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1 de6d9b64 Fabrice Bellard
/*
2
 * Common bit i/o utils
3 ff4ec49e Fabrice Bellard
 * Copyright (c) 2000, 2001 Fabrice Bellard.
4 de6d9b64 Fabrice Bellard
 *
5 ff4ec49e Fabrice Bellard
 * This library is free software; you can redistribute it and/or
6
 * modify it under the terms of the GNU Lesser General Public
7
 * License as published by the Free Software Foundation; either
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 * version 2 of the License, or (at your option) any later version.
9 de6d9b64 Fabrice Bellard
 *
10 ff4ec49e Fabrice Bellard
 * This library is distributed in the hope that it will be useful,
11 de6d9b64 Fabrice Bellard
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 ff4ec49e Fabrice Bellard
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
14 de6d9b64 Fabrice Bellard
 *
15 ff4ec49e Fabrice Bellard
 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18 27a3e2c5 Michael Niedermayer
 *
19 17592475 Michael Niedermayer
 * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
20 de6d9b64 Fabrice Bellard
 */
21 df595131 Zdenek Kabelac
#include "avcodec.h"
22 a9b3f630 Nick Kurshev
23 f36db5df Michael Niedermayer
const UINT8 ff_sqrt_tab[128]={
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        0, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5,
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        5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
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        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
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        9, 9, 9, 9,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,11,11,11,11,11,11,11
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};
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30 de6d9b64 Fabrice Bellard
void init_put_bits(PutBitContext *s, 
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                   UINT8 *buffer, int buffer_size,
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                   void *opaque,
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                   void (*write_data)(void *, UINT8 *, int))
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{
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    s->buf = buffer;
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    s->buf_end = s->buf + buffer_size;
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    s->data_out_size = 0;
38 17592475 Michael Niedermayer
    if(write_data!=NULL) 
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    {
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            fprintf(stderr, "write Data callback is not supported\n");
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    }
42 d8cf5aea Michael Niedermayer
#ifdef ALT_BITSTREAM_WRITER
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    s->index=0;
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    ((uint32_t*)(s->buf))[0]=0;
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//    memset(buffer, 0, buffer_size);
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#else
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    s->buf_ptr = s->buf;
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    s->bit_left=32;
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    s->bit_buf=0;
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#endif
51 de6d9b64 Fabrice Bellard
}
52
53
/* return the number of bits output */
54 1a565432 Fabrice Bellard
INT64 get_bit_count(PutBitContext *s)
55 de6d9b64 Fabrice Bellard
{
56 17592475 Michael Niedermayer
#ifdef ALT_BITSTREAM_WRITER
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    return s->data_out_size * 8 + s->index;
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#else
59 d8cf5aea Michael Niedermayer
    return (s->buf_ptr - s->buf + s->data_out_size) * 8 + 32 - (INT64)s->bit_left;
60 17592475 Michael Niedermayer
#endif
61 de6d9b64 Fabrice Bellard
}
62
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void align_put_bits(PutBitContext *s)
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{
65 17592475 Michael Niedermayer
#ifdef ALT_BITSTREAM_WRITER
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    put_bits(s,(  - s->index) & 7,0);
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#else
68 d8cf5aea Michael Niedermayer
    put_bits(s,s->bit_left & 7,0);
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#endif
70 de6d9b64 Fabrice Bellard
}
71
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/* pad the end of the output stream with zeros */
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void flush_put_bits(PutBitContext *s)
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{
75 17592475 Michael Niedermayer
#ifdef ALT_BITSTREAM_WRITER
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    align_put_bits(s);
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#else
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    s->bit_buf<<= s->bit_left;
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    while (s->bit_left < 32) {
80 de6d9b64 Fabrice Bellard
        /* XXX: should test end of buffer */
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        *s->buf_ptr++=s->bit_buf >> 24;
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        s->bit_buf<<=8;
83 d8cf5aea Michael Niedermayer
        s->bit_left+=8;
84 de6d9b64 Fabrice Bellard
    }
85 d8cf5aea Michael Niedermayer
    s->bit_left=32;
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    s->bit_buf=0;
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#endif
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}
89
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/* pad the end of the output stream with zeros */
91 17592475 Michael Niedermayer
#ifndef ALT_BITSTREAM_WRITER
92 de6d9b64 Fabrice Bellard
void jflush_put_bits(PutBitContext *s)
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{
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    unsigned int b;
95 d8cf5aea Michael Niedermayer
    s->bit_buf<<= s->bit_left;
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    s->bit_buf |= ~1U >> (32 - s->bit_left); /* set all the unused bits to one */
97 de6d9b64 Fabrice Bellard
98 d8cf5aea Michael Niedermayer
    while (s->bit_left < 32) {
99 de6d9b64 Fabrice Bellard
        b = s->bit_buf >> 24;
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        *s->buf_ptr++ = b;
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        if (b == 0xff)
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            *s->buf_ptr++ = 0;
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        s->bit_buf<<=8;
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        s->bit_left+=8;
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    }
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    s->bit_left=32;
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    s->bit_buf=0;
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}
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#else
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void jflush_put_bits(PutBitContext *s)
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{
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    int num= (  - s->index) & 7;
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    jput_bits(s, num,0xFF>>(8-num));
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}
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#endif
116 de6d9b64 Fabrice Bellard
117 9717dad8 Michael Niedermayer
void put_string(PutBitContext * pbc, char *s)
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{
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    while(*s){
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        put_bits(pbc, 8, *s);
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        s++;
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    }
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    put_bits(pbc, 8, 0);
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}
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126 de6d9b64 Fabrice Bellard
/* bit input functions */
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128 8db1a1dd Michael Niedermayer
void init_get_bits(GetBitContext *s,
129 de6d9b64 Fabrice Bellard
                   UINT8 *buffer, int buffer_size)
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{
131 27a3e2c5 Michael Niedermayer
    s->buffer= buffer;
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    s->size= buffer_size;
133 8db1a1dd Michael Niedermayer
    s->buffer_end= buffer + buffer_size;
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#ifdef ALT_BITSTREAM_READER
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    s->index=0;
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#elif defined LIBMPEG2_BITSTREAM_READER
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    s->buffer_ptr = buffer;
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    s->bit_count = 16;
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    s->cache = 0;
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#elif defined A32_BITSTREAM_READER
