/////////////////////////////////////////////////////////////////////////// // // 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