/ 
String-CRC32C-0.01
/ String::CRC32C

NAME

Strihng::CRC32C - Castagnoli CRC

SYNOPSIS

use String::CRC32C; # does not export anything by default
use String::CRC32C 'crc32c';

$crc = crc32 "some string";
$crc = crc32 "some string", $initvalue;

DESCRIPTION

This module calculates the Castagnoli CRC32 variant (polynomial 0x11EDC6F41).

It is used by iSCSI, SCTP, BTRFS, ext4, leveldb, AMD64 CPUs and others.

This module uses an optimized implementation for SSE 4.2 CPUs and the SlicingBy8 algorithm for anything else.

$crc32c = crc32c $string[, $initvalue]

Calculates the CRC32C value of the given $string and returns it as a 32 bit unsigned integer.

To get the common hex form, use one of:

sprintf "%08x", crc32c $string
unpack "H*", pack "L>", crc32c $string

A seed/initial crc value can be given as second argument. Note that both the initial value and the result value are inverted (pre-inversion and post-inversion), e.g. a common init value of -1 from other descriptions needs to be given as 0 (or ~-1).

This allows easy chaining, e.g.

(crc32c "abcdefghi") eq (crc32 "ghi", crc32 "def", crc32 "abc)

AUTHOR

Marc Lehmann <schmorp@schmorp.de>
http://home.schmorp.de/

CRC32C code by various sources, ported from https://github.com/htot/crc32c, see sources for details.