FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
bytestream.h
Go to the documentation of this file.
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  return 0; \
76  return bytestream2_get_ ## name ## u(g); \
77 } \
78 static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g) \
79 { \
80  if (g->buffer_end - g->buffer < bytes) \
81  return 0; \
82  return read(g->buffer); \
83 }
84 
85 DEF(uint64_t, le64, 8, AV_RL64, AV_WL64)
86 DEF(unsigned int, le32, 4, AV_RL32, AV_WL32)
87 DEF(unsigned int, le24, 3, AV_RL24, AV_WL24)
88 DEF(unsigned int, le16, 2, AV_RL16, AV_WL16)
89 DEF(uint64_t, be64, 8, AV_RB64, AV_WB64)
90 DEF(unsigned int, be32, 4, AV_RB32, AV_WB32)
91 DEF(unsigned int, be24, 3, AV_RB24, AV_WB24)
92 DEF(unsigned int, be16, 2, AV_RB16, AV_WB16)
93 DEF(unsigned int, byte, 1, AV_RB8 , AV_WB8)
94 
95 #if HAVE_BIGENDIAN
96 # define bytestream2_get_ne16 bytestream2_get_be16
97 # define bytestream2_get_ne24 bytestream2_get_be24
98 # define bytestream2_get_ne32 bytestream2_get_be32
99 # define bytestream2_get_ne64 bytestream2_get_be64
100 # define bytestream2_get_ne16u bytestream2_get_be16u
101 # define bytestream2_get_ne24u bytestream2_get_be24u
102 # define bytestream2_get_ne32u bytestream2_get_be32u
103 # define bytestream2_get_ne64u bytestream2_get_be64u
104 # define bytestream2_put_ne16 bytestream2_put_be16
105 # define bytestream2_put_ne24 bytestream2_put_be24
106 # define bytestream2_put_ne32 bytestream2_put_be32
107 # define bytestream2_put_ne64 bytestream2_put_be64
108 # define bytestream2_peek_ne16 bytestream2_peek_be16
109 # define bytestream2_peek_ne24 bytestream2_peek_be24
110 # define bytestream2_peek_ne32 bytestream2_peek_be32
111 # define bytestream2_peek_ne64 bytestream2_peek_be64
112 #else
113 # define bytestream2_get_ne16 bytestream2_get_le16
114 # define bytestream2_get_ne24 bytestream2_get_le24
115 # define bytestream2_get_ne32 bytestream2_get_le32
116 # define bytestream2_get_ne64 bytestream2_get_le64
117 # define bytestream2_get_ne16u bytestream2_get_le16u
118 # define bytestream2_get_ne24u bytestream2_get_le24u
119 # define bytestream2_get_ne32u bytestream2_get_le32u
120 # define bytestream2_get_ne64u bytestream2_get_le64u
121 # define bytestream2_put_ne16 bytestream2_put_le16
122 # define bytestream2_put_ne24 bytestream2_put_le24
123 # define bytestream2_put_ne32 bytestream2_put_le32
124 # define bytestream2_put_ne64 bytestream2_put_le64
125 # define bytestream2_peek_ne16 bytestream2_peek_le16
126 # define bytestream2_peek_ne24 bytestream2_peek_le24
127 # define bytestream2_peek_ne32 bytestream2_peek_le32
128 # define bytestream2_peek_ne64 bytestream2_peek_le64
129 #endif
130 
131 static av_always_inline void bytestream2_init(GetByteContext *g,
132  const uint8_t *buf,
133  int buf_size)
134 {
135  av_assert0(buf_size >= 0);
136  g->buffer = buf;
137  g->buffer_start = buf;
138  g->buffer_end = buf + buf_size;
139 }
140 
141 static av_always_inline void bytestream2_init_writer(PutByteContext *p,
142  uint8_t *buf,
143  int buf_size)
144 {
145  av_assert0(buf_size >= 0);
146  p->buffer = buf;
147  p->buffer_start = buf;
148  p->buffer_end = buf + buf_size;
149  p->eof = 0;
150 }
151 
152 static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
153 {
154  return g->buffer_end - g->buffer;
155 }
156 
157 static av_always_inline unsigned int bytestream2_get_bytes_left_p(PutByteContext *p)
158 {
159  return p->buffer_end - p->buffer;
160 }
161 
162 static av_always_inline void bytestream2_skip(GetByteContext *g,
163  unsigned int size)
164 {
165  g->buffer += FFMIN(g->buffer_end - g->buffer, size);
166 }
167 
168 static av_always_inline void bytestream2_skipu(GetByteContext *g,
169  unsigned int size)
170 {
171  g->buffer += size;
172 }
173 
174 static av_always_inline void bytestream2_skip_p(PutByteContext *p,
175  unsigned int size)
176 {
177  int size2;
178  if (p->eof)
179  return;
180  size2 = FFMIN(p->buffer_end - p->buffer, size);
181  if (size2 != size)
182  p->eof = 1;
183  p->buffer += size2;
184 }
185 
186 static av_always_inline int bytestream2_tell(GetByteContext *g)
187 {
188  return (int)(g->buffer - g->buffer_start);
