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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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49
brouter-util/src/main/java/btools/util/DiffCoderDataInputStream.java Normal file
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/**
* DataInputStream extended by varlength diff coding
*
* @author ab
*/
package btools.util;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
public final class DiffCoderDataInputStream extends DataInputStream
{
private long[] lastValues = new long[10];
public DiffCoderDataInputStream( InputStream is )
{
super( is );
}
public long readDiffed( int idx ) throws IOException
{
long d = readSigned();
long v = lastValues[idx] + d;
lastValues[idx] = v;
return v;
}
public long readSigned() throws IOException
{
long v = readUnsigned();
return ( v & 1 ) == 0 ? v >> 1 : -(v >> 1 );
}
public long readUnsigned() throws IOException
{
long v = 0;
int shift = 0;
for(;;)
{
long i7 = readByte() & 0xff;
v |= (( i7 & 0x7f ) << shift);
if ( ( i7 & 0x80 ) == 0 ) break;
shift += 7;
}
return v;
}
}