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1 de6d9b64 Fabrice Bellard
/*
2
 * Common bit i/o utils
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 * Copyright (c) 2000, 2001 Gerard Lantau.
4
 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 27a3e2c5 Michael Niedermayer
 *
19 17592475 Michael Niedermayer
 * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
20 de6d9b64 Fabrice Bellard
 */
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#include "common.h"
22 1a565432 Fabrice Bellard
#include <math.h>
23 a9b3f630 Nick Kurshev
24 de6d9b64 Fabrice Bellard
void init_put_bits(PutBitContext *s, 
25
                   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;
32 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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    }
36 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);
40 17592475 Michael Niedermayer
#else
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    s->buf_ptr = s->buf;
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    s->bit_left=32;
43 17592475 Michael Niedermayer
    s->bit_buf=0;
44
#endif
45 de6d9b64 Fabrice Bellard
}
46
47
/* return the number of bits output */
48 1a565432 Fabrice Bellard
INT64 get_bit_count(PutBitContext *s)
49 de6d9b64 Fabrice Bellard
{
50 17592475 Michael Niedermayer
#ifdef ALT_BITSTREAM_WRITER
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    return s->data_out_size * 8 + s->index;
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#else
53 d8cf5aea Michael Niedermayer
    return (s->buf_ptr - s->buf + s->data_out_size) * 8 + 32 - (INT64)s->bit_left;
54 17592475 Michael Niedermayer
#endif
55 de6d9b64 Fabrice Bellard
}
56
57
void align_put_bits(PutBitContext *s)
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{
59 17592475 Michael Niedermayer
#ifdef ALT_BITSTREAM_WRITER
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    put_bits(s,(  - s->index) & 7,0);
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#else
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    put_bits(s,s->bit_left & 7,0);
63 17592475 Michael Niedermayer
#endif
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}
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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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{
69 17592475 Michael Niedermayer
#ifdef ALT_BITSTREAM_WRITER
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    align_put_bits(s);
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#else
72 d8cf5aea Michael Niedermayer
    s->bit_buf<<= s->bit_left;
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    while (s->bit_left < 32) {
74 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;
77 d8cf5aea Michael Niedermayer
        s->bit_left+=8;
78 de6d9b64 Fabrice Bellard
    }
79 d8cf5aea Michael Niedermayer
    s->bit_left=32;
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    s->bit_buf=0;
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#endif
82 de6d9b64 Fabrice Bellard
}
83
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/* pad the end of the output stream with zeros */
85 17592475 Michael Niedermayer
#ifndef ALT_BITSTREAM_WRITER
86 de6d9b64 Fabrice Bellard
void jflush_put_bits(PutBitContext *s)
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{
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    unsigned int b;
89 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 */
91 de6d9b64 Fabrice Bellard
92 d8cf5aea Michael Niedermayer
    while (s->bit_left < 32) {
93 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;
98 d8cf5aea Michael Niedermayer
        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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}
103 17592475 Michael Niedermayer
#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
110 de6d9b64 Fabrice Bellard
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/* bit input functions */
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void init_get_bits(GetBitContext *s, 
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                   UINT8 *buffer, int buffer_size)
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{
116 27a3e2c5 Michael Niedermayer
#ifdef ALT_BITSTREAM_READER
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    s->index=0;
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    s->buffer= buffer;
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#else
120 de6d9b64 Fabrice Bellard
    s->buf = buffer;
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    s->buf_ptr = buffer;
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    s->buf_end = buffer + buffer_size;
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    s->bit_cnt = 0;
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    s->bit_buf = 0;
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    while (s->buf_ptr < s->buf_end && 
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           s->bit_cnt < 32) {
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        s->bit_buf |= (*s->buf_ptr++ << (24 - s->bit_cnt));
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        s->bit_cnt += 8;
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    }
130 27a3e2c5 Michael Niedermayer
#endif
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    s->size= buffer_size;
132 de6d9b64 Fabrice Bellard
}
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134 27a3e2c5 Michael Niedermayer
#ifndef ALT_BITSTREAM_READER
135 de6d9b64 Fabrice Bellard
/* n must be >= 1 and <= 32 */
136 2931ecb9 Arpi
/* also true: n > s->bit_cnt */
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unsigned int get_bits_long(GetBitContext *s, int n)
138 de6d9b64 Fabrice Bellard
{
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    unsigned int val;
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    int bit_cnt;
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    unsigned int bit_buf;
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#ifdef STATS
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    st_bit_counts[st_current_index] += n;
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#endif
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    bit_buf = s->bit_buf;
148 2931ecb9 Arpi
    bit_cnt = s->bit_cnt - n;
149 de6d9b64 Fabrice Bellard
    
