--- /dev/null
+/*
+rbtree - simple balanced binary search tree (red-black tree) library.
+Copyright (C) 2011-2014 John Tsiombikas <nuclear@member.fsf.org>
+
+rbtree is free software, feel free to use, modify, and redistribute it, under
+the terms of the 3-clause BSD license. See COPYING for details.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <string.h>
+#include "rbtree.h"
+
+#define INT2PTR(x) ((void*)(intptr_t)(x))
+#define PTR2INT(x) ((int)(intptr_t)(x))
+
+struct rbtree {
+ struct rbnode *root;
+
+ rb_alloc_func_t alloc;
+ rb_free_func_t free;
+
+ rb_cmp_func_t cmp;
+ rb_del_func_t del;
+ void *del_cls;
+
+ struct rbnode *rstack, *iter;
+};
+
+static int cmpaddr(const void *ap, const void *bp);
+static int cmpint(const void *ap, const void *bp);
+
+static int count_nodes(struct rbnode *node);
+static void del_tree(struct rbnode *node, void (*delfunc)(struct rbnode*, void*), void *cls);
+static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data);
+static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key);
+/*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key);*/
+static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls);
+
+struct rbtree *rb_create(rb_cmp_func_t cmp_func)
+{
+ struct rbtree *rb;
+
+ if(!(rb = malloc(sizeof *rb))) {
+ return 0;
+ }
+ if(rb_init(rb, cmp_func) == -1) {
+ free(rb);
+ return 0;
+ }
+ return rb;
+}
+
+void rb_free(struct rbtree *rb)
+{
+ rb_destroy(rb);
+ free(rb);
+}
+
+
+int rb_init(struct rbtree *rb, rb_cmp_func_t cmp_func)
+{
+ memset(rb, 0, sizeof *rb);
+
+ if(!cmp_func) {
+ rb->cmp = cmpaddr;
+ } else if(cmp_func == RB_KEY_INT) {
+ rb->cmp = cmpint;
+ } else if(cmp_func == RB_KEY_STRING) {
+ rb->cmp = (rb_cmp_func_t)strcmp;
+ } else {
+ rb->cmp = cmp_func;
+ }
+
+ rb->alloc = malloc;
+ rb->free = free;
+ return 0;
+}
+
+void rb_destroy(struct rbtree *rb)
+{
+ del_tree(rb->root, rb->del, rb->del_cls);
+}
+
+void rb_set_allocator(struct rbtree *rb, rb_alloc_func_t alloc, rb_free_func_t free)
+{
+ rb->alloc = alloc;
+ rb->free = free;
+}
+
+
+void rb_set_compare_func(struct rbtree *rb, rb_cmp_func_t func)
+{
+ rb->cmp = func;
+}
+
+void rb_set_delete_func(struct rbtree *rb, rb_del_func_t func, void *cls)
+{
+ rb->del = func;
+ rb->del_cls = cls;
+}
+
+
+void rb_clear(struct rbtree *rb)
+{
+ del_tree(rb->root, rb->del, rb->del_cls);
+ rb->root = 0;
+}
+
+int rb_copy(struct rbtree *dest, struct rbtree *src)
+{
+ struct rbnode *node;
+
+ rb_clear(dest);
+ rb_begin(src);
+ while((node = rb_next(src))) {
+ if(rb_insert(dest, node->key, node->data) == -1) {
+ return -1;
+ }
+ }
+ return 0;
+}
+
+int rb_size(struct rbtree *rb)
+{
+ return count_nodes(rb->root);
+}
+
+int rb_insert(struct rbtree *rb, void *key, void *data)
+{
+ rb->root = insert(rb, rb->root, key, data);
+ rb->root->red = 0;
+ return 0;
+}
+
+int rb_inserti(struct rbtree *rb, int key, void *data)
+{
+ rb->root = insert(rb, rb->root, INT2PTR(key), data);
+ rb->root->red = 0;
+ return 0;
+}
+
+
+int rb_delete(struct rbtree *rb, void *key)
+{
+ if((rb->root = delete(rb, rb->root, key))) {
+ rb->root->red = 0;
+ }
+ return 0;
+}
+
+int rb_deletei(struct rbtree *rb, int key)
+{
+ if((rb->root = delete(rb, rb->root, INT2PTR(key)))) {
+ rb->root->red = 0;
+ }
+ return 0;
+}
+
+
+struct rbnode *rb_find(struct rbtree *rb, void *key)
+{
+ struct rbnode *node = rb->root;
+
+ while(node) {
+ int cmp = rb->cmp(key, node->key);
+ if(cmp == 0) {
+ return node;
+ }
+ node = cmp < 0 ? node->left : node->right;
+ }
+ return 0;
+}
+
