moving src/common to src/
This commit is contained in:
Henrik Hautakoski
parent
22d7238b36
commit
cfb5e85699
20 changed files with 49 additions and 50 deletions
337
src/rbtree.c
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337
src/rbtree.c
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/* rbtree.c - red black tree implementation
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*
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* Copyright (C) 2010 Henrik Hautakoski <henrik@fiktivkod.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Based on the work of Julienne Walker's rbtree implementation
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* http://www.eternallyconfuzzled.com/tuts/datastructures/jsw_tut_rbtree.aspx
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*/
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#include "xalloc.h"
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#include "debug.h"
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#include "rbtree.h"
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#define is_red(n) ((n) != NULL && (n)->color == RB_RED)
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#define swap(n,d,q) ((n)->child[(n)->child[d] == (q)])
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static rbnode* node_alloc(uint key, void *ptr, size_t len) {
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rbnode *n = xmalloc(sizeof(rbnode));
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n->key = key;
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n->data = ptr;
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n->len = len;
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n->color = RB_RED;
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n->child[0] = NULL;
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n->child[1] = NULL;
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return n;
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}
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/*
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* Recursivly deallocate a tree.
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*/
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static void node_dealloc(rbnode *n, void (*action)(rbnode *)) {
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if (!n)
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return;
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if (action) {
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action(n);
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} else if (n->data) {
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xfree(n->data);
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n->data = NULL;
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}
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node_dealloc(n->child[0], action);
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node_dealloc(n->child[1], action);
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xfree(n);
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}
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/*
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* Recursivly walks a tree, applying action function on every node
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*/
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static void rbwalk(rbnode *n, void (*action)(rbnode *)) {
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if (n == NULL)
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return;
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action(n);
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rbwalk(n->child[0], action);
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rbwalk(n->child[1], action);
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}
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static inline int datacmp(void *d1, void *d2, size_t l) {
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if (d1 == NULL || d2 == NULL)
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return d1 == d2;
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return !memcmp(d1, d2, l);
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}
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/*
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* Compares every node's data member with cmpdata along the
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* path. comparison is done at memory level and returns the first node that match.
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*/
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static rbnode* rbcmp(rbnode *n, void *cmpdata, size_t len) {
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rbnode *r;
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if (!n)
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return NULL;
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dprint("CMP %s - %s\n", (char*)n->data, (char*)cmpdata);
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if (datacmp(n->data, cmpdata, len))
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return n;
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r = rbcmp(n->child[0], cmpdata, len);
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if (r == NULL)
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r = rbcmp(n->child[1], cmpdata, len);
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return r;
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}
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static inline rbnode* rotate_single(rbnode *root, unsigned char dir) {
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rbnode *save = root->child[!dir];
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root->child[!dir] = save->child[dir];
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save->child[dir] = root;
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root->color = RB_RED;
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save->color = RB_BLACK;
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return save;
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}
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static inline rbnode* rotate_double(rbnode *root, unsigned char dir) {
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root->child[!dir] = rotate_single(root->child[!dir], !dir);
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return rotate_single(root, dir);
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}
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inline int rbtree_is_empty(rbtree *tree) {
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return tree == NULL || tree->root == NULL;
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}
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/*
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* Searches a tree by key.
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*/
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rbnode* rbtree_search(rbtree *tree, uint key) {
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rbnode *n;
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if (tree == NULL || tree->root == NULL)
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return NULL;
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n = tree->root;
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while(n) {
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dprint("SEARCH: check %u\n", n->key);
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if (n->key == key)
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break;
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n = n->child[n->key < key];
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}
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return n;
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}
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rbnode* rbtree_cmp_search(rbtree *tree, void *cmpdata, size_t len) {
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if (tree == NULL)
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return NULL;
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return rbcmp(tree->root, cmpdata, len);
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}
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void rbtree_walk(rbtree *tree, void (*action)(rbnode *)) {
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if (tree == NULL)
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return;
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rbwalk(tree->root, action);
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}
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void rbtree_free(rbtree *tree, void (*action)(rbnode *)) {
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if (tree == NULL)
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return;
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node_dealloc(tree->root, action);
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tree->root = NULL;
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}
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/*
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* duplicate keys result in the tree remains unchanged
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* this can cause memory leaks as data fields can (should)
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* be heap allocated, and the client expects us to keep track of it.
