| 1 | /* |
| 2 | * a very simple circular buffer FIFO implementation |
| 3 | * Copyright (c) 2000, 2001, 2002 Fabrice Bellard |
| 4 | * Copyright (c) 2006 Roman Shaposhnik |
| 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 | #include "avassert.h" |
| 24 | #include "common.h" |
| 25 | #include "fifo.h" |
| 26 | |
| 27 | static AVFifoBuffer *fifo_alloc_common(void *buffer, size_t size) |
| 28 | { |
| 29 | AVFifoBuffer *f; |
| 30 | if (!buffer) |
| 31 | return NULL; |
| 32 | f = av_mallocz(sizeof(AVFifoBuffer)); |
| 33 | if (!f) { |
| 34 | av_free(buffer); |
| 35 | return NULL; |
| 36 | } |
| 37 | f->buffer = buffer; |
| 38 | f->end = f->buffer + size; |
| 39 | av_fifo_reset(f); |
| 40 | return f; |
| 41 | } |
| 42 | |
| 43 | AVFifoBuffer *av_fifo_alloc(unsigned int size) |
| 44 | { |
| 45 | void *buffer = av_malloc(size); |
| 46 | return fifo_alloc_common(buffer, size); |
| 47 | } |
| 48 | |
| 49 | AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size) |
| 50 | { |
| 51 | void *buffer = av_malloc_array(nmemb, size); |
| 52 | return fifo_alloc_common(buffer, nmemb * size); |
| 53 | } |
| 54 | |
| 55 | void av_fifo_free(AVFifoBuffer *f) |
| 56 | { |
| 57 | if (f) { |
| 58 | av_freep(&f->buffer); |
| 59 | av_free(f); |
| 60 | } |
| 61 | } |
| 62 | |
| 63 | void av_fifo_freep(AVFifoBuffer **f) |
| 64 | { |
| 65 | if (f) { |
| 66 | av_fifo_free(*f); |
| 67 | *f = NULL; |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | void av_fifo_reset(AVFifoBuffer *f) |
| 72 | { |
| 73 | f->wptr = f->rptr = f->buffer; |
| 74 | f->wndx = f->rndx = 0; |
| 75 | } |
| 76 | |
| 77 | int av_fifo_size(const AVFifoBuffer *f) |
| 78 | { |
| 79 | return (uint32_t)(f->wndx - f->rndx); |
| 80 | } |
| 81 | |
| 82 | int av_fifo_space(const AVFifoBuffer *f) |
| 83 | { |
| 84 | return f->end - f->buffer - av_fifo_size(f); |
| 85 | } |
| 86 | |
| 87 | int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size) |
| 88 | { |
| 89 | unsigned int old_size = f->end - f->buffer; |
| 90 | |
| 91 | if (old_size < new_size) { |
| 92 | int len = av_fifo_size(f); |
| 93 | AVFifoBuffer *f2 = av_fifo_alloc(new_size); |
| 94 | |
| 95 | if (!f2) |
| 96 | return AVERROR(ENOMEM); |
| 97 | av_fifo_generic_read(f, f2->buffer, len, NULL); |
| 98 | f2->wptr += len; |
| 99 | f2->wndx += len; |
| 100 | av_free(f->buffer); |
| 101 | *f = *f2; |
| 102 | av_free(f2); |
| 103 | } |
| 104 | return 0; |
| 105 | } |
| 106 | |
| 107 | int av_fifo_grow(AVFifoBuffer *f, unsigned int size) |
| 108 | { |
| 109 | unsigned int old_size = f->end - f->buffer; |
| 110 | if(size + (unsigned)av_fifo_size(f) < size) |
| 111 | return AVERROR(EINVAL); |
| 112 | |
| 113 | size += av_fifo_size(f); |
| 114 | |
| 115 | if (old_size < size) |
| 116 | return av_fifo_realloc2(f, FFMAX(size, 2*size)); |
| 117 | return 0; |
| 118 | } |
