org.apache.hadoop.util

Class PureJavaCrc32

java.lang.Object

org.apache.hadoop.util.PureJavaCrc32

All Implemented Interfaces:

Checksum

@InterfaceAudience.Public
@InterfaceStability.Stable
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

Constructors

Constructor and Description
PureJavaCrc32() Create a new PureJavaCrc32 object.

Method Summary

Methods

Modifier and Type	Method and Description
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()

Create a new PureJavaCrc32 object.

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