150 2931ecb9 Arpi
//    if (bit_cnt >= 0) {
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//        val = bit_buf >> (32 - n);
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//        bit_buf <<= n; 
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//    } else 
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    {
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        UINT8 *buf_ptr;
156 de6d9b64 Fabrice Bellard
        val = bit_buf >> (32 - n);
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        buf_ptr = s->buf_ptr;
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        buf_ptr += 4;
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        /* handle common case: we can read everything */
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        if (buf_ptr <= s->buf_end) {
161 a9b3f630 Nick Kurshev
#if ARCH_X86
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            bit_buf = bswap_32(*((unsigned long*)(&buf_ptr[-4])));
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#else
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            bit_buf = (buf_ptr[-4] << 24) |
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                (buf_ptr[-3] << 16) |
166 de6d9b64 Fabrice Bellard
                (buf_ptr[-2] << 8) |
167 a9b3f630 Nick Kurshev
                (buf_ptr[-1]);            
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#endif
169 de6d9b64 Fabrice Bellard
        } else {
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            buf_ptr -= 4;
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            bit_buf = 0;
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            if (buf_ptr < s->buf_end)
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                bit_buf |= *buf_ptr++ << 24;
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            if (buf_ptr < s->buf_end)
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                bit_buf |= *buf_ptr++ << 16;
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            if (buf_ptr < s->buf_end)
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                bit_buf |= *buf_ptr++ << 8;
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            if (buf_ptr < s->buf_end)
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                bit_buf |= *buf_ptr++;
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        }
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        s->buf_ptr = buf_ptr;
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        val |= bit_buf >> (32 + bit_cnt);
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        bit_buf <<= - bit_cnt;
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        bit_cnt += 32;
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    }
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    s->bit_buf = bit_buf;
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    s->bit_cnt = bit_cnt;
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    return val;
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}
190 27a3e2c5 Michael Niedermayer
#endif
191 de6d9b64 Fabrice Bellard
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void align_get_bits(GetBitContext *s)
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{
194 27a3e2c5 Michael Niedermayer
#ifdef ALT_BITSTREAM_READER
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    s->index= (s->index + 7) & (~7); 
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#else
197 de6d9b64 Fabrice Bellard
    int n;
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    n = s->bit_cnt & 7;
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    if (n > 0) {
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        get_bits(s, n);
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    }
202 27a3e2c5 Michael Niedermayer
#endif
203 de6d9b64 Fabrice Bellard
}
204 27a3e2c5 Michael Niedermayer
205 49c9325f Michael Niedermayer
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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213 27a3e2c5 Michael Niedermayer
#ifndef ALT_BITSTREAM_READER
214 4949028f Juanjo
/* This function is identical to get_bits_long(), the */
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/* only diference is that it doesn't touch the buffer */
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/* it is usefull to see the buffer.                   */
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218
unsigned int show_bits_long(GetBitContext *s, int n)
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{
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    unsigned int val;
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    int bit_cnt;
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    unsigned int bit_buf;
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        UINT8 *buf_ptr;
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    bit_buf = s->bit_buf;
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    bit_cnt = s->bit_cnt - n;
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228
    val = bit_buf >> (32 - n);
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    buf_ptr = s->buf_ptr;
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    buf_ptr += 4;
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232
    /* handle common case: we can read everything */
233
    if (buf_ptr <= s->buf_end) {
234
#ifdef ARCH_X86
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        bit_buf = bswap_32(*((unsigned long*)(&buf_ptr[-4])));
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#else
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        bit_buf = (buf_ptr[-4] << 24) |
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            (buf_ptr[-3] << 16) |
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            (buf_ptr[-2] << 8) |
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            (buf_ptr[-1]);            
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#endif
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    } else {
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        buf_ptr -= 4;
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        bit_buf = 0;
245
        if (buf_ptr < s->buf_end)
