FFmpeg
bytestream.h
1 /*
2  * Bytestream functions
3  * copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@free.fr>
4  * Copyright (c) 2012 Aneesh Dogra (lionaneesh) <lionaneesh@gmail.com>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #ifndef AVCODEC_BYTESTREAM_H
24 #define AVCODEC_BYTESTREAM_H
25 
26 #include <stdint.h>
27 #include <string.h>
28 
29 #include "libavutil/avassert.h"
30 #include "libavutil/common.h"
31 #include "libavutil/intreadwrite.h"
32 
33 typedef struct GetByteContext {
34  const uint8_t *buffer, *buffer_end, *buffer_start;
35 } GetByteContext;
36 
37 typedef struct PutByteContext {
38  uint8_t *buffer, *buffer_end, *buffer_start;
39  int eof;
40 } PutByteContext;
41 
42 #define DEF(type, name, bytes, read, write) \
43 static av_always_inline type bytestream_get_ ## name(const uint8_t **b) \
44 { \
45  (*b) += bytes; \
46  return read(*b - bytes); \
47 } \
48 static av_always_inline void bytestream_put_ ## name(uint8_t **b, \
49  const type value) \
50 { \
51  write(*b, value); \
52  (*b) += bytes; \
53 } \
54 static av_always_inline void bytestream2_put_ ## name ## u(PutByteContext *p, \
55  const type value) \
56 { \
57  bytestream_put_ ## name(&p->buffer, value); \
58 } \
59 static av_always_inline void bytestream2_put_ ## name(PutByteContext *p, \
60  const type value) \
61 { \
62  if (!p->eof && (p->buffer_end - p->buffer >= bytes)) { \
63  write(p->buffer, value); \
64  p->buffer += bytes; \
65  } else \
66  p->eof = 1; \
67 } \
68 static av_always_inline type bytestream2_get_ ## name ## u(GetByteContext *g) \
69 { \
70  return bytestream_get_ ## name(&g->buffer); \
71 } \
72 static av_always_inline type bytestream2_get_ ## name(GetByteContext *g) \
73 { \
74  if (g->buffer_end - g->buffer < bytes) { \
75  g->buffer = g->buffer_end; \
76  return 0; \
77  } \
78  return bytestream2_get_ ## name ## u(g); \
79 } \
80 static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g) \
81 { \
82  if (g->buffer_end - g->buffer < bytes) \
83  return 0; \
84  return read(g->buffer); \
85 }
86 
87 DEF(uint64_t, le64, 8, AV_RL64, AV_WL64)
88 DEF(unsigned int, le32, 4, AV_RL32, AV_WL32)
89 DEF(unsigned int, le24, 3, AV_RL24, AV_WL24)
90 DEF(unsigned int, le16, 2, AV_RL16, AV_WL16)
91 DEF(uint64_t, be64, 8, AV_RB64, AV_WB64)
92 DEF(unsigned int, be32, 4, AV_RB32, AV_WB32)
93 DEF(unsigned int, be24, 3, AV_RB24, AV_WB24)
94 DEF(unsigned int, be16, 2, AV_RB16, AV_WB16)
95 DEF(unsigned int, byte, 1, AV_RB8 , AV_WB8)
96 
97 #if AV_HAVE_BIGENDIAN
98 # define bytestream2_get_ne16 bytestream2_get_be16
99 # define bytestream2_get_ne24 bytestream2_get_be24
100 # define bytestream2_get_ne32 bytestream2_get_be32
101 # define bytestream2_get_ne64 bytestream2_get_be64
102 # define bytestream2_get_ne16u bytestream2_get_be16u
103 # define bytestream2_get_ne24u bytestream2_get_be24u
104 # define bytestream2_get_ne32u bytestream2_get_be32u
105 # define bytestream2_get_ne64u bytestream2_get_be64u
106 # define bytestream2_put_ne16 bytestream2_put_be16
107 # define bytestream2_put_ne24 bytestream2_put_be24
108 # define bytestream2_put_ne32 bytestream2_put_be32
109 # define bytestream2_put_ne64 bytestream2_put_be64
110 # define bytestream2_peek_ne16 bytestream2_peek_be16
111 # define bytestream2_peek_ne24 bytestream2_peek_be24
112 # define bytestream2_peek_ne32 bytestream2_peek_be32
113 # define bytestream2_peek_ne64 bytestream2_peek_be64
114 #else
115 # define bytestream2_get_ne16 bytestream2_get_le16
116 # define bytestream2_get_ne24 bytestream2_get_le24
117 # define bytestream2_get_ne32 bytestream2_get_le32
118 # define bytestream2_get_ne64 bytestream2_get_le64
