* lib/base64.rb: backported from HEAD (modularised and documented)

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@5682 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 121 insertions, 69 deletions

diff --git a/lib/base64.rb b/lib/base64.rb
index 0e14dde9f7..b551032d90 100644
--- a/lib/base64.rb
+++ b/lib/base64.rb
@@ -1,84 +1,136 @@
-require "kconv"
-
-#  Perform encoding and decoding of binary data using a Base64
-#  representation. This library rather unfortunately loads its four
-#  methods directly into the top level namespace.
-# 
-#      require "base64"
 #
-#      enc   = encode64('Send reinforcements')
-#      puts enc
-#      plain = decode64(enc)
-#      puts plain
+# = base64.rb: methods for base64-encoding and -decoding stings
+#
+# Author:: Yukihiro Matsumoto 
+# Documentation:: Dave Thomas and Gavin Sinclair
+#
+# Until Ruby 1.8.1, these methods were defined at the top-level.  Now
+# they are in the Base64 module but included in the top-level, where
+# their usage is deprecated.
+#
+# See Base64 for documentation.
+#
 
+require "kconv"
 
 
-# Returns the Base64-decoded version of \obj{str}.
+# The Base64 module provides for the encoding (#encode64) and decoding
+# (#decode64) of binary data using a Base64 representation.
+# 
+# The following particular features are also provided:
+# - encode into lines of a given length (#b64encode)
+# - decode the special format specified in RFC2047 for the
+#   representation of email headers (decode_b)
+#
+# == Example
 #
-#   require 'base64'
-#   str = 'VGhpcyBpcyBsaW5lIG9uZQpUaGlzIG' +
-#         'lzIGxpbmUgdHdvClRoaXMgaXMgbGlu' +
-#         'ZSB0aHJlZQpBbmQgc28gb24uLi4K'
-#    puts decode64(str)
+# A simple encoding and decoding. 
+# 
+#     require "base64"
 #
-# <i>Generates:</i>
+#     enc   = Base64.encode64('Send reinforcements')
+#                         # -> "U2VuZCByZWluZm9yY2VtZW50cw==\n" 
+#     plain = Base64.decode64(enc)
+#                         # -> "Send reinforcements"
 #
-#    This is line one
-#    This is line two
-#    This is line three
-#    And so on...
+# The purpose of using base64 to encode data is that it translates any
+# binary data into purely printable characters.  It is specified in
+# RFC 2045 (http://www.faqs.org/rfcs/rfc2045.html).
 
-def decode64(str)
-  str.unpack("m")[0]
-end
+module Base64
+  module_function
 
+  # Returns the Base64-decoded version of +str+.
+  #
+  #   require 'base64'
+  #   str = 'VGhpcyBpcyBsaW5lIG9uZQpUaGlzIG' +
+  #         'lzIGxpbmUgdHdvClRoaXMgaXMgbGlu' +
+  #         'ZSB0aHJlZQpBbmQgc28gb24uLi4K'
+  #   puts Base64.decode64(str)
+  #
+  # <i>Generates:</i>
+  #
+  #    This is line one
+  #    This is line two
+  #    This is line three
+  #    And so on...
 
-# Decodes text formatted using a subset of RFC2047 (the one used for
-# mime-encoding mail headers). Only supports an encoding type of 'b'
-# (base 64), and only supports the character sets ISO-2022-JP and
-# SHIFT_JIS (so the only two encoded word sequences recognized are
-# <tt>=?ISO-2022-JP?B?...=</tt> and
-# <tt>=?SHIFT_JIS?B?...=</tt>). Recognition of these sequences is case
-# insensitive.
-
-def decode_b(str)
-  str.gsub!(/=\?ISO-2022-JP\?B\?([!->@-~]+)\?=/i) {
-    decode64($1)
-  }
-  str = Kconv::toeuc(str)
-  str.gsub!(/=\?SHIFT_JIS\?B\?([!->@-~]+)\?=/i) {
-    decode64($1)
-  }
-  str = Kconv::toeuc(str)
-  str.gsub!(/\n/, ' ') 
-  str.gsub!(/\0/, '')
-  str
-end
+  def decode64(str)
+    str.unpack("m")[0]
+  end
 
-# Returns the Base64-encoded version of \obj{str}.
-#
-#   require 'base64'
-#   str = "Once\nupon\na\ntime."  #!sh!
-#   enc = encode64(str)
-#   decode64(enc)
 
-def encode64(bin)
-  [bin].pack("m")
-end
+  # Decodes text formatted using a subset of RFC2047 (the one used for
+  # mime-encoding mail headers).
+  #
+  # Only supports an encoding type of 'b' (base 64), and only supports
+  # the character sets ISO-2022-JP and SHIFT_JIS (so the only two
+  # encoded word sequences recognized are <tt>=?ISO-2022-JP?B?...=</tt> and
+  # <tt>=?SHIFT_JIS?B?...=</tt>).  Recognition of these sequences is case
+  # insensitive.
+
+  def decode_b(str)
+    str.gsub!(/=\?ISO-2022-JP\?B\?([!->@-~]+)\?=/i) {
+      decode64($1)
+    }
+    str = Kconv::toeuc(str)
+    str.gsub!(/=\?SHIFT_JIS\?B\?([!->@-~]+)\?=/i) {
+      decode64($1)
+    }
+    str = Kconv::toeuc(str)
+    str.gsub!(/\n/, ' ') 
+    str.gsub!(/\0/, '')
+    str
+  end
+
+  # Returns the Base64-encoded version of +str+.
+  #
+  #    require 'base64'
+  #    Base64.b64encode("Now is the time for all good coders\nto learn Ruby")
+  #
+  # <i>Generates:</i>
+  #
+  #    Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4g
+  #    UnVieQ==
+
+  def encode64(bin)
+    [bin].pack("m")
+  end
+
+  # _Prints_ the Base64 encoded version of +bin+ (a +String+) in lines of
+  # +len+ (default 60) characters.
+  #
+  #    require 'base64'
+  #    data = "Now is the time for all good coders\nto learn Ruby" 
+  #    puts Base64.b64encode(data)
+  #
+  # <i>Generates:</i>
+  #
+  #    Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4g
+  #    UnVieQ==
+
+  def b64encode(bin, len = 60)
+    encode64(bin).scan(/.{1,#{len}}/o) do
+      print $&, "\n"
+    end
+  end 
 
-# Prints the Base64 encoded version of _bin_ (a +String+) in lines of
-# _len_ (default 60) characters.
-#
-#    require 'base64'
-#    b64encode("Now is the time for all good coders\nto learn Ruby")
-#
-# Generates
-#
-#    Tm93IGlzIHRoZSB0aW1lIGZvciBhbGwgZ29vZCBjb2RlcnMKdG8gbGVhcm4g
-#    UnVieQ==
 
-def b64encode(bin, len = 60)
-  encode64(bin).scan(/.{1,#{len}}/o) do
-    print $&, "\n"
+  module Deprecated # :nodoc:
+    include Base64
+
+    def _deprecated_base64(*args)
+      m0, m1 = caller(0)
+      m = m0[/\`(.*?)\'\z/, 1]
+      warn("#{m1}: #{m} is deprecated; use Base64.#{m} instead")
+      super
+    end
+    dep = instance_method(:_deprecated_base64)
+    remove_method(:_deprecated_base64)
+    for m in Base64.private_instance_methods(false)
+      define_method(m, dep)
+    end
   end
-end 
+end
+
+include Base64::Deprecated