Acorn User 10/AU_CD10.iso/Updates/Perl/Non-RPC/!Perl/lib/zip/IO/File.pm

Text File | 1998-07-30 | 4KB | 168 lines

#

package IO::File;

=head1 NAME

IO::File - supply object methods for filehandles

=head1 SYNOPSIS

    use IO::File;

    $fh = new IO::File;
    if ($fh->open("< file")) {
        print <$fh>;
        $fh->close;
    }

    $fh = new IO::File "> file";
    if (defined $fh) {
        print $fh "bar\n";
        $fh->close;
    }

    $fh = new IO::File "file", "r";
    if (defined $fh) {
        print <$fh>;
        undef $fh;       # automatically closes the file
    }

    $fh = new IO::File "file", O_WRONLY|O_APPEND;
    if (defined $fh) {
        print $fh "corge\n";

        $pos = $fh->getpos;
        $fh->setpos($pos);

        undef $fh;       # automatically closes the file
    }

    autoflush STDOUT 1;

=head1 DESCRIPTION

C<IO::File> inherits from C<IO::Handle> and C<IO::Seekable>. It extends
these classes with methods that are specific to file handles.

=head1 CONSTRUCTOR

=over 4

=item new ([ ARGS ] )

Creates a C<IO::File>.  If it receives any parameters, they are passed to
the method C<open>; if the open fails, the object is destroyed.  Otherwise,
it is returned to the caller.

=item new_tmpfile

Creates an C<IO::File> opened for read/write on a newly created temporary
file.  On systems where this is possible, the temporary file is anonymous
(i.e. it is unlinked after creation, but held open).  If the temporary
file cannot be created or opened, the C<IO::File> object is destroyed.
Otherwise, it is returned to the caller.

=back

=head1 METHODS

=over 4

=item open( FILENAME [,MODE [,PERMS]] )

C<open> accepts one, two or three parameters.  With one parameter,
it is just a front end for the built-in C<open> function.  With two
parameters, the first parameter is a filename that may include
whitespace or other special characters, and the second parameter is
the open mode, optionally followed by a file permission value.

If C<IO::File::open> receives a Perl mode string ("E<gt>", "+E<lt>", etc.)
or a POSIX fopen() mode string ("w", "r+", etc.), it uses the basic
Perl C<open> operator.

If C<IO::File::open> is given a numeric mode, it passes that mode
and the optional permissions value to the Perl C<sysopen> operator.
For convenience, C<IO::File::import> tries to import the O_XXX
constants from the Fcntl module.  If dynamic loading is not available,
this may fail, but the rest of IO::File will still work.

=back

=head1 SEE ALSO

L<perlfunc>,
L<perlop/"I/O Operators">,
L<IO::Handle>
L<IO::Seekable>

=head1 HISTORY

Derived from FileHandle.pm by Graham Barr E<lt>F<[e-mail]>E<gt>.

=cut

require 5.000;
use strict;
use vars qw($VERSION @EXPORT @EXPORT_OK $AUTOLOAD @ISA);
use Carp;
use Symbol;
use SelectSaver;
use IO::Seekable;

require Exporter;
require DynaLoader;

@ISA = qw(IO::Handle IO::Seekable Exporter DynaLoader);

$VERSION = "1.06021";

@EXPORT = @IO::Seekable::EXPORT;

eval {
    # Make all Fcntl O_XXX constants available for importing
    require Fcntl;
    my @O = grep /^O_/, @Fcntl::EXPORT;
    Fcntl->import(@O);  # first we import what we want to export
    push(@EXPORT, @O);
};


################################################
## Constructor
##

sub new {
    my $type = shift;
    my $class = ref($type) || $type || "IO::File";
    @_ >= 0 && @_ <= 3
    or croak "usage: new $class [FILENAME [,MODE [,PERMS]]]";
    my $fh = $class->SUPER::new();
    if (@_) {
    $fh->open(@_)
        or return undef;
    }
    $fh;
}

################################################
## Open
##

sub open {
    @_ >= 2 && @_ <= 4 or croak 'usage: $fh->open(FILENAME [,MODE [,PERMS]])';
    my ($fh, $file) = @_;
    if (@_ > 2) {
    my ($mode, $perms) = @_[2, 3];
    if ($mode =~ /^\d+$/) {
        defined $perms or $perms = 0666;
        return sysopen($fh, $file, $mode, $perms);
    }
    $file = './' . $file if $file =~ m{\A[^\\/\w]};
    $file = IO::Handle::_open_mode_string($mode) . " $file\0";
    }
    open($fh, $file);
}

1;