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https://github.com/FFmpeg/FFmpeg.git
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2d764069be
In C, qualifiers for arrays are broken: const VLC_TYPE (*foo)[2] is a pointer to an array of two const VLC_TYPE elements and unfortunately this is not compatible with a pointer to a const array of two VLC_TYPE, because the latter does not exist as array types are never qualified (the qualifier applies to the base type instead). This is the reason why get_vlc2() doesn't accept a const VLC table despite not modifying the table at all, as there is no automatic conversion from VLC_TYPE (*)[2] to const VLC_TYPE (*)[2]. Fix this by using a structure VLCElem for the VLC table. This also has the advantage of making it clear which element is which. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
108 lines
3.4 KiB
C
108 lines
3.4 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stdint.h>
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#include <string.h>
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#include "libavutil/attributes.h"
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#include "libavutil/avassert.h"
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#include "rl.h"
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av_cold void ff_rl_init(RLTable *rl,
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uint8_t static_store[2][2 * MAX_RUN + MAX_LEVEL + 3])
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{
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int last, run, level, start, end, i;
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/* compute max_level[], max_run[] and index_run[] */
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for (last = 0; last < 2; last++) {
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int8_t *max_level = static_store[last];
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int8_t *max_run = static_store[last] + MAX_RUN + 1;
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uint8_t *index_run = static_store[last] + MAX_RUN + 1 + MAX_LEVEL + 1;
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if (last == 0) {
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start = 0;
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end = rl->last;
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} else {
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start = rl->last;
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end = rl->n;
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}
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memset(index_run, rl->n, MAX_RUN + 1);
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for (i = start; i < end; i++) {
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run = rl->table_run[i];
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level = rl->table_level[i];
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if (index_run[run] == rl->n)
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index_run[run] = i;
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if (level > max_level[run])
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max_level[run] = level;
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if (run > max_run[level])
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max_run[level] = run;
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}
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rl->max_level[last] = max_level;
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rl->max_run[last] = max_run;
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rl->index_run[last] = index_run;
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}
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}
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av_cold void ff_rl_init_vlc(RLTable *rl, unsigned static_size)
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{
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int i, q;
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VLCElem table[1500] = { 0 };
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VLC vlc = { .table = table, .table_allocated = static_size };
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av_assert0(static_size <= FF_ARRAY_ELEMS(table));
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init_vlc(&vlc, 9, rl->n + 1, &rl->table_vlc[0][1], 4, 2, &rl->table_vlc[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
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for (q = 0; q < 32; q++) {
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int qmul = q * 2;
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int qadd = (q - 1) | 1;
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if (!rl->rl_vlc[q])
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return;
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if (q == 0) {
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qmul = 1;
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qadd = 0;
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}
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for (i = 0; i < vlc.table_size; i++) {
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int code = vlc.table[i].sym;
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int len = vlc.table[i].len;
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int level, run;
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if (len == 0) { // illegal code
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run = 66;
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level = MAX_LEVEL;
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} else if (len < 0) { // more bits needed
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run = 0;
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level = code;
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} else {
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if (code == rl->n) { // esc
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run = 66;
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level = 0;
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} else {
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run = rl->table_run[code] + 1;
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level = rl->table_level[code] * qmul + qadd;
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if (code >= rl->last) run += 192;
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}
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}
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rl->rl_vlc[q][i].len = len;
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rl->rl_vlc[q][i].level = level;
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rl->rl_vlc[q][i].run = run;
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}
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}
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}
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