ref: cf92e8d6208af51fb55ed61554b135585ed33c1b
dir: /codec/decoder/core/inc/dec_golomb.h/
/*!
* \copy
* Copyright (c) 2009-2013, Cisco Systems
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*
* \file golomb.h
*
* \brief Exponential Golomb entropy coding/decoding routine
*
* \date 03/13/2009 Created
*
*************************************************************************************
*/
#ifndef WELS_EXPONENTIAL_GOLOMB_ENTROPY_CODING_H__
#define WELS_EXPONENTIAL_GOLOMB_ENTROPY_CODING_H__
#include "typedefs.h"
#include "bit_stream.h"
#include "macros.h"
//#include <assert.h>
#include "ls_defines.h"
namespace WelsDec {
#define GET_WORD(iCurBits, pBufPtr, iLeftBits) { \
iCurBits |= ((pBufPtr[0] << 8) | pBufPtr[1]) << (iLeftBits); \
iLeftBits -= 16; \
pBufPtr +=2; \
}
#define NEED_BITS(iCurBits, pBufPtr, iLeftBits) { \
if( iLeftBits > 0 ) { \
GET_WORD(iCurBits, pBufPtr, iLeftBits); \
} \
}
#define UBITS(iCurBits, iNumBits) (iCurBits>>(32-(iNumBits)))
#define DUMP_BITS(iCurBits, pBufPtr, iLeftBits, iNumBits) { \
iCurBits <<= (iNumBits); \
iLeftBits += (iNumBits); \
NEED_BITS(iCurBits, pBufPtr, iLeftBits); \
}
static inline int32_t ShowBits( PBitStringAux pBs, int32_t iNumBits )
{
return UBITS( pBs->uiCurBits, iNumBits );
}
static inline void_t FlushBits( PBitStringAux pBs, int32_t iNumBits )
{
DUMP_BITS( pBs->uiCurBits, pBs->pCurBuf, pBs->iLeftBits, iNumBits );
}
static inline int32_t BsGetBits( PBitStringAux pBs, int32_t iNumBits )
{
int32_t iRc = UBITS( pBs->uiCurBits, iNumBits );
DUMP_BITS( pBs->uiCurBits, pBs->pCurBuf, pBs->iLeftBits, iNumBits );
return iRc;
}
/*
* Exponential Golomb codes decoding routines
*/
// for data sharing cross modules and try to reduce size of binary generated, 12/10/2009
extern const uint8_t g_kuiIntra4x4CbpTable[48];
extern const uint8_t g_kuiInterCbpTable[48];
extern const uint8_t g_kuiLeadingZeroTable[256];
static const uint32_t g_kuiPrefix8BitsTable[16] =
{
0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3
};
static inline uint32_t GetPrefixBits(uint32_t uiValue)
{
uint32_t iNumBit = 0;
if (uiValue & 0xffff0000)
{
uiValue >>= 16;
iNumBit += 16;
}
if (uiValue & 0xff00)
{
uiValue >>= 8;
iNumBit += 8;
}
if (uiValue & 0xf0)
{
uiValue >>= 4;
iNumBit += 4;
}
iNumBit += g_kuiPrefix8BitsTable[uiValue];
return (32-iNumBit);
}
/*
* Read one bit from bit stream followed
*/
static inline uint32_t BsGetOneBit(PBitStringAux pBs)
{
return ( BsGetBits(pBs, 1) );
}
static inline int32_t GetLeadingZeroBits( uint32_t iCurBits ) //<=16 bits
{
int32_t iValue;
iValue = UBITS( iCurBits, 8 );//ShowBits( bs, 8 );
if( iValue )
{
return g_kuiLeadingZeroTable[iValue];
}
iValue = UBITS( iCurBits, 16 );//ShowBits( bs, 16 );
if( iValue )
{
return (g_kuiLeadingZeroTable[iValue] + 8);
}
//ASSERT(FALSE); // should not go here
return -1;
}
static inline uint32_t BsGetUe( PBitStringAux pBs )
{
uint32_t iValue = 0;
int32_t iLeadingZeroBits = GetLeadingZeroBits( pBs->uiCurBits );
if ( iLeadingZeroBits == -1 ) //bistream error
{
return 0xffffffff;//-1
}
DUMP_BITS( pBs->uiCurBits, pBs->pCurBuf, pBs->iLeftBits, iLeadingZeroBits + 1 );
if( iLeadingZeroBits )
{
iValue = UBITS( pBs->uiCurBits, iLeadingZeroBits );
DUMP_BITS( pBs->uiCurBits, pBs->pCurBuf, pBs->iLeftBits, iLeadingZeroBits );
}
return ((1<<iLeadingZeroBits) - 1 + iValue);
}
/*
* Read signed exp golomb codes
*/
static inline int32_t BsGetSe(PBitStringAux pBs)
{
uint32_t uiCodeNum;
uiCodeNum = BsGetUe( pBs );
if(uiCodeNum&0x01)
{
return (int32_t)((uiCodeNum+1)>>1);
}
else
{
return NEG_NUM( (int32_t)(uiCodeNum>>1) );
}
}
/*
* Read truncated exp golomb codes
*/
static inline uint32_t BsGetTe(PBitStringAux pBs, uint8_t uiRange)
{
if ( 1 == uiRange )
{
return BsGetOneBit(pBs)^1;
}
else
{
return BsGetUe(pBs);
}
}
/*
* Get unsigned truncated exp golomb code.
*/
static inline int32_t BsGetTe0(PBitStringAux pBs, int32_t iRange)
{
if(iRange==1)
return 0;
else if(iRange==2)
return BsGetOneBit(pBs)^1;
else
return BsGetUe(pBs);
}
/*
* Get number of trailing bits
*/
static inline int32_t BsGetTrailingBits( uint8_t *pBuf )
{
// TODO
uint32_t uiValue = *pBuf;
int32_t iRetNum = 1;
do
{
if (uiValue&1)
return iRetNum;
uiValue >>= 1;
++ iRetNum;
} while(iRetNum < 9);
return 0;
}
} // namespace WelsDec
#endif//WELS_EXPONENTIAL_GOLOMB_ENTROPY_CODING_H__