Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 1 | /* Copyright (C) 2002 Jean-Marc Valin |
| 2 | File: speex_bits.c |
| 3 | |
| 4 | Handles bit packing/unpacking |
| 5 | |
| 6 | Redistribution and use in source and binary forms, with or without |
| 7 | modification, are permitted provided that the following conditions |
| 8 | are met: |
| 9 | |
| 10 | - Redistributions of source code must retain the above copyright |
| 11 | notice, this list of conditions and the following disclaimer. |
| 12 | |
| 13 | - Redistributions in binary form must reproduce the above copyright |
| 14 | notice, this list of conditions and the following disclaimer in the |
| 15 | documentation and/or other materials provided with the distribution. |
| 16 | |
| 17 | - Neither the name of the Xiph.org Foundation nor the names of its |
| 18 | contributors may be used to endorse or promote products derived from |
| 19 | this software without specific prior written permission. |
| 20 | |
| 21 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 22 | ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 23 | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 24 | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
| 25 | CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 26 | EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 27 | PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 28 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 29 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 30 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 31 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 32 | |
| 33 | */ |
| 34 | |
| 35 | #ifdef HAVE_CONFIG_H |
| 36 | #include "config.h" |
| 37 | #endif |
| 38 | |
| 39 | #include <speex/speex_bits.h> |
| 40 | #include "arch.h" |
| 41 | #include "os_support.h" |
| 42 | |
| 43 | /* Maximum size of the bit-stream (for fixed-size allocation) */ |
| 44 | #ifndef MAX_CHARS_PER_FRAME |
| 45 | #define MAX_CHARS_PER_FRAME (2000/BYTES_PER_CHAR) |
| 46 | #endif |
| 47 | |
| 48 | EXPORT void speex_bits_init(SpeexBits *bits) |
| 49 | { |
| 50 | bits->chars = (char*)speex_alloc(MAX_CHARS_PER_FRAME); |
| 51 | if (!bits->chars) |
| 52 | return; |
| 53 | |
| 54 | bits->buf_size = MAX_CHARS_PER_FRAME; |
| 55 | |
| 56 | bits->owner=1; |
| 57 | |
| 58 | speex_bits_reset(bits); |
| 59 | } |
| 60 | |
| 61 | EXPORT void speex_bits_init_buffer(SpeexBits *bits, void *buff, int buf_size) |
| 62 | { |
| 63 | bits->chars = (char*)buff; |
| 64 | bits->buf_size = buf_size; |
| 65 | |
| 66 | bits->owner=0; |
| 67 | |
| 68 | speex_bits_reset(bits); |
| 69 | } |
| 70 | |
| 71 | EXPORT void speex_bits_set_bit_buffer(SpeexBits *bits, void *buff, int buf_size) |
| 72 | { |
| 73 | bits->chars = (char*)buff; |
| 74 | bits->buf_size = buf_size; |
| 75 | |
| 76 | bits->owner=0; |
| 77 | |
| 78 | bits->nbBits=buf_size<<LOG2_BITS_PER_CHAR; |
| 79 | bits->charPtr=0; |
| 80 | bits->bitPtr=0; |
| 81 | bits->overflow=0; |
| 82 | |
| 83 | } |
| 84 | |
| 85 | EXPORT void speex_bits_destroy(SpeexBits *bits) |
| 86 | { |
| 87 | if (bits->owner) |