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    s->buffer_ptr = (uint32_t*)buffer;
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    s->bit_count = 32;
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    s->cache0 = 0;
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    s->cache1 = 0;
145 de6d9b64 Fabrice Bellard
#endif
146 2931ecb9 Arpi
    {
147 8db1a1dd Michael Niedermayer
        OPEN_READER(re, s)
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        UPDATE_CACHE(re, s)
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//        UPDATE_CACHE(re, s)
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        CLOSE_READER(re, s)
151 de6d9b64 Fabrice Bellard
    }
152 8db1a1dd Michael Niedermayer
#ifdef A32_BITSTREAM_READER
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    s->cache1 = 0;
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#endif
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}
156 de6d9b64 Fabrice Bellard
157
void align_get_bits(GetBitContext *s)
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{
159 8db1a1dd Michael Niedermayer
    int n= (-get_bits_count(s)) & 7;
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    if(n) skip_bits(s, n);
161 de6d9b64 Fabrice Bellard
}
162 27a3e2c5 Michael Niedermayer
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int check_marker(GetBitContext *s, char *msg)
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{
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    int bit= get_bits1(s);
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    if(!bit) printf("Marker bit missing %s\n", msg);
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    return bit;
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}
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171 de6d9b64 Fabrice Bellard
/* VLC decoding */
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//#define DEBUG_VLC
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#define GET_DATA(v, table, i, wrap, size) \
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{\
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    UINT8 *ptr = (UINT8 *)table + i * wrap;\
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    switch(size) {\
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    case 1:\
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        v = *(UINT8 *)ptr;\
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        break;\
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    case 2:\
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        v = *(UINT16 *)ptr;\
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        break;\
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    default:\
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        v = *(UINT32 *)ptr;\
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        break;\
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    }\
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}
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191
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static int alloc_table(VLC *vlc, int size)
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{
194
    int index;
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    index = vlc->table_size;
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    vlc->table_size += size;
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    if (vlc->table_size > vlc->table_allocated) {
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        vlc->table_allocated += (1 << vlc->bits);
199 8db1a1dd Michael Niedermayer
        vlc->table = realloc(vlc->table,
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                             sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
201
        if (!vlc->table)
202 de6d9b64 Fabrice Bellard
            return -1;
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    }
204
    return index;
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}
206
207 8db1a1dd Michael Niedermayer
static int build_table(VLC *vlc, int table_nb_bits,
208 de6d9b64 Fabrice Bellard
                       int nb_codes,
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                       const void *bits, int bits_wrap, int bits_size,
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                       const void *codes, int codes_wrap, int codes_size,
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                       UINT32 code_prefix, int n_prefix)
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{
213
    int i, j, k, n, table_size, table_index, nb, n1, index;
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    UINT32 code;
215 8db1a1dd Michael Niedermayer
    VLC_TYPE (*table)[2];
216 de6d9b64 Fabrice Bellard
217
    table_size = 1 << table_nb_bits;
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    table_index = alloc_table(vlc, table_size);
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#ifdef DEBUG_VLC
220 8db1a1dd Michael Niedermayer
    printf("new table index=%d size=%d code_prefix=%x n=%d\n",
221 de6d9b64 Fabrice Bellard
           table_index, table_size, code_prefix, n_prefix);
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#endif
223
    if (table_index < 0)
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        return -1;
225 8db1a1dd Michael Niedermayer
    table = &vlc->table[table_index];
226 de6d9b64 Fabrice Bellard
227
    for(i=0;i<table_size;i++) {
228 8db1a1dd Michael Niedermayer
        table[i][1] = 0; //bits
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        table[i][0] = -1; //codes
230 de6d9b64 Fabrice Bellard
    }
231
232
    /* first pass: map codes and compute auxillary table sizes */
233
    for(i=0;i<nb_codes;i++) {
234
        GET_DATA(n, bits, i, bits_wrap, bits_size);
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        GET_DATA(code, codes, i, codes_wrap, codes_size);
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        /* we accept tables with holes */
237
        if (n <= 0)
238
            continue;
239
#if defined(DEBUG_VLC) && 0
240
        printf("i=%d n=%d code=0x%x\n", i, n, code);
241
#endif
242
        /* if code matches the prefix, it is in the table */
243
        n -= n_prefix;
244
        if (n > 0 && (code >> n) == code_prefix) {
245
            if (n <= table_nb_bits) {
246
                /* no need to add another table */
247
                j = (code << (table_nb_bits - n)) & (table_size - 1);
248
                nb = 1 << (table_nb_bits - n);
249
                for(k=0;k<nb;k++) {
250
#ifdef DEBUG_VLC
251
                    printf("%4x: code=%d n=%d\n",
252
                           j, i, n);
253
#endif
254 8db1a1dd Michael Niedermayer
                    if (table[j][1] /*bits*/ != 0) {
255 de6d9b64 Fabrice Bellard
                        fprintf(stderr, "incorrect codes\n");
256
                        exit(1);
257
                    }
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                    table[j][1] = n; //bits
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                    table[j][0] = i; //code
260 de6d9b64 Fabrice Bellard
                    j++;
261
                }
262
            } else {
263
                n -= table_nb_bits;
264
                j = (code >> n) & ((1 << table_nb_bits) - 1);
265
#ifdef DEBUG_VLC
266
                printf("%4x: n=%d (subtable)\n",
267
                       j, n);
268
#endif
269
                /* compute table size */
270 8db1a1dd Michael Niedermayer
                n1 = -table[j][1]; //bits
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                if (n > n1)
272
                    n1 = n;
273 8db1a1dd Michael Niedermayer
                table[j][1] = -n1; //bits
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            }
275
        }
276
    }
277
278
    /* second pass : fill auxillary tables recursively */
279
    for(i=0;i<table_size;i++) {
280 8db1a1dd Michael Niedermayer
        n = table[i][1]; //bits
281 de6d9b64 Fabrice Bellard
        if (n < 0) {
282
            n = -n;
283
            if (n > table_nb_bits) {
284
                n = table_nb_bits;
285 8db1a1dd Michael Niedermayer
                table[i][1] = -n; //bits
286 de6d9b64 Fabrice Bellard
            }
287
            index = build_table(vlc, n, nb_codes,
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                                bits, bits_wrap, bits_size,
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                                codes, codes_wrap, codes_size,
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                                (code_prefix << table_nb_bits) | i,
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                                n_prefix + table_nb_bits);
292
            if (index < 0)
293
                return -1;
294
            /* note: realloc has been done, so reload tables */
295 8db1a1dd Michael Niedermayer
            table = &vlc->table[table_index];
296 6300c80a Michael Niedermayer
            table[i][0] = index; //code
297 de6d9b64 Fabrice Bellard
        }
298
    }
299
    return table_index;
300
}
301
302
303 4e66ab3b Fabrice Bellard
/* Build VLC decoding tables suitable for use with get_vlc().
304

