/**

 * vim: set ts=4 sw=4 tw=99 noet :

 * =============================================================================

 * SourceMod

 * Copyright (C) 2004-2008 AlliedModders LLC.  All rights reserved.

 * =============================================================================

 *

 * This program is free software; you can redistribute it and/or modify it under

 * the terms of the GNU General Public License, version 3.0, as published by the

 * Free Software Foundation.

 * 

 * This program 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 General Public License for more

 * details.

 *

 * You should have received a copy of the GNU General Public License along with

 * this program.  If not, see <http://www.gnu.org/licenses/>.

 *

 * As a special exception, AlliedModders LLC gives you permission to link the

 * code of this program (as well as its derivative works) to "Half-Life 2," the

 * "Source Engine," the "SourcePawn JIT," and any Game MODs that run on software

 * by the Valve Corporation.  You must obey the GNU General Public License in

 * all respects for all other code used.  Additionally, AlliedModders LLC grants

 * this exception to all derivative works.  AlliedModders LLC defines further

 * exceptions, found in LICENSE.txt (as of this writing, version JULY-31-2007),

 * or <http://www.sourcemod.net/license.php>.

 *

 * Version: $Id$

 */

#ifndef _include_sourcemod_hashtable_h_

#define _include_sourcemod_hashtable_h_

/**

 * @file sm_stringhashmap.h

 *

 * @brief Generic Key -> Value map class, based on a hash table. The Key, in

 * this case, is always an ASCII string, and the value type is a template

 * parameter. This class is intended as a drop-in replacement for KTrie

 * (though the retrieve() signature has been improved).

 *

 * If your Value type already contains the key string, consider using

 * NameHashSet instead.

 */

#include <am-allocator-policies.h>

#include <am-hashmap.h>

#include <am-string.h>

#include <string.h>

namespace SourceMod

{

using namespace ke;

namespace detail

{

	class CharsAndLength

	{

	 public:

	  CharsAndLength(const char *str)

		: str_(str),

		  length_(0)

	  {

		  int c;

		  uint32_t hash = 0;

		  while ((c = *str++))

			  hash = c + (hash << 6) + (hash << 16) - hash;

		  hash_ = hash;

		  length_ = str - str_ - 1;

	  }

	  uint32_t hash() const {

		  return hash_;

	  }

	  const char *chars() const {

		  return str_;

	  }

	  size_t length() const {

		  return length_;

	  }

	 private:

	  const char *str_;

	  size_t length_;

	  uint32_t hash_;

	};

	struct StringHashMapPolicy

	{

		static inline bool matches(const CharsAndLength &lookup, const AString &key) {

			return lookup.length() == key.length() &&

				   memcmp(lookup.chars(), key.chars(), key.length()) == 0;

		}

		static inline uint32_t hash(const CharsAndLength &key) {

			return key.hash();

		}

	};

}

template <typename T>

class StringHashMap

{

	typedef detail::CharsAndLength CharsAndLength;

	typedef HashMap<AString, T, detail::StringHashMapPolicy> Internal;

public:

	StringHashMap()

		: internal_(SystemAllocatorPolicy()),

		  memory_used_(0)

	{

		if (!internal_.init())

			internal_.reportOutOfMemory();

	}

	typedef typename Internal::Result Result;

	// Some KTrie-like helper functions.

	bool retrieve(const char *aKey, T *aResult = NULL)

	{

		CharsAndLength key(aKey);

		Result r = internal_.find(key);

		if (!r.found())

			return false;

		if (aResult)

			*aResult = r->value;

		return true;

	}

	Result find(const char *aKey)

	{

		CharsAndLength key(aKey);

		return internal_.find(key);

	}

	bool contains(const char *aKey)

	{

		CharsAndLength key(aKey);

		Result r = internal_.find(key);

		return r.found();

	}

	bool replace(const char *aKey, const T &value)

	{

		CharsAndLength key(aKey);

		typename Internal::Insert i = internal_.findForAdd(key);

		if (!i.found())

		{

			memory_used_ += key.length() + 1;

			if (!internal_.add(i))

				return false;

			i->key = aKey;

		}

		i->value = value;

		return true;

	}

	bool insert(const char *aKey, const T &value)

	{

		CharsAndLength key(aKey);

		typename Internal::Insert i = internal_.findForAdd(key);

		if (i.found())

			return false;

		if (!internal_.add(i))

			return false;

		memory_used_ += key.length() + 1;

		i->key = aKey;

		i->value = value;

		return true;

	}

	bool remove(const char *aKey)

	{

		CharsAndLength key(aKey);

		Result r = internal_.find(key);

		if (!r.found())

			return false;

		memory_used_ -= key.length() + 1;

		internal_.remove(r);

		return true;

	}

	void remove(Result &r)

	{

		internal_.remove(r);

	}

	void clear()

	{

		internal_.clear();

	}

	size_t mem_usage() const {

		return internal_.estimateMemoryUse() + memory_used_;

	}

private:

	Internal internal_;

	size_t memory_used_;

};

}

#endif // _include_sourcemod_hashtable_h_