119 # define bytestream2_get_ne16u bytestream2_get_le16u
120 # define bytestream2_get_ne24u bytestream2_get_le24u
121 # define bytestream2_get_ne32u bytestream2_get_le32u
122 # define bytestream2_get_ne64u bytestream2_get_le64u
123 # define bytestream2_put_ne16 bytestream2_put_le16
124 # define bytestream2_put_ne24 bytestream2_put_le24
125 # define bytestream2_put_ne32 bytestream2_put_le32
126 # define bytestream2_put_ne64 bytestream2_put_le64
127 # define bytestream2_peek_ne16 bytestream2_peek_le16
128 # define bytestream2_peek_ne24 bytestream2_peek_le24
129 # define bytestream2_peek_ne32 bytestream2_peek_le32
130 # define bytestream2_peek_ne64 bytestream2_peek_le64
131 #endif
132 
133 static av_always_inline void bytestream2_init(GetByteContext *g,
134  const uint8_t *buf,
135  int buf_size)
136 {
137  av_assert0(buf_size >= 0);
138  g->buffer = buf;
139  g->buffer_start = buf;
140  g->buffer_end = buf + buf_size;
141 }
142 
143 static av_always_inline void bytestream2_init_writer(PutByteContext *p,
144  uint8_t *buf,
145  int buf_size)
146 {
147  av_assert0(buf_size >= 0);
148  p->buffer = buf;
149  p->buffer_start = buf;
150  p->buffer_end = buf + buf_size;
151  p->eof = 0;
152 }
153 
154 static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
155 {
156  return g->buffer_end - g->buffer;
157 }
158 
159 static av_always_inline unsigned int bytestream2_get_bytes_left_p(PutByteContext *p)
160 {
161  return p->buffer_end - p->buffer;
162 }
163 
164 static av_always_inline void bytestream2_skip(GetByteContext *g,
165  unsigned int size)
166 {
167  g->buffer += FFMIN(g->buffer_end - g->buffer, size);
168 }
169 
170 static av_always_inline void bytestream2_skipu(GetByteContext *g,
171  unsigned int size)
172 {
173  g->buffer += size;
174 }
175 
176 static av_always_inline void bytestream2_skip_p(PutByteContext *p,
177  unsigned int size)
178 {
179  int size2;
180  if (p->eof)
181  return;
182  size2 = FFMIN(p->buffer_end - p->buffer, size);
183  if (size2 != size)
184  p->eof = 1;
185  p->buffer += size2;
186 }
187 
188 static av_always_inline int bytestream2_tell(GetByteContext *g)
189 {
190  return (int)(g->buffer - g->buffer_start);
191 }
192 
193 static av_always_inline int bytestream2_tell_p(PutByteContext *p)
194 {
195  return (int)(p->buffer - p->buffer_start);
196 }
197 
198 static av_always_inline int bytestream2_size(GetByteContext *g)
199 {
200  return (int)(g->buffer_end - g->buffer_start);
201 }
202 
203 static av_always_inline int bytestream2_size_p(PutByteContext *p)
204 {
205  return (int)(p->buffer_end - p->buffer_start);
206 }
207 
208 static av_always_inline int bytestream2_seek(GetByteContext *g,
209  int offset,
210  int whence)
211 {
212  switch (whence) {
213  case SEEK_CUR:
214  offset = av_clip(offset, -(g->buffer - g->buffer_start),
215  g->buffer_end - g->buffer);
216  g->buffer += offset;
217  break;
218  case SEEK_END:
219  offset = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
220  g->buffer = g->buffer_end + offset;
221  break;
222  case SEEK_SET:
223  offset = av_clip(offset, 0, g->buffer_end - g->buffer_start);
224  g->buffer = g->buffer_start + offset;
225  break;
226  default:
227  return AVERROR(EINVAL);
228  }
229  return bytestream2_tell(g);
230 }
231 
232 static av_always_inline int bytestream2_seek_p(PutByteContext *p,
233  int offset,
234  int whence)
235 {
236  p->eof = 0;
237  switch (whence) {
238  case SEEK_CUR:
239  if (p->buffer_end - p->buffer < offset)
240  p->eof = 1;
241  offset = av_clip(offset, -(p->buffer - p->buffer_start),
242  p->buffer_end - p->buffer);
243  p->buffer += offset;
244  break;
