added potion and restore_health

src/potion.h

@@ -0,0 +1,30 @@
+#ifndef __POTIONS_H__
+#define __POTIONS_H__
+
+#include <vector>
+#include "constants.h"
+
+// IMPORTANT: pop all potions of duration == 0, and when entering a
+//  new level, pop all potions of duration == -1
+
+class potion {
+protected:
+        // Use -1 to denote that the effect will last until leaving the level
+        // Otherwise, use a positive number
+        // Single use potions have a starting duration of 1
+        const potion_type type;
+        int remaining_duration;
+public:
+        potion(const potion_type type, const int duration);
+        // apply decrements remaining_duration if it's positive, and
+        //  won't do anything if it's non-negative
+        virtual void apply(enum race &race, int &HP, int &ATK, int &DEF,
+                           float &base_hit_rate) = 0;
+        virtual int get_priority() const = 0;
+        potion_type get_type() const;
+        int get_duration() const;
+};
+
+typedef std::vector<potion> potion_list;
+
+#endif