NAME

HTTP::Promise::Stream::LZW - Stream Encoder for LZW Compression

SYNOPSIS

    use HTTP::Promise::Stream::LZW;
    my $s = HTTP::Promise::Stream::LZW->new || 
        die( HTTP::Promise::Stream::LZW->error, "\n" );
    $s->encode( $input => $output ) ||
        die( $s->error );
    $s->decode( $input => $output ) || die( $s->error );
    HTTP::Promise::Stream::LZW::encode_lzw( $input => $output ) ||
        die( $HTTP::Promise::Stream::LZW::LZWError );
    HTTP::Promise::Stream::LZW::decode_lzw( $input => $output ) ||
        die( $HTTP::Promise::Stream::LZW::LZWError );

VERSION

    v0.1.0

DESCRIPTION

This implements an encoding and decoding mechanism for LZW compression using either of the following on input and output:

filepath

If the parameter is neither a scalar reference nor a file handle, it will be assumed to be a file path.

file handle

This can be a native file handle, or an object oriented one as long as it implements the print or write, and read methods. The read method is expected to return the number of bytes read or undef upon error. The print and write methods are expected to simply return true upon success and undef upon error.

Alternatively, those methods can die and those exceptions wil be caught.

scalar reference

This can be a simple scalar reference, or an object scalar reference.

This module requires Compress::LZW to be installed or it will return an error.

CONSTRUCTOR

new

Creates a new HTTP::Promise::Stream::LZW object and returns it.

METHODS

decode

This takes 2 arguments: an input and an output. Each one can be either a file path, a file handle, or a scalar reference.

It will decode the LZW encoded data and write the result into the output.

It returns true upon success and sets an error and return undef upon error.

encode

This takes 2 arguments: an input and an output. Each one can be either a file path, a file handle, or a scalar reference.

It will encode the data into LZW encoded data and write the result into the output.

It returns true upon success and sets an error and return undef upon error.

CLASS FUNCTIONS

The following class functions are available and can also be exported, such as:

    use HTTP::Promise::Stream::Brotli qw( decode_lzw encode_lzw );

decode_lzw

This takes the same 2 arguments used in "decode": an input and an output. Each one can be either a file path, a file handle, or a scalar reference.

It will decode the LZW encoded data and write the result into the output.

It returns true upon success, and upon error, it will set the error in the global variable $UUError and return undef

    my $decoded = HTTP::Promise::Stream::LZW::decode_lzw( $encoded );
    die( "Something went wrong: $HTTP::Promise::Stream::LZW::LZWError\n" if( !defined( $decoded ) );
    print( "Decoded data is: $decoded\n" );

encode_lzw

This takes the same 2 arguments used in "encode": an input and an output. Each one can be either a file path, a file handle, or a scalar reference.

It will encode the data into LZW encoded data and write the result into the output.

It returns true upon success, and upon error, it will set the error in the global variable $LZWError and return undef

    my $encoded = HTTP::Promise::Stream::LZW::encode_lzw( $data );
    die( "Something went wrong: $HTTP::Promise::Stream::LZW::LZWError\n" if( !defined( $encoded ) );
    print( "Encoded data is: $encoded\n" );

AUTHOR

Jacques Deguest <jack@deguest.jp>

SEE ALSO

Compress::LZW

Discussion on Stackoverflow, Wikipedia page

HTTP::Promise, HTTP::Promise::Request, HTTP::Promise::Response, HTTP::Promise::Message, HTTP::Promise::Entity, HTTP::Promise::Headers, HTTP::Promise::Body, HTTP::Promise::Body::Form, HTTP::Promise::Body::Form::Data, HTTP::Promise::Body::Form::Field, HTTP::Promise::Status, HTTP::Promise::MIME, HTTP::Promise::Parser, HTTP::Promise::IO, HTTP::Promise::Stream, HTTP::Promise::Exception

COPYRIGHT & LICENSE

Copyright(c) 2022 DEGUEST Pte. Ltd.

All rights reserved.

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

cpanm HTTP::Promise

perl -MCPAN -e shell
install HTTP::Promise