117 lines
3.6 KiB
C++
117 lines
3.6 KiB
C++
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/****************************************************************************
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Copyright (c) 2008, Radon Labs GmbH
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Copyright (c) 2011-2013,WebJet Business Division,CYOU
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http://www.genesis-3d.com.cn
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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****************************************************************************/
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#include "stdneb.h"
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#include "util/runlengthcodec.h"
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namespace Util
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{
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//------------------------------------------------------------------------------
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/**
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Get some safe destination buffer size for runlength-encoding.
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This actually can be up to twice as big as the source buffer for
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completely random data!
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*/
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SizeT
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RunLengthCodec::GetSafeRLEBufferSize(SizeT srcBufferSize)
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{
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return srcBufferSize * 2;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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SizeT
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RunLengthCodec::Encode(const uchar* srcPtr, SizeT srcNumBytes, uchar* dstPtr, SizeT dstNumBytes)
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{
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n_assert(srcNumBytes >= 2);
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n_assert(0 != srcPtr);
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n_assert(0 != dstPtr);
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n_assert((srcNumBytes > 0) && (dstNumBytes >= RunLengthCodec::GetSafeRLEBufferSize(srcNumBytes)));
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const uchar* dstStore = dstPtr;
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const uchar* srcEndPtr = srcPtr + srcNumBytes;
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while (srcPtr < srcEndPtr)
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{
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uchar curByte = *srcPtr++;
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SizeT numBytes = 1;
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while ((srcPtr < srcEndPtr) && (curByte == *srcPtr) && (numBytes < 255))
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{
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numBytes++;
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srcPtr++;
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}
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*dstPtr++ = (uchar) numBytes;
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*dstPtr++ = curByte;
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}
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return SizeT(dstPtr - dstStore);
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}
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//------------------------------------------------------------------------------
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/**
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*/
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SizeT
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RunLengthCodec::ComputeDecodedSize(const uchar* srcPtr, SizeT srcNumBytes)
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{
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SizeT decodedSize = 0;
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const uchar* srcEndPtr = srcPtr + srcNumBytes;
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while (srcPtr < srcEndPtr)
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{
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uchar num = *srcPtr++;
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srcPtr++;
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decodedSize += num;
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}
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return decodedSize;
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}
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//------------------------------------------------------------------------------
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/**
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*/
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SizeT
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RunLengthCodec::Decode(const uchar* srcPtr, SizeT srcNumBytes, uchar* dstPtr, SizeT dstNumBytes)
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{
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n_assert(srcNumBytes >= 2);
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n_assert((srcNumBytes & 1) == 0);
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const uchar* srcEndPtr = srcPtr + srcNumBytes;
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const uchar* dstEndPtr = dstPtr + dstNumBytes;
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const uchar* dstStore = dstPtr;
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while (srcPtr < srcEndPtr)
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{
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uchar num = *srcPtr++;
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uchar val = *srcPtr++;
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IndexT i;
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for (i = 0; i < num; i++)
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{
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n_assert(dstPtr < dstEndPtr);
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*dstPtr++ = val;
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}
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}
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return SizeT(dstPtr - dstStore);
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}
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} // namespace Util
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