/src/FreeImage/Source/OpenEXR/IlmImf/ImfRleCompressor.cpp
https://bitbucket.org/cabalistic/ogredeps/ · C++ · 331 lines · 188 code · 63 blank · 80 comment · 28 complexity · fbfe52074b696f954c806d52581a3227 MD5 · raw file
- ///////////////////////////////////////////////////////////////////////////
- //
- // 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 <ImfCheckedArithmetic.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, size_t maxScanLineSize):
- Compressor (hdr),
- _maxScanLineSize (maxScanLineSize),
- _tmpBuffer (0),
- _outBuffer (0)
- {
- _tmpBuffer = new char [maxScanLineSize];
- _outBuffer = new char [uiMult (maxScanLineSize, size_t (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