public ByteBuffer compress(ByteBuffer input, int elementCount, int unitLength, int maxCompressedLength)
{
DeltaOfDeltaBlockEncoder blockEncoder = new DeltaOfDeltaBlockEncoder(unitLength);
int count = 0;
//TODO: create header in advanced
ByteBuffer output = ByteBuffer.Allocate(maxCompressedLength);
while (elementCount > 0 && count < maxCompressedLength)
{
int blockSize = Math.Min(elementCount * unitLength, DEFAULT_BLOCK_SIZE);
long[] compressed = blockEncoder.compress(input, blockSize);
//write blockSize+data
output.WriteInt(compressed.Length * sizeof(long) * 8);
foreach (long l in compressed)
{
output.WriteLong(l);
}
count += sizeof(int) * 8 + compressed.Length * sizeof(long) * 8;
elementCount -= blockSize / unitLength;
}
return(output);
}
public int compress(AbstractVector input, int elementCount, int unitLength, int maxCompressedLength, ByteBuffer output)
{
DeltaOfDeltaBlockEncoder blockEncoder = new DeltaOfDeltaBlockEncoder(unitLength);
int count = 0;
int dataCount = input.rows();
int dataIndex = 0;
ByteBuffer dataBufer = ByteBuffer.Allocate(DEFAULT_BLOCK_SIZE);
dataBufer.order(output.isLittleEndian);
int partial = 0, elementNum = 0;
while (dataCount > dataIndex)
{
int readBytes = input.serialize(dataIndex, partial, dataCount - dataIndex, out elementNum, out partial, dataBufer);
dataIndex += elementNum;
while (readBytes > 0)
{
int blockSize = Math.Min(readBytes, DEFAULT_BLOCK_SIZE);
long[] compressed = blockEncoder.compress(dataBufer, blockSize);
//write blockSize+data
output.WriteInt(compressed.Length * sizeof(long));
foreach (long l in compressed)
{
if (output.remain() < sizeof(long))
{
output.reserve(output.Capacity * 2);
}
output.WriteLong(l);
}
count += sizeof(int) + compressed.Length * sizeof(long);
readBytes -= blockSize;
dataBufer.Clear();
}
}
return(count);
}