Initial 800x480 cabbiev2 port, based on 480x800x16 one
[kugel-rb.git] / apps / codecs / lib / ffmpeg_bitstream.c
blobe16df8dcce9062af4bf5291faeb3f765943084c6
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
7 * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
9 * This file is part of FFmpeg.
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.
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.
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
26 /**
27 * @file
28 * bitstream api.
31 //#include "avcodec.h"
32 #include "ffmpeg_get_bits.h"
33 #include "ffmpeg_put_bits.h"
34 #include "ffmpeg_intreadwrite.h"
36 #define av_log(...)
38 #ifdef ROCKBOX
39 #undef DEBUGF
40 #define DEBUGF(...)
41 #endif
43 const uint8_t ff_log2_run[32]={
44 0, 0, 0, 0, 1, 1, 1, 1,
45 2, 2, 2, 2, 3, 3, 3, 3,
46 4, 4, 5, 5, 6, 6, 7, 7,
47 8, 9,10,11,12,13,14,15
50 #if 0 // unused in rockbox
51 void align_put_bits(PutBitContext *s)
53 #ifdef ALT_BITSTREAM_WRITER
54 put_bits(s,( - s->index) & 7,0);
55 #else
56 put_bits(s,s->bit_left & 7,0);
57 #endif
60 void ff_put_string(PutBitContext *pb, const char *string, int terminate_string)
62 while(*string){
63 put_bits(pb, 8, *string);
64 string++;
66 if(terminate_string)
67 put_bits(pb, 8, 0);
69 #endif
71 void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
73 int words= length>>4;
74 int bits= length&15;
75 int i;
77 if(length==0) return;
79 if(words < 16 || put_bits_count(pb)&7){
80 for(i=0; i<words; i++) put_bits(pb, 16, AV_RB16(src + 2*i));
81 }else{
82 for(i=0; put_bits_count(pb)&31; i++)
83 put_bits(pb, 8, src[i]);
84 flush_put_bits(pb);
85 memcpy(put_bits_ptr(pb), src+i, 2*words-i);
86 skip_put_bytes(pb, 2*words-i);
89 put_bits(pb, bits, AV_RB16(src + 2*words)>>(16-bits));
92 /* VLC decoding */
94 //#define DEBUG_VLC
96 #define GET_DATA(v, table, i, wrap, size) \
98 const uint8_t *ptr = (const uint8_t *)table + i * wrap;\
99 switch(size) {\
100 case 1:\
101 v = *(const uint8_t *)ptr;\
102 break;\
103 case 2:\
104 v = *(const uint16_t *)ptr;\
105 break;\
106 default:\
107 v = *(const uint32_t *)ptr;\
108 break;\
113 static int alloc_table(VLC *vlc, int size, int use_static)
115 int index;
116 index = vlc->table_size;
117 vlc->table_size += size;
118 if (vlc->table_size > vlc->table_allocated) {
119 if(use_static)
121 DEBUGF("init_vlc() used with too little memory : table_size > allocated_memory\n");
122 return -1;
124 // abort(); //cant do anything, init_vlc() is used with too little memory
125 // vlc->table_allocated += (1 << vlc->bits);
126 // vlc->table = av_realloc(vlc->table,
127 // sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
128 if (!vlc->table)
129 return -1;
131 return index;
135 static av_always_inline uint32_t bitswap_32(uint32_t x) {
136 return av_reverse[x&0xFF]<<24
137 | av_reverse[(x>>8)&0xFF]<<16
138 | av_reverse[(x>>16)&0xFF]<<8
139 | av_reverse[x>>24];
143 typedef struct {
144 uint8_t bits;
145 uint16_t symbol;
146 /** codeword, with the first bit-to-be-read in the msb
147 * (even if intended for a little-endian bitstream reader) */
148 uint32_t code;
149 } __attribute__((__packed__)) VLCcode; /* packed to save space */
151 static int compare_vlcspec(const void *a, const void *b)
153 const VLCcode *sa=a, *sb=b;
154 return (sa->code >> 1) - (sb->code >> 1);
158 * Build VLC decoding tables suitable for use with get_vlc().
