File Coverage

blib/lib/String/CRC/Cksum.pm

Criterion	Covered	Total	%
statement	69	70	98.5
branch	8	10	80.0
condition	1	3	33.3
subroutine	14	14	100.0
pod	7	7	100.0
total	99	104	95.1

package String::CRC::Cksum;

use 5.006_001;
use strict;
use warnings;
use Carp;
use integer;

require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw(cksum);
our @EXPORT = qw();
our $VERSION = '0.91';

use fields qw(cksum size);

my @crctab = (
    0x00000000,
    0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
    0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac,
    0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
    0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58,
    0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe,
    0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95, 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4,
    0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5,
    0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07,
    0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
    0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba, 0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b,
    0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d,
    0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f,
    0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
    0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a,
    0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c,
    0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e,
    0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8,
    0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3, 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2,
    0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74,
    0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21,
    0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087,
    0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec, 0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d,
    0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb,
    0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09,
    0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf,
    0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
);


sub new {
    my $class = shift;
    my String::CRC::Cksum $self = fields::new(ref $class || $class);
    return $self->reset;
}   # new


sub reset {
    my String::CRC::Cksum $self = shift;
    $self->{cksum} = $self->{size} = 0;
    return $self;
}   # reset


sub add {
    my String::CRC::Cksum $self = shift;
    my $cksum = $self->{cksum};
    my $size = $self->{size};

    while(@_) {
        my $n = length $_[0];

        for(my $i = 0; $i < $n; ++$i) {
            my $c = unpack 'C', substr $_[0], $i, 1;
            $cksum = (0xFFFFFFFF & ($cksum << 8)) ^ $crctab[(0xFF & ($cksum >> 24)) ^ $c];
            ++$size;
        }

    }
    continue { shift }

    $self->{cksum} = $cksum;
    $self->{size} = $size;

    return $self;
}   # add


sub addfile {
    my String::CRC::Cksum $self = shift;
    my $stat;

    local $_;
    while(my $ifd = shift) {
        $self->add($_) while $stat = read $ifd, $_, 4096;

        if(! defined $stat) {
            croak "error reading from filehandle: $!";
        }
    }

    return $self;
}   # addfile


sub peek {
    my String::CRC::Cksum $self = shift;
    my $cksum = $self->{cksum};
    my $size = $self->{size};

    # Extend with the length of the data
    while($size != 0) {
        my $c = $size & 0xFF;
        $size >>= 8;
        $cksum = (0xFFFFFFFF & ($cksum << 8)) ^ $crctab[(0xFF & ($cksum >> 24)) ^ $c];
    }
    $cksum = ~ $cksum;

    # positivise the result even on a 32 bit processor
    no integer;
    my $crc = $cksum;
    $crc += 4294967296 if $crc < 0;

    return wantarray ? ($crc, $self->{size}) : $crc;

}   # addfile


sub result {
    my String::CRC::Cksum $self = shift;
    my ($cksum, $size) = $self->peek;
    $self->reset;
    return wantarray ? ($cksum, $size) : $cksum;
}   # result


sub cksum(@) {
    my $sum = String::CRC::Cksum->new;

    while(@_) {
        if(ref $_[0])
            { $sum->addfile($_[0]) }
        else
            { $sum->add($_[0]) }
    }
    continue { shift }

    return $sum->result;
}   # cksum

1;

__END__