Implement limit

lib/rex/limit.rb

@@ -0,0 +1,40 @@
+module Rex
+  class Limit
+    def initialize(price)
+      @price = price
+      @first_order = nil
+      @last_order = nil
+      @order_count = 0
+    end
+
+    def peek_first_order
+      @first_order
+    end
+
+    def pop_first_order
+      order = @first_order
+      @first_order = @first_order.next_order
+      if @first_order == nil
+        @last_order = nil
+      end
+
+      @order_count -= 1
+      order
+    end
+
+    def add_order(order)
+      if empty?
+        @first_order = order
+        @last_order = order
+      else
+        @last_order.next_order = order
+        @last_order = order
+      end
+      @order_count += 1
+    end
+
+    def empty?
+      @order_count == 0
+    end
+  end
+end