ucx: ucx/avl.c@bec61f067ea0 (annotated)

ucx/avl.c@bec61f067ea0 (annotated)

ucx/avl.c

Mon, 18 May 2015 12:54:18 +0200

author: Mike Becker <universe@uap-core.de>
date: Mon, 18 May 2015 12:54:18 +0200
changeset 195: bec61f067ea0
parent 194: 0c1b7676e74c
child 196: 1b4cdafef2eb
permissions: -rw-r--r--

added AVL tree implementation - TODO: free memory + test cases

 /*
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
  *
  * Copyright 2015 Olaf Wintermann. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *   1. Redistributions of source code must retain the above copyright
  *      notice, this list of conditions and the following disclaimer.
  *
  *   2. Redistributions in binary form must reproduce the above copyright
  *      notice, this list of conditions and the following disclaimer in the
  *      documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include "avl.h"
 #define ptrcast(ptr) ((void*)(ptr))
 static void ucx_avl_connect(UcxAVLTree *tree,
         UcxAVLNode *node, UcxAVLNode *child, intptr_t nullkey) {
     if (child) {
         child->parent = node;
     }
     // if child is NULL, nullkey decides if left or right pointer is cleared
     if (tree->cmpfunc(
         ptrcast(child ? child->key : nullkey),
         ptrcast(node->key), tree->userdata) > 0) {
       node->right = child;
     } else {
       node->left = child;
     }
     size_t lh = node->left ? node->left->height : 0;
     size_t rh = node->right ? node->right->height : 0;
     node->height = 1 + (lh > rh ? lh : rh);
 }
 #define avlheight(node) ((node) ? (node)->height : 0)
 static UcxAVLNode* avl_rotright(UcxAVLTree *tree, UcxAVLNode *l0) {
     UcxAVLNode *p = l0->parent;
     UcxAVLNode *l1 = l0->left;
     if (p) {
         ucx_avl_connect(tree, p, l1, 0);
     } else {
         l1->parent = NULL;
     }
     ucx_avl_connect(tree, l0, l1->right, l1->key);
     ucx_avl_connect(tree, l1, l0, 0);
     return l1;
 }
 static UcxAVLNode* avl_rotleft(UcxAVLTree *tree, UcxAVLNode *l0) {
     UcxAVLNode *p = l0->parent;
     UcxAVLNode *l1 = l0->right;
     if (p) {
         ucx_avl_connect(tree, p, l1, 0);
     } else {
         l1->parent = NULL;
     }
     ucx_avl_connect(tree, l0, l1->left, l1->key);
     ucx_avl_connect(tree, l1, l0, 0);
     return l1;
 }
 static void ucx_avl_balance(UcxAVLTree *tree, UcxAVLNode *n) {
     int lh = avlheight(n->left);
     int rh = avlheight(n->right);
     n->height = 1 + (lh > rh ? lh : rh);
     if (lh - rh == 2) {
       UcxAVLNode *c = n->left;
       if (avlheight(c->right) - avlheight(c->left) == 1) {
         avl_rotleft(tree, c);
       }
       n = avl_rotright(tree, n);
     } else if (rh - lh == 2) {
       UcxAVLNode *c = n->right;
       if (avlheight(c->left) - avlheight(c->right) == 1) {
         avl_rotright(tree, c);
       }
       n = avl_rotleft(tree, n);
     }
     if (n->parent) {
       ucx_avl_balance(tree, n->parent);
     } else {
       tree->root = n;
     }
 }
 UcxAVLTree *ucx_avl_new(cmp_func cmpfunc) {
     return ucx_avl_new_a(cmpfunc, ucx_default_allocator());
 }
 UcxAVLTree *ucx_avl_new_a(cmp_func cmpfunc, UcxAllocator *allocator) {
     UcxAVLTree *tree = malloc(sizeof(UcxAVLTree));
     if (tree) {
         tree->allocator = allocator;
         tree->cmpfunc = cmpfunc;
         tree->root = NULL;
         tree->userdata = NULL;
     }
     return tree;
 }
 void *ucx_avl_get(UcxAVLTree *tree, intptr_t key) {
     UcxAVLNode *n = tree->root;
     int cmpresult;
     while (n && (cmpresult = tree->cmpfunc(
             ptrcast(key), ptrcast(n->key), tree->userdata))) {
         n = cmpresult > 0 ? n->right : n->left;
     }
     return n ? n->value : NULL;
 }
 void* ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value) {
     if (tree->root) {
         UcxAVLNode *n = tree->root;
         int cmpresult;
         while (cmpresult = tree->cmpfunc(
                 ptrcast(key), ptrcast(n->key), tree->userdata)) {
             UcxAVLNode *m = cmpresult > 0 ? n->right : n->left;
             if (m) {
                 n = m;
             } else {
                 break;
             }
         }
         if (cmpresult) {
             UcxAVLNode *e = malloc(sizeof(UcxAVLNode));
             e->key = key; e->value = value; e->height = 1;
             e->parent = e->left = e->right = NULL;
             ucx_avl_connect(tree, n, e, 0);
             ucx_avl_balance(tree, n);
             return NULL;
         } else {
             void *prevval = n->value;
             n->value = value;
             return prevval;
         }
     } else {
         tree->root = malloc(sizeof(UcxAVLNode));
         tree->root->key = key; tree->root->value = value;
         tree->root->height = 1;
         tree->root->parent = tree->root->left = tree->root->right = NULL;
         return NULL;
     }
 }
 void* ucx_avl_remove(UcxAVLTree *tree, intptr_t key) {
     UcxAVLNode *n = tree->root;
     int cmpresult;
     while (n && (cmpresult = tree->cmpfunc(
             ptrcast(key), ptrcast(n->key), tree->userdata))) {
         n = cmpresult > 0 ? n->right : n->left;
     }
     if (n) {
         void *prevval = n->value;
         UcxAVLNode *p = n->parent;
         if (n->left && n->right) {
             UcxAVLNode *s = n->right;
             while (s->left) {
                 s = s->left;
             }
             ucx_avl_connect(tree, s->parent, s->right, s->key);
             n->key = s->key; n->value = s->value;
             p = s->parent;
         } else {
             if (p) {
                 ucx_avl_connect(tree, p, n->right ? n->right:n->left, n->key);
             } else {
                 tree->root = n->right ? n->right : n->left;
             }
         }
         // TODO: free the correct memory
         if (p) {
             ucx_avl_balance(tree, p);
         }
         return prevval;
     } else {
         return NULL;
     }
 }

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ucx/avl.c@bec61f067ea0 (annotated)

ucx/avl.c