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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 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 */