160 * @param vlc the context to be initted
162 * @param table_nb_bits max length of vlc codes to store directly in this table
163 * (Longer codes are delegated to subtables.)
165 * @param nb_codes number of elements in codes[]
167 * @param codes descriptions of the vlc codes
168 * These must be ordered such that codes going into the same subtable are contiguous.
169 * Sorting by VLCcode.code is sufficient, though not necessary.
171 static int build_table(VLC *vlc, int table_nb_bits, int nb_codes,
172 VLCcode *codes, int flags)
174 int table_size, table_index, index, symbol, subtable_bits;
175 int i, j, k, n, nb, inc;
176 uint32_t code, code_prefix;
177 VLC_TYPE (*table)[2];
179 table_size = 1 << table_nb_bits;
180 table_index = alloc_table(vlc, table_size, flags & INIT_VLC_USE_NEW_STATIC);
181 #ifdef DEBUG_VLC
182 av_log(NULL,AV_LOG_DEBUG,"new table index=%d size=%d\n",
183 table_index, table_size);
184 #endif
185 if (table_index < 0)
186 return -1;
187 table = &vlc->table[table_index];
189 for (i = 0; i < table_size; i++) {
190 table[i][1] = 0; //bits
191 table[i][0] = -1; //codes
194 /* first pass: map codes and compute auxillary table sizes */
195 for (i = 0; i < nb_codes; i++) {
196 n = codes[i].bits;
197 code = codes[i].code;
198 symbol = codes[i].symbol;
199 #if defined(DEBUG_VLC) && 0
200 av_log(NULL,AV_LOG_DEBUG,"i=%d n=%d code=0x%x\n", i, n, code);
201 #endif
202 if (n <= table_nb_bits) {
203 /* no need to add another table */
204 j = code >> (32 - table_nb_bits);
205 nb = 1 << (table_nb_bits - n);
206 inc = 1;
207 /* if (flags & INIT_VLC_LE) {
208 j = bitswap_32(code);
209 inc = 1 << n;
210 } */
211 for (k = 0; k < nb; k++) {
212 #ifdef DEBUG_VLC
213 av_log(NULL, AV_LOG_DEBUG, "%4x: code=%d n=%d\n",
214 j, i, n);
215 #endif
216 if (table[j][1] /*bits*/ != 0) {
217 av_log(NULL, AV_LOG_ERROR, "incorrect codes\n");
218 return -1;
220 table[j][1] = n; //bits
221 table[j][0] = symbol;
222 j += inc;
224 } else {
225 /* fill auxiliary table recursively */
226 n -= table_nb_bits;
227 code_prefix = code >> (32 - table_nb_bits);
228 subtable_bits = n;
229 codes[i].bits = n;
230 codes[i].code = code << table_nb_bits;
231 for (k = i+1; k < nb_codes; k++) {
232 n = codes[k].bits - table_nb_bits;
233 if (n <= 0)
234 break;
235 code = codes[k].code;
236 if (code >> (32 - table_nb_bits) != code_prefix)
237 break;
238 codes[k].bits = n;
239 codes[k].code = code << table_nb_bits;
240 subtable_bits = FFMAX(subtable_bits, n);
242 subtable_bits = FFMIN(subtable_bits, table_nb_bits);
243 j = /*(flags & INIT_VLC_LE) ? bitswap_32(code_prefix) >> (32 - table_nb_bits) :*/ code_prefix;
244 table[j][1] = -subtable_bits;
245 #ifdef DEBUG_VLC
246 av_log(NULL,AV_LOG_DEBUG,"%4x: n=%d (subtable)\n",
247 j, codes[i].bits + table_nb_bits);
248 #endif
249 index = build_table(vlc, subtable_bits, k-i, codes+i, flags);
250 if (index < 0)
251 return -1;
252 /* note: realloc has been done, so reload tables */
253 table = &vlc->table[table_index];
254 table[j][0] = index; //code
255 i = k-1;
258 return table_index;
262 /* Build VLC decoding tables suitable for use with get_vlc().
