/* $Id: kRbGet.h 35 2009-11-08 19:39:03Z bird $ */
/** @file
 * kRbTmpl - Templated Red-Black Trees, Get a Node.
 */

/*
 * Copyright (c) 1999-2009 Knut St. Osmundsen <bird-kStuff-spamix@anduin.net>
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * Gets a node from the tree (does not remove it!)
 *
 * @returns Pointer to the node holding the given key.
 * @param   pRoot       Pointer to the Red-Back tree's root structure.
 * @param   Key         Key value of the node which is to be found.
 */
KRB_DECL(KRBNODE *) KRB_FN(Get)(KRBROOT *pRoot, KRBKEY Key)
{
    KRBNODE *pNode;
#ifdef KRB_CACHE_SIZE
    KRBTREEPTR *ppEntry;
#endif

    KRB_READ_LOCK(pRoot);
    if (pRoot->mpRoot == KRB_NULL)
    {
        KRB_READ_UNLOCK(pRoot);
        return NULL;
    }

#ifdef KRB_CACHE_SIZE
    ppEntry = &pRoot->maLookthru[KRB_CACHE_HASH(Key)];
    pNode = KRB_GET_POINTER_NULL(ppEntry);
    if (!pNode || KRB_CMP_NE(pNode->mKey, Key))
#endif
    {
        pNode = KRB_GET_POINTER(&pRoot->mpRoot);
        while (KRB_CMP_NE(pNode->mKey, Key))
        {
            if (KRB_CMP_G(pNode->mKey, Key))
            {
                if (pNode->mpLeft == KRB_NULL)
                {
                    KRB_READ_UNLOCK(pRoot);
                    return NULL;
                }
                pNode = KRB_GET_POINTER(&pNode->mpLeft);
            }
            else
            {
                if (pNode->mpRight == KRB_NULL)
                {
                    KRB_READ_UNLOCK(pRoot);
                    return NULL;
                }
                pNode = KRB_GET_POINTER(&pNode->mpRight);
            }
        }

#ifdef KRB_CACHE_SIZE
        KRB_SET_POINTER(ppEntry, pNode);
#endif
    }

    KRB_READ_UNLOCK(pRoot);
    return pNode;
}