Interned tokens to reduce memory footprint

1 files changed, 59 insertions, 0 deletions

@@ -0,0 +1,59 @@
+#ifndef IDENTIFIER_H_D7EE5679
+#define IDENTIFIER_H_D7EE5679
+
+#include <map>
+#include <vector>
+
+template <typename T>
+class identifier {
+public:
+
+  using value_type = T;
+
+private:
+
+  using vector_type = std::vector<value_type>;
+
+public:
+
+  using key_type = typename vector_type::size_type;
+
+  key_type add(const value_type& val)
+  {
+    auto it = ids_.find(val);
+
+    if (it == std::end(ids_))
+    {
+      key_type ret = ids_.size();
+      ids_[val] = ret;
+
+      uniq_.push_back(val);
+
+      return ret;
+    } else {
+      return it->second;
+    }
+  }
+
+  void compile()
+  {
+    ids_.clear();
+  }
+
+  inline const value_type& get(key_type i) const
+  {
+    return uniq_.at(i);
+  }
+
+  inline key_type size() const
+  {
+    return uniq_.size();
+  }
+
+private:
+
+  std::map<value_type, key_type> ids_;
+  vector_type uniq_;
+};
+
+#endif /* end of include guard: IDENTIFIER_H_D7EE5679 */