Module java.base
Package java.util.zip

Class CRC32

  • All Implemented Interfaces:
    Checksum
    public class CRC32
extends Object
implements Checksum
    A class that can be used to compute the CRC-32 of a data stream.

    Passing a null argument to a method in this class will cause a NullPointerException to be thrown.

    Since:
    1.1

    • Constructor Summary

      Constructors 
      Constructor Description
      CRC32()
      Creates a new CRC32 object.

    • Method Summary

      Modifier and Type Method Description
      long getValue()
      Returns CRC-32 value.
      void reset()
      Resets CRC-32 to initial value.
      void update​(byte[] b, int off, int len)
      Updates the CRC-32 checksum with the specified array of bytes.
      void update​(int b)
      Updates the CRC-32 checksum with the specified byte (the low eight bits of the argument b).
      void update​(ByteBuffer buffer)
      Updates the CRC-32 checksum with the bytes from the specified buffer.

    • Constructor Detail

      • CRC32

        public CRC32()
        Creates a new CRC32 object.

    • Method Detail

      • update

        public void update​(int b)
        Updates the CRC-32 checksum with the specified byte (the low eight bits of the argument b).
        Specified by:
        update in interface Checksum
        Parameters:
        b - the byte to update the checksum with

      • update

        public void update​(byte[] b,
                   int off,
                   int len)
        Updates the CRC-32 checksum with the specified array of bytes.
        Specified by:
        update in interface Checksum
        Parameters:
        b - the byte array to update the checksum with
        off - the start offset of the data
        len - the number of bytes to use for the update
        Throws:
        ArrayIndexOutOfBoundsException - if off is negative, or len is negative, or off+len is negative or greater than the length of the array b.

      • update

        public void update​(ByteBuffer buffer)
        Updates the CRC-32 checksum with the bytes from the specified buffer. The checksum is updated with the remaining bytes in the buffer, starting at the buffer's position. Upon return, the buffer's position will be updated to its limit; its limit will not have been changed.
        Specified by:
        update in interface Checksum
        Parameters:
        buffer - the ByteBuffer to update the checksum with
        Since:
        1.8

      • reset

        public void reset()
        Resets CRC-32 to initial value.
        Specified by:
        reset in interface Checksum

      • getValue

        public long getValue()
        Returns CRC-32 value.
        Specified by:
        getValue in interface Checksum
        Returns:
        the current checksum value