package IO::Lines;
=head1 NAME
IO::Lines - IO:: interface for reading/writing an array of lines
=head1 SYNOPSIS
use IO::Lines;
### See IO::ScalarArray for details
=head1 DESCRIPTION
This class implements objects which behave just like FileHandle
(or IO::Handle) objects, except that you may use them to write to
(or read from) an array of lines. They can be tiehandle'd as well.
This is a subclass of L<IO::ScalarArray|IO::ScalarArray>
in which the underlying
array has its data stored in a line-oriented-format: that is,
every element ends in a C<"\n">, with the possible exception of the
final element. This makes C<getline()> I<much> more efficient;
if you plan to do line-oriented reading/printing, you want this class.
The C<print()> method will enforce this rule, so you can print
arbitrary data to the line-array: it will break the data at
newlines appropriately.
See L<IO::ScalarArray> for full usage and warnings.
=cut
use Carp;
use strict;
use IO::ScalarArray;
use vars qw($VERSION @ISA);
# The package version, both in 1.23 style *and* usable by MakeMaker:
$VERSION = "2.111";
# Inheritance:
@ISA = qw(IO::ScalarArray); ### also gets us new_tie :-)
#------------------------------
#
# getline
#
# Instance method, override.
# Return the next line, or undef on end of data.
# Can safely be called in an array context.
# Currently, lines are delimited by "\n".
#
sub getline {
my $self = shift;
if (!defined $/) {
return join( '', $self->_getlines_for_newlines );
}
elsif ($/ eq "\n") {
if (!*$self->{Pos}) { ### full line...
return *$self->{AR}[*$self->{Str}++];
}
else { ### partial line...
my $partial = substr(*$self->{AR}[*$self->{Str}++], *$self->{Pos});
*$self->{Pos} = 0;
return $partial;
}
}
else {
croak 'unsupported $/: must be "\n" or undef';
}
}
#------------------------------
#
# getlines
#
# Instance method, override.
# Return an array comprised of the remaining lines, or () on end of data.
# Must be called in an array context.
# Currently, lines are delimited by "\n".
#
sub getlines {
my $self = shift;
wantarray or croak("can't call getlines in scalar context!");
if ((defined $/) and ($/ eq "\n")) {
return $self->_getlines_for_newlines(@_);
}
else { ### slow but steady
return $self->SUPER::getlines(@_);
}
}
#------------------------------
#
# _getlines_for_newlines
#
# Instance method, private.
# If $/ is newline, do fast getlines.
# This CAN NOT invoke getline!
#
sub _getlines_for_newlines {
my $self = shift;
my ($rArray, $Str, $Pos) = @{*$self}{ qw( AR Str Pos ) };
my @partial = ();
if ($Pos) { ### partial line...
@partial = (substr( $rArray->[ $Str++ ], $Pos ));
*$self->{Pos} = 0;
}
*$self->{Str} = scalar @$rArray; ### about to exhaust @$rArray
return (@partial,
@$rArray[ $Str .. $#$rArray ]); ### remaining full lines...
}
#------------------------------
#
# print ARGS...
#
# Instance method, override.
# Print ARGS to the underlying line array.
#
sub print {
if (defined $\ && $\ ne "\n") {
croak 'unsupported $\: must be "\n" or undef';
}
my $self = shift;
### print STDERR "\n[[ARRAY WAS...\n", @{*$self->{AR}}, "<<EOF>>\n";
my @lines = split /^/, join('', @_); @lines or return 1;
### Did the previous print not end with a newline?
### If so, append first line:
if (@{*$self->{AR}} and (*$self->{AR}[-1] !~ /\n\Z/)) {
*$self->{AR}[-1] .= shift @lines;
}
push @{*$self->{AR}}, @lines; ### add the remainder
### print STDERR "\n[[ARRAY IS NOW...\n", @{*$self->{AR}}, "<<EOF>>\n";
1;
}
#------------------------------
1;
__END__
=head1 VERSION
$Id: Lines.pm,v 1.3 2005/02/10 21:21:53 dfs Exp $
=head1 AUTHORS
=head2 Primary Maintainer
Dianne Skoll (F<dfs@roaringpenguin.com>).
=head2 Principal author
Eryq (F<eryq@zeegee.com>).
President, ZeeGee Software Inc (F<http://www.zeegee.com>).
=head2 Other contributors
Thanks to the following individuals for their invaluable contributions
(if I've forgotten or misspelled your name, please email me!):
I<Morris M. Siegel,>
for his $/ patch and the new C<getlines()>.
I<Doug Wilson,>
for the IO::Handle inheritance and automatic tie-ing.
=cut
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