SERVER-7639 fast StringMap class, no std::string copies

1 files changed, 52 insertions, 0 deletions

diff --git a/src/mongo/util/string_map.h b/src/mongo/util/string_map.h
new file mode 100644
index 00000000000..e2fd7e01bc7
--- /dev/null
+++ b/src/mongo/util/string_map.h
@@ -0,0 +1,52 @@
+// string_map.h
+
+/*    Copyright 2012 10gen Inc.
+ *
+ *    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.
+ */
+
+#pragma once
+
+#include <string>
+#include "mongo/util/unordered_fast_key_table.h"
+
+namespace mongo {
+
+    struct StringMapDefaultHash {
+        size_t operator()( const char* k ) const;
+    };
+
+    struct StringMapDefaultEqual {
+        bool operator()( const char* a, const char* b ) const {
+            return strcmp( a,b ) == 0;
+        }
+    };
+
+    struct StringMapDefaultConvertor {
+        const char* operator()( const std::string& s ) const {
+            return s.c_str();
+        }
+    };
+
+    template< typename V >
+    class StringMap : public UnorderedFastKeyTable< const char*, // K_L
+                                      std::string, // K_S
+                                      V,           // V
+                                      StringMapDefaultHash,
+                                      StringMapDefaultEqual,
+                                      StringMapDefaultConvertor > {
+    };
+}
+
+#include "mongo/util/string_map_internal.h"
+