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/**
* @file llbitpack.h
* @brief Convert data to packed bit stream
*
* $LicenseInfo:firstyear=2000&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#ifndef LL_BITPACK_H
#define LL_BITPACK_H
#include "llerror.h"
const U32 MAX_DATA_BITS = 8;
class LLBitPack
{
public:
LLBitPack(U8 *buffer, U32 max_size) : mBuffer(buffer), mBufferSize(0), mLoad(0), mLoadSize(0), mTotalBits(0), mMaxSize(max_size)
{
}
~LLBitPack()
{
}
void resetBitPacking()
{
mLoad = 0;
mLoadSize = 0;
mTotalBits = 0;
mBufferSize = 0;
}
U32 bitPack(U8 *total_data, U32 total_dsize)
{
U32 dsize;
U8 data;
while (total_dsize > 0)
{
if (total_dsize > MAX_DATA_BITS)
{
dsize = MAX_DATA_BITS;
total_dsize -= MAX_DATA_BITS;
}
else
{
dsize = total_dsize;
total_dsize = 0;
}
data = *total_data++;
data <<= (MAX_DATA_BITS - dsize);
while (dsize > 0)
{
if (mLoadSize == MAX_DATA_BITS)
{
*(mBuffer + mBufferSize++) = mLoad;
if (mBufferSize > mMaxSize)
{
LL_ERRS() << "mBufferSize exceeding mMaxSize!" << LL_ENDL;
}
mLoadSize = 0;
mLoad = 0x00;
}
mLoad <<= 1;
mLoad |= (data >> (MAX_DATA_BITS - 1));
data <<= 1;
mLoadSize++;
mTotalBits++;
dsize--;
}
}
return mBufferSize;
}
U32 bitCopy(U8 *total_data, U32 total_dsize)
{
U32 dsize;
U8 data;
while (total_dsize > 0)
{
if (total_dsize > MAX_DATA_BITS)
{
dsize = MAX_DATA_BITS;
total_dsize -= MAX_DATA_BITS;
}
else
{
dsize = total_dsize;
total_dsize = 0;
}
data = *total_data++;
while (dsize > 0)
{
if (mLoadSize == MAX_DATA_BITS)
{
*(mBuffer + mBufferSize++) = mLoad;
if (mBufferSize > mMaxSize)
{
LL_ERRS() << "mBufferSize exceeding mMaxSize!" << LL_ENDL;
}
mLoadSize = 0;
mLoad = 0x00;
}
mLoad <<= 1;
mLoad |= (data >> (MAX_DATA_BITS - 1));
data <<= 1;
mLoadSize++;
mTotalBits++;
dsize--;
}
}
return mBufferSize;
}
U32 bitUnpack(U8 *total_retval, U32 total_dsize)
{
U32 dsize;
U8 *retval;
while (total_dsize > 0)
{
if (total_dsize > MAX_DATA_BITS)
{
dsize = MAX_DATA_BITS;
total_dsize -= MAX_DATA_BITS;
}
else
{
dsize = total_dsize;
total_dsize = 0;
}
retval = total_retval++;
*retval = 0x00;
while (dsize > 0)
{
if (mLoadSize == 0)
{
#ifdef _DEBUG
if (mBufferSize > mMaxSize)
{
LL_ERRS() << "mBufferSize exceeding mMaxSize" << LL_ENDL;
LL_ERRS() << mBufferSize << " > " << mMaxSize << LL_ENDL;
}
#endif
mLoad = *(mBuffer + mBufferSize++);
mLoadSize = MAX_DATA_BITS;
}
*retval <<= 1;
*retval |= (mLoad >> (MAX_DATA_BITS - 1));
mLoadSize--;
mLoad <<= 1;
dsize--;
}
}
return mBufferSize;
}
U32 flushBitPack()
{
if (mLoadSize)
{
mLoad <<= (MAX_DATA_BITS - mLoadSize);
*(mBuffer + mBufferSize++) = mLoad;
if (mBufferSize > mMaxSize)
{
LL_ERRS() << "mBufferSize exceeding mMaxSize!" << LL_ENDL;
}
mLoadSize = 0;
}
return mBufferSize;
}
U8 *mBuffer;
U32 mBufferSize;
U8 mLoad;
U32 mLoadSize;
U32 mTotalBits;
U32 mMaxSize;
};
#endif
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