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authorNicholas Clark <nick@ccl4.org>2009-10-02 13:45:44 +0100
committerNicholas Clark <nick@ccl4.org>2009-10-02 13:45:44 +0100
commitb7c8007e17dac1921298ae21cba58fd10cfde840 (patch)
treeffdab895a91852a8e0b278ff9c95b68488dabb65 /cpan/MIME-Base64/Base64.pm
parent6a9d70dc5bc1e24d7b72e48b62cd53b961f288cc (diff)
downloadperl-b7c8007e17dac1921298ae21cba58fd10cfde840.tar.gz
Move MIME::Base64 from ext/ to cpan/
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diff --git a/cpan/MIME-Base64/Base64.pm b/cpan/MIME-Base64/Base64.pm
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+package MIME::Base64;
+
+use strict;
+use vars qw(@ISA @EXPORT $VERSION);
+
+require Exporter;
+@ISA = qw(Exporter);
+@EXPORT = qw(encode_base64 decode_base64);
+
+$VERSION = '3.08';
+
+require XSLoader;
+XSLoader::load('MIME::Base64', $VERSION);
+
+*encode = \&encode_base64;
+*decode = \&decode_base64;
+
+1;
+
+__END__
+
+=head1 NAME
+
+MIME::Base64 - Encoding and decoding of base64 strings
+
+=head1 SYNOPSIS
+
+ use MIME::Base64;
+
+ $encoded = encode_base64('Aladdin:open sesame');
+ $decoded = decode_base64($encoded);
+
+=head1 DESCRIPTION
+
+This module provides functions to encode and decode strings into and from the
+base64 encoding specified in RFC 2045 - I<MIME (Multipurpose Internet
+Mail Extensions)>. The base64 encoding is designed to represent
+arbitrary sequences of octets in a form that need not be humanly
+readable. A 65-character subset ([A-Za-z0-9+/=]) of US-ASCII is used,
+enabling 6 bits to be represented per printable character.
+
+The following functions are provided:
+
+=over 4
+
+=item encode_base64($str)
+
+=item encode_base64($str, $eol);
+
+Encode data by calling the encode_base64() function. The first
+argument is the string to encode. The second argument is the
+line-ending sequence to use. It is optional and defaults to "\n". The
+returned encoded string is broken into lines of no more than 76
+characters each and it will end with $eol unless it is empty. Pass an
+empty string as second argument if you do not want the encoded string
+to be broken into lines.
+
+=item decode_base64($str)
+
+Decode a base64 string by calling the decode_base64() function. This
+function takes a single argument which is the string to decode and
+returns the decoded data.
+
+Any character not part of the 65-character base64 subset is
+silently ignored. Characters occurring after a '=' padding character
+are never decoded.
+
+If the length of the string to decode, after ignoring
+non-base64 chars, is not a multiple of 4 or if padding occurs too early,
+then a warning is generated if perl is running under C<-w>.
+
+=back
+
+If you prefer not to import these routines into your namespace, you can
+call them as:
+
+ use MIME::Base64 ();
+ $encoded = MIME::Base64::encode($decoded);
+ $decoded = MIME::Base64::decode($encoded);
+
+=head1 DIAGNOSTICS
+
+The following warnings can be generated if perl is invoked with the
+C<-w> switch:
+
+=over 4
+
+=item Premature end of base64 data
+
+The number of characters to decode is not a multiple of 4. Legal
+base64 data should be padded with one or two "=" characters to make
+its length a multiple of 4. The decoded result will be the same
+whether the padding is present or not.
+
+=item Premature padding of base64 data
+
+The '=' padding character occurs as the first or second character
+in a base64 quartet.
+
+=back
+
+The following exception can be raised:
+
+=over 4
+
+=item Wide character in subroutine entry
+
+The string passed to encode_base64() contains characters with code
+above 255. The base64 encoding is only defined for single-byte
+characters. Use the Encode module to select the byte encoding you
+want.
+
+=back
+
+=head1 EXAMPLES
+
+If you want to encode a large file, you should encode it in chunks
+that are a multiple of 57 bytes. This ensures that the base64 lines
+line up and that you do not end up with padding in the middle. 57
+bytes of data fills one complete base64 line (76 == 57*4/3):
+
+ use MIME::Base64 qw(encode_base64);
+
+ open(FILE, "/var/log/wtmp") or die "$!";
+ while (read(FILE, $buf, 60*57)) {
+ print encode_base64($buf);
+ }
+
+or if you know you have enough memory
+
+ use MIME::Base64 qw(encode_base64);
+ local($/) = undef; # slurp
+ print encode_base64(<STDIN>);
+
+The same approach as a command line:
+
+ perl -MMIME::Base64 -0777 -ne 'print encode_base64($_)' <file
+
+Decoding does not need slurp mode if every line contains a multiple
+of four base64 chars:
+
+ perl -MMIME::Base64 -ne 'print decode_base64($_)' <file
+
+Perl v5.8 and better allow extended Unicode characters in strings.
+Such strings cannot be encoded directly, as the base64
+encoding is only defined for single-byte characters. The solution is
+to use the Encode module to select the byte encoding you want. For
+example:
+
+ use MIME::Base64 qw(encode_base64);
+ use Encode qw(encode);
+
+ $encoded = encode_base64(encode("UTF-8", "\x{FFFF}\n"));
+ print $encoded;
+
+=head1 COPYRIGHT
+
+Copyright 1995-1999, 2001-2004 Gisle Aas.
+
+This library is free software; you can redistribute it and/or
+modify it under the same terms as Perl itself.
+
+Distantly based on LWP::Base64 written by Martijn Koster
+<m.koster@nexor.co.uk> and Joerg Reichelt <j.reichelt@nexor.co.uk> and
+code posted to comp.lang.perl <3pd2lp$6gf@wsinti07.win.tue.nl> by Hans
+Mulder <hansm@wsinti07.win.tue.nl>
+
+The XS implementation uses code from metamail. Copyright 1991 Bell
+Communications Research, Inc. (Bellcore)
+
+=head1 SEE ALSO
+
+L<MIME::QuotedPrint>
+
+=cut