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bstree.c
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bstree.c
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#ifdef __cplusplus
extern "C" {
#endif
#include "bstree.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
static void error_exit(const char* fmt, ...)
{
fprintf(stderr, "\nError:\n");
va_list args;
va_start(args, fmt);
vfprintf(stderr, fmt, args);
va_end(args);
exit(1);
}
static void* emalloc(size_t size)
{
void* mem = malloc(size);
if(!mem) error_exit("Out of memory!\n");
return mem;
}
static int default_compare(const void* a, const void* b)
{
return strcmp(a, b);
}
void bs_tree_init(bs_tree_t* tree, bs_tree_compare_t compare)
{
tree->count = 0;
tree->compare = compare ? compare : default_compare;
tree->root = NULL;
}
static int destroy_node(bs_tree_node_t* node)
{
free(node);
return 0;
}
void bs_tree_destroy(bs_tree_t* tree)
{
bs_tree_traverse(tree, destroy_node);
}
static bs_tree_node_t* create_node(bs_tree_node_t* parent, void* key, void* value)
{
bs_tree_node_t* node = emalloc(sizeof(bs_tree_node_t));
node->key = key;
node->value = value;
node->parent = parent;
node->left = NULL;
node->right = NULL;
return node;
}
static void set_node(bs_tree_t* tree, bs_tree_node_t* node, void* key, void* value)
{
int cmp = tree->compare(node->key, key);
if(cmp <= 0)
{
if(node->left) set_node(tree, node->left, key, value);
else node->left = create_node(node, key, value);
}
else
{
if(node->right) set_node(tree, node->right, key, value);
else node->right = create_node(node, key, value);
}
}
int bs_tree_set(bs_tree_t* tree, void* key, void* value)
{
if(!tree->root)
tree->root = create_node(NULL, key, value);
else
set_node(tree, tree->root, key, value);
}
static bs_tree_node_t* get_node(bs_tree_t* tree, bs_tree_node_t* node, void* key)
{
int cmp = tree->compare(node->key, key);
if(cmp == 0)
return node;
else if(cmp < 0)
return node->left ? get_node(tree, node->left, key) : NULL;
else
return node->right ? get_node(tree, node->right, key) : NULL;
}
void* bs_tree_get(bs_tree_t* tree, void* key)
{
if(!tree->root) return NULL;
else
{
bs_tree_node_t* node = get_node(tree, tree->root, key);
return node ? node->value : NULL;
}
}
static int traverse_nodes(bs_tree_node_t* node, bs_tree_traverse_t traverse)
{
int rc = 0;
if(node->left)
{
rc = traverse_nodes(node->left, traverse);
if(rc != 0) return rc;
}
if(node->right)
{
rc = traverse_nodes(node->right, traverse);
if(rc != 0) return rc;
}
return traverse(node);
}
int bs_tree_traverse(bs_tree_t* tree, bs_tree_traverse_t traverse)
{
if(tree->root) return traverse_nodes(tree->root, traverse);
return 0;
}
static bs_tree_node_t* find_min(bs_tree_node_t* node)
{
while(node->left) node = node->left;
return node;
}
static void replace_node_in_parent(bs_tree_t* tree, bs_tree_node_t* node, bs_tree_node_t* new_node)
{
if(node->parent)
{
if(node->parent->left == node) node->parent->left = new_node;
else node->parent->right = new_node;
}
else
tree->root = new_node;
if(new_node)
new_node->parent = node->parent;
}
static void swap_nodes(bs_tree_node_t* a, bs_tree_node_t* b)
{
void* temp = NULL;
temp = b->key; b->key = a->key; a->key = temp;
temp = b->value; b->value = a->value; a->value = temp;
}
static bs_tree_node_t* delete_node(bs_tree_t* tree, bs_tree_node_t* node, void* key)
{
int cmp = tree->compare(node->key, key);
if(cmp < 0)
{
if(node->left) delete_node(tree, node->left, key);
else return NULL;
}
else if(cmp > 0)
{
if(node->right) delete_node(tree, node->right, key);
else return NULL;
}
else
{
if(node->left && node->right)
{
bs_tree_node_t* successor = find_min(node->right);
swap_nodes(successor, node);
replace_node_in_parent(tree, successor, successor->right);
return successor;
}
else if(node->left) replace_node_in_parent(tree, node, node->left);
else if(node->right) replace_node_in_parent(tree, node, node->right);
else replace_node_in_parent(tree, node, NULL);
return node;
}
}
void* bs_tree_remove(bs_tree_t* tree, void* key)
{
void* value = NULL;
if(tree->root)
{
bs_tree_node_t* node = delete_node(tree, tree->root, key);
if(node)
{
value = node->value;
free(node);
}
}
return value;
}
#ifdef __cplusplus
}
#endif