package MIME::Base64; # $Id: Base64.pm,v 3.1 2004/03/29 11:55:49 gisle Exp $ use strict; use vars qw(@ISA @EXPORT $VERSION); require Exporter; require DynaLoader; @ISA = qw(Exporter DynaLoader); @EXPORT = qw(encode_base64 decode_base64); $VERSION = '3.01'; MIME::Base64->bootstrap($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. 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 anyway be as if the padding was there. =item Premature padding of base64 data The '=' padding character occurs as the first or second character in a base64 quartet. =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($/) = undef; # slurp print encode_base64(); The same approach as a command line: perl -MMIME::Base64 -0777 -ne 'print encode_base64($_)' and Joerg Reichelt and code posted to comp.lang.perl <3pd2lp$6gf@wsinti07.win.tue.nl> by Hans Mulder The XS implementation uses code from metamail. Copyright 1991 Bell Communications Research, Inc. (Bellcore) =head1 SEE ALSO L =cut