+struct rbnode *rb_findi(struct rbtree *rb, int key)
+{
+ return rb_find(rb, INT2PTR(key));
+}
+
+
+void rb_foreach(struct rbtree *rb, void (*func)(struct rbnode*, void*), void *cls)
+{
+ traverse(rb->root, func, cls);
+}
+
+
+struct rbnode *rb_root(struct rbtree *rb)
+{
+ return rb->root;
+}
+
+void rb_begin(struct rbtree *rb)
+{
+ rb->rstack = 0;
+ rb->iter = rb->root;
+}
+
+#define push(sp, x) ((x)->next = (sp), (sp) = (x))
+#define pop(sp) ((sp) = (sp)->next)
+#define top(sp) (sp)
+
+struct rbnode *rb_next(struct rbtree *rb)
+{
+ struct rbnode *res = 0;
+
+ while(rb->rstack || rb->iter) {
+ if(rb->iter) {
+ push(rb->rstack, rb->iter);
+ rb->iter = rb->iter->left;
+ } else {
+ rb->iter = top(rb->rstack);
+ pop(rb->rstack);
+ res = rb->iter;
+ rb->iter = rb->iter->right;
+ break;
+ }
+ }
+ return res;
+}
+
+void *rb_node_key(struct rbnode *node)
+{
+ return node ? node->key : 0;
+}
+
+int rb_node_keyi(struct rbnode *node)
+{
+ return node ? PTR2INT(node->key) : 0;
+}
+
+void *rb_node_data(struct rbnode *node)
+{
+ return node ? node->data : 0;
+}
+
+static int cmpaddr(const void *ap, const void *bp)
+{
+ return ap < bp ? -1 : (ap > bp ? 1 : 0);
+}
+
+static int cmpint(const void *ap, const void *bp)
+{
+ return PTR2INT(ap) - PTR2INT(bp);
+}
+
+
+/* ---- left-leaning 2-3 red-black implementation ---- */
+
+/* helper prototypes */
+static int is_red(struct rbnode *tree);
+static void color_flip(struct rbnode *tree);
+static struct rbnode *rot_left(struct rbnode *a);
+static struct rbnode *rot_right(struct rbnode *a);
+static struct rbnode *find_min(struct rbnode *tree);
+static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree);
+/*static struct rbnode *move_red_right(struct rbnode *tree);*/
+static struct rbnode *move_red_left(struct rbnode *tree);
+static struct rbnode *fix_up(struct rbnode *tree);
+
+static int count_nodes(struct rbnode *node)
+{
+ if(!node)
+ return 0;
+
+ return 1 + count_nodes(node->left) + count_nodes(node->right);
+}
+
+static void del_tree(struct rbnode *node, rb_del_func_t delfunc, void *cls)
+{
+ if(!node)
+ return;
+
+ del_tree(node->left, delfunc, cls);
+ del_tree(node->right, delfunc, cls);
+
+ if(delfunc) {
+ delfunc(node, cls);
+ }
+ free(node);
+}
+
+static struct rbnode *insert(struct rbtree *rb, struct rbnode *tree, void *key, void *data)
+{
+ int cmp;
+
+ if(!tree) {
+ struct rbnode *node = rb->alloc(sizeof *node);
+ node->red = 1;
+ node->key = key;
+ node->data = data;
+ node->left = node->right = 0;
+ return node;
+ }
+
+ cmp = rb->cmp(key, tree->key);
+
+ if(cmp < 0) {
+ tree->left = insert(rb, tree->left, key, data);
+ } else if(cmp > 0) {
+ tree->right = insert(rb, tree->right, key, data);
+ } else {
+ tree->data = data;
+ }
+
+ /* fix right-leaning reds */
+ if(is_red(tree->right)) {
+ tree = rot_left(tree);
+ }
+ /* fix two reds in a row */
+ if(is_red(tree->left) && is_red(tree->left->left)) {
+ tree = rot_right(tree);
+ }
+
+ /* if 4-node, split it by color inversion */
+ if(is_red(tree->left) && is_red(tree->right)) {
+ color_flip(tree);
+ }
+
+ return tree;
+}
+
+static struct rbnode *delete(struct rbtree *rb, struct rbnode *tree, void *key)
+{
+ int cmp;
+
+ if(!tree) {
+ return 0;
+ }
+
+ cmp = rb->cmp(key, tree->key);
+
+ if(cmp < 0) {
+ if(!is_red(tree->left) && !is_red(tree->left->left)) {
+ tree = move_red_left(tree);
+ }
+ tree->left = delete(rb, tree->left, key);
+ } else {
+ /* need reds on the right */
+ if(is_red(tree->left)) {
+ tree = rot_right(tree);
+ }
+
