ref: ea574ee13f0bcd87cb5fda68a0e35784eddc5a4c
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 #if defined(_MSC_VER) && defined(_M_IX86) 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