IO::InnerFile

Section: User Contributed Perl Documentation (3)
Updated: 2020-01-30
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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

Copyright (c) 1997 Erik (Eryq) Dorfman, ZeeGee Software, Inc. All rights reserved.

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


 

Index

NAME
SYNOPSIS
DESCRIPTION
CONSTRUCTORS
new
METHODS
add_length
add_start
binmode
close
fileno
flush
get_end
get_length
get_start
getc
getline
print LIST
printf
read
readline
seek
set_end
set_length
set_start
tell
write
AUTHOR
CONTRIBUTORS
COPYRIGHT & LICENSE
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