/indra/llcommon/llsimplehash.h
C++ Header | 155 lines | 119 code | 9 blank | 27 comment | 10 complexity | 303a298c59745b98a766257b720adc83 MD5 | raw file
Possible License(s): LGPL-2.1
- /**
- * @file llsimplehash.h
- *
- * $LicenseInfo:firstyear=2003&license=viewerlgpl$
- * 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_LLSIMPLEHASH_H
- #define LL_LLSIMPLEHASH_H
- #include "llstl.h"
- template <typename HASH_KEY_TYPE>
- class LLSimpleHashEntry
- {
- protected:
- HASH_KEY_TYPE mHashKey;
- LLSimpleHashEntry<HASH_KEY_TYPE>* mNextEntry;
- public:
- LLSimpleHashEntry(HASH_KEY_TYPE key) :
- mHashKey(key),
- mNextEntry(0)
- {
- }
- virtual ~LLSimpleHashEntry()
- {
- }
- HASH_KEY_TYPE getHashKey() const
- {
- return mHashKey;
- }
- LLSimpleHashEntry<HASH_KEY_TYPE>* getNextEntry() const
- {
- return mNextEntry;
- }
- void setNextEntry(LLSimpleHashEntry<HASH_KEY_TYPE>* next)
- {
- mNextEntry = next;
- }
- };
- template <typename HASH_KEY_TYPE, int TABLE_SIZE>
- class LL_COMMON_API LLSimpleHash
- {
- public:
- LLSimpleHash()
- {
- llassert(TABLE_SIZE);
- llassert((TABLE_SIZE ^ (TABLE_SIZE-1)) == (TABLE_SIZE | (TABLE_SIZE-1))); // power of 2
- memset(mEntryTable, 0, sizeof(mEntryTable));
- }
- virtual ~LLSimpleHash()
- {
- }
- virtual int getIndex(HASH_KEY_TYPE key)
- {
- return key & (TABLE_SIZE-1);
- }
-
- bool insert(LLSimpleHashEntry<HASH_KEY_TYPE>* entry)
- {
- llassert(entry->getNextEntry() == 0);
- int index = getIndex(entry->getHashKey());
- entry->setNextEntry(mEntryTable[index]);
- mEntryTable[index] = entry;
- return true;
- }
- LLSimpleHashEntry<HASH_KEY_TYPE>* find(HASH_KEY_TYPE key)
- {
- int index = getIndex(key);
- LLSimpleHashEntry<HASH_KEY_TYPE>* res = mEntryTable[index];
- while(res && (res->getHashKey() != key))
- {
- res = res->getNextEntry();
- }
- return res;
- }
- bool erase(LLSimpleHashEntry<HASH_KEY_TYPE>* entry)
- {
- return erase(entry->getHashKey());
- }
- bool erase(HASH_KEY_TYPE key)
- {
- int index = getIndex(key);
- LLSimpleHashEntry<HASH_KEY_TYPE>* prev = 0;
- LLSimpleHashEntry<HASH_KEY_TYPE>* res = mEntryTable[index];
- while(res && (res->getHashKey() != key))
- {
- prev = res;
- res = res->getNextEntry();
- }
- if (res)
- {
- LLSimpleHashEntry<HASH_KEY_TYPE>* next = res->getNextEntry();
- if (prev)
- {
- prev->setNextEntry(next);
- }
- else
- {
- mEntryTable[index] = next;
- }
- return true;
- }
- else
- {
- return false;
- }
- }
- // Removes and returns an arbitrary ("first") element from the table
- // Used for deleting the entire table.
- LLSimpleHashEntry<HASH_KEY_TYPE>* pop_element()
- {
- for (int i=0; i<TABLE_SIZE; i++)
- {
- LLSimpleHashEntry<HASH_KEY_TYPE>* entry = mEntryTable[i];
- if (entry)
- {
- mEntryTable[i] = entry->getNextEntry();
- return entry;
- }
- }
- return 0;
- }
- // debugging
- LLSimpleHashEntry<HASH_KEY_TYPE>* get_element_at_index(S32 index) const
- {
- return mEntryTable[index];
- }
-
-
- private:
- LLSimpleHashEntry<HASH_KEY_TYPE>* mEntryTable[TABLE_SIZE];
- };
- #endif // LL_LLSIMPLEHASH_H