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1 | /* |
2 | * This file is part of FFmpeg. | |
3 | * | |
4 | * FFmpeg is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU Lesser General Public | |
6 | * License as published by the Free Software Foundation; either | |
7 | * version 2.1 of the License, or (at your option) any later version. | |
8 | * | |
9 | * FFmpeg is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | * Lesser General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU Lesser General Public | |
15 | * License along with FFmpeg; if not, write to the Free Software | |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
17 | */ | |
18 | ||
19 | /** | |
20 | * @file | |
21 | * a very simple circular buffer FIFO implementation | |
22 | */ | |
23 | ||
24 | #ifndef AVUTIL_FIFO_H | |
25 | #define AVUTIL_FIFO_H | |
26 | ||
27 | #include <stdint.h> | |
28 | #include "avutil.h" | |
29 | #include "attributes.h" | |
30 | ||
31 | typedef struct AVFifoBuffer { | |
32 | uint8_t *buffer; | |
33 | uint8_t *rptr, *wptr, *end; | |
34 | uint32_t rndx, wndx; | |
35 | } AVFifoBuffer; | |
36 | ||
37 | /** | |
38 | * Initialize an AVFifoBuffer. | |
39 | * @param size of FIFO | |
40 | * @return AVFifoBuffer or NULL in case of memory allocation failure | |
41 | */ | |
42 | AVFifoBuffer *av_fifo_alloc(unsigned int size); | |
43 | ||
44 | /** | |
45 | * Initialize an AVFifoBuffer. | |
46 | * @param nmemb number of elements | |
47 | * @param size size of the single element | |
48 | * @return AVFifoBuffer or NULL in case of memory allocation failure | |
49 | */ | |
50 | AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size); | |
51 | ||
52 | /** | |
53 | * Free an AVFifoBuffer. | |
54 | * @param f AVFifoBuffer to free | |
55 | */ | |
56 | void av_fifo_free(AVFifoBuffer *f); | |
57 | ||
58 | /** | |
59 | * Free an AVFifoBuffer and reset pointer to NULL. | |
60 | * @param f AVFifoBuffer to free | |
61 | */ | |
62 | void av_fifo_freep(AVFifoBuffer **f); | |
63 | ||
64 | /** | |
65 | * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied. | |
66 | * @param f AVFifoBuffer to reset | |
67 | */ | |
68 | void av_fifo_reset(AVFifoBuffer *f); | |
69 | ||
70 | /** | |
71 | * Return the amount of data in bytes in the AVFifoBuffer, that is the | |
72 | * amount of data you can read from it. | |
73 | * @param f AVFifoBuffer to read from | |
74 | * @return size | |
75 | */ | |
f6fa7814 | 76 | int av_fifo_size(const AVFifoBuffer *f); |
2ba45a60 DM |
77 | |
78 | /** | |
79 | * Return the amount of space in bytes in the AVFifoBuffer, that is the | |
80 | * amount of data you can write into it. | |
81 | * @param f AVFifoBuffer to write into | |
82 | * @return size | |
83 | */ | |
f6fa7814 | 84 | int av_fifo_space(const AVFifoBuffer *f); |
2ba45a60 DM |
85 | |
86 | /** | |
87 | * Feed data from an AVFifoBuffer to a user-supplied callback. | |
88 | * @param f AVFifoBuffer to read from | |
89 | * @param buf_size number of bytes to read | |
90 | * @param func generic read function | |
91 | * @param dest data destination | |
92 | */ | |
93 | int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int)); | |
94 | ||
95 | /** | |
96 | * Feed data from a user-supplied callback to an AVFifoBuffer. | |
97 | * @param f AVFifoBuffer to write to | |
98 | * @param src data source; non-const since it may be used as a | |
99 | * modifiable context by the function defined in func | |
100 | * @param size number of bytes to write | |
101 | * @param func generic write function; the first parameter is src, | |
102 | * the second is dest_buf, the third is dest_buf_size. | |
103 | * func must return the number of bytes written to dest_buf, or <= 0 to | |
104 | * indicate no more data available to write. | |
105 | * If func is NULL, src is interpreted as a simple byte array for source data. | |
106 | * @return the number of bytes written to the FIFO | |
107 | */ | |
108 | int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int)); | |
109 | ||
110 | /** | |
111 | * Resize an AVFifoBuffer. | |
112 | * In case of reallocation failure, the old FIFO is kept unchanged. | |
113 | * | |
114 | * @param f AVFifoBuffer to resize | |
115 | * @param size new AVFifoBuffer size in bytes | |
116 | * @return <0 for failure, >=0 otherwise | |
117 | */ | |
118 | int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size); | |
119 | ||
120 | /** | |
121 | * Enlarge an AVFifoBuffer. | |
122 | * In case of reallocation failure, the old FIFO is kept unchanged. | |
123 | * The new fifo size may be larger than the requested size. | |
124 | * | |
125 | * @param f AVFifoBuffer to resize | |
126 | * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size() | |
127 | * @return <0 for failure, >=0 otherwise | |
128 | */ | |
129 | int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space); | |
130 | ||
131 | /** | |
132 | * Read and discard the specified amount of data from an AVFifoBuffer. | |
133 | * @param f AVFifoBuffer to read from | |
134 | * @param size amount of data to read in bytes | |
135 | */ | |
136 | void av_fifo_drain(AVFifoBuffer *f, int size); | |
137 | ||
138 | /** | |
139 | * Return a pointer to the data stored in a FIFO buffer at a certain offset. | |
140 | * The FIFO buffer is not modified. | |
141 | * | |
142 | * @param f AVFifoBuffer to peek at, f must be non-NULL | |
143 | * @param offs an offset in bytes, its absolute value must be less | |
144 | * than the used buffer size or the returned pointer will | |
145 | * point outside to the buffer data. | |
146 | * The used buffer size can be checked with av_fifo_size(). | |
147 | */ | |
148 | static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs) | |
149 | { | |
150 | uint8_t *ptr = f->rptr + offs; | |
151 | if (ptr >= f->end) | |
152 | ptr = f->buffer + (ptr - f->end); | |
153 | else if (ptr < f->buffer) | |
154 | ptr = f->end - (f->buffer - ptr); | |
155 | return ptr; | |
156 | } | |
157 | ||
158 | #endif /* AVUTIL_FIFO_H */ |