245  case SEEK_END:
246  if (offset > 0)
247  p->eof = 1;
248  offset = av_clip(offset, -(p->buffer_end - p->buffer_start), 0);
249  p->buffer = p->buffer_end + offset;
250  break;
251  case SEEK_SET:
252  if (p->buffer_end - p->buffer_start < offset)
253  p->eof = 1;
254  offset = av_clip(offset, 0, p->buffer_end - p->buffer_start);
255  p->buffer = p->buffer_start + offset;
256  break;
257  default:
258  return AVERROR(EINVAL);
259  }
260  return bytestream2_tell_p(p);
261 }
262 
263 static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
264  uint8_t *dst,
265  unsigned int size)
266 {
267  int size2 = FFMIN(g->buffer_end - g->buffer, size);
268  memcpy(dst, g->buffer, size2);
269  g->buffer += size2;
270  return size2;
271 }
272 
273 static av_always_inline unsigned int bytestream2_get_bufferu(GetByteContext *g,
274  uint8_t *dst,
275  unsigned int size)
276 {
277  memcpy(dst, g->buffer, size);
278  g->buffer += size;
279  return size;
280 }
281 
282 static av_always_inline unsigned int bytestream2_put_buffer(PutByteContext *p,
283  const uint8_t *src,
284  unsigned int size)
285 {
286  int size2;
287  if (p->eof)
288  return 0;
289  size2 = FFMIN(p->buffer_end - p->buffer, size);
290  if (size2 != size)
291  p->eof = 1;
292  memcpy(p->buffer, src, size2);
293  p->buffer += size2;
294  return size2;
295 }
296 
297 static av_always_inline unsigned int bytestream2_put_bufferu(PutByteContext *p,
298  const uint8_t *src,
299  unsigned int size)
300 {
301  memcpy(p->buffer, src, size);
302  p->buffer += size;
303  return size;
304 }
305 
306 static av_always_inline void bytestream2_set_buffer(PutByteContext *p,
307  const uint8_t c,
308  unsigned int size)
309 {
310  int size2;
311  if (p->eof)
312  return;
313  size2 = FFMIN(p->buffer_end - p->buffer, size);
314  if (size2 != size)
315  p->eof = 1;
316  memset(p->buffer, c, size2);
317  p->buffer += size2;
318 }
319 
320 static av_always_inline void bytestream2_set_bufferu(PutByteContext *p,
321  const uint8_t c,
322  unsigned int size)
323 {
324  memset(p->buffer, c, size);
325  p->buffer += size;
326 }
327 
328 static av_always_inline unsigned int bytestream2_get_eof(PutByteContext *p)
329 {
330  return p->eof;
331 }
332 
333 static av_always_inline unsigned int bytestream2_copy_bufferu(PutByteContext *p,
334  GetByteContext *g,
335  unsigned int size)
336 {
337  memcpy(p->buffer, g->buffer, size);
338  p->buffer += size;
339  g->buffer += size;
340  return size;
341 }
342 
343 static av_always_inline unsigned int bytestream2_copy_buffer(PutByteContext *p,
344  GetByteContext *g,
345  unsigned int size)
346 {
347  int size2;
348 
349  if (p->eof)
350  return 0;
351  size = FFMIN(g->buffer_end - g->buffer, size);
352  size2 = FFMIN(p->buffer_end - p->buffer, size);
353  if (size2 != size)
354  p->eof = 1;
355 
356  return bytestream2_copy_bufferu(p, g, size2);
357 }
358 
359 static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b,
360  uint8_t *dst,
361  unsigned int size)
362 {
363  memcpy(dst, *b, size);
364  (*b) += size;
365  return size;
366 }
367 
368 static av_always_inline void bytestream_put_buffer(uint8_t **b,
369  const uint8_t *src,
370  unsigned int size)
371 {
372  memcpy(*b, src, size);
373  (*b) += size;
374 }
375 
376 #endif /* AVCODEC_BYTESTREAM_H */
GetByteContext
Definition: bytestream.h:33
av_assert0
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
avassert.h
simple assert() macros that are a bit more flexible than ISO C assert().
PutByteContext
Definition: bytestream.h:37
common.h
common internal and external API header
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