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Diffstat (limited to 'Source/OpenEXR/IlmImf/ImfRleCompressor.cpp')
| -rw-r--r-- | Source/OpenEXR/IlmImf/ImfRleCompressor.cpp | 330 |
1 files changed, 330 insertions, 0 deletions
diff --git a/Source/OpenEXR/IlmImf/ImfRleCompressor.cpp b/Source/OpenEXR/IlmImf/ImfRleCompressor.cpp new file mode 100644 index 0000000..cd79609 --- /dev/null +++ b/Source/OpenEXR/IlmImf/ImfRleCompressor.cpp @@ -0,0 +1,330 @@ +/////////////////////////////////////////////////////////////////////////// +// +// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas +// Digital Ltd. LLC +// +// 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. +// * Neither the name of Industrial Light & Magic nor the names of +// its contributors may be used to endorse or promote products derived +// from this software without specific prior written permission. +// +// 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 +// OWNER 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. +// +/////////////////////////////////////////////////////////////////////////// + + + +//----------------------------------------------------------------------------- +// +// class RleCompressor +// +//----------------------------------------------------------------------------- + +#include <ImfRleCompressor.h> +#include "Iex.h" + +namespace Imf { +namespace { + +const int MIN_RUN_LENGTH = 3; +const int MAX_RUN_LENGTH = 127; + + +// +// Compress an array of bytes, using run-length encoding, +// and return the length of the compressed data. +// + +int +rleCompress (int inLength, const char in[], signed char out[]) +{ + const char *inEnd = in + inLength; + const char *runStart = in; + const char *runEnd = in + 1; + signed char *outWrite = out; + + while (runStart < inEnd) + { + while (runEnd < inEnd && + *runStart == *runEnd && + runEnd - runStart - 1 < MAX_RUN_LENGTH) + { + ++runEnd; + } + + if (runEnd - runStart >= MIN_RUN_LENGTH) + { + // + // Compressable run + // + + *outWrite++ = (runEnd - runStart) - 1; + *outWrite++ = *(signed char *) runStart; + runStart = runEnd; + } + else + { + // + // Uncompressable run + // + + while (runEnd < inEnd && + ((runEnd + 1 >= inEnd || + *runEnd != *(runEnd + 1)) || + (runEnd + 2 >= inEnd || + *(runEnd + 1) != *(runEnd + 2))) && + runEnd - runStart < MAX_RUN_LENGTH) + { + ++runEnd; + } + + *outWrite++ = runStart - runEnd; + + while (runStart < runEnd) + { + *outWrite++ = *(signed char *) (runStart++); + } + } + + ++runEnd; + } + + return outWrite - out; +} + + +// +// Uncompress an array of bytes compressed with rleCompress(). +// Returns the length of the oncompressed data, or 0 if the +// length of the uncompressed data would be more than maxLength. +// + +int +rleUncompress (int inLength, int maxLength, const signed char in[], char out[]) +{ + char *outStart = out; + + while (inLength > 0) + { + if (*in < 0) + { + int count = -((int)*in++); + inLength -= count + 1; + + if (0 > (maxLength -= count)) + return 0; + + while (count-- > 0) + *out++ = *(char *) (in++); + } + else + { + int count = *in++; + inLength -= 2; + + if (0 > (maxLength -= count + 1)) + return 0; + + while (count-- >= 0) + *out++ = *(char *) in; + + in++; + } + } + + return out - outStart; +} + +} // namespace + + +RleCompressor::RleCompressor (const Header &hdr, int maxScanLineSize): + Compressor (hdr), + _maxScanLineSize (maxScanLineSize), + _tmpBuffer (0), + _outBuffer (0) +{ + _tmpBuffer = new char [maxScanLineSize]; + _outBuffer = new char [maxScanLineSize * 3 / 2]; +} + + +RleCompressor::~RleCompressor () +{ + delete [] _tmpBuffer; + delete [] _outBuffer; +} + + +int +RleCompressor::numScanLines () const +{ + // + // This compressor compresses individual scan lines. + // + + return 1; +} + + +int +RleCompressor::compress (const char *inPtr, + int inSize, + int minY, + const char *&outPtr) +{ + // + // Special case - empty input buffer + // + + if (inSize == 0) + { + outPtr = _outBuffer; + return 0; + } + + // + // Reorder the pixel data. + // + + { + char *t1 = _tmpBuffer; + char *t2 = _tmpBuffer + (inSize + 1) / 2; + const char *stop = inPtr + inSize; + + while (true) + { + if (inPtr < stop) + *(t1++) = *(inPtr++); + else + break; + + if (inPtr < stop) + *(t2++) = *(inPtr++); + else + break; + } + } + + // + // Predictor. + // + + { + unsigned char *t = (unsigned char *) _tmpBuffer + 1; + unsigned char *stop = (unsigned char *) _tmpBuffer + inSize; + int p = t[-1]; + + while (t < stop) + { + int d = int (t[0]) - p + (128 + 256); + p = t[0]; + t[0] = d; + ++t; + } + } + + // + // Run-length encode the data. + // + + outPtr = _outBuffer; + return rleCompress (inSize, _tmpBuffer, (signed char *) _outBuffer); +} + + +int +RleCompressor::uncompress (const char *inPtr, + int inSize, + int minY, + const char *&outPtr) +{ + // + // Special case - empty input buffer + // + + if (inSize == 0) + { + outPtr = _outBuffer; + return 0; + } + + // + // Decode the run-length encoded data + // + + int outSize; + + if (0 == (outSize = rleUncompress (inSize, _maxScanLineSize, + (const signed char *) inPtr, + _tmpBuffer))) + { + throw Iex::InputExc ("Data decoding (rle) failed."); + } + + // + // Predictor. + // + + { + unsigned char *t = (unsigned char *) _tmpBuffer + 1; + unsigned char *stop = (unsigned char *) _tmpBuffer + outSize; + + while (t < stop) + { + int d = int (t[-1]) + int (t[0]) - 128; + t[0] = d; + ++t; + } + } + + // + // Reorder the pixel data. + // + + { + const char *t1 = _tmpBuffer; + const char *t2 = _tmpBuffer + (outSize + 1) / 2; + char *s = _outBuffer; + char *stop = s + outSize; + + while (true) + { + if (s < stop) + *(s++) = *(t1++); + else + break; + + if (s < stop) + *(s++) = *(t2++); + else + break; + } + } + + outPtr = _outBuffer; + return outSize; +} + + +} // namespace Imf |