remove multiple enumerations from ActiveSupport::JSON#convert_json_to_yaml when dealing with date/time values. [rick]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8505 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* remove multiple enumerations from ActiveSupport::JSON#convert_json_to_yaml when dealing with date/time values.  [rick]
+
 * Hash#symbolize_keys skips keys that can't be symbolized.  #10500 [Brad Greenlee]
 
 * Ruby 1.9 compatibility.  #1689, #10466, #10468, #10554 [Cheah Chu Yeow, Pratik Naik, Jeremy Kemper, Dirkjan Bussink]

activesupport/lib/active_support/json/decoding.rb

@@ -45,11 +45,14 @@ def convert_json_to_yaml(json) #:nodoc:
           if marks.empty?
             json.gsub(/\\\//, '/')
           else
-            # FIXME: multiple slow enumerations
-            output = ([0] + marks.map(&:succ)).
-                      zip(marks + [json.length]).
-                      map { |left, right| json[left..right] }.
-                      join(" ")
+            left_pos  = [-1].push(*marks)
+            right_pos = marks << json.length
+            output    = []
+            left_pos.each_with_index do |left, i|
+              output << json[left.succ..right_pos[i]]
+            end
+            output = output * " "
+            
             times.each { |i| output[i-1] = ' ' }
             output.gsub!(/\\\//, '/')
             output