| 88 | speex_free(bits->chars); |
| 89 | /* Will do something once the allocation is dynamic */ |
| 90 | } |
| 91 | |
| 92 | EXPORT void speex_bits_reset(SpeexBits *bits) |
| 93 | { |
| 94 | /* We only need to clear the first byte now */ |
| 95 | bits->chars[0]=0; |
| 96 | bits->nbBits=0; |
| 97 | bits->charPtr=0; |
| 98 | bits->bitPtr=0; |
| 99 | bits->overflow=0; |
| 100 | } |
| 101 | |
| 102 | EXPORT void speex_bits_rewind(SpeexBits *bits) |
| 103 | { |
| 104 | bits->charPtr=0; |
| 105 | bits->bitPtr=0; |
| 106 | bits->overflow=0; |
| 107 | } |
| 108 | |
| 109 | EXPORT void speex_bits_read_from(SpeexBits *bits, char *chars, int len) |
| 110 | { |
| 111 | int i; |
| 112 | int nchars = len / BYTES_PER_CHAR; |
| 113 | if (nchars > bits->buf_size) |
| 114 | { |
| 115 | speex_notify("Packet is larger than allocated buffer"); |
| 116 | if (bits->owner) |
| 117 | { |
| 118 | char *tmp = (char*)speex_realloc(bits->chars, nchars); |
| 119 | if (tmp) |
| 120 | { |
| 121 | bits->buf_size=nchars; |
| 122 | bits->chars=tmp; |
| 123 | } else { |
| 124 | nchars=bits->buf_size; |
| 125 | speex_warning("Could not resize input buffer: truncating input"); |
| 126 | } |
| 127 | } else { |
| 128 | speex_warning("Do not own input buffer: truncating oversize input"); |
| 129 | nchars=bits->buf_size; |
| 130 | } |
| 131 | } |
| 132 | #if (BYTES_PER_CHAR==2) |
| 133 | /* Swap bytes to proper endian order (could be done externally) */ |
| 134 | #define HTOLS(A) ((((A) >> 8)&0xff)|(((A) & 0xff)<<8)) |
| 135 | #else |
| 136 | #define HTOLS(A) (A) |
| 137 | #endif |
| 138 | for (i=0;i<nchars;i++) |
| 139 | bits->chars[i]=HTOLS(chars[i]); |
| 140 | |
| 141 | bits->nbBits=nchars<<LOG2_BITS_PER_CHAR; |
| 142 | bits->charPtr=0; |
| 143 | bits->bitPtr=0; |
| 144 | bits->overflow=0; |
| 145 | } |
| 146 | |
| 147 | static void speex_bits_flush(SpeexBits *bits) |
| 148 | { |
| 149 | int nchars = ((bits->nbBits+BITS_PER_CHAR-1)>>LOG2_BITS_PER_CHAR); |
| 150 | if (bits->charPtr>0) |
| 151 | SPEEX_MOVE(bits->chars, &bits->chars[bits->charPtr], nchars-bits->charPtr); |
| 152 | bits->nbBits -= bits->charPtr<<LOG2_BITS_PER_CHAR; |
| 153 | bits->charPtr=0; |
| 154 | } |
| 155 | |
| 156 | EXPORT void speex_bits_read_whole_bytes(SpeexBits *bits, char *chars, int nbytes) |
| 157 | { |
| 158 | int i,pos; |
| 159 | int nchars = nbytes/BYTES_PER_CHAR; |
| 160 | |
| 161 | if (((bits->nbBits+BITS_PER_CHAR-1)>>LOG2_BITS_PER_CHAR)+nchars > bits->buf_size) |
| 162 | { |
| 163 | /* Packet is larger than allocated buffer */ |
| 164 | if (bits->owner) |
| 165 | { |
| 166 | char *tmp = (char*)speex_realloc(bits->chars, (bits->nbBits>>LOG2_BITS_PER_CHAR)+nchars+1); |
| 167 | if (tmp) |
| 168 | { |
| 169 | bits->buf_size=(bits->nbBits>>LOG2_BITS_PER_CHAR)+nchars+1; |
| 170 | bits->chars=tmp; |
| 171 | } else { |
| 172 | nchars=bits->buf_size-(bits->nbBits>>LOG2_BITS_PER_CHAR)-1; |
| 173 | speex_warning("Could not resize input buffer: truncating oversize input"); |
| 174 | } |
| 175 | } else { |
| 176 | speex_warning("Do not own input buffer: truncating oversize input"); |
