1 files changed, 97 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb b/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb
new file mode 100644
index 0000000000..b7d24f2bb3
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/array_parser.rb
@@ -0,0 +1,97 @@
+module ActiveRecord
+  module ConnectionAdapters
+    class PostgreSQLColumn < Column
+      module ArrayParser
+        private
+          # Loads pg_array_parser if available. String parsing can be
+          # performed quicker by a native extension, which will not create
+          # a large amount of Ruby objects that will need to be garbage
+          # collected. pg_array_parser has a C and Java extension
+          begin
+            require 'pg_array_parser'
+            include PgArrayParser
+          rescue LoadError
+            def parse_pg_array(string)
+              parse_data(string, 0)
+            end
+          end
+
+          def parse_data(string, index)
+            local_index = index
+            array = []
+            while(local_index < string.length)
+              case string[local_index]
+              when '{'
+                local_index,array = parse_array_contents(array, string, local_index + 1)
+              when '}'
+                return array
+              end
+              local_index += 1
+            end
+
+            array
+          end
+
+          def parse_array_contents(array, string, index)
+            is_escaping = false
+            is_quoted = false
+            was_quoted = false
+            current_item = ''
+
+            local_index = index
+            while local_index
+              token = string[local_index]
+              if is_escaping
+                current_item << token
+                is_escaping = false
+              else
+                if is_quoted
+                  case token
+                  when '"'
+                    is_quoted = false
+                    was_quoted = true
+                  when "\\"
+                    is_escaping = true
+                  else
+                    current_item << token
+                  end
+                else
+                  case token
+                  when "\\"
+                    is_escaping = true
+                  when ','
+                    add_item_to_array(array, current_item, was_quoted)
+                    current_item = ''
+                    was_quoted = false
+                  when '"'
+                    is_quoted = true
+                  when '{'
+                    internal_items = []
+                    local_index,internal_items = parse_array_contents(internal_items, string, local_index + 1)
+                    array.push(internal_items)
+                  when '}'
+                    add_item_to_array(array, current_item, was_quoted)
+                    return local_index,array
+                  else
+                    current_item << token
+                  end
+                end
+              end
+
+              local_index += 1
+            end
+            return local_index,array
+          end
+
+          def add_item_to_array(array, current_item, quoted)
+            if current_item.length == 0
+            elsif !quoted && current_item == 'NULL'
+              array.push nil
+            else
+              array.push current_item
+            end
+          end
+      end
+    end
+  end
+end