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*
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* for general purposes, we should notify client about it so
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* then they can choose what to do
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*
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* the function now returns -1 in that situation // H Hautakoski
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*/
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int rbtree_insert(rbtree *tree, uint key, void *data, size_t len) {
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rbnode head = {0};
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/* grandparent and parent */
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rbnode *g, *t;
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/* iterator and parent */
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rbnode *p, *q;
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unsigned char dir = 0, dir2, last, inserted = 0;
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if (tree->root == NULL) {
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tree->root = node_alloc(key, data, len);
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if (tree->root == NULL)
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return 0;
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goto done;
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}
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t = &head;
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g = p = NULL;
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q = t->child[1] = tree->root;
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/* somewhere in here, there should be dragons */
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for(;;) {
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if (q == NULL) {
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p->child[dir] = q = node_alloc(key, data, len);
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if (q == NULL)
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return 0;
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inserted = 1;
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} else if (is_red(q->child[0]) && is_red(q->child[1])) {
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/* color flip case */
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q->color = RB_RED;
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q->child[0]->color = RB_BLACK;
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q->child[1]->color = RB_BLACK;
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}
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/* fix red validation */
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if (is_red(q) && is_red(p)) {
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dir2 = (t->child[1] == g);
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if (q == p->child[last])
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t->child[dir2] = rotate_single(g, !last);
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else
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t->child[dir2] = rotate_double(g, !last);
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}
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if (q->key == key)
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break;
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last = dir;
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dir = q->key < key;
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if (g)
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t = g;
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g = p, p = q;
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q = q->child[dir];
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}
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tree->root = head.child[1];
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done:
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/* root should be black */
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tree->root->color = RB_BLACK;
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if (!inserted)
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return -1;
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return 1;
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}
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void* rbtree_delete(rbtree *tree, uint key) {
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rbnode head = {0};
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/* helpers*/
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rbnode *q, *p, *g, *s;
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/* found item */
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rbnode *f = NULL;
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/* pointer to the data member of the node we delete,
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returned so it can be free'd */
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void *ret = NULL;
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unsigned char dir = 1, dir2, last;
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if (rbtree_is_empty(tree))
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return NULL;
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q = &head;
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g = p = NULL;
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q->child[1] = tree->root;
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/* more dragons (killed some of them though) */
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while(q->child[dir]) {
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last = dir;
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g = p, p = q;
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q = q->child[dir];
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dir = q->key < key;
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if (q->key == key)
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f = q;
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if (is_red(q) || is_red(q->child[dir]))
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continue;
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if (is_red(q->child[!dir])) {
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p = p->child[last] = rotate_single(q, dir);
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} else {
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s = p->child[!last];
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if (s == NULL)
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continue;
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if (!is_red(s->child[!last]) && !is_red(s->child[last])) {
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p->color = RB_BLACK;
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s->color = q->color = RB_RED;
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} else {
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dir2 = (g->child[1] == p);
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if (is_red(s->child[last]))
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g->child[dir2] = rotate_double(p, last);
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else if (is_red(s->child[!last]))
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g->child[dir2] = rotate_single(p, last);
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q->color = g->child[dir2]->color = RB_RED;
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g->child[dir2]->child[0]->color = RB_BLACK;
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g->child[dir2]->child[1]->color = RB_BLACK;
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}
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}
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}
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tree->root = head.child[1];
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if (tree->root)
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tree->root->color = RB_BLACK;
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/* remove if found */
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if (f) {
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ret = f->data;
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if (f != q) {
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f->key = q->key;
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f->data = xmemdup(q->data, q->len);
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f->len = q->len;
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}
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swap(p, 1, q) = swap(q, 0, NULL);
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xfree(q);
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}
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return ret;
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}
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