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            bit_buf |= *buf_ptr++ << 24;
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        if (buf_ptr < s->buf_end)
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            bit_buf |= *buf_ptr++ << 16;
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        if (buf_ptr < s->buf_end)
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            bit_buf |= *buf_ptr++ << 8;
251
        if (buf_ptr < s->buf_end)
252
            bit_buf |= *buf_ptr++;
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    }
254
    val |= bit_buf >> (32 + bit_cnt);
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    bit_buf <<= - bit_cnt;
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    bit_cnt += 32;
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258
    return val;
259
}
260 27a3e2c5 Michael Niedermayer
#endif
261 de6d9b64 Fabrice Bellard
262
/* VLC decoding */
263
264
//#define DEBUG_VLC
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266
#define GET_DATA(v, table, i, wrap, size) \
267
{\
268
    UINT8 *ptr = (UINT8 *)table + i * wrap;\
269
    switch(size) {\
270
    case 1:\
271
        v = *(UINT8 *)ptr;\
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        break;\
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    case 2:\
274
        v = *(UINT16 *)ptr;\
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        break;\
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    default:\
277
        v = *(UINT32 *)ptr;\
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        break;\
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    }\
280
}
281
282
283
static int alloc_table(VLC *vlc, int size)
284
{
285
    int index;
286
    index = vlc->table_size;
287
    vlc->table_size += size;
288
    if (vlc->table_size > vlc->table_allocated) {
289
        vlc->table_allocated += (1 << vlc->bits);
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        vlc->table_bits = realloc(vlc->table_bits, 
291
                                  sizeof(INT8) * vlc->table_allocated);
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        vlc->table_codes = realloc(vlc->table_codes,
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                                   sizeof(INT16) * vlc->table_allocated);
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        if (!vlc->table_bits ||
295
            !vlc->table_codes)
296
            return -1;
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    }
298
    return index;
299
}
300
301
static int build_table(VLC *vlc, int table_nb_bits, 
302
                       int nb_codes,
303
                       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)
306
{
307
    int i, j, k, n, table_size, table_index, nb, n1, index;
308
    UINT32 code;
309
    INT8 *table_bits;
310
    INT16 *table_codes;
311
312
    table_size = 1 << table_nb_bits;
313
    table_index = alloc_table(vlc, table_size);
314
#ifdef DEBUG_VLC
315
    printf("new table index=%d size=%d code_prefix=%x n=%d\n", 
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           table_index, table_size, code_prefix, n_prefix);
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#endif
318
    if (table_index < 0)
319
        return -1;
320
    table_bits = &vlc->table_bits[table_index];
321
    table_codes = &vlc->table_codes[table_index];
322
323
    for(i=0;i<table_size;i++) {
324
        table_bits[i] = 0;
325
        table_codes[i] = -1;
326
    }
327
328
    /* first pass: map codes and compute auxillary table sizes */
329
    for(i=0;i<nb_codes;i++) {
330
        GET_DATA(n, bits, i, bits_wrap, bits_size);
331
        GET_DATA(code, codes, i, codes_wrap, codes_size);
332
        /* we accept tables with holes */
333
        if (n <= 0)
334
            continue;
335
#if defined(DEBUG_VLC) && 0
336
        printf("i=%d n=%d code=0x%x\n", i, n, code);
337
#endif
338
        /* if code matches the prefix, it is in the table */
339
        n -= n_prefix;
340
        if (n > 0 && (code >> n) == code_prefix) {
341
            if (n <= table_nb_bits) {
342
                /* no need to add another table */
343
                j = (code << (table_nb_bits - n)) & (table_size - 1);
344
                nb = 1 << (table_nb_bits - n);
345
                for(k=0;k<nb;k++) {
346
#ifdef DEBUG_VLC
347
                    printf("%4x: code=%d n=%d\n",
348
                           j, i, n);
349
#endif
350
                    if (table_bits[j] != 0) {
351
                        fprintf(stderr, "incorrect codes\n");
352
                        exit(1);
353
                    }
354
                    table_bits[j] = n;
355
                    table_codes[j] = i;
356
                    j++;
357
                }
358
            } else {
359
                n -= table_nb_bits;
360
                j = (code >> n) & ((1 << table_nb_bits) - 1);
361
#ifdef DEBUG_VLC
362
                printf("%4x: n=%d (subtable)\n",
363
                       j, n);
364
#endif
365
                /* compute table size */
366
                n1 = -table_bits[j];
367
                if (n > n1)
368
                    n1 = n;
369
                table_bits[j] = -n1;
370
            }
371
        }
372
    }
373
374
    /* second pass : fill auxillary tables recursively */
375
    for(i=0;i<table_size;i++) {
376
        n = table_bits[i];
377
        if (n < 0) {
378
            n = -n;
379
            if (n > table_nb_bits) {
380
                n = table_nb_bits;
381
                table_bits[i] = -n;
382
            }
383
            index = build_table(vlc, n, nb_codes,
384
                                bits, bits_wrap, bits_size,
385
                                codes, codes_wrap, codes_size,
386
                                (code_prefix << table_nb_bits) | i,
387
                                n_prefix + table_nb_bits);
388
            if (index < 0)
389
                return -1;
390
            /* note: realloc has been done, so reload tables */
391
            table_bits = &vlc->table_bits[table_index];
392
            table_codes = &vlc->table_codes[table_index];
393
            table_codes[i] = index;
394
        }
395
    }
396
    return table_index;
397
}
398
399
400 4e66ab3b Fabrice Bellard
/* Build VLC decoding tables suitable for use with get_vlc().
401