264 'nb_bits' set thee decoding table size (2^nb_bits) entries. The
265 bigger it is, the faster is the decoding. But it should not be too
266 big to save memory and L1 cache. '9' is a good compromise.
268 'nb_codes' : number of vlcs codes
270 'bits' : table which gives the size (in bits) of each vlc code.
272 'codes' : table which gives the bit pattern of of each vlc code.
274 'symbols' : table which gives the values to be returned from get_vlc().
276 'xxx_wrap' : give the number of bytes between each entry of the
277 'bits' or 'codes' tables.
279 'xxx_size' : gives the number of bytes of each entry of the 'bits'
280 or 'codes' tables.
282 'wrap' and 'size' allows to use any memory configuration and types
283 (byte/word/long) to store the 'bits', 'codes', and 'symbols' tables.
285 'use_static' should be set to 1 for tables, which should be freed
286 with av_free_static(), 0 if free_vlc() will be used.
289 /* Rockbox: support for INIT_VLC_LE is currently disabled since none of our
290 codecs use it, there's a LUT based bit reverse function for this commented
291 out above (bitswap_32) and an inline asm version in libtremor/codebook.c
292 if we ever want this */
294 static VLCcode buf[1336+1]; /* worst case is wma, which has one table with 1336 entries */
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,
300 int flags)
302 if (nb_codes+1 > (int)(sizeof (buf)/ sizeof (VLCcode)))
304 DEBUGF("Table is larger than temp buffer!\n");
305 return -1;
308 int i, j, ret;
310 vlc->bits = nb_bits;
311 if(flags & INIT_VLC_USE_NEW_STATIC){
312 if(vlc->table_size && vlc->table_size == vlc->table_allocated){
313 return 0;
314 }else if(vlc->table_size){
315 DEBUGF("fatal error, we are called on a partially initialized table\n");
316 return -1;
317 // abort(); // fatal error, we are called on a partially initialized table
319 }else {
320 vlc->table = NULL;
321 vlc->table_allocated = 0;
322 vlc->table_size = 0;
325 #ifdef DEBUG_VLC
326 av_log(NULL,AV_LOG_DEBUG,"build table nb_codes=%d\n", nb_codes);
327 #endif
329 // buf = av_malloc((nb_codes+1)*sizeof(VLCcode));
331 // assert(symbols_size <= 2 || !symbols);
332 j = 0;
333 #define COPY(condition)\
334 for (i = 0; i < nb_codes; i++) {\
335 GET_DATA(buf[j].bits, bits, i, bits_wrap, bits_size);\
336 if (!(condition))\
337 continue;\
338 GET_DATA(buf[j].code, codes, i, codes_wrap, codes_size);\
339 /* if (flags & INIT_VLC_LE)*/\
340 /* buf[j].code = bitswap_32(buf[j].code);*/\
341 /* else*/\
342 buf[j].code <<= 32 - buf[j].bits;\
343 if (symbols)\
344 GET_DATA(buf[j].symbol, symbols, i, symbols_wrap, symbols_size)\
345 else\
346 buf[j].symbol = i;\
347 j++;\
349 COPY(buf[j].bits > nb_bits);
350 // qsort is the slowest part of init_vlc, and could probably be improved or avoided
351 qsort(buf, j, sizeof(VLCcode), compare_vlcspec);
352 COPY(buf[j].bits && buf[j].bits <= nb_bits);
353 nb_codes = j;
355 ret = build_table(vlc, nb_bits, nb_codes, buf, flags);
357 // av_free(buf);
358 if (ret < 0) {
359 // av_freep(&vlc->table);
360 return -1;
362 if((flags & INIT_VLC_USE_NEW_STATIC) && vlc->table_size != vlc->table_allocated) {
363 av_log(NULL, AV_LOG_ERROR, "needed %d had %d\n", vlc->table_size, vlc->table_allocated);
365 return 0;
368 /* not used in rockbox
369 void free_vlc(VLC *vlc)
371 av_freep(&vlc->table);