ref: fa8e56e944ae8163e8ac7b66fea2ae2845aa1bce
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"
namespace WelsDec {
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 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