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/*
* $Id$
*
* (C) 2006-2010 see AUTHORS
*
* This file is part of mplayerc.
*
* Mplayerc 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 3 of the License, or
* (at your option) any later version.
*
* Mplayerc 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "stdafx.h"
#include "GolombBuffer.h"
CGolombBuffer::CGolombBuffer(BYTE* pBuffer, int nSize)
{
m_pBuffer = pBuffer;
m_nSize = nSize;
Reset();
}
UINT64 CGolombBuffer::BitRead(int nBits, bool fPeek)
{
// ASSERT(nBits >= 0 && nBits <= 64);
while(m_bitlen < nBits)
{
m_bitbuff <<= 8;
if (m_nBitPos >= m_nSize) return 0;
*(BYTE*)&m_bitbuff = m_pBuffer[m_nBitPos++];
m_bitlen += 8;
}
int bitlen = m_bitlen - nBits;
UINT64 ret = (m_bitbuff >> bitlen) & ((1ui64 << nBits) - 1);
if(!fPeek)
{
m_bitbuff &= ((1ui64 << bitlen) - 1);
m_bitlen = bitlen;
}
return ret;
}
UINT64 CGolombBuffer::UExpGolombRead()
{
int n = -1;
for(BYTE b = 0; !b; n++) b = (BYTE)BitRead(1);
return (1ui64 << n) - 1 + BitRead(n);
}
INT64 CGolombBuffer::SExpGolombRead()
{
UINT64 k = UExpGolombRead();
return ((k&1) ? 1 : -1) * ((k + 1) >> 1);
}
void CGolombBuffer::BitByteAlign()
{
m_bitlen &= ~7;
}
__int64 CGolombBuffer::GetPos()
{
return m_nBitPos - (m_bitlen>>3);
}
void CGolombBuffer::ReadBuffer(BYTE* pDest, int nSize)
{
ASSERT (m_nBitPos + nSize <= m_nSize);
ASSERT (m_bitlen == 0);
nSize = min (nSize, m_nSize - m_nBitPos);
memcpy (pDest, m_pBuffer+m_nBitPos, nSize);
m_nBitPos += nSize;
}
void CGolombBuffer::Reset()
{
m_nBitPos = 0;
m_bitlen = 0;
m_bitbuff = 0;
}
void CGolombBuffer::Reset(BYTE* pNewBuffer, int nNewSize)
{
m_pBuffer = pNewBuffer;
m_nSize = nNewSize;
Reset();
}
void CGolombBuffer::SkipBytes(int nCount)
{
m_nBitPos += nCount;
m_bitlen = 0;
m_bitbuff = 0;
}
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