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Implemented a simlpe red-black tree which should give better performance

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for certain lookups.

The rb_tree will act as a general purpose key/value storage, and
also give a performance boost in the cases where the other
simple alternative would be to use a linked_list.

On average this should give on average O(log n) lookups, while the linked_list
would be O(n) at worst.
This commit is contained in:
Jan Vidar Krey
2012-11-01 02:52:00 +01:00
parent 5d6184961b
commit 3dcbb63a31
4 changed files with 598 additions and 79 deletions
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115
src/util/rbtree.h
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@@ -1,6 +1,6 @@
/*
* uhub - A tiny ADC p2p connection hub
* Copyright (C) 2007-2009, Jan Vidar Krey
* Copyright (C) 2007-2012, Jan Vidar Krey
*
* 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
@@ -20,18 +20,121 @@
#ifndef HAVE_UHUB_RED_BLACK_TREE_H
#define HAVE_UHUB_RED_BLACK_TREE_H
struct rb_tree;
struct rb_node
{
const void* key;
const void* value; /* data */
int red;
struct rb_node* link[2];
};
typedef int (*rb_tree_compare)(const void* a, const void* b);
typedef void* (*rb_tree_alloc)(size_t);
typedef void (*rb_tree_free)(void*);
typedef void (*rb_tree_free_node)(struct rb_node*);
struct rb_iterator
{
struct rb_node* node; // current node.
struct linked_list* stack; // stack from the top -- needed since we don't have parent pointers.
};
struct rb_tree
{
struct rb_node* root;
size_t elements;
rb_tree_alloc alloc;
rb_tree_free free;
rb_tree_compare compare;
struct rb_iterator iterator;
};
extern struct rb_tree* rb_tree_create(rb_tree_compare, rb_tree_alloc, rb_tree_free);
/**
* Create a tree.
*
* @param compare Comparison function
* @param alloc Allocator (if NULL then hub_malloc() is used)
* @param dealloc Deallocator (if NULL then hub_free() is used)
* @return a tree handle.
*/
extern struct rb_tree* rb_tree_create(rb_tree_compare compare, rb_tree_alloc alloc, rb_tree_free dealloc);
/**
* Deletes the tree and all the nodes.
* But not the content inside the nodes.
*/
extern void rb_tree_destroy(struct rb_tree*);
extern void* rb_tree_insert(struct rb_tree* tree, const void* key, const void* data);
extern void* rb_tree_remove(struct rb_tree* tree, const void* key);
extern void* rb_tree_get(struct rb_tree* tree, const void* key);
/**
* Insert a key into the tree, returns 1 if successful,
* or 0 if the key already existed.
*/
extern int rb_tree_insert(struct rb_tree* tree, const void* key, const void* data);
/**
* Remove a key from the tree.
* Returns 1 if the node was removed, or 0 if it was not removed (i.e. not found!)
*
* NOTE: the content of the node is not freed if it needs to be then use rb_tree_remove_node
* where you can specify a callback cleanup function.
*/
extern int rb_tree_remove(struct rb_tree* tree, const void* key);
/**
* Remove the node, but call the free callback before the node is removed.
* This is useful in cases where you need to deallocate the key and/or value from the node.
* Returns 1 if the node was removed, or 0 if not found.
*/
extern int rb_tree_remove_node(struct rb_tree* tree, const void* key, rb_tree_free_node free);
/**
* Returns NULL if the key was not found in the tree.
*/
extern void* rb_tree_get(struct rb_tree* tree, const void* key);
/**
* Returns the number of elements inside the tree.
*/
extern size_t rb_tree_size(struct rb_tree* tree);
/**
* Returns the first node in the tree.
* (leftmost, or lowest value in sorted order).
*
* Example:
*
* <code>
* struct rb_node* it;
* for (it = rb_tree_first(tree); it; it = rb_tree_next())
* {
* void* key = rb_iterator_key(it);
* void* value = rb_iterator_value(it);
* }
* </code>
*/
extern struct rb_node* rb_tree_first(struct rb_tree* tree);
/**
* Points the iterator at the next node.
* If the next node is NULL then the iterator becomes NULL too.
*/
extern struct rb_node* rb_tree_next(struct rb_tree* tree);
extern struct rb_node* rb_tree_prev(struct rb_tree* tree);
/**
* Returnst the key of the node pointed to by the iterator.
* If this iterator is the same as rb_tree_end() then NULL is returned.
*/
extern void* rb_iterator_key(struct rb_iterator* it);
/**
* Returnst the value of the node pointed to by the iterator.
* If this iterator is the same as rb_tree_end() then the behavior is undefined.
*/
extern void* rb_iterator_value(struct rb_iterator* it);
#endif /* HAVE_UHUB_RED_BLACK_TREE_H */