c't freeware shareware 1997/CT_SW_97.ISO/pc/software/entwickl/win95/pw32i306.exe/lib/IO/file.pm

Text File | 1996-10-07 | 4KB | 173 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 "> FOO";
    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";
        undef $fh;       # automatically closes the file
    }

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

    $fh->setvbuf($buffer_var, _IOLBF, 1024);

    autoflush STDOUT 1;

=head1 DESCRIPTION

C<IO::File> is inherits from C<IO::Handle> ans 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.

=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>.

=head1 REVISION

$Revision: 1.5 $

=cut

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

require Exporter;
require DynaLoader;

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

$VERSION = sprintf("%d.%02d", q$Revision: 1.5 $ =~ /(\d+)\.(\d+)/);

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

################################################
## If the Fcntl extension is available,
##  export its constants.
##

sub import {
    my $pkg = shift;
    my $callpkg = caller;
    Exporter::export $pkg, $callpkg;
    eval {
    require Fcntl;
    Exporter::export 'Fcntl', $callpkg;
    };
};


################################################
## 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 unless $file =~ m#^/#;
    $file = _open_mode_string($mode) . " $file\0";
    }
    open($fh, $file);
}

1;