| 177 | nchars=bits->buf_size; |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | speex_bits_flush(bits); |
| 182 | pos=bits->nbBits>>LOG2_BITS_PER_CHAR; |
| 183 | for (i=0;i<nchars;i++) |
| 184 | bits->chars[pos+i]=HTOLS(chars[i]); |
| 185 | bits->nbBits+=nchars<<LOG2_BITS_PER_CHAR; |
| 186 | } |
| 187 | |
| 188 | EXPORT int speex_bits_write(SpeexBits *bits, char *chars, int max_nbytes) |
| 189 | { |
| 190 | int i; |
| 191 | int max_nchars = max_nbytes/BYTES_PER_CHAR; |
| 192 | int charPtr, bitPtr, nbBits; |
| 193 | |
| 194 | /* Insert terminator, but save the data so we can put it back after */ |
| 195 | bitPtr=bits->bitPtr; |
| 196 | charPtr=bits->charPtr; |
| 197 | nbBits=bits->nbBits; |
| 198 | speex_bits_insert_terminator(bits); |
| 199 | bits->bitPtr=bitPtr; |
| 200 | bits->charPtr=charPtr; |
| 201 | bits->nbBits=nbBits; |
| 202 | |
| 203 | if (max_nchars > ((bits->nbBits+BITS_PER_CHAR-1)>>LOG2_BITS_PER_CHAR)) |
| 204 | max_nchars = ((bits->nbBits+BITS_PER_CHAR-1)>>LOG2_BITS_PER_CHAR); |
| 205 | |
| 206 | for (i=0;i<max_nchars;i++) |
| 207 | chars[i]=HTOLS(bits->chars[i]); |
| 208 | return max_nchars*BYTES_PER_CHAR; |
| 209 | } |
| 210 | |
| 211 | EXPORT int speex_bits_write_whole_bytes(SpeexBits *bits, char *chars, int max_nbytes) |
| 212 | { |
| 213 | int max_nchars = max_nbytes/BYTES_PER_CHAR; |
| 214 | int i; |
| 215 | if (max_nchars > ((bits->nbBits)>>LOG2_BITS_PER_CHAR)) |
| 216 | max_nchars = ((bits->nbBits)>>LOG2_BITS_PER_CHAR); |
| 217 | for (i=0;i<max_nchars;i++) |
| 218 | chars[i]=HTOLS(bits->chars[i]); |
| 219 | |
| 220 | if (bits->bitPtr>0) |
| 221 | bits->chars[0]=bits->chars[max_nchars]; |
| 222 | else |
| 223 | bits->chars[0]=0; |
| 224 | bits->charPtr=0; |
| 225 | bits->nbBits &= (BITS_PER_CHAR-1); |
| 226 | return max_nchars*BYTES_PER_CHAR; |
| 227 | } |
| 228 | |
| 229 | EXPORT void speex_bits_pack(SpeexBits *bits, int data, int nbBits) |
| 230 | { |
| 231 | unsigned int d=data; |
| 232 | |
| 233 | if (bits->charPtr+((nbBits+bits->bitPtr)>>LOG2_BITS_PER_CHAR) >= bits->buf_size) |
| 234 | { |
| 235 | speex_notify("Buffer too small to pack bits"); |
| 236 | if (bits->owner) |
| 237 | { |
| 238 | int new_nchars = ((bits->buf_size+5)*3)>>1; |
| 239 | char *tmp = (char*)speex_realloc(bits->chars, new_nchars); |
| 240 | if (tmp) |
| 241 | { |
| 242 | bits->buf_size=new_nchars; |
| 243 | bits->chars=tmp; |
| 244 | } else { |
| 245 | speex_warning("Could not resize input buffer: not packing"); |
| 246 | return; |
| 247 | } |
| 248 | } else { |
| 249 | speex_warning("Do not own input buffer: not packing"); |
| 250 | return; |
| 251 | } |
| 252 | } |
| 253 | |
| 254 | while(nbBits) |
| 255 | { |
| 256 | int bit; |
| 257 | bit = (d>>(nbBits-1))&1; |
| 258 | bits->chars[bits->charPtr] |= bit<<(BITS_PER_CHAR-1-bits->bitPtr); |
| 259 | bits->bitPtr++; |
| 260 | |
| 261 | if (bits->bitPtr==BITS_PER_CHAR) |
| 262 | { |
| 263 | bits->bitPtr=0; |
| 264 | bits->charPtr++; |
| 265 | bits->chars[bits->charPtr] = 0; |
| 266 | } |
| 267 | bits->nbBits++; |
| 268 | nbBits--; |
| 269 | } |
| 270 | } |
| 271 | |
