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FFmpeg/libavcodec/tableprint_vlc.h
Andreas Rheinhardt 2d764069be avcodec/vlc: Use structure instead of VLC_TYPE array as VLC element
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>
2022-06-17 16:47:29 +02:00

80 lines
3.1 KiB
C

/*
* Helpers for generating hard-coded VLC tables
*
* Copyright (c) 2014 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
*
* 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_TABLEPRINT_VLC_H
#define AVCODEC_TABLEPRINT_VLC_H
#define AVUTIL_LOG_H
#define av_log(a, ...) while(0)
#define ff_dlog(a, ...) while(0)
#define AVUTIL_MEM_H
#define av_malloc(s) NULL
#define av_malloc_array(a, b) NULL
#define av_realloc_f(p, o, n) NULL
#define av_free(p) while(0)
#define av_freep(p) while(0)
#define AVUTIL_INTERNAL_H
#define avpriv_request_sample(...)
#include "tableprint.h"
#include "vlc.h"
#include "libavutil/reverse.c"
#include "vlc.c"
// The following will have to be modified if VLCBaseType changes.
WRITE_1D_FUNC_ARGV(VLCElem, 3, "{ .sym =%5" PRId16 ", .len =%2"PRIi16 " }",
data[i].sym, data[i].len)
static void write_vlc_type(const VLC *vlc, const VLCElem *base_table, const char *base_table_name)
{
printf(" .bits = %i,\n", vlc->bits);
// Unfortunately need to cast away const currently
printf(" .table = (VLCElem *)(%s + 0x%x),\n", base_table_name, (int)(vlc->table - base_table));
printf(" .table_size = 0x%x,\n", vlc->table_size);
printf(" .table_allocated = 0x%x,\n", vlc->table_allocated);
}
#define WRITE_VLC_TABLE(prefix, name) \
WRITE_ARRAY(prefix, VLCElem, name)
#define WRITE_VLC_TYPE(prefix, name, base_table) \
do { \
printf(prefix" VLC "#name" = {\n"); \
write_vlc_type(&name, base_table, #base_table); \
printf("};\n"); \
} while(0)
#define WRITE_VLC_ARRAY(prefix, name, base_table) \
do { \
int i; \
const size_t array_size = FF_ARRAY_ELEMS(name); \
printf(prefix" VLC "#name"[%"FMT"] = {{\n", \
array_size); \
for (i = 0; i < array_size; i++) { \
write_vlc_type(name + i, \
base_table, #base_table); \
if (i != array_size - 1) printf("}, {\n"); \
} \
printf("}};\n"); \
} while(0)
#endif /* AVCODEC_TABLEPRINT_VLC_H */