mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
483 lines
13 KiB
483 lines
13 KiB
/* |
|
* Common bit i/o utils |
|
* Copyright (c) 2000, 2001 Gerard Lantau. |
|
* |
|
* This program is free software; you can redistribute it and/or modify |
|
* it under the terms of the GNU General Public License as published by |
|
* the Free Software Foundation; either version 2 of the License, or |
|
* (at your option) any later version. |
|
* |
|
* This program is distributed in the hope that it will be useful, |
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of |
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
|
* GNU General Public License for more details. |
|
* |
|
* You should have received a copy of the GNU General Public License |
|
* along with this program; if not, write to the Free Software |
|
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
|
*/ |
|
#include "common.h" |
|
#include <math.h> |
|
|
|
void init_put_bits(PutBitContext *s, |
|
UINT8 *buffer, int buffer_size, |
|
void *opaque, |
|
void (*write_data)(void *, UINT8 *, int)) |
|
{ |
|
s->buf = buffer; |
|
s->buf_ptr = s->buf; |
|
s->buf_end = s->buf + buffer_size; |
|
s->bit_cnt=0; |
|
s->bit_buf=0; |
|
s->data_out_size = 0; |
|
s->write_data = write_data; |
|
s->opaque = opaque; |
|
} |
|
|
|
static void flush_buffer(PutBitContext *s) |
|
{ |
|
int size; |
|
if (s->write_data) { |
|
size = s->buf_ptr - s->buf; |
|
if (size > 0) |
|
s->write_data(s->opaque, s->buf, size); |
|
s->buf_ptr = s->buf; |
|
s->data_out_size += size; |
|
} |
|
} |
|
|
|
void put_bits(PutBitContext *s, int n, unsigned int value) |
|
{ |
|
unsigned int bit_buf; |
|
int bit_cnt; |
|
|
|
#ifdef STATS |
|
st_out_bit_counts[st_current_index] += n; |
|
#endif |
|
// printf("put_bits=%d %x\n", n, value); |
|
assert(n == 32 || value < (1U << n)); |
|
|
|
bit_buf = s->bit_buf; |
|
bit_cnt = s->bit_cnt; |
|
|
|
// printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf); |
|
/* XXX: optimize */ |
|
if (n < (32-bit_cnt)) { |
|
bit_buf |= value << (32 - n - bit_cnt); |
|
bit_cnt+=n; |
|
} else { |
|
bit_buf |= value >> (n + bit_cnt - 32); |
|
*(UINT32 *)s->buf_ptr = be2me_32(bit_buf); |
|
//printf("bitbuf = %08x\n", bit_buf); |
|
s->buf_ptr+=4; |
|
if (s->buf_ptr >= s->buf_end) |
|
flush_buffer(s); |
|
bit_cnt=bit_cnt + n - 32; |
|
if (bit_cnt == 0) { |
|
bit_buf = 0; |
|
} else { |
|
bit_buf = value << (32 - bit_cnt); |
|
} |
|
} |
|
|
|
s->bit_buf = bit_buf; |
|
s->bit_cnt = bit_cnt; |
|
} |
|
|
|
/* return the number of bits output */ |
|
INT64 get_bit_count(PutBitContext *s) |
|
{ |
|
return (s->buf_ptr - s->buf + s->data_out_size) * 8 + (INT64)s->bit_cnt; |
|
} |
|
|
|
void align_put_bits(PutBitContext *s) |
|
{ |
|
put_bits(s,(8 - s->bit_cnt) & 7,0); |
|
} |
|
|
|
/* pad the end of the output stream with zeros */ |
|
void flush_put_bits(PutBitContext *s) |
|
{ |
|
while (s->bit_cnt > 0) { |
|
/* XXX: should test end of buffer */ |
|
*s->buf_ptr++=s->bit_buf >> 24; |
|
s->bit_buf<<=8; |
|
s->bit_cnt-=8; |
|
} |
|
flush_buffer(s); |
|
s->bit_cnt=0; |
|
