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| 4349 | Serge | 1 | /* |
| 2 | * This file is part of FFmpeg. |
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| 3 | * |
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| 4 | * FFmpeg is free software; you can redistribute it and/or |
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| 5 | * modify it under the terms of the GNU Lesser General Public |
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| 6 | * License as published by the Free Software Foundation; either |
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| 7 | * version 2.1 of the License, or (at your option) any later version. |
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| 8 | * |
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| 9 | * FFmpeg is distributed in the hope that it will be useful, |
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| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 12 | * Lesser General Public License for more details. |
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| 13 | * |
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| 14 | * You should have received a copy of the GNU Lesser General Public |
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| 15 | * License along with FFmpeg; if not, write to the Free Software |
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| 16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 17 | */ |
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| 18 | |||
| 19 | /** |
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| 20 | * @file |
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| 21 | * a very simple circular buffer FIFO implementation |
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| 22 | */ |
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| 23 | |||
| 24 | #ifndef AVUTIL_FIFO_H |
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| 25 | #define AVUTIL_FIFO_H |
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| 26 | |||
| 27 | #include |
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| 28 | #include "avutil.h" |
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| 29 | #include "attributes.h" |
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| 30 | |||
| 31 | typedef struct AVFifoBuffer { |
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| 32 | uint8_t *buffer; |
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| 33 | uint8_t *rptr, *wptr, *end; |
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| 34 | uint32_t rndx, wndx; |
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| 35 | } AVFifoBuffer; |
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| 36 | |||
| 37 | /** |
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| 38 | * Initialize an AVFifoBuffer. |
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| 39 | * @param size of FIFO |
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| 40 | * @return AVFifoBuffer or NULL in case of memory allocation failure |
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| 41 | */ |
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| 42 | AVFifoBuffer *av_fifo_alloc(unsigned int size); |
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| 43 | |||
| 44 | /** |
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| 45 | * Free an AVFifoBuffer. |
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| 46 | * @param f AVFifoBuffer to free |
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| 47 | */ |
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| 48 | void av_fifo_free(AVFifoBuffer *f); |
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| 49 | |||
| 50 | /** |
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| 51 | * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied. |
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| 52 | * @param f AVFifoBuffer to reset |
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| 53 | */ |
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| 54 | void av_fifo_reset(AVFifoBuffer *f); |
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| 55 | |||
| 56 | /** |
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| 57 | * Return the amount of data in bytes in the AVFifoBuffer, that is the |
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| 58 | * amount of data you can read from it. |
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| 59 | * @param f AVFifoBuffer to read from |
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| 60 | * @return size |
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| 61 | */ |
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| 62 | int av_fifo_size(AVFifoBuffer *f); |
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| 63 | |||
| 64 | /** |
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| 65 | * Return the amount of space in bytes in the AVFifoBuffer, that is the |
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| 66 | * amount of data you can write into it. |
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| 67 | * @param f AVFifoBuffer to write into |
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| 68 | * @return size |
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| 69 | */ |
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| 70 | int av_fifo_space(AVFifoBuffer *f); |
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| 71 | |||
| 72 | /** |
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| 73 | * Feed data from an AVFifoBuffer to a user-supplied callback. |
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| 74 | * @param f AVFifoBuffer to read from |
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| 75 | * @param buf_size number of bytes to read |
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| 76 | * @param func generic read function |
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| 77 | * @param dest data destination |
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| 78 | */ |
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| 79 | int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int)); |
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| 80 | |||
| 81 | /** |
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| 82 | * Feed data from a user-supplied callback to an AVFifoBuffer. |
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| 83 | * @param f AVFifoBuffer to write to |
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| 84 | * @param src data source; non-const since it may be used as a |
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| 85 | * modifiable context by the function defined in func |
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| 86 | * @param size number of bytes to write |
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| 87 | * @param func generic write function; the first parameter is src, |
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| 88 | * the second is dest_buf, the third is dest_buf_size. |
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| 89 | * func must return the number of bytes written to dest_buf, or <= 0 to |
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| 90 | * indicate no more data available to write. |
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| 91 | * If func is NULL, src is interpreted as a simple byte array for source data. |
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| 92 | * @return the number of bytes written to the FIFO |
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| 93 | */ |
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| 94 | int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int)); |
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| 95 | |||
| 96 | /** |
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| 97 | * Resize an AVFifoBuffer. |
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| 98 | * In case of reallocation failure, the old FIFO is kept unchanged. |
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| 99 | * |
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| 100 | * @param f AVFifoBuffer to resize |
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| 101 | * @param size new AVFifoBuffer size in bytes |
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| 102 | * @return <0 for failure, >=0 otherwise |
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| 103 | */ |
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| 104 | int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size); |
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| 105 | |||
| 106 | /** |
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| 107 | * Enlarge an AVFifoBuffer. |
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| 108 | * In case of reallocation failure, the old FIFO is kept unchanged. |
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| 109 | * The new fifo size may be larger than the requested size. |
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| 110 | * |
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| 111 | * @param f AVFifoBuffer to resize |
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| 112 | * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size() |
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| 113 | * @return <0 for failure, >=0 otherwise |
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| 114 | */ |
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| 115 | int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space); |
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| 116 | |||
| 117 | /** |
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| 118 | * Read and discard the specified amount of data from an AVFifoBuffer. |
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| 119 | * @param f AVFifoBuffer to read from |
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| 120 | * @param size amount of data to read in bytes |
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| 121 | */ |
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| 122 | void av_fifo_drain(AVFifoBuffer *f, int size); |
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| 123 | |||
| 124 | /** |
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| 125 | * Return a pointer to the data stored in a FIFO buffer at a certain offset. |
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| 126 | * The FIFO buffer is not modified. |
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| 127 | * |
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| 128 | * @param f AVFifoBuffer to peek at, f must be non-NULL |
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| 129 | * @param offs an offset in bytes, its absolute value must be less |
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| 130 | * than the used buffer size or the returned pointer will |
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| 131 | * point outside to the buffer data. |
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| 132 | * The used buffer size can be checked with av_fifo_size(). |
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| 133 | */ |
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| 134 | static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs) |
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| 135 | { |
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| 136 | uint8_t *ptr = f->rptr + offs; |
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| 137 | if (ptr >= f->end) |
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| 138 | ptr = f->buffer + (ptr - f->end); |
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| 139 | else if (ptr < f->buffer) |
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| 140 | ptr = f->end - (f->buffer - ptr); |
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| 141 | return ptr; |
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| 142 | } |
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| 143 | |||
| 144 | #endif /* AVUTIL_FIFO_H */ |