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diff --git a/src/mongo/bson/stringdata.h b/src/mongo/bson/stringdata.h
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+++ b/src/mongo/bson/stringdata.h
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+// stringdata.h
+
+/*    Copyright 2010 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 <cstring>
+
+namespace mongo {
+
+    using std::string;
+
+    /** A StringData object wraps a 'const string&' or a 'const char*' without
+     * copying its contents. The most common usage is as a function argument that
+     * takes any of the two forms of strings above. Fundamentally, this class tries
+     * go around the fact that string literals in C++ are char[N]'s.
+     *
+     * Note that the object StringData wraps around must be alive while the StringData
+     * is.
+    */
+    class StringData {
+    public:
+        /** Construct a StringData, for the case where the length of
+         * string is not known. 'c' must be a pointer to a null-terminated string.
+         */
+        StringData( const char* c )
+            : _data(c), _size((unsigned) strlen(c)) {}
+
+        /** Construct a StringData explicitly, for the case where the length of the string
+         * is already known. 'c' must be a pointer to a null-terminated string, and strlenOfc
+         * must be the length that std::strlen(c) would return, a.k.a the index of the
+         * terminator in c.
+         */
+        StringData( const char* c, unsigned len )
+            : _data(c), _size(len) {}
+
+        /** Construct a StringData, for the case of a std::string. */
+        StringData( const string& s )
+            : _data(s.c_str()), _size((unsigned) s.size()) {}
+
+        // Construct a StringData explicitly, for the case of a literal whose size is
+        // known at compile time.
+        struct LiteralTag {};
+        template<size_t N>
+        StringData( const char (&val)[N], LiteralTag )
+            : _data(&val[0]), _size(N-1) {}
+
+        // accessors
+        const char* data() const { return _data; }
+        unsigned size() const { return _size; }
+
+    private:
+        const char* const _data;  // is always null terminated
+        const unsigned    _size;  // 'size' does not include the null terminator
+    };
+
+} // namespace mongo