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/* |
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* Dynamips |
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* Copyright (c) 2005 Christophe Fillot. |
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* E-mail: cf@utc.fr |
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* |
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* rbtree.c: Red/Black Trees. |
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*/ |
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|
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static const char rcsid[] = "$Id$"; |
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|
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <stdarg.h> |
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#include <unistd.h> |
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#include <errno.h> |
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#include <signal.h> |
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#include <fcntl.h> |
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#include <ctype.h> |
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|
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#include "utils.h" |
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#include "rbtree.h" |
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|
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#define rbtree_nil(tree) (&(tree)->nil) |
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#define NIL(tree,x) (((x) == rbtree_nil(tree)) || !x) |
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|
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/* Allocate memory for a new node */ |
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static rbtree_node *rbtree_node_alloc(rbtree_tree *tree,void *key,void *value) |
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{ |
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rbtree_node *node; |
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|
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if (!(node = mp_alloc_n0(&tree->mp,sizeof(*node)))) |
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return NULL; |
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|
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node->key = key; |
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node->value = value; |
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node->left = rbtree_nil(tree); |
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node->right = rbtree_nil(tree); |
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node->parent = rbtree_nil(tree); |
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node->color = -1; |
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return node; |
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} |
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|
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/* Free memory used by a node */ |
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static inline void rbtree_node_free(rbtree_tree *tree,rbtree_node *node) |
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{ |
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mp_free(node); |
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} |
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|
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/* Returns the node which represents the minimum value */ |
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static inline rbtree_node *rbtree_min(rbtree_tree *tree,rbtree_node *x) |
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{ |
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while(!NIL(tree,x->left)) |
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x = x->left; |
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|
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return(x); |
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} |
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|
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/* Returns the node which represents the maximum value */ |
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static inline rbtree_node *rbtree_max(rbtree_tree *tree,rbtree_node *x) |
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{ |
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while(!NIL(tree,x->right)) |
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x = x->right; |
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|
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return(x); |
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} |
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|
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/* Returns the successor of a node */ |
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static inline rbtree_node *rbtree_successor(rbtree_tree *tree,rbtree_node *x) |
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{ |
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rbtree_node *y; |
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|
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if (!NIL(tree,x->right)) |
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return(rbtree_min(tree,x->right)); |
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|
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y = x->parent; |
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while(!NIL(tree,y) && (x == y->right)) { |
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x = y; |
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y = y->parent; |
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} |
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|
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return(y); |
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} |
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|
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/* Left rotation */ |
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static inline void rbtree_left_rotate(rbtree_tree *tree,rbtree_node *x) |
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{ |
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rbtree_node *y; |
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|
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y = x->right; |
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x->right = y->left; |
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|
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if (!NIL(tree,x->right)) |
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x->right->parent = x; |
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|
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y->parent = x->parent; |
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|
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if (NIL(tree,x->parent)) |
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tree->root = y; |
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else { |
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if (x == x->parent->left) |
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x->parent->left = y; |
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else |
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x->parent->right = y; |
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} |
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|
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y->left = x; |
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x->parent = y; |
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} |
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|
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/* Right rotation */ |
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static inline void rbtree_right_rotate(rbtree_tree *tree,rbtree_node *y) |
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{ |
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rbtree_node *x; |
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|
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x = y->left; |
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y->left = x->right; |
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|
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if (!NIL(tree,y->left)) |
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y->left->parent = y; |
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|
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x->parent = y->parent; |
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|
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if (NIL(tree,y->parent)) |
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tree->root = x; |
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else { |
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if (y->parent->left == y) |
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y->parent->left = x; |
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else |
