ch19.038_best

来自「Perl Best Practices the source code」· 038_BEST 代码 · 共 38 行

##############################################################################
##   Code fragment (Recommended) from Chapter 19 of "Perl Best Practices"   ##
##     Copyright (c) O'Reilly & Associates, 2005. All Rights Reserved.      ##
##  See: http://www.oreilly.com/pub/a/oreilly/ask_tim/2001/codepolicy.html  ##
##############################################################################


# Standard modules...
use strict;
use warnings;
use IO::Prompt;
use Carp;
use English qw( -no_match_vars );
use Data::Alias;
use Readonly;

use Benchmark qw( cmpthese );
use Memoize;

our @real_data = 'foo bar' x 1_000_000;

sub lc_digest {
    my ($text) = @_;
 
    use Digest::SHA qw( sha512 );
    return sha512(lc $text);
}

# Install a memoized version of lc_digest() as fast_lc_digest()...
memoize( 'lc_digest', INSTALL=>'fast_lc_digest' );
 
# See if it is actually any faster on real data sets...
cmpthese -30, {
    nomemo => q{ for my $text (@real_data) { my $res = lc_digest($text); }      },
    memo   => q{ for my $text (@real_data) { my $res = fast_lc_digest($text); } },
};