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/**************************************************************************
*
* Copyright 2011 Christian König.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/**
* This file is based uppon slice_xvmc.c and vlc.h from the xine project,
* which in turn is based on mpeg2dec. The following is the original copyright:
*
* Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
*
* This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
* See http://libmpeg2.sourceforge.net/ for updates.
*
* mpeg2dec 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.
*
* mpeg2dec 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
*/
#ifndef vl_vlc_h
#define vl_vlc_h
struct vl_vlc
{
uint32_t buf; /* current 32 bit working set of buffer */
int bits; /* used bits in working set */
const uint8_t *ptr; /* buffer with stream data */
const uint8_t *max; /* ptr+len of buffer */
};
static inline void
vl_vlc_restart(struct vl_vlc *vlc)
{
vlc->buf = (vlc->ptr[0] << 24) | (vlc->ptr[1] << 16) | (vlc->ptr[2] << 8) | vlc->ptr[3];
vlc->bits = -16;
vlc->ptr += 4;
}
static inline void
vl_vlc_init(struct vl_vlc *vlc, const uint8_t *data, unsigned len)
{
vlc->ptr = data;
vlc->max = data + len;
vl_vlc_restart(vlc);
}
static inline bool
vl_vlc_getbyte(struct vl_vlc *vlc)
{
vlc->buf <<= 8;
vlc->buf |= vlc->ptr[0];
vlc->ptr++;
return vlc->ptr < vlc->max;
}
#define vl_vlc_getword(vlc, shift) \
do { \
(vlc)->buf |= (((vlc)->ptr[0] << 8) | (vlc)->ptr[1]) << (shift); \
(vlc)->ptr += 2; \
} while (0)
/* make sure that there are at least 16 valid bits in bit_buf */
#define vl_vlc_needbits(vlc) \
do { \
if ((vlc)->bits >= 0) { \
vl_vlc_getword(vlc, (vlc)->bits); \
(vlc)->bits -= 16; \
} \
} while (0)
/* make sure that the full 32 bit of the buffer are valid */
static inline void
vl_vlc_need32bits(struct vl_vlc *vlc)
{
vl_vlc_needbits(vlc);
if (vlc->bits > -8) {
unsigned n = -vlc->bits;
vlc->buf <<= n;
vlc->buf |= *vlc->ptr << 8;
vlc->bits = -8;
vlc->ptr++;
}
if (vlc->bits > -16) {
unsigned n = -vlc->bits - 8;
vlc->buf <<= n;
vlc->buf |= *vlc->ptr;
vlc->bits = -16;
vlc->ptr++;
}
}
/* remove num valid bits from bit_buf */
#define vl_vlc_dumpbits(vlc, num) \
do { \
(vlc)->buf <<= (num); \
(vlc)->bits += (num); \
} while (0)
/* take num bits from the high part of bit_buf and zero extend them */
#define vl_vlc_ubits(vlc, num) (((uint32_t)((vlc)->buf)) >> (32 - (num)))
/* take num bits from the high part of bit_buf and sign extend them */
#define vl_vlc_sbits(vlc, num) (((int32_t)((vlc)->buf)) >> (32 - (num)))
#endif /* vl_vlc_h */
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