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/*
* 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 */
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