332 lines
7.0 KiB
C++
332 lines
7.0 KiB
C++
///////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
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// Digital Ltd. LLC
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Industrial Light & Magic nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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///////////////////////////////////////////////////////////////////////////
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//-----------------------------------------------------------------------------
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//
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// class RleCompressor
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//
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//-----------------------------------------------------------------------------
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#include <ImfRleCompressor.h>
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#include <ImfCheckedArithmetic.h>
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#include "Iex.h"
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namespace Imf {
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namespace {
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const int MIN_RUN_LENGTH = 3;
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const int MAX_RUN_LENGTH = 127;
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//
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// Compress an array of bytes, using run-length encoding,
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// and return the length of the compressed data.
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//
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int
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rleCompress (int inLength, const char in[], signed char out[])
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{
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const char *inEnd = in + inLength;
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const char *runStart = in;
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const char *runEnd = in + 1;
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signed char *outWrite = out;
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while (runStart < inEnd)
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{
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while (runEnd < inEnd &&
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*runStart == *runEnd &&
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runEnd - runStart - 1 < MAX_RUN_LENGTH)
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{
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++runEnd;
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}
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if (runEnd - runStart >= MIN_RUN_LENGTH)
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{
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//
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// Compressable run
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//
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*outWrite++ = (runEnd - runStart) - 1;
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*outWrite++ = *(signed char *) runStart;
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runStart = runEnd;
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}
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else
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{
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//
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// Uncompressable run
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//
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while (runEnd < inEnd &&
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((runEnd + 1 >= inEnd ||
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*runEnd != *(runEnd + 1)) ||
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(runEnd + 2 >= inEnd ||
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*(runEnd + 1) != *(runEnd + 2))) &&
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runEnd - runStart < MAX_RUN_LENGTH)
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{
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++runEnd;
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}
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*outWrite++ = runStart - runEnd;
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while (runStart < runEnd)
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{
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*outWrite++ = *(signed char *) (runStart++);
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}
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}
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++runEnd;
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}
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return outWrite - out;
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}
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//
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// Uncompress an array of bytes compressed with rleCompress().
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// Returns the length of the oncompressed data, or 0 if the
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// length of the uncompressed data would be more than maxLength.
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//
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int
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rleUncompress (int inLength, int maxLength, const signed char in[], char out[])
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{
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char *outStart = out;
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while (inLength > 0)
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{
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if (*in < 0)
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{
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int count = -((int)*in++);
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inLength -= count + 1;
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if (0 > (maxLength -= count))
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return 0;
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while (count-- > 0)
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*out++ = *(char *) (in++);
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}
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else
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{
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int count = *in++;
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inLength -= 2;
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if (0 > (maxLength -= count + 1))
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return 0;
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while (count-- >= 0)
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*out++ = *(char *) in;
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in++;
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}
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}
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return out - outStart;
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}
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} // namespace
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RleCompressor::RleCompressor (const Header &hdr, size_t maxScanLineSize):
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Compressor (hdr),
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_maxScanLineSize (maxScanLineSize),
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_tmpBuffer (0),
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_outBuffer (0)
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{
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_tmpBuffer = new char [maxScanLineSize];
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_outBuffer = new char [uiMult (maxScanLineSize, size_t (3)) / 2];
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}
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RleCompressor::~RleCompressor ()
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{
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delete [] _tmpBuffer;
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delete [] _outBuffer;
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}
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int
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RleCompressor::numScanLines () const
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{
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//
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// This compressor compresses individual scan lines.
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//
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return 1;
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}
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int
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RleCompressor::compress (const char *inPtr,
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int inSize,
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int /*minY*/,
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const char *&outPtr)
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{
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//
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// Special case <20>- empty input buffer
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//
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if (inSize == 0)
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{
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outPtr = _outBuffer;
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return 0;
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}
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//
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// Reorder the pixel data.
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//
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{
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char *t1 = _tmpBuffer;
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char *t2 = _tmpBuffer + (inSize + 1) / 2;
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const char *stop = inPtr + inSize;
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while (true)
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{
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if (inPtr < stop)
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*(t1++) = *(inPtr++);
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else
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break;
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if (inPtr < stop)
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*(t2++) = *(inPtr++);
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else
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break;
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}
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}
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//
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// Predictor.
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//
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{
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unsigned char *t = (unsigned char *) _tmpBuffer + 1;
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unsigned char *stop = (unsigned char *) _tmpBuffer + inSize;
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int p = t[-1];
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while (t < stop)
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{
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int d = int (t[0]) - p + (128 + 256);
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p = t[0];
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t[0] = d;
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++t;
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}
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}
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//
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// Run-length encode the data.
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//
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outPtr = _outBuffer;
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return rleCompress (inSize, _tmpBuffer, (signed char *) _outBuffer);
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}
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int
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RleCompressor::uncompress (const char *inPtr,
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int inSize,
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int /*minY*/,
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const char *&outPtr)
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{
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//
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// Special case <20>- empty input buffer
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//
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if (inSize == 0)
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{
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outPtr = _outBuffer;
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return 0;
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}
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//
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// Decode the run-length encoded data
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//
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int outSize;
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if (0 == (outSize = rleUncompress (inSize, _maxScanLineSize,
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(const signed char *) inPtr,
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_tmpBuffer)))
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{
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throw Iex::InputExc ("Data decoding (rle) failed.");
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}
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//
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// Predictor.
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//
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{
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unsigned char *t = (unsigned char *) _tmpBuffer + 1;
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unsigned char *stop = (unsigned char *) _tmpBuffer + outSize;
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while (t < stop)
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{
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int d = int (t[-1]) + int (t[0]) - 128;
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t[0] = d;
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++t;
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}
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}
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//
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// Reorder the pixel data.
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//
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{
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const char *t1 = _tmpBuffer;
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const char *t2 = _tmpBuffer + (outSize + 1) / 2;
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char *s = _outBuffer;
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char *stop = s + outSize;
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while (true)
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{
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if (s < stop)
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*(s++) = *(t1++);
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else
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break;
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if (s < stop)
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*(s++) = *(t2++);
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else
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break;
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}
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}
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outPtr = _outBuffer;
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return outSize;
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}
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} // namespace Imf
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