Initial Commit

database/perl/vendor/lib/Parse/Binary/FixedFormat/Variants.pm

@@ -0,0 +1,149 @@
+package Parse::Binary::FixedFormat::Variants;
+
+use strict;
+our $VERSION = "0.03";
+
+sub new {
+    my ($class,$recfmt) = @_;
+    my $self;
+    $self = { Layouts=>[], Chooser=>$recfmt->{Chooser}, Formats => $recfmt->{Formats} };
+    bless $self, $class;
+    foreach my $fmt (@{$recfmt->{Formats}}) {
+	push @{$self->{Layouts}},new Parse::Binary::FixedFormat $fmt;
+    }
+    return $self;
+}
+
+sub unformat {
+    my ($self,$frec) = @_;
+    my $rec = $self->{Layouts}[0]->unformat($frec);
+    if ($self->{Chooser}) {
+	my $w = &{$self->{Chooser}}($rec, $self, 'unformat');
+	$rec = $self->{Layouts}[$w]->unformat($frec) if $w;
+    }
+    return $rec;
+}
+
+sub format {
+    my ($self,$rec) = @_;
+    my $w = 0;
+    if ($self->{Chooser}) {
+	$w = &{$self->{Chooser}}($rec, $self, 'format');
+    }
+    my $frec = $self->{Layouts}[$w]->format($rec);
+    return $frec;
+}
+
+sub blank {
+    my ($self,$w) = @_;
+    $w = 0 unless $w;
+    my $rec = $self->{Layouts}[$w]->blank();
+    return $rec;
+}
+
+1;
+
+=head1 NAME
+
+Parse::Binary::FixedFormat::Variants - Convert between variant records and hashes
+
+=head1 DESCRIPTION
+
+B<Parse::Binary::FixedFormat> supports variant record formats.  To describe a
+variant structure, pass a hash reference containing the following
+elements to B<new>.  The object returned to handle variant records
+will be a B<Parse::Binary::FixedFormat::Variants>.
+
+=over 4
+
+=item Chooser
+
+When converting a buffer to a hash, this subroutine is invoked after
+applying the first format to the buffer.  The generated hash reference
+is passed to this routine.  Any field names specified in the first
+format are available to be used in making a decision on which format
+to use to decipher the buffer.  This routine should return the index
+of the proper format specification.
+
+When converting a hash to a buffer, this subroutine is invoked first
+to choose a packing format.  Since the same function is used for both
+conversions, this function should restrict itself to field names that
+exist in format 0 and those fields should exist in the same place in
+all formats.
+
+=item Formats
+
+This is a reference to a list of formats.  Each format contains a list
+of field specifications.
+
+=back
+
+For example:
+
+    my $cvt = new Parse::Binary::FixedFormat {
+        Chooser => sub { my $rec=shift;
+		         $rec->{RecordType} eq '0' ? 1 : 2
+		       },
+	Formats => [ [ 'RecordType:A1' ],
+		     [ 'RecordType:A1', 'FieldA:A6', 'FieldB:A4:4' ],
+		     [ 'RecordType:A1', 'FieldC:A4', 'FieldD:A18' ] ]
+        };
+    my $rec0 = $cvt->unformat("0FieldAB[0]B[1]B[2]B[3]");
+    my $rec1 = $cvt->unformat("1FldC<-----FieldD----->");
+
+In the above example, the C<Chooser> function looks at the contents of
+the C<RecordType> field.  If it contains a '0', format 1 is used.
+Otherwise, format 2 is used.
+
+B<Parse::Binary::FixedFormat::Variants> can be used is if it were a
+B<Parse::Binary::FixedFormat>.  The C<format> and C<unformat> methods will
+determine which variant to use automatically.  The C<blank> method
+requires an argument that specifies the variant number.
+
+=head1 ATTRIBUTES
+
+Each Parse::Binary::FixedFormat::Variants instance contains the following
+attributes.
+
+=over 4
+
+=item Layouts
+
+Contains an array of Parse::Binary::FixedFormat objects.  Each of these objects
+is responsible for converting a single record format variant.
+
+=item Chooser
+
+This attribute contains the function that chooses which variant to
+apply to the record.
+
+=back
+
+=head1 AUTHORS
+
+Audrey Tang E<lt>cpan@audreyt.orgE<gt>
+
+Based on Data::FixedFormat::Variants, written by Thomas Pfau <pfau@nbpfaus.net>
+http://nbpfaus.net/~pfau/.
+
+=head1 COPYRIGHT
+
+Copyright 2004-2009 by Audrey Tang E<lt>cpan@audreyt.orgE<gt>.
+
+Copyright (C) 2000,2002 Thomas Pfau.  All rights reserved.
+
+This module is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2 of the License, or (at your
+option) any later version.
+
+This library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software Foundation,
+Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+=cut