/ 
IO-ReadHandle-Chain-1.0
River stage zero No dependents
/ IO::ReadHandle::Chain

NAME

IO::ReadHandle::Chain - Chain several sources through a single file read handle

VERSION

Version 1.0

SYNOPSIS

This module chains any number of data sources (scalar, file, IO handle) together for reading through a single file read handle.

This is convenient if you have multiple data sources of which some are very large and you need to pretend that they are all inside a single data source.

Use the IO::ReadHandle::Chain object for reading as you would any other file handle.

use IO::ReadHandle::Chain;

open $ifh, '<', 'somefile.txt';
$text = 'This is some text.';
$cfh = IO::ReadHandle::Chain->new('file.txt', \$text, $ifh);
print while <$cfh>;
# prints lines from file 'file.txt', then lines from scalar $text,
# then lines from file handle $ifh

@lines = <$cfh>;              # or get all lines at once

# or read bytes instead
$buffer = '';
$bytecount = read($cfh, $buffer, 100);
$bytecount = sysread($cfh, $buffer, 100);

close($cfh);

# OO, too
$line = $cfh->getline;
@lines = $cfh->getlines;
$bytecount = $cfh->read($buffer, $size, $offset);
$bytecount = $cfh->sysread($buffer, $size, $offset);
$cfh->close;
print "end!\n" if $cfh->eof;

You cannot write or seek through an IO::ReadHandle::Chain.

When reading by lines, then for each data source the associated input record separator is used to separate the data into lines.

For any of the data sources that are file handles, when the end of the associated data stream is reached, or if the chain filehandle object is closed, then it tries to reset the file handle's position to what it was when the module started reading from the file handle.

The chain filehandle object does not close any of the file handles that are passed to it as data sources.

SUBROUTINES/METHODS

new(@sources)

Creates a filehandle object based on the specified @sources. The sources are read in the order in which they are specified. To read from a particular file, specify that file's path as a source. To read the contents of a scalar, specify a reference to that scalar as a source. To read from an already open file handle, specify that file handle as a source.

Croaks if any of the sources are not a scalar, a scalar reference, or a file handle.

AUTHOR

Louis Strous, <lstrous at cpan.org>

BUGS

Please report any bugs or feature requests to bug-io-readhandle-chain at rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=IO-ReadHandle-Chain. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc IO::ReadHandle::Chain

You can also look for information at:

LICENSE AND COPYRIGHT

Copyright 2017 Louis Strous.

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.