aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/bytestream.h
blob: 71c70aac8479b3042154d9bdb9108e76a0f0239c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
/*
 * Bytestream functions
 * copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@free.fr>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVCODEC_BYTESTREAM_H
#define AVCODEC_BYTESTREAM_H

#include <string.h>
#include "libavutil/common.h"
#include "libavutil/intreadwrite.h"

typedef struct {
    const uint8_t *buffer, *buffer_end, *buffer_start;
} GetByteContext;

#define DEF_T(type, name, bytes, read, write)                             \
static av_always_inline type bytestream_get_ ## name(const uint8_t **b){\
    (*b) += bytes;\
    return read(*b - bytes);\
}\
static av_always_inline void bytestream_put_ ##name(uint8_t **b, const type value){\
    write(*b, value);\
    (*b) += bytes;\
}\
static av_always_inline type bytestream2_get_ ## name ## u(GetByteContext *g)\
{\
    return bytestream_get_ ## name(&g->buffer);\
}\
static av_always_inline type bytestream2_get_ ## name(GetByteContext *g)\
{\
    if (g->buffer_end - g->buffer < bytes)\
        return 0;\
    return bytestream2_get_ ## name ## u(g);\
}\
static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g)\
{\
    if (g->buffer_end - g->buffer < bytes)\
        return 0;\
    return read(g->buffer);\
}

#define DEF(name, bytes, read, write) \
    DEF_T(unsigned int, name, bytes, read, write)
#define DEF64(name, bytes, read, write) \
    DEF_T(uint64_t, name, bytes, read, write)

DEF64(le64, 8, AV_RL64, AV_WL64)
DEF  (le32, 4, AV_RL32, AV_WL32)
DEF  (le24, 3, AV_RL24, AV_WL24)
DEF  (le16, 2, AV_RL16, AV_WL16)
DEF64(be64, 8, AV_RB64, AV_WB64)
DEF  (be32, 4, AV_RB32, AV_WB32)
DEF  (be24, 3, AV_RB24, AV_WB24)
DEF  (be16, 2, AV_RB16, AV_WB16)
DEF  (byte, 1, AV_RB8 , AV_WB8 )

#undef DEF
#undef DEF64
#undef DEF_T

#if HAVE_BIGENDIAN
#   define bytestream2_get_ne16  bytestream2_get_be16
#   define bytestream2_get_ne24  bytestream2_get_be24
#   define bytestream2_get_ne32  bytestream2_get_be32
#   define bytestream2_get_ne64  bytestream2_get_be64
#   define bytestream2_get_ne16u bytestream2_get_be16u
#   define bytestream2_get_ne24u bytestream2_get_be24u
#   define bytestream2_get_ne32u bytestream2_get_be32u
#   define bytestream2_get_ne64u bytestream2_get_be64u
#   define bytestream2_put_ne16  bytestream2_put_be16
#   define bytestream2_put_ne24  bytestream2_put_be24
#   define bytestream2_put_ne32  bytestream2_put_be32
#   define bytestream2_put_ne64  bytestream2_put_be64
#   define bytestream2_peek_ne16 bytestream2_peek_be16
#   define bytestream2_peek_ne24 bytestream2_peek_be24
#   define bytestream2_peek_ne32 bytestream2_peek_be32
#   define bytestream2_peek_ne64 bytestream2_peek_be64
#else
#   define bytestream2_get_ne16  bytestream2_get_le16
#   define bytestream2_get_ne24  bytestream2_get_le24
#   define bytestream2_get_ne32  bytestream2_get_le32
#   define bytestream2_get_ne64  bytestream2_get_le64
#   define bytestream2_get_ne16u bytestream2_get_le16u
#   define bytestream2_get_ne24u bytestream2_get_le24u
#   define bytestream2_get_ne32u bytestream2_get_le32u
#   define bytestream2_get_ne64u bytestream2_get_le64u
#   define bytestream2_put_ne16  bytestream2_put_le16
#   define bytestream2_put_ne24  bytestream2_put_le24
#   define bytestream2_put_ne32  bytestream2_put_le32
#   define bytestream2_put_ne64  bytestream2_put_le64
#   define bytestream2_peek_ne16 bytestream2_peek_le16
#   define bytestream2_peek_ne24 bytestream2_peek_le24
#   define bytestream2_peek_ne32 bytestream2_peek_le32
#   define bytestream2_peek_ne64 bytestream2_peek_le64
#endif

static av_always_inline void bytestream2_init(GetByteContext *g,
                                              const uint8_t *buf, int buf_size)
{
    g->buffer =  buf;
    g->buffer_start = buf;
    g->buffer_end = buf + buf_size;
}

static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
{
    return g->buffer_end - g->buffer;
}

static av_always_inline void bytestream2_skip(GetByteContext *g,
                                              unsigned int size)
{
    g->buffer += FFMIN(g->buffer_end - g->buffer, size);
}

static av_always_inline int bytestream2_tell(GetByteContext *g)
{
    return (int)(g->buffer - g->buffer_start);
}

static av_always_inline int bytestream2_seek(GetByteContext *g, int offset,
                                             int whence)
{
    switch (whence) {
    case SEEK_CUR:
        offset = av_clip(offset, -(g->buffer - g->buffer_start),
                         g->buffer_end - g->buffer);
        g->buffer += offset;
        break;
    case SEEK_END:
        offset = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
        g->buffer = g->buffer_end + offset;
        break;
    case SEEK_SET:
        offset = av_clip(offset, 0, g->buffer_end - g->buffer_start);
        g->buffer = g->buffer_start + offset;
        break;
    default:
        return AVERROR(EINVAL);
    }
    return bytestream2_tell(g);
}

static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
                                                            uint8_t *dst,
                                                            unsigned int size)
{
    int size2 = FFMIN(g->buffer_end - g->buffer, size);
    memcpy(dst, g->buffer, size2);
    g->buffer += size2;
    return size2;
}

static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b, uint8_t *dst, unsigned int size)
{
    memcpy(dst, *b, size);
    (*b) += size;
    return size;
}

static av_always_inline void bytestream_put_buffer(uint8_t **b, const uint8_t *src, unsigned int size)
{
    memcpy(*b, src, size);
    (*b) += size;
}

#endif /* AVCODEC_BYTESTREAM_H */