Package org.xiph.speex
Class OggCrc
java.lang.Object
org.xiph.speex.OggCrc
Calculates the CRC checksum for Ogg packets.
Ogg uses the same generator polynomial as ethernet, although with an unreflected alg and an init/final of 0, not 0xffffffff.
- Version:
- $Revision: 1.2 $
- Author:
- Jim Lawrence, helloNetwork.com, Marc Gimpel, Wimba S.A. (mgimpel@horizonwimba.com)
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Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic int
checksum
(int crc, byte[] data, int offset, int length) Calculates the checksum on the given data, from the give offset and for the given length, using the given initial value.
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Field Details
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crc_lookup
private static int[] crc_lookupCRC checksum lookup table
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Constructor Details
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OggCrc
public OggCrc()
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Method Details
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checksum
public static int checksum(int crc, byte[] data, int offset, int length) Calculates the checksum on the given data, from the give offset and for the given length, using the given initial value. This allows on to calculate the checksum iteratively, by reinjecting the last returned value as the initial value when the function is called for the next data chunk. The initial value should be 0 for the first iteration.- Parameters:
crc
- - the initial valuedata
- - the dataoffset
- - the offset at which to start calculating the checksum.length
- - the length of data over which to calculate the checksum.- Returns:
- the checksum.
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