FFmpeg
bitstream.c
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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
6  *
7  * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
8  *
9  * This file is part of FFmpeg.
10  *
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.
15  *
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.
20  *
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
24  */
25 
26 /**
27  * @file
28  * bitstream api.
29  */
30 
31 #include <stdint.h>
32 #include <string.h>
33 
34 #include "config.h"
35 #include "libavutil/avassert.h"
36 #include "libavutil/intreadwrite.h"
37 #include "put_bits.h"
38 
39 void ff_put_string(PutBitContext *pb, const char *string, int terminate_string)
40 {
41  while (*string) {
42  put_bits(pb, 8, *string);
43  string++;
44  }
45  if (terminate_string)
46  put_bits(pb, 8, 0);
47 }
48 
49 void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
50 {
51  int words = length >> 4;
52  int bits = length & 15;
53  int i;
54 
55  if (length == 0)
56  return;
57 
58  av_assert0(length <= put_bits_left(pb));
59 
60  if (CONFIG_SMALL || words < 16 || put_bits_count(pb) & 7) {
61  for (i = 0; i < words; i++)
62  put_bits(pb, 16, AV_RB16(src + 2 * i));
63  } else {
64  for (i = 0; put_bits_count(pb) & 31; i++)
65  put_bits(pb, 8, src[i]);
66  flush_put_bits(pb);
67  memcpy(put_bits_ptr(pb), src + i, 2 * words - i);
68  skip_put_bytes(pb, 2 * words - i);
69  }
70 
71  put_bits(pb, bits, AV_RB16(src + 2 * words) >> (16 - bits));
72 }
put_bits
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:221
ff_copy_bits
void ff_copy_bits(PutBitContext *pb, const uint8_t *src, int length)
Copy the content of src to the bitstream.
Definition: bitstream.c:49
put_bits_left
static int put_bits_left(PutBitContext *s)
Definition: put_bits.h:125
avassert.h
intreadwrite.h
bits
uint8_t bits
Definition: vp3data.h:128
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
ff_put_string
void ff_put_string(PutBitContext *pb, const char *string, int terminate_string)
Put the string string in the bitstream.
Definition: bitstream.c:39
PutBitContext
Definition: put_bits.h:50
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
put_bits_count
static int put_bits_count(PutBitContext *s)
Definition: put_bits.h:80
put_bits_ptr
static uint8_t * put_bits_ptr(PutBitContext *s)
Return the pointer to the byte where the bitstream writer will put the next bit.
Definition: put_bits.h:370
skip_put_bytes
static void skip_put_bytes(PutBitContext *s, int n)
Skip the given number of bytes.
Definition: put_bits.h:379
flush_put_bits
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:143
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
put_bits.h
AV_RB16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition: bytestream.h:98