402
   'nb_bits' set thee decoding table size (2^nb_bits) entries. The
403
   bigger it is, the faster is the decoding. But it should not be too
404
   big to save memory and L1 cache. '9' is a good compromise.
405
   
406
   'nb_codes' : number of vlcs codes
407

408
   'bits' : table which gives the size (in bits) of each vlc code.
409

410
   'codes' : table which gives the bit pattern of of each vlc code.
411

412
   'xxx_wrap' : give the number of bytes between each entry of the
413
   'bits' or 'codes' tables.
414

415
   'xxx_size' : gives the number of bytes of each entry of the 'bits'
416
   or 'codes' tables.
417

418
   'wrap' and 'size' allows to use any memory configuration and types
419
   (byte/word/long) to store the 'bits' and 'codes' tables.  
420
*/
421 de6d9b64 Fabrice Bellard
int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
422
             const void *bits, int bits_wrap, int bits_size,
423
             const void *codes, int codes_wrap, int codes_size)
424
{
425
    vlc->bits = nb_bits;
426
    vlc->table_bits = NULL;
427
    vlc->table_codes = NULL;
428
    vlc->table_allocated = 0;
429
    vlc->table_size = 0;
430
#ifdef DEBUG_VLC
431
    printf("build table nb_codes=%d\n", nb_codes);
432
#endif
433
434
    if (build_table(vlc, nb_bits, nb_codes,
435
                    bits, bits_wrap, bits_size,
436
                    codes, codes_wrap, codes_size,
437
                    0, 0) < 0) {
438
        if (vlc->table_bits)
439
            free(vlc->table_bits);
440
        if (vlc->table_codes)
441
            free(vlc->table_codes);
442
        return -1;
443
    }
444
    return 0;
445
}
446
447
448
void free_vlc(VLC *vlc)
449
{
450
    free(vlc->table_bits);
451
    free(vlc->table_codes);
452
}
453
454 9dbcbd92 Michael Niedermayer
int ff_gcd(int a, int b){
455
    if(b) return ff_gcd(b, a%b);
456
    else  return a;
457
}