ref: edba95536681d8c589ed6dccc1b88a8499a98d3b
dir: /codec/decoder/core/src/bit_stream.cpp/
/*!
* \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 bit_stream.cpp
*
* \brief Reading / writing bit-stream
*
* \date 03/10/2009 Created
*
*************************************************************************************
*/
#include "bit_stream.h"
#include "macros.h"
namespace WelsDec {
#ifdef WORDS_BIGENDIAN
inline uint32_t EndianFix(uint32_t uiX)
{
return uiX;
}
#else //WORDS_BIGENDIAN
#ifdef _MSC_VER
inline uint32_t EndianFix(uint32_t uiX)
{
__asm
{
mov eax, uiX
bswap eax
mov uiX, eax
}
return uiX;
}
#else //_MSC_VER
inline uint32_t EndianFix(uint32_t uiX)
{
#ifdef ARM_ARCHv7
__asm__ __volatile__("rev %0, %0":"+r"(uiX)); //Just for the ARMv7
#elif defined (X86_ARCH)
__asm__ __volatile__("bswap %0":"+r"(uiX));
#else
uiX = ((uiX & 0xff000000)>> 24) | ((uiX & 0xff0000) >> 8) |
((uiX & 0xff00) << 8) | ((uiX&0xff) << 24);
#endif
return uiX;
}
#endif //_MSC_VER
#endif //WORDS_BIGENDIAN
inline uint32_t GetValue4Bytes( uint8_t* pDstNal )
{
uint32_t uiValue = 0;
uiValue = (pDstNal[0]<<24) | (pDstNal[1]<<16) | (pDstNal[2]<<8) | (pDstNal[3]);
return uiValue;
}
void_t InitReadBits( PBitStringAux pBitString )
{
pBitString->uiCurBits = GetValue4Bytes( pBitString->pCurBuf );
pBitString->pCurBuf += 4;
pBitString->iLeftBits = -16;
}
/*!
* \brief input bits for decoder or initialize bitstream writing in encoder
*
* \param pBitString Bit string auxiliary pointer
* \param kpBuf bit-stream buffer
* \param kiSize size in bits for decoder; size in bytes for encoder
*
* \return size of buffer data in byte; failed in -1 return
*/
int32_t InitBits( PBitStringAux pBitString, const uint8_t *kpBuf, const int32_t kiSize )
{
const int32_t kiSizeBuf = (kiSize + 7) >> 3;
uint8_t *pTmp = (uint8_t *)kpBuf;
if ( NULL == pTmp )
return -1;
pBitString->pStartBuf = pTmp; // buffer to start position
pBitString->pEndBuf = pTmp + kiSizeBuf; // buffer + length
pBitString->iBits = kiSize; // count bits of overall bitstreaming inputindex;
pBitString->pCurBuf = pBitString->pStartBuf;
InitReadBits( pBitString );
return kiSizeBuf;
}
} // namespace WelsDec