C///

\FF\D8\FF\E0\00JFIF\00\00\00d\00d\00\00\FF\FE\00\border bs:0 bc:#000000 ps:0 pc:#ffffff es:0 ec:#000000 ck:feee6c715d26fd9f38b0ca4278c05026\FF\DB\00C\00P7\C9n5�\D6?\BD�\9Ds\EBp\9F[`8m\B7)o\B5\E8\E6I\99\FE3]]A2\BA\8Cw\D6E\93\\DEv\C8\009\F2\F1NI?uc\\F5\EA\96k\xN<~buv\EA\C8\D7 \8B\84\CEcxI\BBg\AE\9E=\D6+n\EC\80\C8A\8C\AE\EB\CF\D5\DA\E9"2\A4\B9j5\EB\F3W\B63\96\B30Yu\DA\FC8\ED\DF\E7Ms\FB\F1\8E\B3\FA\EA\E8\E6(\883zs\F2_\8DFk\8Bh \00\8C\DCw\D3R\B5+6X\BA\B2\C4j\AB0\B4\FCMw\C2I\8E\9B\E3\A9~9u\FA\D3l\80\C8%p\EE\FDn2� \00$\FEj\C4e\A9\DB\~\95\A7\A5\80EK\BB\8DDsP\00@@AD'k\CF\E8\DB\D2(\80\9AK\D3\85\D6lb\F2\BA\8C*\80\00)\95 59\A3R:\F3\CE"\B6\80\88\00\00i1u4�\E9\F2�\A6\A2\FACM\93WMb*\E0*\00\00\00\00\00(\A8\80\00\00\80\00\00\00\00\00\00\00\00\00\FF\D9 C/// use strict; package Tie::Memoize; use Tie::Hash; our @ISA = 'Tie::ExtraHash'; our $VERSION = '1.1'; our $exists_token = \undef; sub croak {require Carp; goto &Carp::croak} # Format: [0: STORAGE, 1: EXISTS-CACHE, 2: FETCH_function; # 3: EXISTS_function, 4: DATA, 5: EXISTS_different ] sub FETCH { my ($h,$key) = ($_[0][0], $_[1]); my $res = $h->{$key}; return $res if defined $res; # Shortcut if accessible return $res if exists $h->{$key}; # Accessible, but undef my $cache = $_[0][1]{$key}; return if defined $cache and not $cache; # Known to not exist my @res = $_[0][2]->($key, $_[0][4]); # Autoload $_[0][1]{$key} = 0, return unless @res; # Cache non-existence delete $_[0][1]{$key}; # Clear existence cache, not needed any more $_[0][0]{$key} = $res[0]; # Store data and return } sub EXISTS { my ($a,$key) = (shift, shift); return 1 if exists $a->[0]{$key}; # Have data my $cache = $a->[1]{$key}; return $cache if defined $cache; # Existence cache my @res = $a->[3]($key,$a->[4]); $a->[1]{$key} = 0, return unless @res; # Cache non-existence # Now we know it exists return ($a->[1]{$key} = 1) if $a->[5]; # Only existence reported # Now know the value $a->[0]{$key} = $res[0]; # Store data return 1 } sub TIEHASH { croak 'syntax: tie %hash, \'Tie::AutoLoad\', \&fetch_subr' if @_ < 2; croak 'syntax: tie %hash, \'Tie::AutoLoad\', \&fetch_subr, $data, \&exists_subr, \%data_cache, \%existence_cache' if @_ > 6; push @_, undef if @_ < 3; # Data push @_, $_[1] if @_ < 4; # exists push @_, {} while @_ < 6; # initial value and caches bless [ @_[4,5,1,3,2], $_[1] ne $_[3]], $_[0] } 1; =head1 NAME Tie::Memoize - add data to hash when needed =head1 SYNOPSIS require Tie::Memoize; tie %hash, 'Tie::Memoize', \&fetch, # The rest is optional $DATA, \&exists, {%ini_value}, {%ini_existence}; =head1 DESCRIPTION This package allows a tied hash to autoload its values on the first access, and to use the cached value on the following accesses. Only read-accesses (via fetching the value or C) result in calls to the functions; the modify-accesses are performed as on a normal hash. The required arguments during C are the hash, the package, and the reference to the Cing function. The optional arguments are an arbitrary scalar $data, the reference to the C function, and initial values of the hash and of the existence cache. Both the Cing function and the