3 * Copyright (c) 2000, 2001 Fabrice Bellard.
4 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
6 * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
8 * This file is part of FFmpeg.
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
31 #include "bitstream.h"
34 * Same as av_mallocz_static(), but does a realloc.
36 * @param[in] ptr The block of memory to reallocate.
37 * @param[in] size The requested size.
38 * @return Block of memory of requested size.
39 * @deprecated. Code which uses ff_realloc_static is broken/misdesigned
40 * and should correctly use static arrays
42 attribute_deprecated av_alloc_size(2)
43 static void *ff_realloc_static(void *ptr, unsigned int size);
45 static unsigned int last_static = 0;
46 static unsigned int allocated_static = 0;
47 static void** array_static = NULL;
49 static void *av_mallocz_static(unsigned int size)
51 void *ptr = av_mallocz(size);
54 array_static =av_fast_realloc(array_static, &allocated_static, sizeof(void*)*(last_static+1));
57 array_static[last_static++] = ptr;
63 static void *ff_realloc_static(void *ptr, unsigned int size)
67 return av_mallocz_static(size);
68 /* Look for the old ptr */
69 for(i = 0; i < last_static; i++) {
70 if(array_static[i] == ptr) {
71 array_static[i] = av_realloc(array_static[i], size);
72 return array_static[i];
79 void align_put_bits(PutBitContext *s)
81 #ifdef ALT_BITSTREAM_WRITER
82 put_bits(s,( - s->index) & 7,0);
84 put_bits(s,s->bit_left & 7,0);
88 void ff_put_string(PutBitContext * pbc, const char *s, int put_zero)
98 void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
100 const uint16_t *srcw= (const uint16_t*)src;
101 int words= length>>4;
105 if(length==0) return;
107 if(ENABLE_SMALL || words < 16 || put_bits_count(pb)&7){
108 for(i=0; i<words; i++) put_bits(pb, 16, be2me_16(srcw[i]));
110 for(i=0; put_bits_count(pb)&31; i++)
111 put_bits(pb, 8, src[i]);
113 memcpy(pbBufPtr(pb), src+i, 2*words-i);
114 skip_put_bytes(pb, 2*words-i);
117 put_bits(pb, bits, be2me_16(srcw[words])>>(16-bits));
124 #define GET_DATA(v, table, i, wrap, size) \
126 const uint8_t *ptr = (const uint8_t *)table + i * wrap;\
129 v = *(const uint8_t *)ptr;\
132 v = *(const uint16_t *)ptr;\
135 v = *(const uint32_t *)ptr;\
141 static int alloc_table(VLC *vlc, int size, int use_static)
144 index = vlc->table_size;
145 vlc->table_size += size;
146 if (vlc->table_size > vlc->table_allocated) {
148 abort(); //cant do anything, init_vlc() is used with too little memory
149 vlc->table_allocated += (1 << vlc->bits);
151 vlc->table = ff_realloc_static(vlc->table,
152 sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
154 vlc->table = av_realloc(vlc->table,
155 sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
162 static int build_table(VLC *vlc, int table_nb_bits,
164 const void *bits, int bits_wrap, int bits_size,
165 const void *codes, int codes_wrap, int codes_size,
166 const void *symbols, int symbols_wrap, int symbols_size,
167 uint32_t code_prefix, int n_prefix, int flags)
169 int i, j, k, n, table_size, table_index, nb, n1, index, code_prefix2, symbol;
171 VLC_TYPE (*table)[2];
173 table_size = 1 << table_nb_bits;
174 table_index = alloc_table(vlc, table_size, flags & (INIT_VLC_USE_STATIC|INIT_VLC_USE_NEW_STATIC));
176 av_log(NULL,AV_LOG_DEBUG,"new table index=%d size=%d code_prefix=%x n=%d\n",
177 table_index, table_size, code_prefix, n_prefix);
181 table = &vlc->table[table_index];
183 for(i=0;i<table_size;i++) {
184 table[i][1] = 0; //bits
185 table[i][0] = -1; //codes
188 /* first pass: map codes and compute auxillary table sizes */
189 for(i=0;i<nb_codes;i++) {
190 GET_DATA(n, bits, i, bits_wrap, bits_size);
191 GET_DATA(code, codes, i, codes_wrap, codes_size);
