Add llstaticstringtable.h

indra/llcommon/llstaticstringtable.h

+/** 
+ * @file llstringtable.h
+ * @brief The LLStringTable class provides a _fast_ method for finding
+ * unique copies of strings.
+ *
+ * $LicenseInfo:firstyear=2001&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2010, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_STATIC_STRING_TABLE_H
+#define LL_STATIC_STRING_TABLE_H
+
+#include "lldefs.h"
+#include <boost/unordered_map.hpp>
+#include "llstl.h"
+
+class LLStaticHashedString
+{
+public:
+
+	LLStaticHashedString(const std::string& s)
+	{
+		string_hash = makehash(s);
+		string		= s;
+	}
+
+	const std::string&	String() const { return string;		}
+	size_t				Hash()	 const { return string_hash;  }
+
+	bool operator==(const LLStaticHashedString& b) const { return Hash() == b.Hash(); }
+
+protected:
+
+	size_t makehash(const std::string& s)
+	{
+		size_t len = s.size();
+		const char* c = s.c_str();
+		size_t hashval = 0;
+		for (size_t i=0; i<len; i++)
+		{
+			hashval = ((hashval<<5) + hashval) + *c++;
+		}
+		return hashval;
+	}
+
+	std::string string;
+	size_t		string_hash;
+};
+
+struct LLStaticStringHasher
+{
+	enum { bucket_size = 8 };
+	size_t operator()(const LLStaticHashedString& key_value) const { return key_value.Hash(); }
+	bool operator()(const LLStaticHashedString& left, const LLStaticHashedString& right) const { return left.Hash() < right.Hash(); }
+};
+
+template< typename MappedObject >
+class LL_COMMON_API LLStaticStringTable
+	: public boost::unordered_map< LLStaticHashedString, MappedObject, LLStaticStringHasher >
+{
+};
+
+#endif
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