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This commit is contained in:
Arndt 2014-06-19 09:15:51 +02:00
parent 55717c6e71
commit 8fa82633d4
34 changed files with 742 additions and 462 deletions
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45
brouter-util/src/main/java/btools/util/DiffCoderDataOutputStream.java Normal file
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/**
* DataOutputStream extended by varlength diff coding
*
* @author ab
*/
package btools.util;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
public final class DiffCoderDataOutputStream extends DataOutputStream
{
private long[] lastValues = new long[10];
public DiffCoderDataOutputStream( OutputStream os )
{
super( os );
}
public void writeDiffed( long v, int idx ) throws IOException
{
long d = v - lastValues[idx];
lastValues[idx] = v;
writeSigned( d );
}
public void writeSigned( long v ) throws IOException
{
writeUnsigned( v < 0 ? ( (-v) << 1 ) | 1 : v << 1 );
}
public void writeUnsigned( long v ) throws IOException
{
do
{
long i7 = v & 0x7f;
v >>= 7;
if ( v != 0 ) i7 |= 0x80;
writeByte( (byte)( i7 & 0xff ) );
}
while( v != 0 );
}
}