| /* |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #ifndef AVCODEC_VLC_H |
| #define AVCODEC_VLC_H |
| |
| #include <stdint.h> |
| |
| // When changing this, be sure to also update tableprint_vlc.h accordingly. |
| typedef int16_t VLCBaseType; |
| |
| typedef struct VLCElem { |
| VLCBaseType sym, len; |
| } VLCElem; |
| |
| typedef struct VLC { |
| int bits; |
| VLCElem *table; |
| int table_size, table_allocated; |
| } VLC; |
| |
| typedef struct RL_VLC_ELEM { |
| int16_t level; |
| int8_t len; |
| uint8_t run; |
| } RL_VLC_ELEM; |
| |
| #define init_vlc(vlc, nb_bits, nb_codes, \ |
| bits, bits_wrap, bits_size, \ |
| codes, codes_wrap, codes_size, \ |
| flags) \ |
| ff_init_vlc_sparse(vlc, nb_bits, nb_codes, \ |
| bits, bits_wrap, bits_size, \ |
| codes, codes_wrap, codes_size, \ |
| NULL, 0, 0, flags) |
| |
| int ff_init_vlc_sparse(VLC *vlc, int nb_bits, int nb_codes, |
| const void *bits, int bits_wrap, int bits_size, |
| const void *codes, int codes_wrap, int codes_size, |
| const void *symbols, int symbols_wrap, int symbols_size, |
| int flags); |
| |
| /** |
| * Build VLC decoding tables suitable for use with get_vlc2() |
| * |
| * This function takes lengths and symbols and calculates the codes from them. |
| * For this the input lengths and symbols have to be sorted according to "left |
| * nodes in the corresponding tree first". |
| * |
| * @param[in,out] vlc The VLC to be initialized; table and table_allocated |
| * must have been set when initializing a static VLC, |
| * otherwise this will be treated as uninitialized. |
| * @param[in] nb_bits The number of bits to use for the VLC table; |
| * higher values take up more memory and cache, but |
| * allow to read codes with fewer reads. |
| * @param[in] nb_codes The number of provided length and (if supplied) symbol |
| * entries. |
| * @param[in] lens The lengths of the codes. Entries > 0 correspond to |
| * valid codes; entries == 0 will be skipped and entries |
| * with len < 0 indicate that the tree is incomplete and |
| * has an open end of length -len at this position. |
| * @param[in] lens_wrap Stride (in bytes) of the lengths. |
| * @param[in] symbols The symbols, i.e. what is returned from get_vlc2() |
| * when the corresponding code is encountered. |
| * May be NULL, then 0, 1, 2, 3, 4,... will be used. |
| * @param[in] symbols_wrap Stride (in bytes) of the symbols. |
| * @param[in] symbols_size Size of the symbols. 1 and 2 are supported. |
| * @param[in] offset An offset to apply to all the valid symbols. |
| * @param[in] flags A combination of the INIT_VLC_* flags; notice that |
| * INIT_VLC_INPUT_LE is pointless and ignored. |
| */ |
| int ff_init_vlc_from_lengths(VLC *vlc, int nb_bits, int nb_codes, |
| const int8_t *lens, int lens_wrap, |
| const void *symbols, int symbols_wrap, int symbols_size, |
| int offset, int flags, void *logctx); |
| |
| void ff_free_vlc(VLC *vlc); |
| |
| /* If INIT_VLC_INPUT_LE is set, the LSB bit of the codes used to |
| * initialize the VLC table is the first bit to be read. */ |
| #define INIT_VLC_INPUT_LE 2 |
| /* If set the VLC is intended for a little endian bitstream reader. */ |
| #define INIT_VLC_OUTPUT_LE 8 |
| #define INIT_VLC_LE (INIT_VLC_INPUT_LE | INIT_VLC_OUTPUT_LE) |
| #define INIT_VLC_USE_NEW_STATIC 4 |
| #define INIT_VLC_STATIC_OVERLONG (1 | INIT_VLC_USE_NEW_STATIC) |
| |
| #define INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \ |
| h, i, j, flags, static_size) \ |
| do { \ |
| static VLCElem table[static_size]; \ |
| (vlc)->table = table; \ |
| (vlc)->table_allocated = static_size; \ |
| ff_init_vlc_sparse(vlc, bits, a, b, c, d, e, f, g, h, i, j, \ |
| flags | INIT_VLC_USE_NEW_STATIC); \ |
| } while (0) |
| |
| #define INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j, static_size) \ |
| INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \ |
| h, i, j, 0, static_size) |
| |
| #define INIT_LE_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, h, i, j, static_size) \ |
| INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \ |
| h, i, j, INIT_VLC_LE, static_size) |
| |
| #define INIT_CUSTOM_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, flags, static_size) \ |
| INIT_CUSTOM_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, \ |
| NULL, 0, 0, flags, static_size) |
| |
| #define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size) \ |
| INIT_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, NULL, 0, 0, static_size) |
| |
| #define INIT_LE_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size) \ |
| INIT_LE_VLC_SPARSE_STATIC(vlc, bits, a, b, c, d, e, f, g, NULL, 0, 0, static_size) |
| |
| #define INIT_VLC_STATIC_FROM_LENGTHS(vlc, bits, nb_codes, lens, len_wrap, \ |
| symbols, symbols_wrap, symbols_size, \ |
| offset, flags, static_size) \ |
| do { \ |
| static VLCElem table[static_size]; \ |
| (vlc)->table = table; \ |
| (vlc)->table_allocated = static_size; \ |
| ff_init_vlc_from_lengths(vlc, bits, nb_codes, lens, len_wrap, \ |
| symbols, symbols_wrap, symbols_size, \ |
| offset, flags | INIT_VLC_USE_NEW_STATIC, \ |
| NULL); \ |
| } while (0) |
| |
| #endif /* AVCODEC_VLC_H */ |