s->bit_buf=0; |
|
} |
|
|
|
/* for jpeg : escape 0xff with 0x00 after it */ |
|
void jput_bits(PutBitContext *s, int n, unsigned int value) |
|
{ |
|
unsigned int bit_buf, b; |
|
int bit_cnt, i; |
|
|
|
assert(n == 32 || value < (1U << n)); |
|
|
|
bit_buf = s->bit_buf; |
|
bit_cnt = s->bit_cnt; |
|
|
|
//printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf); |
|
/* XXX: optimize */ |
|
if (n < (32-bit_cnt)) { |
|
bit_buf |= value << (32 - n - bit_cnt); |
|
bit_cnt+=n; |
|
} else { |
|
bit_buf |= value >> (n + bit_cnt - 32); |
|
/* handle escape */ |
|
for(i=0;i<4;i++) { |
|
b = (bit_buf >> 24); |
|
*(s->buf_ptr++) = b; |
|
if (b == 0xff) |
|
*(s->buf_ptr++) = 0; |
|
bit_buf <<= 8; |
|
} |
|
/* we flush the buffer sooner to handle worst case */ |
|
if (s->buf_ptr >= (s->buf_end - 8)) |
|
flush_buffer(s); |
|
|
|
bit_cnt=bit_cnt + n - 32; |
|
if (bit_cnt == 0) { |
|
bit_buf = 0; |
|
} else { |
|
bit_buf = value << (32 - bit_cnt); |
|
} |
|
} |
|
|
|
s->bit_buf = bit_buf; |
|
s->bit_cnt = bit_cnt; |
|
} |
|
|
|
/* pad the end of the output stream with zeros */ |
|
void jflush_put_bits(PutBitContext *s) |
|
{ |
|
unsigned int b; |
|
|
|
while (s->bit_cnt > 0) { |
|
b = s->bit_buf >> 24; |
|
*s->buf_ptr++ = b; |
|
if (b == 0xff) |
|
*s->buf_ptr++ = 0; |
|
s->bit_buf<<=8; |
|
s->bit_cnt-=8; |
|
} |
|
flush_buffer(s); |
|
s->bit_cnt=0; |
|
s->bit_buf=0; |
|
} |
|
|
|
/* bit input functions */ |
|
|
|
void init_get_bits(GetBitContext *s, |
|
UINT8 *buffer, int buffer_size) |
|
{ |
|
s->buf = buffer; |
|
s->buf_ptr = buffer; |
|
s->buf_end = buffer + buffer_size; |
|
s->bit_cnt = 0; |
|
s->bit_buf = 0; |
|
while (s->buf_ptr < s->buf_end && |
|
s->bit_cnt < 32) { |
|
s->bit_buf |= (*s->buf_ptr++ << (24 - s->bit_cnt)); |
|
s->bit_cnt += 8; |
|
} |
|
} |
|
|
|
/* n must be >= 1 and <= 32 */ |
|
/* also true: n > s->bit_cnt */ |
|
unsigned int get_bits_long(GetBitContext *s, int n) |
|
{ |
|
unsigned int val; |
|
int bit_cnt; |
|
unsigned int bit_buf; |
|
|
|
#ifdef STATS |
|
st_bit_counts[st_current_index] += n; |
|
#endif |
|
|
|
bit_buf = s->bit_buf; |
|
bit_cnt = s->bit_cnt - n; |
|
|
|
// if (bit_cnt >= 0) { |
|
// val = bit_buf >> (32 - n); |
|
// bit_buf <<= n; |
|
// } else |
|
{ |
|
UINT8 *buf_ptr; |
|
val = bit_buf >> (32 - n); |
|
buf_ptr = s->buf_ptr; |
|
buf_ptr += 4; |
|
/* handle common case: we can read everything */ |
|
if (buf_ptr <= s->buf_end) { |
|
#if ARCH_X86 |
|
bit_buf = bswap_32(*((unsigned long*)(&buf_ptr[-4]))); |
|
#else |
|
bit_buf = (buf_ptr[-4] << 24) | |
|
(buf_ptr[-3] << 16) | |
|
(buf_ptr[-2] << 8) | |
|
(buf_ptr[-1]); |
|
#endif |
|
} else { |
|
buf_ptr -= 4; |
|
bit_buf = 0; |
|
if (buf_ptr < s->buf_end) |
|
bit_buf |= *buf_ptr++ << 24; |
|
if (buf_ptr < s->buf_end) |
|
bit_buf |= *buf_ptr++ << 16; |
|
if (buf_ptr < s->buf_end) |
|
bit_buf |= *buf_ptr++ << 8; |
|
if (buf_ptr < s->buf_end) |
|
bit_buf |= *buf_ptr++; |
|
} |
|
s->buf_ptr = buf_ptr; |
|
val |= bit_buf >> (32 + bit_cnt); |
|
bit_buf <<= - bit_cnt; |
|
bit_cnt += 32; |
|
} |
|
s->bit_buf = bit_buf; |
|
s->bit_cnt = bit_cnt; |