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y->parent->right = x; |
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} |
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|
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x->right = y; |
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y->parent = x; |
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} |
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|
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/* insert a new node */ |
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static rbtree_node *rbtree_insert_new(rbtree_tree *tree,void *key,void *value, |
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int *exists) |
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{ |
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rbtree_node *parent,*node,*new_node,**nodeplace; |
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int comp; |
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|
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nodeplace = &tree->root; |
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parent = NULL; |
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*exists = FALSE; |
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|
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for(;;) |
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{ |
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node = *nodeplace; |
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|
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if (NIL(tree,node)) |
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break; |
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|
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comp = tree->key_cmp(key,node->key,tree->opt_data); |
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|
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if (!comp) { |
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*exists = TRUE; |
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node->value = value; |
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return node; |
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} |
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|
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parent = node; |
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nodeplace = (comp > 0) ? &node->right : &node->left; |
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} |
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|
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/* create a new node */ |
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if (!(new_node = rbtree_node_alloc(tree,key,value))) |
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return NULL; |
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|
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*nodeplace = new_node; |
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new_node->parent = parent; |
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|
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tree->node_count++; |
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return new_node; |
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} |
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|
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/* Insert a node in a Red/Black Tree */ |
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int rbtree_insert(rbtree_tree *tree,void *key,void *value) |
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{ |
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rbtree_node *x,*y; |
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int exists; |
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|
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/* insert a new node (if necessary) */ |
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x = rbtree_insert_new(tree,key,value,&exists); |
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|
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if (exists) return(0); |
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if (!x) return(-1); |
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|
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tree->node_count++; |
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|
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/* maintains red-black properties */ |
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x->color = RBTREE_RED; |
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|
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while((x != tree->root) && (x->parent->color == RBTREE_RED)) |
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{ |
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if (x->parent == x->parent->parent->left) |
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{ |
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y = x->parent->parent->right; |
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|
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if (y->color == RBTREE_RED) |
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{ |
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x->parent->color = RBTREE_BLACK; |
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y->color = RBTREE_BLACK; |
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x->parent->parent->color = RBTREE_RED; |
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x = x->parent->parent; |
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} |
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else |
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{ |
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if (x == x->parent->right) { |
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x = x->parent; |
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rbtree_left_rotate(tree,x); |
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} |
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|
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x->parent->color = RBTREE_BLACK; |
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x->parent->parent->color = RBTREE_RED; |
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rbtree_right_rotate(tree,x->parent->parent); |
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} |
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} |
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else |
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{ |
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y = x->parent->parent->left; |
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|
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if (y->color == RBTREE_RED) |
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{ |
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x->parent->color = RBTREE_BLACK; |
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y->color = RBTREE_BLACK; |
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x->parent->parent->color = RBTREE_RED; |
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x = x->parent->parent; |
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} |
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else |
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{ |
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if (x == x->parent->left) { |
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x = x->parent; |
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rbtree_right_rotate(tree,x); |
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} |
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|
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x->parent->color = RBTREE_BLACK; |
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x->parent->parent->color = RBTREE_RED; |
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rbtree_left_rotate(tree,x->parent->parent); |
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} |
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} |
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} |
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|
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tree->root->color = RBTREE_BLACK; |
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return(0); |
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} |
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|
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/* Lookup for a node corresponding to "key" */ |
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static inline rbtree_node *rbtree_lookup_node(rbtree_tree *tree,void *key) |
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{ |
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rbtree_node *node; |
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int comp; |
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|
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node = tree->root; |
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|
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for (;;) { |
