rbtree.c: use generic keys.
to make the rbtree more usefull. allow generic keys and user defined compare functions.
This commit is contained in:
Henrik Hautakoski
parent
f76f494dcc
commit
027bf154a7
4 changed files with 85 additions and 164 deletions
95
src/rbtree.c
95
src/rbtree.c
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@ -18,12 +18,11 @@
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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(unsigned key, void *data) {
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static rbnode* node_alloc(const void *key) {
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rbnode *n = xmalloc(sizeof(rbnode));
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n->key = key;
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n->data = data;
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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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@ -40,11 +39,11 @@ static void node_dealloc(rbnode *n, void (*dealloc)(void *)) {
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return;
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if (dealloc)
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dealloc(n->data);
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dealloc((void *)n->key);
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node_dealloc(n->child[0], dealloc);
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node_dealloc(n->child[1], dealloc);
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free(n);
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}
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@ -61,22 +60,6 @@ static void rbwalk(rbnode *n, void (*action)(rbnode *)) {
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rbwalk(n->child[1], action);
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}
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static rbnode* rbcmp(rbnode *n, int (*cmp_fn)(const char *, const char *), const void *cmpdata) {
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if (!n)
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return NULL;
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if (cmp_fn(n->data, cmpdata) == 0)
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return n;
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rbnode *r = rbcmp(n->child[0], cmp_fn, cmpdata);
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if (!r)
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r = rbcmp(n->child[1], cmp_fn, cmpdata);
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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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@ -103,34 +86,27 @@ inline int rbtree_is_empty(rbtree *tree) {
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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, unsigned key) {
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rbnode* rbtree_search(rbtree *tree, const void *key) {
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rbnode *n;
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if (tree == NULL || tree->root == NULL)
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if (tree == NULL || tree->root == NULL || tree->cmp_fn == NULL)
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return NULL;
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n = tree->root;
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while(n) {
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if (n->key == key)
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int cmp = tree->cmp_fn(n->key, key);
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if (cmp == 0)
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break;
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n = n->child[n->key < key];
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n = n->child[cmp < 0];
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}
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return n;
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}
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rbnode* rbtree_cmp_search(rbtree *tree, const void *cmpdata) {
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if (tree == NULL || tree->cmp_fn == NULL)
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return NULL;
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return rbcmp(tree->root, tree->cmp_fn, cmpdata);
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}
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void rbtree_walk(rbtree *tree, void (*action)(rbnode *)) {
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if (tree == NULL || action == NULL)
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@ -148,7 +124,7 @@ void rbtree_free(rbtree *tree) {
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tree->root = NULL;
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}
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int rbtree_insert(rbtree *tree, unsigned key, void *data) {
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int rbtree_insert(rbtree *tree, const void *key) {
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rbnode head = {0};
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@ -159,9 +135,12 @@ int rbtree_insert(rbtree *tree, unsigned key, void *data) {
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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 || !tree->cmp_fn)
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return 0;
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if (tree->root == NULL) {
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tree->root = node_alloc(key, data);
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tree->root = node_alloc(key);
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inserted = 1;
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goto done;
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}
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@ -173,8 +152,10 @@ int rbtree_insert(rbtree *tree, unsigned key, void *data) {
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/* somewhere in here, there should be dragons */
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for(;;) {
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int cmp;
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if (q == NULL) {
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p->child[dir] = q = node_alloc(key, data);
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p->child[dir] = q = node_alloc(key);
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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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@ -191,12 +172,14 @@ int rbtree_insert(rbtree *tree, unsigned key, void *data) {
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else
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t->child[dir2] = rotate_double(g, !last);
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}
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cmp = tree->cmp_fn(q->key, key);
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if (q->key == key)
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if (cmp == 0)
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break;
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last = dir;
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dir = q->key < key;
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dir = cmp < 0;
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if (g)
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t = g;
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@ -205,11 +188,9 @@ int rbtree_insert(rbtree *tree, unsigned key, void *data) {
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}
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if (!inserted) {
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if (tree->update_fn)
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tree->update_fn(q->data, data);
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if (tree->delete_fn)
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tree->delete_fn(q->data);
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q->data = data;
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tree->delete_fn((void*)q->key);
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q->key = key;
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}
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tree->root = head.child[1];
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@ -221,7 +202,7 @@ done:
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return inserted;
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}
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int rbtree_delete(rbtree *tree, unsigned key) {
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int rbtree_delete(rbtree *tree, const void *key) {
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rbnode head = {0};
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@ -233,7 +214,7 @@ int rbtree_delete(rbtree *tree, unsigned key) {
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unsigned char dir = 1, dir2, last;
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if (rbtree_is_empty(tree))
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if (rbtree_is_empty(tree) || !tree->cmp_fn)
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return 0;
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q = &head;
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@ -243,13 +224,15 @@ int rbtree_delete(rbtree *tree, unsigned key) {
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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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int cmp;
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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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q = q->child[dir];
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last = dir;
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cmp = tree->cmp_fn(q->key, key);
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dir = cmp < 0;
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if (cmp == 0)
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f = q;
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if (is_red(q) || is_red(q->child[dir]))
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@ -288,12 +271,10 @@ int rbtree_delete(rbtree *tree, unsigned key) {
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/* remove if found */
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if (f) {
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if (tree->delete_fn)
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tree->delete_fn(f->data);
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tree->delete_fn((void*)f->key);
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if (f != q) {
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f->key = q->key;
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f->data = q->data;
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}
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if (f != q)
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f->key = q->key;
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swap(p, 1, q) = swap(q, 0, NULL);
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xfree(q);
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return 1;
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14
src/rbtree.h
14
src/rbtree.h
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@ -18,8 +18,7 @@
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/* node definition */
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typedef struct _rbn {
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unsigned key;
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void *data;
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const void *key;
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struct _rbn *child[2];
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unsigned char color;
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} rbnode;
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@ -29,24 +28,21 @@ typedef struct {
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/* user defined operations */
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void (*delete_fn)(void *);
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void (*update_fn)(void *, void *);
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/* note: char* is used here to make dereference easier inside the function */
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int (*cmp_fn)(const char *, const char *);
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int (*cmp_fn)(const void *, const void *);
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} rbtree;
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#define RBTREE_INIT(delete, update, cmp) { NULL, delete, update, cmp}
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int rbtree_is_empty(rbtree *tree);
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rbnode* rbtree_search(rbtree *tree, unsigned key);
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rbnode* rbtree_cmp_search(rbtree *tree, const void *data);
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rbnode* rbtree_search(rbtree *tree, const void *key);
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void rbtree_walk(rbtree *tree, void (*action)(rbnode *));
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void rbtree_free(rbtree *tree);
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int rbtree_insert(rbtree *tree, unsigned key, void *data);
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int rbtree_insert(rbtree *tree, const void *key);
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int rbtree_delete(rbtree *tree, unsigned key);
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int rbtree_delete(rbtree *tree, const void *key);
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#endif /* __RBTREE_H */
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