Added Encoding.asciicompat_encoding.

kernel/common/encoding.rb

@@ -10,9 +10,10 @@ class UndefinedConversionError < EncodingError
   class CompatibilityError < EncodingError
   end
 
-  EncodingMap   = Rubinius::EncodingClass::EncodingMap
-  EncodingList  = Rubinius::EncodingClass::EncodingList
-  LocaleCharmap = Rubinius::EncodingClass::LocaleCharmap
+  EncodingMap     = Rubinius::EncodingClass::EncodingMap
+  EncodingList    = Rubinius::EncodingClass::EncodingList
+  LocaleCharmap   = Rubinius::EncodingClass::LocaleCharmap
+  TranscodingMap  = Rubinius::EncodingClass::TranscodingMap
 
   class Transcoder
     attr_accessor :source
@@ -29,6 +30,18 @@ class Converter
     attr_accessor :replacement
     attr_accessor :convpath
 
+    def self.asciicompat_encoding(string_or_encoding)
+      encoding = Rubinius::Type.try_convert_to_encoding string_or_encoding
+
+      return if not encoding or encoding.equal? undefined
+      return if encoding.ascii_compatible?
+
+      transcoding = TranscodingMap[encoding.name]
+      return unless transcoding and transcoding.size == 1
+
+      Encoding.find transcoding.keys.first.to_s
+    end
+
     def initialize(from, to, options=undefined)
       @source_encoding = Rubinius::Type.coerce_to_encoding from
       @destination_encoding = Rubinius::Type.coerce_to_encoding to
@@ -121,13 +134,8 @@ def self.default_internal=(enc)
   end
 
   def self.find(name)
-    key = StringValue(name).upcase.to_sym
-
-    pair = EncodingMap[key]
-    if pair
-      index = pair.last
-      return index && EncodingList[index]
-    end
+    enc = Rubinius::Type.try_convert_to_encoding name
+    return enc unless enc.equal? undefined
 
     raise ArgumentError, "unknown encoding name - #{name}"
   end

kernel/common/type19.rb

@@ -8,13 +8,32 @@ def self.coerce_to_encoding(obj)
         return obj
       when String
         return Encoding.find obj
-      when nil
-        # TODO: temporary until __ENCODING__ is fixed
       else
         return Encoding.find StringValue(obj)
       end
     end
 
+    def self.try_convert_to_encoding(obj)
+      case obj
+      when Encoding
+        return obj
+      when String
+        str = obj
+      else
+        str = StringValue obj
+      end
+
+      key = str.upcase.to_sym
+
+      pair = Encoding::EncodingMap[key]
+      if pair
+        index = pair.last
+        return index && Encoding::EncodingList[index]
+      end
+
+      return undefined
+    end
+
     def self.compatible_encoding(a, b)
       enc = Encoding.compatible? a, b