diff options
Diffstat (limited to 'src/search/tsearch_avl.c')
-rw-r--r-- | src/search/tsearch_avl.c | 204 |
1 files changed, 0 insertions, 204 deletions
diff --git a/src/search/tsearch_avl.c b/src/search/tsearch_avl.c deleted file mode 100644 index 57194c84..00000000 --- a/src/search/tsearch_avl.c +++ /dev/null @@ -1,204 +0,0 @@ -#include <stdlib.h> -#include <search.h> - -/* -avl tree implementation using recursive functions -the height of an n node tree is less than 1.44*log2(n+2)-1 -(so the max recursion depth in case of a tree with 2^32 nodes is 45) -*/ - -struct node { - const void *key; - struct node *left; - struct node *right; - int height; -}; - -static int delta(struct node *n) { - return (n->left ? n->left->height:0) - (n->right ? n->right->height:0); -} - -static void updateheight(struct node *n) { - n->height = 0; - if (n->left && n->left->height > n->height) - n->height = n->left->height; - if (n->right && n->right->height > n->height) - n->height = n->right->height; - n->height++; -} - -static struct node *rotl(struct node *n) { - struct node *r = n->right; - n->right = r->left; - r->left = n; - updateheight(n); - updateheight(r); - return r; -} - -static struct node *rotr(struct node *n) { - struct node *l = n->left; - n->left = l->right; - l->right = n; - updateheight(n); - updateheight(l); - return l; -} - -static struct node *balance(struct node *n) { - int d = delta(n); - - if (d < -1) { - if (delta(n->right) > 0) - n->right = rotr(n->right); - return rotl(n); - } else if (d > 1) { - if (delta(n->left) < 0) - n->left = rotl(n->left); - return rotr(n); - } - updateheight(n); - return n; -} - -static struct node *find(struct node *n, const void *k, - int (*cmp)(const void *, const void *)) -{ - int c; - - if (!n) - return 0; - c = cmp(k, n->key); - if (c == 0) - return n; - if (c < 0) - return find(n->left, k, cmp); - else - return find(n->right, k, cmp); -} - -static struct node *insert(struct node *n, const void *k, - int (*cmp)(const void *, const void *), struct node **found) -{ - struct node *r; - int c; - - if (!n) { - n = malloc(sizeof *n); - if (n) { - n->key = k; - n->left = n->right = 0; - n->height = 1; - } - *found = n; - return n; - } - c = cmp(k, n->key); - if (c == 0) { - *found = n; - return 0; - } - r = insert(c < 0 ? n->left : n->right, k, cmp, found); - if (r) { - if (c < 0) - n->left = r; - else - n->right = r; - r = balance(n); - } - return r; -} - -static struct node *remove_rightmost(struct node *n, struct node **rightmost) -{ - if (!n->right) { - *rightmost = n; - return n->left; - } - n->right = remove_rightmost(n->right, rightmost); - return balance(n); -} - -static struct node *remove(struct node **n, const void *k, - int (*cmp)(const void *, const void *), struct node *parent) -{ - int c; - - if (!*n) - return 0; - c = cmp(k, (*n)->key); - if (c == 0) { - struct node *r = *n; - if (r->left) { - r->left = remove_rightmost(r->left, n); - (*n)->left = r->left; - (*n)->right = r->right; - *n = balance(*n); - } else - *n = r->right; - free(r); - return parent; - } - if (c < 0) - parent = remove(&(*n)->left, k, cmp, *n); - else - parent = remove(&(*n)->right, k, cmp, *n); - if (parent) - *n = balance(*n); - return parent; -} - -void *tdelete(const void *restrict key, void **restrict rootp, - int(*compar)(const void *, const void *)) -{ - if (!rootp) - return 0; - struct node *n = *rootp; - struct node *ret; - /* last argument is arbitrary non-null pointer - which is returned when the root node is deleted */ - ret = remove(&n, key, compar, n); - *rootp = n; - return ret; -} - -void *tfind(const void *key, void *const *rootp, - int(*compar)(const void *, const void *)) -{ - if (!rootp) - return 0; - return find(*rootp, key, compar); -} - -void *tsearch(const void *key, void **rootp, - int (*compar)(const void *, const void *)) -{ - struct node *update; - struct node *ret; - if (!rootp) - return 0; - update = insert(*rootp, key, compar, &ret); - if (update) - *rootp = update; - return ret; -} - -static void walk(const struct node *r, void (*action)(const void *, VISIT, int), int d) -{ - if (r == 0) - return; - if (r->left == 0 && r->right == 0) - action(r, leaf, d); - else { - action(r, preorder, d); - walk(r->left, action, d+1); - action(r, postorder, d); - walk(r->right, action, d+1); - action(r, endorder, d); - } -} - -void twalk(const void *root, void (*action)(const void *, VISIT, int)) -{ - walk(root, action, 0); -} |