|
return val; |
|
} |
|
|
|
void align_get_bits(GetBitContext *s) |
|
{ |
|
int n; |
|
n = s->bit_cnt & 7; |
|
if (n > 0) { |
|
get_bits(s, n); |
|
} |
|
} |
|
|
|
/* VLC decoding */ |
|
|
|
//#define DEBUG_VLC |
|
|
|
#define GET_DATA(v, table, i, wrap, size) \ |
|
{\ |
|
UINT8 *ptr = (UINT8 *)table + i * wrap;\ |
|
switch(size) {\ |
|
case 1:\ |
|
v = *(UINT8 *)ptr;\ |
|
break;\ |
|
case 2:\ |
|
v = *(UINT16 *)ptr;\ |
|
break;\ |
|
default:\ |
|
v = *(UINT32 *)ptr;\ |
|
break;\ |
|
}\ |
|
} |
|
|
|
|
|
static int alloc_table(VLC *vlc, int size) |
|
{ |
|
int index; |
|
index = vlc->table_size; |
|
vlc->table_size += size; |
|
if (vlc->table_size > vlc->table_allocated) { |
|
vlc->table_allocated += (1 << vlc->bits); |
|
vlc->table_bits = realloc(vlc->table_bits, |
|
sizeof(INT8) * vlc->table_allocated); |
|
vlc->table_codes = realloc(vlc->table_codes, |
|
sizeof(INT16) * vlc->table_allocated); |
|
if (!vlc->table_bits || |
|
!vlc->table_codes) |
|
return -1; |
|
} |
|
return index; |
|
} |
|
|
|
static int build_table(VLC *vlc, int table_nb_bits, |
|
int nb_codes, |
|
const void *bits, int bits_wrap, int bits_size, |
|
const void *codes, int codes_wrap, int codes_size, |
|
UINT32 code_prefix, int n_prefix) |
|
{ |
|
int i, j, k, n, table_size, table_index, nb, n1, index; |
|
UINT32 code; |
|
INT8 *table_bits; |
|
INT16 *table_codes; |
|
|
|
table_size = 1 << table_nb_bits; |
|
table_index = alloc_table(vlc, table_size); |
|
#ifdef DEBUG_VLC |
|
printf("new table index=%d size=%d code_prefix=%x n=%d\n", |
|
table_index, table_size, code_prefix, n_prefix); |
|
#endif |
|
if (table_index < 0) |
|
return -1; |
|
table_bits = &vlc->table_bits[table_index]; |
|
table_codes = &vlc->table_codes[table_index]; |
|
|
|
for(i=0;i<table_size;i++) { |
|
table_bits[i] = 0; |
|
table_codes[i] = -1; |
|
} |
|
|
|
/* first pass: map codes and compute auxillary table sizes */ |
|
for(i=0;i<nb_codes;i++) { |
|
GET_DATA(n, bits, i, bits_wrap, bits_size); |
|
GET_DATA(code, codes, i, codes_wrap, codes_size); |
|
/* we accept tables with holes */ |
|
if (n <= 0) |
|
continue; |
|
#if defined(DEBUG_VLC) && 0 |
|
printf("i=%d n=%d code=0x%x\n", i, n, code); |
|
#endif |
|
/* if code matches the prefix, it is in the table */ |
|
n -= n_prefix; |
|
if (n > 0 && (code >> n) == code_prefix) { |
|
if (n <= table_nb_bits) { |
|
/* no need to add another table */ |
|
j = (code << (table_nb_bits - n)) & (table_size - 1); |
|
nb = 1 << (table_nb_bits - n); |
|
for(k=0;k<nb;k++) { |
|
#ifdef DEBUG_VLC |
|
printf("%4x: code=%d n=%d\n", |
|
j, i, n); |
|
#endif |
|
if (table_bits[j] != 0) { |
|
fprintf(stderr, "incorrect codes\n"); |
|
exit(1); |
|
} |
|
table_bits[j] = n; |
|
table_codes[j] = i; |
|
j++; |
|
} |
|
} else { |
|
n -= table_nb_bits; |
|
j = (code >> n) & ((1 << table_nb_bits) - 1); |
|
#ifdef DEBUG_VLC |
|
printf("%4x: n=%d (subtable)\n", |
|
j, n); |
|
#endif |
|
/* compute table size */ |
|
n1 = -table_bits[j]; |
|
if (n > n1) |
|
n1 = n; |
|
table_bits[j] = -n1; |
|
} |
|
} |
|
} |
|
|
|
/* second pass : fill auxillary tables recursively */ |