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if (NIL(tree,node)) /* key not found */ |
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break; |
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|
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if (!(comp = tree->key_cmp(key,node->key,tree->opt_data))) |
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break; /* exact match */ |
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|
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node = (comp > 0) ? node->right : node->left; |
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} |
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|
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return(node); |
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} |
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|
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/* |
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* Lookup for a node corresponding to "key". If node does not exist, |
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* function returns null pointer. |
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*/ |
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void *rbtree_lookup(rbtree_tree *tree,void *key) |
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{ |
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return(rbtree_lookup_node(tree,key)->value); |
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} |
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|
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/* Restore Red/black tree properties after a removal */ |
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static void rbtree_removal_fixup(rbtree_tree *tree,rbtree_node *x) |
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{ |
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rbtree_node *w; |
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|
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while((x != tree->root) && (x->color == RBTREE_BLACK)) |
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{ |
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if (x == x->parent->left) |
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{ |
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w = x->parent->right; |
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|
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if (w->color == RBTREE_RED) { |
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w->color = RBTREE_BLACK; |
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x->parent->color = RBTREE_RED; |
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rbtree_left_rotate(tree,x->parent); |
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w = x->parent->right; |
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} |
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|
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if ((w->left->color == RBTREE_BLACK) && |
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(w->right->color == RBTREE_BLACK)) |
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{ |
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w->color = RBTREE_RED; |
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x = x->parent; |
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} |
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else |
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{ |
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if (w->right->color == RBTREE_BLACK) { |
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w->left->color = RBTREE_BLACK; |
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w->color = RBTREE_RED; |
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rbtree_right_rotate(tree,w); |
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w = x->parent->right; |
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} |
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|
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w->color = x->parent->color; |
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x->parent->color = RBTREE_BLACK; |
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w->right->color = RBTREE_BLACK; |
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rbtree_left_rotate(tree,x->parent); |
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x = tree->root; |
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} |
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} |
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else |
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{ |
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w = x->parent->left; |
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|
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if (w->color == RBTREE_RED) { |
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w->color = RBTREE_BLACK; |
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x->parent->color = RBTREE_RED; |
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rbtree_right_rotate(tree,x->parent); |
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w = x->parent->left; |
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} |
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|
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if ((w->right->color == RBTREE_BLACK) && |
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(w->left->color == RBTREE_BLACK)) |
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{ |
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w->color = RBTREE_RED; |
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x = x->parent; |
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} |
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else |
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{ |
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if (w->left->color == RBTREE_BLACK) { |
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w->right->color = RBTREE_BLACK; |
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w->color = RBTREE_RED; |
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rbtree_left_rotate(tree,w); |
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w = x->parent->left; |
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} |
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|
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w->color = x->parent->color; |
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x->parent->color = RBTREE_BLACK; |
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w->left->color = RBTREE_BLACK; |
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rbtree_right_rotate(tree,x->parent); |
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x = tree->root; |
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} |
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} |
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} |
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|
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x->color = RBTREE_BLACK; |
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} |
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|
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/* Removes a node out of a tree */ |
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void *rbtree_remove(rbtree_tree *tree,void *key) |
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{ |
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rbtree_node *z = rbtree_lookup_node(tree,key); |
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rbtree_node *x,*y; |
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void *value; |
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|
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if (NIL(tree,z)) |
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return NULL; |
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|
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value = z->value; |
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|
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if (NIL(tree,z->left) || NIL(tree,z->right)) |
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y = z; |
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else |
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y = rbtree_successor(tree,z); |
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|
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if (!NIL(tree,y->left)) |
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x = y->left; |
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else |
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x = y->right; |
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|
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x->parent = y->parent; |
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|
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if (NIL(tree,y->parent)) |
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tree->root = x; |
