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mirror of https://github.com/mpv-player/mpv synced 2024-12-21 22:30:22 +00:00
mpv/liba52/bitstream.c
rathann e7db4ccf1a Patch by Stefan Huehner / stefan % huehner ! org \
patch replaces '()' for the correct '(void)' in function
declarations/prototypes which have no parameters. The '()' syntax tell
thats there is a variable list of arguments, so that the compiler cannot
check this. The extra CFLAG '-Wstrict-declarations' shows those cases.

Comments about a similar patch applied to ffmpeg:

That in C++ these mean the same, but in ANSI C the semantics are
different; function() is an (obsolete) K&R C style forward declaration,
it basically means that the function can have any number and any types
of parameters, effectively completely preventing the compiler from doing
any sort of type checking. -- Erik Slagter

Defining functions with unspecified arguments is allowed but bad.
With arguments unspecified the compiler can't report an error/warning
if the function is called with incorrect arguments. -- Måns Rullgård


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@17567 b3059339-0415-0410-9bf9-f77b7e298cf2
2006-02-09 14:08:03 +00:00

114 lines
2.6 KiB
C

/*
* bitstream.c
* Copyright (C) 2000-2001 Michel Lespinasse <walken@zoy.org>
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
*
* This file is part of a52dec, a free ATSC A-52 stream decoder.
* See http://liba52.sourceforge.net/ for updates.
*
* Modified for use with MPlayer, changes contained in liba52_changes.diff.
* detailed CVS changelog at http://www.mplayerhq.hu/cgi-bin/cvsweb.cgi/main/
* $Id$
*
* a52dec is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* a52dec 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "config.h"
#include <inttypes.h>
#include "a52.h"
#include "a52_internal.h"
#include "bitstream.h"
#define BUFFER_SIZE 4096
#ifdef ALT_BITSTREAM_READER
int indx=0;
uint32_t * buffer_start;
#else
static uint32_t * buffer_start;
#endif
uint32_t bits_left;
uint32_t current_word;
void bitstream_set_ptr (uint8_t * buf)
{
int align;
align = (int)buf & 3;
buffer_start = (uint32_t *) (buf - align);
bits_left = 0;
#ifdef ALT_BITSTREAM_READER
indx=0;
#endif
bitstream_get (align * 8);
}
static inline void
bitstream_fill_current(void)
{
uint32_t tmp;
tmp = *(buffer_start++);
current_word = swab32 (tmp);
}
/*
* The fast paths for _get is in the
* bitstream.h header file so it can be inlined.
*
* The "bottom half" of this routine is suffixed _bh
*
* -ah
*/
uint32_t
bitstream_get_bh(uint32_t num_bits)
{
uint32_t result;
num_bits -= bits_left;
result = (current_word << (32 - bits_left)) >> (32 - bits_left);
bitstream_fill_current();
if(num_bits != 0)
result = (result << num_bits) | (current_word >> (32 - num_bits));
bits_left = 32 - num_bits;
return result;
}
int32_t
bitstream_get_bh_2(uint32_t num_bits)
{
int32_t result;
num_bits -= bits_left;
result = (((int32_t)current_word) << (32 - bits_left)) >> (32 - bits_left);
bitstream_fill_current();
if(num_bits != 0)
result = (result << num_bits) | (current_word >> (32 - num_bits));
bits_left = 32 - num_bits;
return result;
}