MIME::Base64 man page on SuSE

Man page or keyword search:  
man Server   14857 pages
apropos Keyword Search (all sections)
Output format
SuSE logo
[printable version]

MIME::Base64(3pm)      Perl Programmers Reference Guide	     MIME::Base64(3pm)

NAME
       MIME::Base64 - Encoding and decoding of base64 strings

SYNOPSIS
	use MIME::Base64;

	$encoded = encode_base64('Aladdin:open sesame');
	$decoded = decode_base64($encoded);

DESCRIPTION
       This module provides functions to encode and decode strings into and
       from the base64 encoding specified in RFC 2045 - 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:

       encode_base64($str)
       encode_base64($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.

       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 "-w".

       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);

DIAGNOSTICS
       The following warnings can be generated if perl is invoked with the
       "-w" switch:

       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.

       Premature padding of base64 data
	   The '=' padding character occurs as the first or second character
	   in a base64 quartet.

       The following exception can be raised:

       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.

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;

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)

SEE ALSO
       MIME::QuotedPrint

perl v5.10.0			  2007-12-18		     MIME::Base64(3pm)
[top]

List of man pages available for SuSE

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Tweet
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
....................................................................
Vote for polarhome
Free Shell Accounts :: the biggest list on the net