IO::InnerFile

Section: User Contributed Perl Documentation (3)
Updated: 2021-01-27
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NAME

IO::InnerFile - define a file inside another file

SYNOPSIS

    use strict;
    use warnings;
    use IO::InnerFile;

    # Read a subset of a file:
    my $fh = _some_file_handle;
    my $start = 10;
    my $length = 50;
    my $inner = IO::InnerFile->new($fh, $start, $length);
    while (my $line = <$inner>) {
        # ...
    }

DESCRIPTION

If you have a file handle that can "seek" and "tell", then you can open an IO::InnerFile on a range of the underlying file.

CONSTRUCTORS

IO::InnerFile implements the following constructors.

new

    my $inner = IO::InnerFile->new($fh);
    $inner = IO::InnerFile->new($fh, 10);
    $inner = IO::InnerFile->new($fh, 10, 50);

Create a new IO::InnerFile opened on the given file handle. The file handle supplied MUST be able to both "seek" and "tell".

The second and third parameters are start and length. Both are defaulted to zero (0). Negative values are silently coerced to zero.

METHODS

IO::InnerFile implements the following methods.

add_length

    $inner->add_length(30);

Add to the virtual length of the inner file by the number given in bytes.

add_start

    $inner->add_start(30);

Add to the virtual position of the inner file by the number given in bytes.

binmode

    $inner->binmode();

This is a NOOP method just to satisfy the normal IO::File interface.

close

fileno

    $inner->fileno();

This is a NOOP method just to satisfy the normal IO::File interface.

flush

    $inner->flush();

This is a NOOP method just to satisfy the normal IO::File interface.

get_end

    my $num_bytes = $inner->get_end();

Get the virtual end position of the inner file in bytes.

get_length

    my $num_bytes = $inner->get_length();

Get the virtual length of the inner file in bytes.

get_start

    my $num_bytes = $inner->get_start();

Get the virtual position of the inner file in bytes.

getc

getline

print LIST

printf

read

readline

seek

set_end

    $inner->set_end(30);

Set the virtual end of the inner file in bytes (this basically just alters the length).

set_length

    $inner->set_length(30);

Set the virtual length of the inner file in bytes.

set_start

    $inner->set_start(30);

Set the virtual start position of the inner file in bytes.

tell

write

AUTHOR

Eryq (eryq@zeegee.com). President, ZeeGee Software Inc (http://www.zeegee.com).

CONTRIBUTORS

Dianne Skoll (dfs@roaringpenguin.com).

COPYRIGHT & LICENSE

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.