gps/GPSResources/tcpmp/mpeg1/mpeg_stream.h

108 lines
2.9 KiB
C
Executable File

/*****************************************************************************
*
* This program 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.
*
* This program 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
*
* $Id: mpeg_stream.h 271 2005-08-09 08:31:35Z picard $
*
* The Core Pocket Media Player
* Copyright (c) 2004-2005 Gabor Kovacs
*
****************************************************************************/
#ifndef __MPEG_STREAM_H
#define __MPEG_STREAM_H
#ifdef MIPS
static INLINE void inlineloadbits( mpeg_decode* dec )
{
int n = dec->bitpos-8;
if (n>=0)
{
const uint8_t* bitptr = dec->bitptr;
int bits = dec->bits;
do
{
bits = (bits << 8) | *bitptr++;
n -= 8;
}
while (n>=0);
dec->bits = bits;
dec->bitptr = bitptr;
dec->bitpos = n+8;
}
}
#else
#define inlineloadbits(dec) loadbits(dec)
#endif
// n=1..24 (or ..32 after bytealign)
#define showbits(dec,n) ((uint32_t)(dec->bits << dec->bitpos) >> (32-(n)))
#define flushbits(dec,n) dec->bitpos += n;
// use this only in boolean expression. to get a 1 bit value use getbits(dec,1)
#define getbits1(dec) ((dec->bits << dec->bitpos++) < 0)
static INLINE int getbits(mpeg_decode* dec,int n)
{
int i = showbits(dec,n);
flushbits(dec,n);
return i;
}
static INLINE int eofbits(mpeg_decode* dec)
{
return dec->bitptr >= dec->bitend;
}
static INLINE void bytealign(mpeg_decode* dec)
{
dec->bitpos = (dec->bitpos + 7) & ~7;
}
static INLINE int bitstonextbyte(mpeg_decode* dec)
{
return 8-(dec->bitpos & 7);
}
static INLINE const uint8_t *bytepos(mpeg_decode* dec)
{
return dec->bitptr - 4 + ((dec->bitpos+7) >> 3);
}
//**************************************************************************
#define loadbits_pos( dec, bitpos ) \
bitpos -= 8; \
if (bitpos >= 0) { \
int bits = dec->bits; \
const uint8_t* bitptr = dec->bitptr; \
do { \
bits = (bits << 8) | *bitptr++; \
bitpos -= 8; \
} while (bitpos>=0); \
dec->bits = bits; \
dec->bitptr = bitptr; \
} \
bitpos += 8;
#define showbits_pos(dec,bitpos,n) ((uint32_t)(dec->bits << bitpos) >> (32-(n)))
#define flushbits_pos(dec,bitpos,n) bitpos += n
#define getbits1_pos(dec,bitpos) ((dec->bits << bitpos++) < 0)
#endif