+ /* found it at the bottom (XXX what certifies left is null?) */
+ if(cmp == 0 && !tree->right) {
+ if(rb->del) {
+ rb->del(tree, rb->del_cls);
+ }
+ rb->free(tree);
+ return 0;
+ }
+
+ if(!is_red(tree->right) && !is_red(tree->right->left)) {
+ tree = move_red_left(tree);
+ }
+
+ if(key == tree->key) {
+ struct rbnode *rmin = find_min(tree->right);
+ tree->key = rmin->key;
+ tree->data = rmin->data;
+ tree->right = del_min(rb, tree->right);
+ } else {
+ tree->right = delete(rb, tree->right, key);
+ }
+ }
+
+ return fix_up(tree);
+}
+
+/*static struct rbnode *find(struct rbtree *rb, struct rbnode *node, void *key)
+{
+ int cmp;
+
+ if(!node)
+ return 0;
+
+ if((cmp = rb->cmp(key, node->key)) == 0) {
+ return node;
+ }
+ return find(rb, cmp < 0 ? node->left : node->right, key);
+}*/
+
+static void traverse(struct rbnode *node, void (*func)(struct rbnode*, void*), void *cls)
+{
+ if(!node)
+ return;
+
+ traverse(node->left, func, cls);
+ func(node, cls);
+ traverse(node->right, func, cls);
+}
+
+/* helpers */
+
+static int is_red(struct rbnode *tree)
+{
+ return tree && tree->red;
+}
+
+static void color_flip(struct rbnode *tree)
+{
+ tree->red = !tree->red;
+ tree->left->red = !tree->left->red;
+ tree->right->red = !tree->right->red;
+}
+
+static struct rbnode *rot_left(struct rbnode *a)
+{
+ struct rbnode *b = a->right;
+ a->right = b->left;
+ b->left = a;
+ b->red = a->red;
+ a->red = 1;
+ return b;
+}
+
+static struct rbnode *rot_right(struct rbnode *a)
+{
+ struct rbnode *b = a->left;
+ a->left = b->right;
+ b->right = a;
+ b->red = a->red;
+ a->red = 1;
+ return b;
+}
+
+static struct rbnode *find_min(struct rbnode *tree)
+{
+ if(!tree)
+ return 0;
+
+ while(tree->left) {
+ tree = tree->left;
+ }
+ return tree;
+}
+
+static struct rbnode *del_min(struct rbtree *rb, struct rbnode *tree)
+{
+ if(!tree->left) {
+ if(rb->del) {
+ rb->del(tree->left, rb->del_cls);
+ }
+ rb->free(tree->left);
+ return 0;
+ }
+
+ /* make sure we've got red (3/4-nodes) at the left side so we can delete at the bottom */
+ if(!is_red(tree->left) && !is_red(tree->left->left)) {
+ tree = move_red_left(tree);
+ }
+ tree->left = del_min(rb, tree->left);
+
+ /* fix right-reds, red-reds, and split 4-nodes on the way up */
+ return fix_up(tree);
+}
+
+#if 0
+/* push a red link on this node to the right */
+static struct rbnode *move_red_right(struct rbnode *tree)
+{
+ /* flipping it makes both children go red, so we have a red to the right */
+ color_flip(tree);
+
+ /* if after the flip we've got a red-red situation to the left, fix it */
+ if(is_red(tree->left->left)) {
+ tree = rot_right(tree);
+ color_flip(tree);
+ }
+ return tree;
+}
+#endif
+
+/* push a red link on this node to the left */
+static struct rbnode *move_red_left(struct rbnode *tree)
+{
+ /* flipping it makes both children go red, so we have a red to the left */
+ color_flip(tree);
+
+ /* if after the flip we've got a red-red on the right-left, fix it */
+ if(is_red(tree->right->left)) {
+ tree->right = rot_right(tree->right);
+ tree = rot_left(tree);
+ color_flip(tree);
+ }
+ return tree;
+}
+
+static struct rbnode *fix_up(struct rbnode *tree)
+{
+ /* fix right-leaning */
+ if(is_red(tree->right)) {
+ tree = rot_left(tree);
+ }
+ /* change invalid red-red pairs into a proper 4-node */
+ if(is_red(tree->left) && is_red(tree->left->left)) {
+ tree = rot_right(tree);
+ }
+ /* split 4-nodes */
+ if(is_red(tree->left) && is_red(tree->right)) {
+ color_flip(tree);
+ }
+ return tree;
+}
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