From: Florian Forster Date: Wed, 14 Feb 2007 16:42:00 +0000 (+0100) Subject: src/utils_avltree.c: Insertion works correktly. X-Git-Tag: collectd-4.0.0~187^2~2 X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=312e8cdc9c83155cd1fa0eab1509d0cc25d7a8e6;p=collectd.git src/utils_avltree.c: Insertion works correktly. --- diff --git a/src/utils_avltree.c b/src/utils_avltree.c index f2c5d06f..f6b15b15 100644 --- a/src/utils_avltree.c +++ b/src/utils_avltree.c @@ -1,10 +1,32 @@ +/** + * collectd - src/utils_avltree.c + * Copyright (C) 2006,2007 Florian octo Forster + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Authors: + * Florian octo Forster + **/ #include +#include #include #include "utils_avltree.h" -#define BALANCE(n) ((((n)->right == NULL) ? 0 : (n)->right->height) \ - - (((n)->left == NULL) ? 0 : (n)->left->height)) +#define BALANCE(n) ((((n)->left == NULL) ? 0 : (n)->left->height) \ + - (((n)->right == NULL) ? 0 : (n)->right->height)) /* * private data types @@ -36,6 +58,22 @@ struct avl_iterator_s /* * private functions */ +#if 1 +static void verify_tree (avl_node_t *n) +{ + if (n == NULL) + return; + + verify_tree (n->left); + verify_tree (n->right); + + assert ((BALANCE (n) >= -1) && (BALANCE (n) <= 1)); + assert ((n->parent == NULL) || (n->parent->right == n) || (n->parent->left == n)); +} /* void verify_tree */ +#else +# define verify_tree(n) /**/ +#endif + static void free_node (avl_node_t *n) { if (n == NULL) @@ -49,6 +87,22 @@ static void free_node (avl_node_t *n) free (n); } +static int calc_height (avl_node_t *n) +{ + int height_left; + int height_right; + + if (n == NULL) + return (0); + + height_left = (n->left == NULL) ? 0 : n->left->height; + height_right = (n->right == NULL) ? 0 : n->right->height; + + return (((height_left > height_right) + ? height_left + : height_right) + 1); +} /* int calc_height */ + static avl_node_t *search (avl_tree_t *t, const void *key) { avl_node_t *n; @@ -69,142 +123,140 @@ static avl_node_t *search (avl_tree_t *t, const void *key) return (NULL); } -static void rebalance (avl_tree_t *t, avl_node_t *n) +/* (x) (y) + * / \ / \ + * (y) /\ /\ (x) + * / \ /_c\ ==> / a\ / \ + * /\ /\ /____\/\ /\ + * / a\ /_b\ /_b\ /_c\ + * /____\ + */ +static avl_node_t *rotate_right (avl_tree_t *t, avl_node_t *x) { - int height_left; - int height_right; - int height_new; - int cmp; + avl_node_t *p; + avl_node_t *y; + avl_node_t *b; + + p = x->parent; + y = x->left; + b = y->right; + + x->left = b; + if (b != NULL) + b->parent = x; + + x->parent = y; + y->right = x; + + y->parent = p; + assert ((p == NULL) || (p->left == x) || (p->right == x)); + if (p == NULL) + t->root = y; + else if (p->left == x) + p->left = y; + else + p->right = y; - while (n != NULL) - { - height_left = (n->left == NULL) ? 0 : n->left->height; - height_right = (n->right == NULL) ? 0 : n->right->height; + x->height = calc_height (x); + y->height = calc_height (y); - height_new = 1 + ((height_left > height_right) ? height_left : height_right); + return (y); +} /* void rotate_left */ - if (height_new == n->height) - break; +/* + * (x) (y) + * / \ / \ + * /\ (y) (x) /\ + * /_a\ / \ ==> / \ / c\ + * /\ /\ /\ /\/____\ + * /_b\ / c\ /_a\ /_b\ + * /____\ + */ +static avl_node_t *rotate_left (avl_tree_t *t, avl_node_t *x) +{ + avl_node_t *p; + avl_node_t *y; + avl_node_t *b; + + p = x->parent; + y = x->right; + b = y->left; + + x->right = b; + if (b != NULL) + b->parent = x; + + x->parent = y; + y->left = x; + + y->parent = p; + assert ((p == NULL) || (p->left == x) || (p->right == x)); + if (p == NULL) + t->root = y; + else if (p->left == x) + p->left = y; + else + p->right = y; - /* FIXME */ - if (n->left != NULL) - { - cmp = BALANCE(n->left); - assert ((cmp >= -1) && (cmp <= 1)); - } - if (n->right != NULL) - { - cmp = BALANCE(n->right); - assert ((cmp >= -1) && (cmp <= 1)); - } + x->height = calc_height (x); + y->height = calc_height (y); - n->height = height_new; + return (y); +} /* void rotate_left */ - cmp = height_right - height_left; - if (cmp < -1) - { - avl_node_t *l; - avl_node_t *lr; +static avl_node_t *rotate_left_right (avl_tree_t *t, avl_node_t *x) +{ + rotate_left (t, x->left); + return (rotate_right (t, x)); +} /* void rotate_left_right */ - l = n->left; - lr = l->right; +static avl_node_t *rotate_right_left (avl_tree_t *t, avl_node_t *x) +{ + rotate_right (t, x->right); + return (rotate_left (t, x)); +} /* void rotate_right_left */ - l->right = n; - l->parent = n->parent; - n->parent = l; - n->left = lr; +static void rebalance (avl_tree_t *t, avl_node_t *n) +{ + int b_top; + int b_bottom; - if (lr != NULL) - lr->parent = n; + while (n != NULL) + { + b_top = BALANCE (n); + assert ((b_top >= -2) && (b_top <= 2)); - if (l->parent == NULL) - { - assert (t->root == n); - t->root = l; - } + if (b_top == -2) + { + assert (n->right != NULL); + b_bottom = BALANCE (n->right); + assert ((b_bottom == -1) || (b_bottom == 1)); + if (b_bottom == -1) + n = rotate_left (t, n); else - { - assert ((l->parent->left == n) || (l->parent->right == n)); - if (l->parent->left == n) - l->parent->left = l; - else - l->parent->right = l; - } - - height_left = (n->left == NULL) ? 0 : n->left->height; - height_right = (n->right == NULL) ? 0 : n->right->height; - height_new = 1 + ((height_left > height_right) ? height_left : height_right); - cmp = BALANCE(n); - assert (height_new < n->height); - assert ((cmp >= -1) || (cmp <= 1)); - n->height = height_new; - - height_left = (l->left == NULL) ? 0 : l->left->height; - height_right = (l->right == NULL) ? 0 : l->right->height; - height_new = 1 + ((height_left > height_right) ? height_left : height_right); - cmp = BALANCE(l); - assert (height_new >= l->height); - assert ((cmp >= -1) || (cmp <= 1)); - l->height = height_new; - - n = l->parent; + n = rotate_right_left (t, n); } - else if (cmp > 1) + else if (b_top == 2) { - avl_node_t *r; - avl_node_t *rl; - - r = n->right; - rl = r->left; - - r->left = n; - r->parent = n->parent; - n->parent = r; - n->right = rl; - - if (rl != NULL) - rl->parent = n; - - if (r->parent == NULL) - { - assert (t->root == n); - t->root = r; - } + assert (n->left != NULL); + b_bottom = BALANCE (n->left); + assert ((b_bottom == -1) || (b_bottom == 1)); + if (b_bottom == -1) + n = rotate_left_right (t, n); else - { - assert ((r->parent->left == n) || (r->parent->right == n)); - if (r->parent->left == n) - r->parent->left = r; - else - r->parent->right = r; - } - - height_left = (n->left == NULL) ? 0 : n->left->height; - height_right = (n->right == NULL) ? 0 : n->right->height; - height_new = 1 + ((height_left > height_right) ? height_left : height_right); - cmp = BALANCE(n); - assert (height_new < n->height); - assert ((cmp >= -1) || (cmp <= 1)); - n->height = height_new; - - height_left = (r->left == NULL) ? 0 : r->left->height; - height_right = (r->right == NULL) ? 0 : r->right->height; - height_new = 1 + ((height_left > height_right) ? height_left : height_right); - cmp = BALANCE(r); - assert (height_new >= r->height); - assert ((cmp >= -1) || (cmp <= 1)); - r->height = height_new; - - n = r->parent; + n = rotate_right (t, n); } else { - n = n->parent; + int height = calc_height (n); + if (height == n->height) + break; + n->height = height; } - assert ((n == NULL) || (n->parent == NULL) - || (n->parent->left == n) - || (n->parent->right == n)); + assert (n->height == calc_height (n)); + + n = n->parent; } /* while (n != NULL) */ } /* void rebalance */ @@ -311,7 +363,7 @@ static int _remove (avl_tree_t *t, avl_node_t *n) else { avl_node_t *r; /* replacement node */ - if (BALANCE (n) < 0) + if (BALANCE (n) > 0) { assert (n->left != NULL); r = avl_node_prev (t, n); @@ -321,6 +373,8 @@ static int _remove (avl_tree_t *t, avl_node_t *n) assert (n->right != NULL); r = avl_node_next (t, n); } + + /* copy content */ n->key = r->key; n->value = r->value; @@ -390,7 +444,7 @@ int avl_insert (avl_tree_t *t, void *key, void *value) { nptr->right = new; new->parent = nptr; - nptr = NULL; + rebalance (t, nptr); break; } else @@ -405,7 +459,7 @@ int avl_insert (avl_tree_t *t, void *key, void *value) { nptr->left = new; new->parent = nptr; - nptr = NULL; + rebalance (t, nptr); break; } else @@ -415,16 +469,14 @@ int avl_insert (avl_tree_t *t, void *key, void *value) } } /* while (42) */ - assert ((new->parent != NULL) - && ((new->parent->left == new) - || (new->parent->right == new))); - + verify_tree (t->root); return (0); } /* int avl_insert */ int avl_remove (avl_tree_t *t, void *key, void **rkey, void **rvalue) { avl_node_t *n; + int status; assert (t != NULL); @@ -437,7 +489,9 @@ int avl_remove (avl_tree_t *t, void *key, void **rkey, void **rvalue) if (rvalue != NULL) *rvalue = n->value; - return (_remove (t, n)); + status = _remove (t, n); + verify_tree (t->root); + return (status); } /* void *avl_remove */ int avl_get (avl_tree_t *t, const void *key, void **value)