t len;
 320 } bits_t;
 321
 322
 323 static INLINE uint32_t showbits_hcr(bits_t *ld, uint8_t bits)
 324 {
 325     if (bits == 0) return 0;
 326     if (ld->len <= 32)
 327     {
 328         /* huffman_spectral_data_2 needs to read more than may be available, bits maybe
 329            > ld->len, deliver 0 than */
 330         if (ld->len >= bits)
 331             return ((ld->bufa >> (ld->len - bits)) & (0xFFFFFFFF >> (32 - bits)));
 332         else
 333             return ((ld->bufa << (bits - ld->len)) & (0xFFFFFFFF >> (32 - bits)));
 334     } else {
 335         if ((ld->len - bits) < 32)
 336         {
 337             return ( (ld->bufb & (0xFFFFFFFF >> (64 - ld->len))) << (bits - ld->len + 32)) |
 338                 (ld->bufa >> (ld->len - bits));
 339         } else {
 340             return ((ld->bufb >> (ld->len - bits - 32)) & (0xFFFFFFFF >> (32 - bits)));
 341         }
 342     }
 343 }
 344
 345 /* return 1 if position is outside of buffer, 0 otherwise */
 346 static INLINE int8_t flushbits_hcr( bits_t *ld, uint8_t bits)
 347 {
 348     ld->len -= bits;
 349
 350     if (ld->len <0)
 351     {
 352         ld->len = 0;
 353         return 1;
 354     } else {
 355         return 0;
 356     }
 357 }
 358
 359 static INLINE int8_t getbits_hcr(bits_t *ld, uint8_t n, uint32_t *result)
 360 {
 361     *result = showbits_hcr(ld, n);
 362     return flushbits_hcr(ld, n);
 363 }
 364
 365 static INLINE int8_t get1bit_hcr(bits_t *ld, uint8_t *result)
 366 {
 367     uint32_t res;
 368     int8_t ret;
 369
 370     ret = getbits_hcr(ld, 1, &res);
 371     *result = (int8_t)(res & 1);
 372     return ret;
 373 }
 374
 375 #endif
 376
 377
 378 #ifdef __cplusplus
 379 }
 380 #endif
 381 #endif