[C++] Introduce Symbol

1 files changed, 76 insertions, 0 deletions

diff --git a/symtab.h b/symtab.h
new file mode 100644
index 0000000..55e1ce3
--- /dev/null
+++ b/symtab.h
@@ -0,0 +1,76 @@
+// Copyright 2015 Google Inc. All rights reserved
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef SYMTAB_H_
+#define SYMTAB_H_
+
+#include <string>
+#include <vector>
+
+#include "string_piece.h"
+
+using namespace std;
+
+extern vector<string>* g_symbols;
+
+class Symtab;
+
+class Symbol {
+ public:
+  const string& str() const {
+    return (*g_symbols)[v_];
+  }
+
+  const char* c_str() const {
+    return str().c_str();
+  }
+
+  bool empty() const { return !v_; }
+
+  int val() const { return v_; }
+
+  char get(size_t i) const {
+    const string& s = str();
+    if (i >= s.size())
+      return 0;
+    return s[i];
+  }
+
+ private:
+  explicit Symbol(int v);
+
+  int v_;
+
+  friend class Symtab;
+};
+
+inline bool operator==(const Symbol& x, const Symbol& y) {
+  return x.val() == y.val();
+}
+
+namespace std {
+template<> struct hash<Symbol> {
+  size_t operator()(const Symbol& s) const {
+    return s.val();
+  }
+};
+}
+
+void InitSymtab();
+void QuitSymtab();
+Symbol Intern(StringPiece s);
+
+string JoinSymbols(const vector<Symbol>& syms, const char* sep);
+
+#endif  // SYMTAB_H_