This version builds on plain crc32, evading the suffering from immoderate buffering. 

#! /usr/bin/perl

use strict;
use warnings;

use String::CRC32;
#use Digest::CRC q(crc32);

use open IN => ':raw';
binmode(STDIN);

# reverse bits in byte(s)
my $revb = do {
    my @H = split //, q(084c2a6e195d3b7f);
    my $xlat = join "", map "\\x".$H[$_&15].$H[$_>>4], 0..255;
    eval qq(sub{ pop =~ tr/\\x00-\\xff/$xlat/r });
};

do {
    my ($crc, $len) = (0xffffffff, 0);

    local $/ = \32768;
    while (<>) {
        $len += length;
        $crc = crc32($_->$revb, $crc);
        last if eof;
    }
    my $zz = (pack "J<", $len) =~ s/\0*$//r;
    $crc = crc32($zz->$revb, $crc);

    $crc = unpack "V", (pack "N", $crc)->$revb;

    print "$crc $len $ARGV\n";

} while @ARGV;

[download]
Now if someone could golf that $revb, please?

In reply to Re: Find cksum (Linux) equivalent in Perl windows by oiskuu
in thread Find checksum (Linux) equivalent in Perl windows by mihirk

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