305
   'nb_bits' set thee decoding table size (2^nb_bits) entries. The
306
   bigger it is, the faster is the decoding. But it should not be too
307
   big to save memory and L1 cache. '9' is a good compromise.
308
   
309
   'nb_codes' : number of vlcs codes
310

311
   'bits' : table which gives the size (in bits) of each vlc code.
312

313
   'codes' : table which gives the bit pattern of of each vlc code.
314

315
   'xxx_wrap' : give the number of bytes between each entry of the
316
   'bits' or 'codes' tables.
317

318
   'xxx_size' : gives the number of bytes of each entry of the 'bits'
319
   or 'codes' tables.
320

321
   'wrap' and 'size' allows to use any memory configuration and types
322
   (byte/word/long) to store the 'bits' and 'codes' tables.  
323
*/
324 de6d9b64 Fabrice Bellard
int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
325
             const void *bits, int bits_wrap, int bits_size,
326
             const void *codes, int codes_wrap, int codes_size)
327
{
328
    vlc->bits = nb_bits;
329 8db1a1dd Michael Niedermayer
    vlc->table = NULL;
330 de6d9b64 Fabrice Bellard
    vlc->table_allocated = 0;
331
    vlc->table_size = 0;
332
#ifdef DEBUG_VLC
333
    printf("build table nb_codes=%d\n", nb_codes);
334
#endif
335
336
    if (build_table(vlc, nb_bits, nb_codes,
337
                    bits, bits_wrap, bits_size,
338
                    codes, codes_wrap, codes_size,
339
                    0, 0) < 0) {
340 8db1a1dd Michael Niedermayer
        av_free(vlc->table);
341 de6d9b64 Fabrice Bellard
        return -1;
342
    }
343
    return 0;
344
}
345
346
347
void free_vlc(VLC *vlc)
348
{
349 8db1a1dd Michael Niedermayer
    av_free(vlc->table);
350 de6d9b64 Fabrice Bellard
}
351
352 9dbcbd92 Michael Niedermayer
int ff_gcd(int a, int b){
353
    if(b) return ff_gcd(b, a%b);
354
    else  return a;
355
}