bytestream.h
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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 Libav.
7  *
8  * Libav 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  * Libav 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 Libav; 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 <string.h>
27 
28 #include "libavutil/common.h"
29 #include "libavutil/intreadwrite.h"
30 
31 typedef struct {
32  const uint8_t *buffer, *buffer_end, *buffer_start;
34 
35 typedef struct {
36  uint8_t *buffer, *buffer_end, *buffer_start;
37  int eof;
39 
40 #define DEF_T(type, name, bytes, read, write) \
41 static av_always_inline type bytestream_get_ ## name(const uint8_t **b) \
42 { \
43  (*b) += bytes; \
44  return read(*b - bytes); \
45 } \
46 static av_always_inline void bytestream_put_ ## name(uint8_t **b, \
47  const type value) \
48 { \
49  write(*b, value); \
50  (*b) += bytes; \
51 } \
52 static av_always_inline void bytestream2_put_ ## name ## u(PutByteContext *p, \
53  const type value) \
54 { \
55  bytestream_put_ ## name(&p->buffer, value); \
56 } \
57 static av_always_inline void bytestream2_put_ ## name(PutByteContext *p, \
58  const type value) \
59 { \
60  if (!p->eof && (p->buffer_end - p->buffer >= bytes)) { \
61  write(p->buffer, value); \
62  p->buffer += bytes; \
63  } else \
64  p->eof = 1; \
65 } \
66 static av_always_inline type bytestream2_get_ ## name ## u(GetByteContext *g) \
67 { \
68  return bytestream_get_ ## name(&g->buffer); \
69 } \
70 static av_always_inline type bytestream2_get_ ## name(GetByteContext *g) \
71 { \
72  if (g->buffer_end - g->buffer < bytes) \
73  return 0; \
74  return bytestream2_get_ ## name ## u(g); \
75 } \
76 static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g) \
77 { \
78  if (g->buffer_end - g->buffer < bytes) \
79  return 0; \
80  return read(g->buffer); \
81 }
82 
83 #define DEF(name, bytes, read, write) \
84  DEF_T(unsigned int, name, bytes, read, write)
85 #define DEF64(name, bytes, read, write) \
86  DEF_T(uint64_t, name, bytes, read, write)
87 
88 DEF64(le64, 8, AV_RL64, AV_WL64)
89 DEF (le32, 4, AV_RL32, AV_WL32)
90 DEF (le24, 3, AV_RL24, AV_WL24)
91 DEF (le16, 2, AV_RL16, AV_WL16)
92 DEF64(be64, 8, AV_RB64, AV_WB64)
93 DEF (be32, 4, AV_RB32, AV_WB32)
94 DEF (be24, 3, AV_RB24, AV_WB24)
95 DEF (be16, 2, AV_RB16, AV_WB16)
96 DEF (byte, 1, AV_RB8 , AV_WB8 )
97 
98 #undef DEF
99 #undef DEF64
100 #undef DEF_T
101 
102 #if HAVE_BIGENDIAN
103 # define bytestream2_get_ne16 bytestream2_get_be16
104 # define bytestream2_get_ne24 bytestream2_get_be24
105 # define bytestream2_get_ne32 bytestream2_get_be32
106 # define bytestream2_get_ne64 bytestream2_get_be64
107 # define bytestream2_get_ne16u bytestream2_get_be16u
108 # define bytestream2_get_ne24u bytestream2_get_be24u
109 # define bytestream2_get_ne32u bytestream2_get_be32u
110 # define bytestream2_get_ne64u bytestream2_get_be64u
111 # define bytestream2_put_ne16 bytestream2_put_be16
112 # define bytestream2_put_ne24 bytestream2_put_be24
113 # define bytestream2_put_ne32 bytestream2_put_be32
114 # define bytestream2_put_ne64 bytestream2_put_be64
115 # define bytestream2_peek_ne16 bytestream2_peek_be16
116 # define bytestream2_peek_ne24 bytestream2_peek_be24
117 # define bytestream2_peek_ne32 bytestream2_peek_be32
118 # define bytestream2_peek_ne64 bytestream2_peek_be64
119 #else
120 # define bytestream2_get_ne16 bytestream2_get_le16
121 # define bytestream2_get_ne24 bytestream2_get_le24
122 # define bytestream2_get_ne32 bytestream2_get_le32
123 # define bytestream2_get_ne64 bytestream2_get_le64
124 # define bytestream2_get_ne16u bytestream2_get_le16u
125 # define bytestream2_get_ne24u bytestream2_get_le24u
126 # define bytestream2_get_ne32u bytestream2_get_le32u
127 # define bytestream2_get_ne64u bytestream2_get_le64u
128 # define bytestream2_put_ne16 bytestream2_put_le16
129 # define bytestream2_put_ne24 bytestream2_put_le24
130 # define bytestream2_put_ne32 bytestream2_put_le32
131 # define bytestream2_put_ne64 bytestream2_put_le64