192 /* we accept tables with holes */
198 GET_DATA(symbol, symbols, i, symbols_wrap, symbols_size);
199 #if defined(DEBUG_VLC) && 0
200 av_log(NULL,AV_LOG_DEBUG,"i=%d n=%d code=0x%x\n", i, n, code);
202 /* if code matches the prefix, it is in the table */
204 if(flags & INIT_VLC_LE)
205 code_prefix2= code & (n_prefix>=32 ? 0xffffffff : (1 << n_prefix)-1);
207 code_prefix2= code >> n;
208 if (n > 0 && code_prefix2 == code_prefix) {
209 if (n <= table_nb_bits) {
210 /* no need to add another table */
211 j = (code << (table_nb_bits - n)) & (table_size - 1);
212 nb = 1 << (table_nb_bits - n);
214 if(flags & INIT_VLC_LE)
215 j = (code >> n_prefix) + (k<<n);
217 av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n",
220 if (table[j][1] /*bits*/ != 0) {
221 av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
224 table[j][1] = n; //bits
225 table[j][0] = symbol;
230 j = (code >> ((flags & INIT_VLC_LE) ? n_prefix : n)) & ((1 << table_nb_bits) - 1);
232 av_log(NULL,AV_LOG_DEBUG,"%4x: n=%d (subtable)\n",
235 /* compute table size */
236 n1 = -table[j][1]; //bits
239 table[j][1] = -n1; //bits
244 /* second pass : fill auxillary tables recursively */
245 for(i=0;i<table_size;i++) {
246 n = table[i][1]; //bits
249 if (n > table_nb_bits) {
251 table[i][1] = -n; //bits
253 index = build_table(vlc, n, nb_codes,
254 bits, bits_wrap, bits_size,
255 codes, codes_wrap, codes_size,
256 symbols, symbols_wrap, symbols_size,
257 (flags & INIT_VLC_LE) ? (code_prefix | (i << n_prefix)) : ((code_prefix << table_nb_bits) | i),
258 n_prefix + table_nb_bits, flags);
261 /* note: realloc has been done, so reload tables */
262 table = &vlc->table[table_index];
263 table[i][0] = index; //code
270 /* Build VLC decoding tables suitable for use with get_vlc().
272 'nb_bits' set thee decoding table size (2^nb_bits) entries. The
273 bigger it is, the faster is the decoding. But it should not be too
274 big to save memory and L1 cache. '9' is a good compromise.
276 'nb_codes' : number of vlcs codes
278 'bits' : table which gives the size (in bits) of each vlc code.
280 'codes' : table which gives the bit pattern of of each vlc code.
282 'symbols' : table which gives the values to be returned from get_vlc().
284 'xxx_wrap' : give the number of bytes between each entry of the
285 'bits' or 'codes' tables.
287 'xxx_size' : gives the number of bytes of each entry of the 'bits'
290 'wrap' and 'size' allows to use any memory configuration and types
291 (byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
293 'use_static' should be set to 1 for tables, which should be freed
294 with av_free_static(), 0 if free_vlc() will be used.
296 int init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes,
297 const void *bits, int bits_wrap, int bits_size,
298 const void *codes, int codes_wrap, int codes_size,
299 const void *symbols, int symbols_wrap, int symbols_size,
303 if(flags & INIT_VLC_USE_NEW_STATIC){
304 if(vlc->table_size && vlc->table_size == vlc->table_allocated){
306 }else if(vlc->table_size){
307 abort(); // fatal error, we are called on a partially initialized table
309 }else if(!(flags & INIT_VLC_USE_STATIC)) {
311 vlc->table_allocated = 0;
314 /* Static tables are initially always NULL, return
315 if vlc->table != NULL to avoid double allocation */
321 av_log(NULL,AV_LOG_DEBUG,"build table nb_codes=%d\n", nb_codes);
324 if (build_table(vlc, nb_bits, nb_codes,
325 bits, bits_wrap, bits_size,
326 codes, codes_wrap, codes_size,
327 symbols, symbols_wrap, symbols_size,
329 av_freep(&vlc->table);
332 if((flags & INIT_VLC_USE_NEW_STATIC) && vlc->table_size != vlc->table_allocated)
333 av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
338 void free_vlc(VLC *vlc)
340 av_freep(&vlc->table);