Use String#scrub when available to tidy bytes

activesupport/lib/active_support/multibyte/unicode.rb

@@ -212,37 +212,43 @@ def compose(codepoints)
         codepoints
       end
 
-      # Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent
-      # resulting in a valid UTF-8 string.
-      #
-      # Passing +true+ will forcibly tidy all bytes, assuming that the string's
-      # encoding is entirely CP1252 or ISO-8859-1.
-      def tidy_bytes(string, force = false)
-        return string if string.empty?
-
-        if force
-          return string.encode(Encoding::UTF_8, Encoding::Windows_1252, invalid: :replace, undef: :replace)
+      # Ruby >= 2.1 has String#scrub, which is faster than the workaround used for < 2.1.
+      if RUBY_VERSION >= '2.1'
+        # Replaces all ISO-8859-1 or CP1252 characters by their UTF-8 equivalent
+        # resulting in a valid UTF-8 string.
+        #
+        # Passing +true+ will forcibly tidy all bytes, assuming that the string's
+        # encoding is entirely CP1252 or ISO-8859-1.
+        def tidy_bytes(string, force = false)
+          return string if string.empty?
+          return recode_windows1252_chars(string) if force
+          string.scrub { |bad| recode_windows1252_chars(bad) }
         end
+      else
+        def tidy_bytes(string, force = false)
+          return string if string.empty?
+          return recode_windows1252_chars(string) if force
 
-        # We can't transcode to the same format, so we choose a nearly-identical encoding.
-        # We're going to 'transcode' bytes from UTF-8 when possible, then fall back to
-        # CP1252 when we get errors. The final string will be 'converted' back to UTF-8
-        # before returning.
-        reader = Encoding::Converter.new(Encoding::UTF_8, Encoding::UTF_8_MAC)
+          # We can't transcode to the same format, so we choose a nearly-identical encoding.
+          # We're going to 'transcode' bytes from UTF-8 when possible, then fall back to
+          # CP1252 when we get errors. The final string will be 'converted' back to UTF-8
+          # before returning.
+          reader = Encoding::Converter.new(Encoding::UTF_8, Encoding::UTF_8_MAC)
 
-        source = string.dup
-        out = ''.force_encoding(Encoding::UTF_8_MAC)
+          source = string.dup
+          out = ''.force_encoding(Encoding::UTF_8_MAC)
 
-        loop do
-          reader.primitive_convert(source, out)
-          _, _, _, error_bytes, _ = reader.primitive_errinfo
-          break if error_bytes.nil?
-          out << error_bytes.encode(Encoding::UTF_8_MAC, Encoding::Windows_1252, invalid: :replace, undef: :replace)
+          loop do
+            reader.primitive_convert(source, out)
+            _, _, _, error_bytes, _ = reader.primitive_errinfo
+            break if error_bytes.nil?
+            out << error_bytes.encode(Encoding::UTF_8_MAC, Encoding::Windows_1252, invalid: :replace, undef: :replace)
+          end
+
+          reader.finish
+
+          out.encode!(Encoding::UTF_8)
         end
-
-        reader.finish
-
-        out.encode!(Encoding::UTF_8)
       end
 
       # Returns the KC normalization of the string by default. NFKC is
@@ -371,14 +377,8 @@ def apply_mapping(string, mapping) #:nodoc:
         end.pack('U*')
       end
 
-      def tidy_byte(byte)
-        if byte < 160
-          [database.cp1252[byte] || byte].pack("U").unpack("C*")
-        elsif byte < 192
-          [194, byte]
-        else
-          [195, byte - 64]
-        end
+      def recode_windows1252_chars(string)
+        string.encode(Encoding::UTF_8, Encoding::Windows_1252, invalid: :replace, undef: :replace)
       end
 
       def database