132 # define bytestream2_peek_ne16 bytestream2_peek_le16
133 # define bytestream2_peek_ne24 bytestream2_peek_le24
134 # define bytestream2_peek_ne32 bytestream2_peek_le32
135 # define bytestream2_peek_ne64 bytestream2_peek_le64
136 #endif
137 
139  const uint8_t *buf,
140  int buf_size)
141 {
142  g->buffer = buf;
143  g->buffer_start = buf;
144  g->buffer_end = buf + buf_size;
145 }
146 
148  uint8_t *buf,
149  int buf_size)
150 {
151  p->buffer = buf;
152  p->buffer_start = buf;
153  p->buffer_end = buf + buf_size;
154  p->eof = 0;
155 }
156 
158 {
159  return g->buffer_end - g->buffer;
160 }
161 
163 {
164  return p->buffer_end - p->buffer;
165 }
166 
168  unsigned int size)
169 {
170  g->buffer += FFMIN(g->buffer_end - g->buffer, size);
171 }
172 
174  unsigned int size)
175 {
176  g->buffer += size;
177 }
178 
180  unsigned int size)
181 {
182  int size2;
183  if (p->eof)
184  return;
185  size2 = FFMIN(p->buffer_end - p->buffer, size);
186  if (size2 != size)
187  p->eof = 1;
188  p->buffer += size2;
189 }
190 
192 {
193  return (int)(g->buffer - g->buffer_start);
194 }
195 
197 {
198  return (int)(p->buffer - p->buffer_start);
199 }
200 
202  int offset,
203  int whence)
204 {
205  switch (whence) {
206  case SEEK_CUR:
207  offset = av_clip(offset, -(g->buffer - g->buffer_start),
208  g->buffer_end - g->buffer);
209  g->buffer += offset;
210  break;
211  case SEEK_END:
212  offset = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
213  g->buffer = g->buffer_end + offset;
214  break;
215  case SEEK_SET:
216  offset = av_clip(offset, 0, g->buffer_end - g->buffer_start);
217  g->buffer = g->buffer_start + offset;
218  break;
219  default:
220  return AVERROR(EINVAL);
221  }
222  return bytestream2_tell(g);
223 }
224 
226  int offset,
227  int whence)
228 {
229  p->eof = 0;
230  switch (whence) {
231  case SEEK_CUR:
232  if (p->buffer_end - p->buffer < offset)
233  p->eof = 1;
234  offset = av_clip(offset, -(p->buffer - p->buffer_start),
235  p->buffer_end - p->buffer);
236  p->buffer += offset;
237  break;
238  case SEEK_END:
239  if (offset > 0)
240  p->eof = 1;
241  offset = av_clip(offset, -(p->buffer_end - p->buffer_start), 0);
242  p->buffer = p->buffer_end + offset;
243  break;
244  case SEEK_SET:
245  if (p->buffer_end - p->buffer_start < offset)
246  p->eof = 1;
247  offset = av_clip(offset, 0, p->buffer_end - p->buffer_start);
248  p->buffer = p->buffer_start + offset;
249  break;
250  default:
251  return AVERROR(EINVAL);
252  }
253  return bytestream2_tell_p(p);
254 }
255 
257  uint8_t *dst,
258  unsigned int size)
259 {
260  int size2 = FFMIN(g->buffer_end - g->buffer, size);
261  memcpy(dst, g->buffer, size2);
262  g->buffer += size2;
263  return size2;
264 }
265 
267  uint8_t *dst,
268  unsigned int size)
269 {
270  memcpy(dst, g->buffer, size);
271  g->buffer += size;
272  return size;
273 }
274 
276  const uint8_t *src,
277  unsigned int size)
278 {
279  int size2;
280  if (p->eof)
281  return 0;
282  size2 = FFMIN(p->buffer_end - p->buffer, size);
283  if (size2 != size)
284  p->eof = 1;
285  memcpy(p->buffer, src, size2);
286  p->buffer += size2;
287  return size2;
288 }
289 
291  const uint8_t *src,
292  unsigned int size)
293 {
294  memcpy(p->buffer, src, size);
295  p->buffer += size;
296  return size;
297 }
298 
300  const uint8_t c,
301  unsigned int size)
302 {
303  int size2;
304  if (p->eof)
305  return;
306  size2 = FFMIN(p->buffer_end - p->buffer, size);
307  if (size2 != size)
308  p->eof = 1;
309  memset(p->buffer, c, size2);
310  p->buffer += size2;
311 }
312 
314  const uint8_t c,
315  unsigned int size)
316 {
317  memset(p->buffer, c, size);
318  p->buffer += size;
319 }
320 
322 {
323  return p->eof;
324 }
325 
326 static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b,
327  uint8_t *dst,
328  unsigned int size)
329 {
330  memcpy(dst, *b, size);
331  (*b) += size;
332  return size;
333 }
334 
336  const uint8_t *src,
337  unsigned int size)
338 {
339  memcpy(*b, src, size);
340  (*b) += size;
341 }
342 
343 #endif /* AVCODEC_BYTESTREAM_H */