/////////////////////////////////////////////////////////////////////////// // // 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. // /////////////////////////////////////////////////////////////////////////// #include <string.h> #include "ImfRle.h" #include "ImfNamespace.h" OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER 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; memcpy(out, in, count); out += count; in += count; } else { int count = *in++; inLength -= 2; if (0 > (maxLength -= count + 1)) return 0; memset(out, *(char*)in, count+1); out += count+1; in++; } } return out - outStart; } OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT