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/**************************************************************************/
/* */
/* Copyright (c) 2001, 2007 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 NoMachine S.r.l. */
/* */
/* All rights reserved. */
/* */
/**************************************************************************/
#include <string.h>
#include "Misc.h"
#include "IntCache.h"
#define PANIC
#define WARNING
#undef TEST
#undef DEBUG
#undef DUMP
IntCache::IntCache(unsigned int size)
: size_(size), length_(0), buffer_(new unsigned int[size]),
lastDiff_(0), lastValueInserted_(0), predictedBlockSize_(0)
{
}
int IntCache::lookup(unsigned int &value, unsigned int &index,
unsigned int mask, unsigned int &sameDiff)
{
for (unsigned int i = 0; i < length_; i++)
{
if (value == buffer_[i])
{
index = i;
if (i)
{
unsigned int target = (i >> 1);
do
{
buffer_[i] = buffer_[i - 1];
i--;
}
while (i > target);
buffer_[target] = value;
}
return 1;
}
}
unsigned int insertionPoint;
if (2 >= length_)
insertionPoint = length_;
else
insertionPoint = 2;
unsigned int start;
if (length_ >= size_)
start = size_ - 1;
else
{
start = length_;
length_++;
}
for (unsigned int k = start; k > insertionPoint; k--)
buffer_[k] = buffer_[k - 1];
buffer_[insertionPoint] = value;
unsigned int diff = value - lastValueInserted_;
lastValueInserted_ = (value & mask);
value = (diff & mask);
sameDiff = (value == lastDiff_);
if (!sameDiff)
{
lastDiff_ = value;
unsigned int lastChangeIndex = 0;
unsigned int lastBitIsOne = (lastDiff_ & 0x1);
unsigned int j = 1;
for (unsigned int nextMask = 0x2; nextMask & mask; nextMask <<= 1)
{
unsigned int nextBitIsOne = (lastDiff_ & nextMask);
if (nextBitIsOne)
{
if (!lastBitIsOne)
{
lastChangeIndex = j;
lastBitIsOne = nextBitIsOne;
}
}
else
{
if (lastBitIsOne)
{
lastChangeIndex = j;
lastBitIsOne = nextBitIsOne;
}
}
j++;
}
predictedBlockSize_ = lastChangeIndex + 1;
if (predictedBlockSize_ < 2)
predictedBlockSize_ = 2;
}
return 0;
}
void IntCache::insert(unsigned int &value, unsigned int mask)
{
unsigned int insertionPoint;
if (2 >= length_)
insertionPoint = length_;
else
insertionPoint = 2;
unsigned int start;
if (length_ >= size_)
start = size_ - 1;
else
{
start = length_;
length_++;
}
for (unsigned int k = start; k > insertionPoint; k--)
buffer_[k] = buffer_[k - 1];
if (lastDiff_ != value)
{
lastDiff_ = value;
unsigned int lastChangeIndex = 0;
unsigned int lastBitIsOne = (lastDiff_ & 0x1);
unsigned int j = 1;
for (unsigned int nextMask = 0x2; nextMask & mask; nextMask <<= 1)
{
unsigned int nextBitIsOne = (lastDiff_ & nextMask);
if (nextBitIsOne)
{
if (!lastBitIsOne)
{
lastChangeIndex = j;
lastBitIsOne = nextBitIsOne;
}
}
else
{
if (lastBitIsOne)
{
lastChangeIndex = j;
lastBitIsOne = nextBitIsOne;
}
}
j++;
}
predictedBlockSize_ = lastChangeIndex + 1;
if (predictedBlockSize_ < 2)
predictedBlockSize_ = 2;
}
lastValueInserted_ += value;
lastValueInserted_ &= mask;
buffer_[insertionPoint] = lastValueInserted_;
value = lastValueInserted_;
}
void IntCache::push(unsigned int &value, unsigned int mask)
{
//
// Using a memmove() appears to be slower.
//
// memmove((char *) &buffer_[1], (char *) &buffer_[0],
// sizeof(unsigned int) * (size_ - 1));
//
// if (length_ < size_)
// {
// length_++;
// }
//
unsigned int start;
if (length_ >= size_)
{
start = size_ - 1;
}
else
{
start = length_;
length_++;
}
for (unsigned int k = start; k > 0; k--)
{
buffer_[k] = buffer_[k - 1];
}
value &= mask;
buffer_[0] = value;
}
void IntCache::dump()
{
#ifdef DUMP
*logofs << "IntCache: Dumping content of cache at "
<< (void *) this << ":\n" << logofs_flush;
for (unsigned int i = 0; i < length_; i++)
{
*logofs << "IntCache: [" << i << "][" << buffer_[i] << "]\n";
}
#endif
}
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