diff -r 55adc92e7c09 -r 80609f9675f1 ucx/avl.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/avl.c	Mon May 23 12:28:32 2016 +0200
@@ -0,0 +1,272 @@
+/*
+ * 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 = almalloc(allocator, sizeof(UcxAVLTree));
+    if (tree) {
+        tree->allocator = allocator;
+        tree->cmpfunc = cmpfunc;
+        tree->root = NULL;
+        tree->userdata = NULL;
+    }
+    
+    return tree;
+}
+
+static void ucx_avl_free_node(UcxAllocator *al, UcxAVLNode *node) {
+    if (node) {
+        ucx_avl_free_node(al, node->left);
+        ucx_avl_free_node(al, node->right);
+        alfree(al, node);
+    }
+}
+
+void ucx_avl_free(UcxAVLTree *tree) {
+    UcxAllocator *al = tree->allocator;
+    ucx_avl_free_node(al, tree->root);
+    alfree(al, tree);
+}
+
+UcxAVLNode *ucx_avl_get_node(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;
+}
+
+void *ucx_avl_get(UcxAVLTree *tree, intptr_t key) {
+    UcxAVLNode *n = ucx_avl_get_node(tree, key);
+    return n ? n->value : NULL;
+}
+
+int ucx_avl_put(UcxAVLTree *tree, intptr_t key, void *value) {
+    return ucx_avl_put_s(tree, key, value, NULL);
+}
+
+int ucx_avl_put_s(UcxAVLTree *tree, intptr_t key, void *value,
+        void **oldvalue) {
+    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 = almalloc(tree->allocator, sizeof(UcxAVLNode));
+            if (e) {
+                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 0;
+            } else {
+                return 1;
+            }
+        } else {
+            if (oldvalue) {
+                *oldvalue = n->value;
+            }
+            n->value = value;
+            return 0;
+        }
+    } else {
+        tree->root = almalloc(tree->allocator, sizeof(UcxAVLNode));
+        if (tree->root) {
+            tree->root->key = key; tree->root->value = value;
+            tree->root->height = 1;
+            tree->root->parent = tree->root->left = tree->root->right = NULL;
+            
+            if (oldvalue) {
+                *oldvalue = NULL;
+            }
+            
+            return 0;
+        } else {
+            return 1;
+        }
+    }
+}
+
+int ucx_avl_remove(UcxAVLTree *tree, intptr_t key) {
+    return ucx_avl_remove_s(tree, key, NULL, NULL);
+}
+    
+int ucx_avl_remove_node(UcxAVLTree *tree, UcxAVLNode *node) {
+    return ucx_avl_remove_s(tree, node->key, NULL, NULL);
+}
+
+int ucx_avl_remove_s(UcxAVLTree *tree, intptr_t key,
+        intptr_t *oldkey, void **oldvalue) {
+    
+    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) {
+        if (oldkey) {
+            *oldkey = n->key;
+        }
+        if (oldvalue) {
+            *oldvalue = 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;
+            alfree(tree->allocator, s);
+        } 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;
+                if (tree->root) {
+                    tree->root->parent = NULL;
+                }
+            }
+            alfree(tree->allocator, n);
+        }
+
+        if (p) {
+            ucx_avl_balance(tree, p);
+        }
+        
+        return 0;
+    } else {
+        return 1;
+    }
+}
+
+static size_t ucx_avl_countn(UcxAVLNode *node) {
+    if (node) {
+        return 1 + ucx_avl_countn(node->left) + ucx_avl_countn(node->right);
+    } else {
+        return 0;
+    }
+}
+
+size_t ucx_avl_count(UcxAVLTree *tree) {
+    return ucx_avl_countn(tree->root);
+}