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else { |
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if (y == y->parent->left) |
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y->parent->left = x; |
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else |
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y->parent->right = x; |
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} |
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|
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if (y != z) { |
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z->key = y->key; |
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z->value = y->value; |
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} |
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|
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if (y->color == RBTREE_BLACK) |
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rbtree_removal_fixup(tree,x); |
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|
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rbtree_node_free(tree,y); |
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tree->node_count++; |
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return(value); |
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} |
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|
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static void rbtree_foreach_node(rbtree_tree *tree,rbtree_node *node, |
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tree_fforeach user_fn,void *opt) |
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{ |
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if (!NIL(tree,node)) { |
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rbtree_foreach_node(tree,node->left,user_fn,opt); |
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user_fn(node->key,node->value,opt); |
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rbtree_foreach_node(tree,node->right,user_fn,opt); |
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} |
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} |
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|
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/* Call the specified function for each node */ |
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int rbtree_foreach(rbtree_tree *tree,tree_fforeach user_fn,void *opt) |
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{ |
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if (!tree) return(-1); |
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|
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rbtree_foreach_node(tree,tree->root,user_fn,opt); |
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return(0); |
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} |
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|
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/* Returns the maximum height of the right and left sub-trees */ |
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static int rbtree_height_node(rbtree_tree *tree,rbtree_node *node) |
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{ |
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int lh,rh; |
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|
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lh = (!NIL(tree,node->left)) ? rbtree_height_node(tree,node->left) : 0; |
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rh = (!NIL(tree,node->right)) ? rbtree_height_node(tree,node->right) : 0; |
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return(1 + m_max(lh,rh)); |
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} |
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|
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/* Compute the height of a Red/Black tree */ |
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int rbtree_height(rbtree_tree *tree) |
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{ |
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return(!NIL(tree,tree->root) ? rbtree_height_node(tree,tree->root) : 0); |
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} |
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|
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/* Returns the number of nodes */ |
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int rbtree_node_count(rbtree_tree *tree) |
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{ |
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return(tree->node_count); |
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} |
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|
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/* Purge all nodes */ |
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void rbtree_purge(rbtree_tree *tree) |
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{ |
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mp_free_all_blocks(&tree->mp); |
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tree->node_count = 0; |
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|
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/* just in case */ |
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memset(rbtree_nil(tree),0,sizeof(rbtree_node)); |
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rbtree_nil(tree)->color = RBTREE_BLACK; |
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|
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/* reset root */ |
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tree->root = rbtree_nil(tree); |
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} |
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|
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/* Check a node */ |
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static int rbtree_check_node(rbtree_tree *tree,rbtree_node *node) |
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{ |
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if (!NIL(tree,node)) return(0); |
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|
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if (!NIL(tree,node->left)) { |
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if (tree->key_cmp(node->key,node->left->key,tree->opt_data) <= 0) |
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return(-1); |
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|
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if (rbtree_check_node(tree,node->left) == -1) |
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return(-1); |
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} |
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|
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if (!NIL(tree,node->right)) { |
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if (tree->key_cmp(node->key,node->right->key,tree->opt_data) >= 0) |
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return(-1); |
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|
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if (rbtree_check_node(tree,node->right) == -1) |
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return(-1); |
477 |
} |
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|
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return(0); |
480 |
} |
481 |
|
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/* Check tree consistency */ |
483 |
int rbtree_check(rbtree_tree *tree) |
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{ |
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return(rbtree_check_node(tree,tree->root)); |
486 |
} |
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|
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/* Create a new Red/Black tree */ |
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rbtree_tree *rbtree_create(tree_fcompare key_cmp,void *opt_data) |
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{ |
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rbtree_tree *tree; |
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|
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if (!(tree = malloc(sizeof(*tree)))) |
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return NULL; |
495 |
|
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memset(tree,0,sizeof(*tree)); |
497 |
|
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/* initialize the memory pool */ |
499 |
if (!mp_create_fixed_pool(&tree->mp,"Red-Black Tree")) { |
500 |
free(tree); |
501 |
return NULL; |
502 |
} |
503 |
|
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/* initialize the "nil" pointer */ |
505 |
memset(rbtree_nil(tree),0,sizeof(rbtree_node)); |
506 |
rbtree_nil(tree)->color = RBTREE_BLACK; |
507 |
|
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tree->key_cmp = key_cmp; |
509 |
tree->opt_data = opt_data; |
510 |
tree->root = rbtree_nil(tree); |
511 |
return tree; |
512 |
} |
513 |
|
514 |
/* Delete a Red/Black tree */ |
515 |
void rbtree_delete(rbtree_tree *tree) |
516 |
{ |
517 |
if (tree) { |
518 |
mp_free_pool(&tree->mp); |
519 |
free(tree); |
520 |
} |
521 |
} |