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Tools.pm  view on Meta::CPAN

B<Input:> a filename (or a scalar ref to a string, see below)

B<Output:> a string of 32 hexadecimal chars from 0-9 or a-f.

Example, the md5sum gnu/linux command without options could be implementet like this:

 use Acme::Tools;
 print eval{ md5sum($_)."  $_\n" } || $@ for @ARGV;

This sub requires L<Digest::MD5>, which is a core perl-module since
version 5.?.?  It does not slurp the files or spawn new processes.

If the input argument is a scalar ref then the MD5 of the string referenced is returned in hex.

=cut

sub md5sum {
  require Digest::MD5;
  my $fn=shift;
  return Digest::MD5::md5_hex($$fn) if ref($fn) eq 'SCALAR';
  croak "md5sum: $fn is a directory (no md5sum)" if -d $fn;

Tools.pm  view on Meta::CPAN

    while ( ++$n and &$f(@_[@i]) ) {
	my $p = $#i || last;
	--$p || last while $i[$p-1] > $i[$p];
	push @i, reverse splice @i, my$q=$p;
	++$q while $i[$p-1] > $i[$q];
	@i[$p-1,$q] = @i[$q,$p-1];
    }
    $n;
}

#Fischer-Krause permutation starting from a specific sequence, for example to farm out permute to more than one process
sub permute_continue (&\@\@) {
    my ($f,$begin,$from) = @_;
    my %h; @h{@$begin} = 0 .. $#$begin;
    my @idx = @h{@$from};
    my $n = 0;
    while ( ++$n and &$f(@$begin[@idx]) ) {
	my $p = $#idx || last;
	--$p || last while $idx[$p-1] > $idx[$p];
	push @idx, reverse splice @idx, my$q=$p;
	++$q while $idx[$p-1] > $idx[$q];