org.apache.commons.codec.digest

Class PureJavaCrc32

java.lang.Object

org.apache.commons.codec.digest.PureJavaCrc32

All Implemented Interfaces:

java.util.zip.Checksum

public class PureJavaCrc32
extends java.lang.Object
implements java.util.zip.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

Copied from Apache Hadoop 2.6.3. The code agrees with the following file in the 2.6.3 tag: https://gitbox.apache.org/repos/asf?p=hadoop.git;a=blob_plain; f=hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/PureJavaCrc32.java; hb=2120de588b92b9f22b1cc4188761d6a8c61aa778

This class is Not ThreadSafe

Since:

1.11

See Also:

CRC32

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
long	getValue()
void	reset()
void	update(byte[] b, int offset, int len)
void	update(int b)

Methods inherited from class java.lang.Object

equals, 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 java.util.zip.Checksum

reset

public void reset()

Specified by:

reset in interface java.util.zip.Checksum

update

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

Specified by:

update in interface java.util.zip.Checksum

update

public final void update(int b)

Specified by:

update in interface java.util.zip.Checksum