| 272 | EXPORT int speex_bits_unpack_signed(SpeexBits *bits, int nbBits) |
| 273 | { |
| 274 | unsigned int d=speex_bits_unpack_unsigned(bits,nbBits); |
| 275 | /* If number is negative */ |
| 276 | if (d>>(nbBits-1)) |
| 277 | { |
| 278 | d |= (-1)<<nbBits; |
| 279 | } |
| 280 | return d; |
| 281 | } |
| 282 | |
| 283 | EXPORT unsigned int speex_bits_unpack_unsigned(SpeexBits *bits, int nbBits) |
| 284 | { |
| 285 | unsigned int d=0; |
| 286 | if ((bits->charPtr<<LOG2_BITS_PER_CHAR)+bits->bitPtr+nbBits>bits->nbBits) |
| 287 | bits->overflow=1; |
| 288 | if (bits->overflow) |
| 289 | return 0; |
| 290 | while(nbBits) |
| 291 | { |
| 292 | d<<=1; |
| 293 | d |= (bits->chars[bits->charPtr]>>(BITS_PER_CHAR-1 - bits->bitPtr))&1; |
| 294 | bits->bitPtr++; |
| 295 | if (bits->bitPtr==BITS_PER_CHAR) |
| 296 | { |
| 297 | bits->bitPtr=0; |
| 298 | bits->charPtr++; |
| 299 | } |
| 300 | nbBits--; |
| 301 | } |
| 302 | return d; |
| 303 | } |
| 304 | |
| 305 | EXPORT unsigned int speex_bits_peek_unsigned(SpeexBits *bits, int nbBits) |
| 306 | { |
| 307 | unsigned int d=0; |
| 308 | int bitPtr, charPtr; |
| 309 | char *chars; |
| 310 | |
| 311 | if ((bits->charPtr<<LOG2_BITS_PER_CHAR)+bits->bitPtr+nbBits>bits->nbBits) |
| 312 | bits->overflow=1; |
| 313 | if (bits->overflow) |
| 314 | return 0; |
| 315 | |
| 316 | bitPtr=bits->bitPtr; |
| 317 | charPtr=bits->charPtr; |
| 318 | chars = bits->chars; |
| 319 | while(nbBits) |
| 320 | { |
| 321 | d<<=1; |
| 322 | d |= (chars[charPtr]>>(BITS_PER_CHAR-1 - bitPtr))&1; |
| 323 | bitPtr++; |
| 324 | if (bitPtr==BITS_PER_CHAR) |
| 325 | { |
| 326 | bitPtr=0; |
| 327 | charPtr++; |
| 328 | } |
| 329 | nbBits--; |
| 330 | } |
| 331 | return d; |
| 332 | } |
| 333 | |
| 334 | EXPORT int speex_bits_peek(SpeexBits *bits) |
| 335 | { |
| 336 | if ((bits->charPtr<<LOG2_BITS_PER_CHAR)+bits->bitPtr+1>bits->nbBits) |
| 337 | bits->overflow=1; |
| 338 | if (bits->overflow) |
| 339 | return 0; |
| 340 | return (bits->chars[bits->charPtr]>>(BITS_PER_CHAR-1 - bits->bitPtr))&1; |
| 341 | } |
| 342 | |
| 343 | EXPORT void speex_bits_advance(SpeexBits *bits, int n) |
| 344 | { |
| 345 | if (((bits->charPtr<<LOG2_BITS_PER_CHAR)+bits->bitPtr+n>bits->nbBits) || bits->overflow){ |
| 346 | bits->overflow=1; |
| 347 | return; |
| 348 | } |
| 349 | bits->charPtr += (bits->bitPtr+n) >> LOG2_BITS_PER_CHAR; /* divide by BITS_PER_CHAR */ |
| 350 | bits->bitPtr = (bits->bitPtr+n) & (BITS_PER_CHAR-1); /* modulo by BITS_PER_CHAR */ |
| 351 | } |
| 352 | |
| 353 | EXPORT int speex_bits_remaining(SpeexBits *bits) |
| 354 | { |
| 355 | if (bits->overflow) |
| 356 | return -1; |
| 357 | else |
| 358 | return bits->nbBits-((bits->charPtr<<LOG2_BITS_PER_CHAR)+bits->bitPtr); |
| 359 | } |
| 360 | |
| 361 | EXPORT int speex_bits_nbytes(SpeexBits *bits) |
| 362 | { |
| 363 | return ((bits->nbBits+BITS_PER_CHAR-1)>>LOG2_BITS_PER_CHAR); |
| 364 | } |
| 365 | |
| 366 | EXPORT void speex_bits_insert_terminator(SpeexBits *bits) |
| 367 | { |
| 368 | if (bits->bitPtr) |
| 369 | speex_bits_pack(bits, 0, 1); |
| 370 | while (bits->bitPtr) |
| 371 | speex_bits_pack(bits, 1, 1); |
| 372 | } |