| 119 | |
| 120 | /* src must NOT be const as it can be a context for func that may need |
| 121 | * updating (like a pointer or byte counter) */ |
| 122 | int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, |
| 123 | int (*func)(void *, void *, int)) |
| 124 | { |
| 125 | int total = size; |
| 126 | uint32_t wndx= f->wndx; |
| 127 | uint8_t *wptr= f->wptr; |
| 128 | |
| 129 | do { |
| 130 | int len = FFMIN(f->end - wptr, size); |
| 131 | if (func) { |
| 132 | if (func(src, wptr, len) <= 0) |
| 133 | break; |
| 134 | } else { |
| 135 | memcpy(wptr, src, len); |
| 136 | src = (uint8_t *)src + len; |
| 137 | } |
| 138 | // Write memory barrier needed for SMP here in theory |
| 139 | wptr += len; |
| 140 | if (wptr >= f->end) |
| 141 | wptr = f->buffer; |
| 142 | wndx += len; |
| 143 | size -= len; |
| 144 | } while (size > 0); |
| 145 | f->wndx= wndx; |
| 146 | f->wptr= wptr; |
| 147 | return total - size; |
| 148 | } |
| 149 | |
| 150 | int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, |
| 151 | void (*func)(void *, void *, int)) |
| 152 | { |
| 153 | // Read memory barrier needed for SMP here in theory |
| 154 | do { |
| 155 | int len = FFMIN(f->end - f->rptr, buf_size); |
| 156 | if (func) |
| 157 | func(dest, f->rptr, len); |
| 158 | else { |
| 159 | memcpy(dest, f->rptr, len); |
| 160 | dest = (uint8_t *)dest + len; |
| 161 | } |
| 162 | // memory barrier needed for SMP here in theory |
| 163 | av_fifo_drain(f, len); |
| 164 | buf_size -= len; |
| 165 | } while (buf_size > 0); |
| 166 | return 0; |
| 167 | } |
| 168 | |
| 169 | /** Discard data from the FIFO. */ |
| 170 | void av_fifo_drain(AVFifoBuffer *f, int size) |
| 171 | { |
| 172 | av_assert2(av_fifo_size(f) >= size); |
| 173 | f->rptr += size; |
| 174 | if (f->rptr >= f->end) |
| 175 | f->rptr -= f->end - f->buffer; |
| 176 | f->rndx += size; |
| 177 | } |
| 178 | |
| 179 | #ifdef TEST |
| 180 | |
| 181 | int main(void) |
| 182 | { |
| 183 | /* create a FIFO buffer */ |
| 184 | AVFifoBuffer *fifo = av_fifo_alloc(13 * sizeof(int)); |
| 185 | int i, j, n; |
| 186 | |
| 187 | /* fill data */ |
| 188 | for (i = 0; av_fifo_space(fifo) >= sizeof(int); i++) |
| 189 | av_fifo_generic_write(fifo, &i, sizeof(int), NULL); |
| 190 | |
| 191 | /* peek at FIFO */ |
| 192 | n = av_fifo_size(fifo) / sizeof(int); |
| 193 | for (i = -n + 1; i < n; i++) { |
| 194 | int *v = (int *)av_fifo_peek2(fifo, i * sizeof(int)); |
| 195 | printf("%d: %d\n", i, *v); |
| 196 | } |
| 197 | printf("\n"); |
| 198 | |
| 199 | /* read data */ |
| 200 | for (i = 0; av_fifo_size(fifo) >= sizeof(int); i++) { |
| 201 | av_fifo_generic_read(fifo, &j, sizeof(int), NULL); |
| 202 | printf("%d ", j); |
| 203 | } |
| 204 | printf("\n"); |
| 205 | |
| 206 | av_fifo_free(fifo); |
| 207 | |
| 208 | return 0; |
| 209 | } |
| 210 | |
| 211 | #endif |