CRC32C (Java SE 23 & JDK 23)
Description: declaration: module: java.base, package: java.util.zip, class: CRC32C
Keywords: java.util.zip.CRC32C class

# Class CRC32C

java.lang.Object
java.util.zip.CRC32C

All Implemented Interfaces:
  `Checksum`

public final class CRC32C extends Object implements Checksum
A class that can be used to compute the CRC-32C of a data stream.

CRC-32C is defined in RFC 3720: Internet Small Computer Systems Interface (iSCSI).

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

Since:
  9
External Specifications
  - RFC 3720: Internet Small Computer Systems Interface (iSCSI)

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `CRC32C()`
  Creates a new CRC32C object.

- ## Method Summary

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

  ### Methods declared in class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

  ### Methods declared in interface java.util.zip.Checksum

  `update`

- ## Constructor Details

  - ### CRC32C

    public CRC32C()
    Creates a new CRC32C object.

- ## Method Details

  - ### update

    public void update(int b)
    Updates the CRC-32C 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-32C 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-32C 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

  - ### reset

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

  - ### getValue

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