org.apache.hadoop.util
Class PureJavaCrc32

java.lang.Object
  extended by 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


Copyright © 2009 The Apache Software Foundation