public void Non_equal_blocks_yield_different_result()
{
var sourceBytes = new byte[]
{
#region BYTES
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254, 255, 254, 254
#endregion
};
var genA = new RollingChecksum();
genA.ProcessBlock(sourceBytes, 0, sourceBytes.Length);
var destinationBytes = new byte[]
{
#region BYTES
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255
#endregion
};
var genB = new RollingChecksum();
genB.ProcessBlock(destinationBytes, 0, destinationBytes.Length);
Assert.AreNotEqual(genA.Value, genB.Value);
}
public void Checksums_are_equal_for_two_whole_block_updates()
{
var genA = new RollingChecksum();
genA.ProcessBlock(_validByteBlock, 0, 500);
var genB = new RollingChecksum();
genB.ProcessBlock(_validByteBlock, 0, 500);
Assert.AreEqual(genA.Value, genB.Value);
}
public void Trim_updates_value_correctly()
{
var genA = new RollingChecksum();
genA.ProcessBlock(_validByteBlock, 0, 501);
genA.TrimFront();
var genB = new RollingChecksum();
genB.ProcessBlock(_validByteBlock, 1, 500);
Assert.AreEqual(genA.Value, genB.Value);
}
public void Checksums_are_equal_for_full_block_and_rolling_updates()
{
int blockSize = 500;
var genA = new RollingChecksum();
int start = 10;
int rolls = 4;
genA.ProcessBlock(_validByteBlock, start, blockSize);
for (var i = 0; i < rolls; ++i)
{
genA.RollByte(_validByteBlock[start + blockSize + i]);
}
var genB = new RollingChecksum();
genB.ProcessBlock(_validByteBlock, (start + rolls), blockSize);
Assert.AreEqual(genA.Value, genB.Value);
}
private void BuildIndexTable(IEnumerable <HashBlock> entries)
{
if (entries == null)
{
return;
}
foreach (HashBlock entry in entries)
{
ushort hash = RollingChecksum.HashChecksum(entry.Checksum);
if (_remoteBlocksIndexTable.ContainsKey(hash))
{
if (_remoteBlocksIndexTable[hash].Any(existingEntry => entry.Hash.SequenceEqual(existingEntry.Hash)))
{
continue;
}
_remoteBlocksIndexTable[hash].Add(entry);
}
else
{
_remoteBlocksIndexTable[hash] = new List <HashBlock>(new[] { entry });
}
}
}
public IEnumerable <IDelta> GetDeltas(Stream inputStream)
{
if (inputStream == null)
{
throw new ArgumentNullException("inputStream");
}
if (_initialized == false)
{
throw new InvalidOperationException("Initialize must be called");
}
ChecksumProvider.Reset();
var slidingBuffer = new SlidingStreamBuffer(inputStream, _blockSize);
slidingBuffer.Warmup();
bool startingNewBlock = true;
long offset = 0;
var deltas = new List <IDelta>();
var currentByteDelta = new ByteDelta();
#if DEBUG
Statistics.Matching = 0;
Statistics.PossibleMatches = 0;
Statistics.NonMatching = 0;
#endif
int currentBlockSize;
while ((currentBlockSize = (int)slidingBuffer.GetNumBytesAvailable()) > 0)
{
// Deal with signed integer limits
if (IsSignedIntLength(offset - currentByteDelta.Offset))
{
currentByteDelta.Length = (int)(offset - currentByteDelta.Offset);
deltas.Add(currentByteDelta);
startingNewBlock = true;
}
if (startingNewBlock)
{
currentByteDelta = new ByteDelta {
Offset = offset
};
ChecksumProvider.ProcessBlock(slidingBuffer.GetBuffer(), 0, currentBlockSize);
}
else if (currentBlockSize < _blockSize)
{
ChecksumProvider.TrimFront(); // remaining bytes < block_size, so read nothing new - just trim
}
else
{
ChecksumProvider.RollByte(slidingBuffer[(int)(currentBlockSize - 1)]);
}
// at this point, sigGen needs the last byte of the current block
uint currentBlockChecksum = ChecksumProvider.Value;
ushort currentBlockChecksumHash = RollingChecksum.HashChecksum(currentBlockChecksum);
if (_remoteBlocksIndexTable.ContainsKey(currentBlockChecksumHash))
{
List <HashBlock> possibleRemoteBlockMatches = _remoteBlocksIndexTable[currentBlockChecksumHash];
if (possibleRemoteBlockMatches.Any(entry => entry.Checksum == currentBlockChecksum))
{
#if DEBUG
++Statistics.PossibleMatches;
#endif
byte[] currentBlockHash = HashProvider.ComputeHash(slidingBuffer.GetBuffer(), 0,
(int)currentBlockSize);
HashBlock matchingTargetBlock;
if ((matchingTargetBlock =
possibleRemoteBlockMatches.FirstOrDefault(
entry => entry.Hash.SequenceEqual(currentBlockHash))) != null)
{
#if DEBUG
Statistics.Matching += 1;
#endif
if ((currentByteDelta.Length = (int)(offset - currentByteDelta.Offset)) > 0)
{
deltas.Add(currentByteDelta);
}
deltas.Add(new CopyDelta
{
Offset = matchingTargetBlock.Offset,
Length = matchingTargetBlock.Length
});
slidingBuffer.MoveForward((int)currentBlockSize);
offset += currentBlockSize;
startingNewBlock = true;
continue;
}
}
}
#if DEBUG
++Statistics.NonMatching;
#endif
slidingBuffer.MoveForward(1);
++offset;
startingNewBlock = false;
}
Statistics.FileLength = offset;
if (!startingNewBlock && (currentByteDelta.Length = (int)(offset - currentByteDelta.Offset)) > 0)
{
deltas.Add(currentByteDelta);
}
#if DEBUG
Statistics.FileLength = offset;
#endif
return(deltas);
}