org.apache.hadoop.util
Class PureJavaCrc32

java.lang.Object
  org.apache.hadoop.util.PureJavaCrc32

All Implemented Interfaces:

Checksum

public class PureJavaCrc32
extends Object
implements Checksum

A pure-java implementation of the CRC32 checksum that uses the same polynomial as the built-in native CRC32. This is to avoid the JNI overhead for certain uses of Checksumming where many small pieces of data are checksummed in succession. The current version is ~10x to 1.8x as fast as Sun's native java.util.zip.CRC32 in Java 1.6

See Also:

CRC32

Constructor Summary

PureJavaCrc32()

Method Summary

long	getValue()
void	reset()
void	update(byte[] b, int off, int len)
void	update(int b)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PureJavaCrc32

public PureJavaCrc32()

Method Detail

getValue

public long getValue()

Specified by:

getValue in interface Checksum

reset

public void reset()

Specified by:

reset in interface Checksum

update

public void update(byte[] b,
                   int off,
                   int len)

Specified by:

update in interface Checksum

update

public final void update(int b)

Specified by:

update in interface Checksum