blob: dc7bc6f0dd7925a6c0e94847d537fa62164a4639
| 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 | */ |
| 76 | int av_fifo_size(const AVFifoBuffer *f); |
| 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 | */ |
| 84 | int av_fifo_space(const AVFifoBuffer *f); |
| 85 | |
| 86 | /** |
| 87 | * Feed data at specific position from an AVFifoBuffer to a user-supplied callback. |
| 88 | * Similar as av_fifo_gereric_read but without discarding data. |
| 89 | * @param f AVFifoBuffer to read from |
| 90 | * @param offset offset from current read position |
| 91 | * @param buf_size number of bytes to read |
| 92 | * @param func generic read function |
| 93 | * @param dest data destination |
| 94 | */ |
| 95 | int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int)); |
| 96 | |
| 97 | /** |
| 98 | * Feed data from an AVFifoBuffer to a user-supplied callback. |
| 99 | * Similar as av_fifo_gereric_read but without discarding data. |
| 100 | * @param f AVFifoBuffer to read from |
| 101 | * @param buf_size number of bytes to read |
| 102 | * @param func generic read function |
| 103 | * @param dest data destination |
| 104 | */ |
| 105 | int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int)); |
| 106 | |
| 107 | /** |
| 108 | * Feed data from an AVFifoBuffer to a user-supplied callback. |
| 109 | * @param f AVFifoBuffer to read from |
| 110 | * @param buf_size number of bytes to read |
| 111 | * @param func generic read function |
| 112 | * @param dest data destination |
| 113 | */ |
| 114 | int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int)); |
| 115 | |
| 116 | /** |
| 117 | * Feed data from a user-supplied callback to an AVFifoBuffer. |
| 118 | * @param f AVFifoBuffer to write to |
| 119 | * @param src data source; non-const since it may be used as a |
| 120 | * modifiable context by the function defined in func |
| 121 | * @param size number of bytes to write |
| 122 | * @param func generic write function; the first parameter is src, |
| 123 | * the second is dest_buf, the third is dest_buf_size. |
| 124 | * func must return the number of bytes written to dest_buf, or <= 0 to |
| 125 | * indicate no more data available to write. |
| 126 | * If func is NULL, src is interpreted as a simple byte array for source data. |
| 127 | * @return the number of bytes written to the FIFO |
| 128 | */ |
| 129 | int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int)); |
| 130 | |
| 131 | /** |
| 132 | * Resize an AVFifoBuffer. |
| 133 | * In case of reallocation failure, the old FIFO is kept unchanged. |
| 134 | * |
| 135 | * @param f AVFifoBuffer to resize |
| 136 | * @param size new AVFifoBuffer size in bytes |
| 137 | * @return <0 for failure, >=0 otherwise |
| 138 | */ |
| 139 | int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size); |
| 140 | |
| 141 | /** |
| 142 | * Enlarge an AVFifoBuffer. |
| 143 | * In case of reallocation failure, the old FIFO is kept unchanged. |
| 144 | * The new fifo size may be larger than the requested size. |
| 145 | * |
| 146 | * @param f AVFifoBuffer to resize |
| 147 | * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size() |
| 148 | * @return <0 for failure, >=0 otherwise |
| 149 | */ |
| 150 | int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space); |
| 151 | |
| 152 | /** |
| 153 | * Read and discard the specified amount of data from an AVFifoBuffer. |
| 154 | * @param f AVFifoBuffer to read from |
| 155 | * @param size amount of data to read in bytes |
| 156 | */ |
| 157 | void av_fifo_drain(AVFifoBuffer *f, int size); |
| 158 | |
| 159 | /** |
| 160 | * Return a pointer to the data stored in a FIFO buffer at a certain offset. |
| 161 | * The FIFO buffer is not modified. |
| 162 | * |
| 163 | * @param f AVFifoBuffer to peek at, f must be non-NULL |
| 164 | * @param offs an offset in bytes, its absolute value must be less |
| 165 | * than the used buffer size or the returned pointer will |
| 166 | * point outside to the buffer data. |
| 167 | * The used buffer size can be checked with av_fifo_size(). |
| 168 | */ |
| 169 | static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs) |
| 170 | { |
| 171 | uint8_t *ptr = f->rptr + offs; |
| 172 | if (ptr >= f->end) |
| 173 | ptr = f->buffer + (ptr - f->end); |
| 174 | else if (ptr < f->buffer) |
| 175 | ptr = f->end - (f->buffer - ptr); |
| 176 | return ptr; |
| 177 | } |
| 178 | |
| 179 | #endif /* AVUTIL_FIFO_H */ |
| 180 |