189 }
190 
191 static av_always_inline int bytestream2_tell_p(PutByteContext *p)
192 {
193  return (int)(p->buffer - p->buffer_start);
194 }
195 
196 static av_always_inline int bytestream2_size(GetByteContext *g)
197 {
198  return (int)(g->buffer_end - g->buffer_start);
199 }
200 
201 static av_always_inline int bytestream2_size_p(PutByteContext *p)
202 {
203  return (int)(p->buffer_end - p->buffer_start);
204 }
205 
206 static av_always_inline int bytestream2_seek(GetByteContext *g,
207  int offset,
208  int whence)
209 {
210  switch (whence) {
211  case SEEK_CUR:
212  offset = av_clip(offset, -(g->buffer - g->buffer_start),
213  g->buffer_end - g->buffer);
214  g->buffer += offset;
215  break;
216  case SEEK_END:
217  offset = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
218  g->buffer = g->buffer_end + offset;
219  break;
220  case SEEK_SET:
221  offset = av_clip(offset, 0, g->buffer_end - g->buffer_start);
222  g->buffer = g->buffer_start + offset;
223  break;
224  default:
225  return AVERROR(EINVAL);
226  }
227  return bytestream2_tell(g);
228 }
229 
230 static av_always_inline int bytestream2_seek_p(PutByteContext *p,
231  int offset,
232  int whence)
233 {
234  p->eof = 0;
235  switch (whence) {
236  case SEEK_CUR:
237  if (p->buffer_end - p->buffer < offset)
238  p->eof = 1;
239  offset = av_clip(offset, -(p->buffer - p->buffer_start),
240  p->buffer_end - p->buffer);
241  p->buffer += offset;
242  break;
243  case SEEK_END:
244  if (offset > 0)
245  p->eof = 1;
246  offset = av_clip(offset, -(p->buffer_end - p->buffer_start), 0);
247  p->buffer = p->buffer_end + offset;
248  break;
249  case SEEK_SET:
250  if (p->buffer_end - p->buffer_start < offset)
251  p->eof = 1;
252  offset = av_clip(offset, 0, p->buffer_end - p->buffer_start);
253  p->buffer = p->buffer_start + offset;
254  break;
255  default:
256  return AVERROR(EINVAL);
257  }
258  return bytestream2_tell_p(p);
259 }
260 
261 static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
262  uint8_t *dst,
263  unsigned int size)
264 {
265  int size2 = FFMIN(g->buffer_end - g->buffer, size);
266  memcpy(dst, g->buffer, size2);
267  g->buffer += size2;
268  return size2;
269 }
270 
271 static av_always_inline unsigned int bytestream2_get_bufferu(GetByteContext *g,
272  uint8_t *dst,
273  unsigned int size)
274 {
275  memcpy(dst, g->buffer, size);
276  g->buffer += size;
277  return size;
278 }
279 
280 static av_always_inline unsigned int bytestream2_put_buffer(PutByteContext *p,
281  const uint8_t *src,
282  unsigned int size)
283 {
284  int size2;
285  if (p->eof)
286  return 0;
287  size2 = FFMIN(p->buffer_end - p->buffer, size);
288  if (size2 != size)
289  p->eof = 1;
290  memcpy(p->buffer, src, size2);
291  p->buffer += size2;
292  return size2;
293 }
294 
295 static av_always_inline unsigned int bytestream2_put_bufferu(PutByteContext *p,
296  const uint8_t *src,
297  unsigned int size)
298 {
299  memcpy(p->buffer, src, size);
300  p->buffer += size;
301  return size;
302 }
303 
304 static av_always_inline void bytestream2_set_buffer(PutByteContext *p,
305  const uint8_t c,
306  unsigned int size)
307 {
308  int size2;
309  if (p->eof)
310  return;
311  size2 = FFMIN(p->buffer_end - p->buffer, size);
312  if (size2 != size)
313  p->eof = 1;
314  memset(p->buffer, c, size2);
315  p->buffer += size2;
316 }
317 
318 static av_always_inline void bytestream2_set_bufferu(PutByteContext *p,
319  const uint8_t c,
320  unsigned int size)
321 {
322  memset(p->buffer, c, size);
323  p->buffer += size;
324 }
325 
326 static av_always_inline unsigned int bytestream2_get_eof(PutByteContext *p)
327 {
328  return p->eof;
329 }
330 
331 static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b,
332  uint8_t *dst,
333  unsigned int size)
334 {
335  memcpy(dst, *b, size);
336  (*b) += size;
337  return size;
338 }
339 
340 static av_always_inline void bytestream_put_buffer(uint8_t **b,
341  const uint8_t *src,
342  unsigned int size)
343 {
344  memcpy(*b, src, size);
345  (*b) += size;
346 }
347 
348 #endif /* AVCODEC_BYTESTREAM_H */
Generated on Wed Jul 10 2013 23:47:56 for FFmpeg by   doxygen 1.8.2