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package MIME::Decoder::Base64;
use strict;
use warnings;
=head1 NAME
MIME::Decoder::Base64 - encode/decode a "base64" stream
=head1 SYNOPSIS
A generic decoder object; see L<MIME::Decoder> for usage.
=head1 DESCRIPTION
A L<MIME::Decoder> subclass for the C<"base64"> encoding.
The name was chosen to jibe with the pre-existing MIME::Base64
utility package, which this class actually uses to translate each chunk.
=over 4
=item *
When B<decoding>, the input is read one line at a time.
The input accumulates in an internal buffer, which is decoded in
multiple-of-4-sized chunks (plus a possible "leftover" input chunk,
of course).
=item *
When B<encoding>, the input is read 6840 (120 * 57) bytes at a time.
Each section of 57 bytes is encoded as a line containing 76 Base64
characters.
=back
=head1 SEE ALSO
L<MIME::Decoder>
=head1 AUTHOR
Eryq (F<eryq@zeegee.com>), ZeeGee Software Inc (F<http://www.zeegee.com>).
All rights reserved. This program is free software; you can redistribute
it and/or modify it under the same terms as Perl itself.
=cut
use vars qw(@ISA $VERSION);
use MIME::Decoder;
use MIME::Base64 2.04;
use MIME::Tools qw(debug);
@ISA = qw(MIME::Decoder);
### The package version, both in 1.23 style *and* usable by MakeMaker:
$VERSION = "5.515";
### How many bytes to encode at a time (must be a multiple of 3)
my $EncodeChunkLength = 120 * 57;
### How many bytes to decode at a time?
my $DecodeChunkLength = 32 * 1024;
#------------------------------
#
# decode_it IN, OUT
#
sub decode_it {
my ($self, $in, $out) = @_;
my $len_4xN;
### Create a suitable buffer:
my $buffer = ' ' x (120 + $DecodeChunkLength); $buffer = '';
debug "in = $in; out = $out";
### Get chunks until done:
local($_) = ' ' x $DecodeChunkLength;
while ($in->read($_, $DecodeChunkLength)) {
tr{A-Za-z0-9+/}{}cd; ### get rid of non-base64 chars
### Concat any new input onto any leftover from the last round:
$buffer .= $_;
length($buffer) >= $DecodeChunkLength or next;
### Extract substring with highest multiple of 4 bytes:
### 0 means not enough to work with... get more data!
$len_4xN = length($buffer) & ~3;
### Partition into largest-multiple-of-4 (which we decode),
### and the remainder (which gets handled next time around):
$out->print(decode_base64(substr($buffer, 0, $len_4xN)));
$buffer = substr($buffer, $len_4xN);
}
### No more input remains. Dispose of anything left in buffer:
if (length($buffer)) {
### Pad to 4-byte multiple, and decode:
$buffer .= "==="; ### need no more than 3 pad chars
$len_4xN = length($buffer) & ~3;
### Decode it!
$out->print(decode_base64(substr($buffer, 0, $len_4xN)));
}
1;
}
#------------------------------
#
# encode_it IN, OUT
#
sub encode_it {
my ($self, $in, $out) = @_;
my $encoded;
my $nread;
my $buf = '';
my $nl = $MIME::Entity::BOUNDARY_DELIMITER || "\n";
while ($nread = $in->read($buf, $EncodeChunkLength)) {
$encoded = encode_base64($buf, $nl);
$encoded .= $nl unless ($encoded =~ /$nl\Z/); ### ensure newline!
$out->print($encoded);
}
1;
}
#------------------------------
1;