/**************************************************************************/ /* */ /* Copyright (c) 2001, 2010 NoMachine, http://www.nomachine.com/. */ /* */ /* NXCOMP, NX protocol compression and NX extensions to this software */ /* are copyright of NoMachine. Redistribution and use of the present */ /* software is allowed according to terms specified in the file LICENSE */ /* which comes in the source distribution. */ /* */ /* Check http://www.nomachine.com/licensing.html for applicability. */ /* */ /* NX and NoMachine are trademarks of Medialogic S.p.A. */ /* */ /* All rights reserved. */ /* */ /**************************************************************************/ #include <string.h> #include "BlockCache.h" int BlockCache::compare(unsigned int size, const unsigned char *data, int overwrite) { int match = 0; if (size == size_) { match = 1; for (unsigned int i = 0; i < size_; i++) if (data[i] != buffer_[i]) { match = 0; break; } } if (!match && overwrite) set(size, data); return match; } void BlockCache::set(unsigned int size, const unsigned char *data) { if (size_ < size) { delete[]buffer_; buffer_ = new unsigned char[size]; } size_ = size; memcpy(buffer_, data, size); checksum_ = checksum(size, data); } unsigned int BlockCache::checksum(unsigned int size, const unsigned char *data) { unsigned int sum = 0; unsigned int shift = 0; const unsigned char *next = data; for (unsigned int i = 0; i < size; i++) { unsigned int value = (unsigned int) *next++; sum += (value << shift); shift++; if (shift == 8) shift = 0; } return sum; }