Remove runtime dependency on base64 gem to fix Ruby 3.3 warning (#63)

* Add base64 dependency to fix Ruby 3.3 warning

* Remove runtime dependency on base64 gem

* Clarify pack/unpack1 with comments

* Replace unpack1 with unpack()[0] for old Ruby

Gemfile

@@ -7,4 +7,8 @@ else
   gem "rake", "~> 13.0"
 end
 
+if Gem::Requirement.new(">= 3.3").satisfied_by?(Gem::Version.new(RUBY_VERSION))
+  gem "base64"
+end
+
 gem "test-unit", "~> 3.5"

lib/plist.rb

@@ -9,7 +9,6 @@
 # Distributed under the MIT License
 #
 
-require 'base64'
 require 'cgi'
 require 'stringio'
 

lib/plist/generator.rb

@@ -124,11 +124,9 @@ def tag(type, contents, level, &block)
 
       def data_tag(data, level)
         # note that apple plists are wrapped at a different length then
-        # what ruby's base64 wraps by default.
-        # I used #encode64 instead of #b64encode (which allows a length arg)
-        # because b64encode is b0rked and ignores the length arg.
+        # what ruby's pack wraps by default.
         tag('data', nil, level) do
-          Base64.encode64(data)
+          [data].pack("m") # equivalent to Base64.encode64(data)
                 .gsub(/\s+/, '')
                 .scan(/.{1,68}/o)
                 .collect { |line| indent(line, level) }

lib/plist/parser.rb

@@ -246,10 +246,10 @@ def to_ruby
     end
   end
 
-  require 'base64'
   class PData < PTag
     def to_ruby
-      data = Base64.decode64(text.gsub(/\s+/, '')) unless text.nil?
+      # unpack("m")[0] is equivalent to Base64.decode64
+      data = text.gsub(/\s+/, '').unpack("m")[0] unless text.nil?
       begin
         return Marshal.load(data) if options[:marshal]
       rescue Exception

test/test_parser.rb

@@ -1,4 +1,5 @@
 require 'test/unit'
+require 'base64'
 require 'plist'
 
 class TestParser < Test::Unit::TestCase