|
for(i=0;i<table_size;i++) { |
|
n = table_bits[i]; |
|
if (n < 0) { |
|
n = -n; |
|
if (n > table_nb_bits) { |
|
n = table_nb_bits; |
|
table_bits[i] = -n; |
|
} |
|
index = build_table(vlc, n, nb_codes, |
|
bits, bits_wrap, bits_size, |
|
codes, codes_wrap, codes_size, |
|
(code_prefix << table_nb_bits) | i, |
|
n_prefix + table_nb_bits); |
|
if (index < 0) |
|
return -1; |
|
/* note: realloc has been done, so reload tables */ |
|
table_bits = &vlc->table_bits[table_index]; |
|
table_codes = &vlc->table_codes[table_index]; |
|
table_codes[i] = index; |
|
} |
|
} |
|
return table_index; |
|
} |
|
|
|
|
|
/* Build VLC decoding tables suitable for use with get_vlc(). |
|
|
|
'nb_bits' set thee decoding table size (2^nb_bits) entries. The |
|
bigger it is, the faster is the decoding. But it should not be too |
|
big to save memory and L1 cache. '9' is a good compromise. |
|
|
|
'nb_codes' : number of vlcs codes |
|
|
|
'bits' : table which gives the size (in bits) of each vlc code. |
|
|
|
'codes' : table which gives the bit pattern of of each vlc code. |
|
|
|
'xxx_wrap' : give the number of bytes between each entry of the |
|
'bits' or 'codes' tables. |
|
|
|
'xxx_size' : gives the number of bytes of each entry of the 'bits' |
|
or 'codes' tables. |
|
|
|
'wrap' and 'size' allows to use any memory configuration and types |
|
(byte/word/long) to store the 'bits' and 'codes' tables. |
|
*/ |
|
int init_vlc(VLC *vlc, int nb_bits, int nb_codes, |
|
const void *bits, int bits_wrap, int bits_size, |
|
const void *codes, int codes_wrap, int codes_size) |
|
{ |
|
vlc->bits = nb_bits; |
|
vlc->table_bits = NULL; |
|
vlc->table_codes = NULL; |
|
vlc->table_allocated = 0; |
|
vlc->table_size = 0; |
|
#ifdef DEBUG_VLC |
|
printf("build table nb_codes=%d\n", nb_codes); |
|
#endif |
|
|
|
if (build_table(vlc, nb_bits, nb_codes, |
|
bits, bits_wrap, bits_size, |
|
codes, codes_wrap, codes_size, |
|
0, 0) < 0) { |
|
if (vlc->table_bits) |
|
free(vlc->table_bits); |
|
if (vlc->table_codes) |
|
free(vlc->table_codes); |
|
return -1; |
|
} |
|
return 0; |
|
} |
|
|
|
|
|
void free_vlc(VLC *vlc) |
|
{ |
|
free(vlc->table_bits); |
|
free(vlc->table_codes); |
|
} |
|
|
|
int get_vlc(GetBitContext *s, VLC *vlc) |
|
{ |
|
int bit_cnt, code, n, nb_bits, index; |
|
UINT32 bit_buf; |
|
INT16 *table_codes; |
|
INT8 *table_bits; |
|
UINT8 *buf_ptr; |
|
|
|
SAVE_BITS(s); |
|
nb_bits = vlc->bits; |
|
table_codes = vlc->table_codes; |
|
table_bits = vlc->table_bits; |
|
for(;;) { |
|
SHOW_BITS(s, index, nb_bits); |
|
code = table_codes[index]; |
|
n = table_bits[index]; |
|
if (n > 0) { |
|
/* most common case */ |
|
FLUSH_BITS(n); |
|
#ifdef STATS |
|
st_bit_counts[st_current_index] += n; |
|
#endif |
|
break; |
|
} else if (n == 0) { |
|
return -1; |
|
} else { |
|
FLUSH_BITS(nb_bits); |
|
#ifdef STATS |
|
st_bit_counts[st_current_index] += nb_bits; |
|
#endif |
|
nb_bits = -n; |
|
table_codes = vlc->table_codes + code; |
|
table_bits = vlc->table_bits + code; |
|
} |
|
} |
|
RESTORE_BITS(s); |
|
return code; |
|
}
|
|
|