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/*
* Copyright (c) 2007 Vreixo Formoso
*
* This file is part of the libisofs project; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* or later as published by the Free Software Foundation.
* See COPYING file for details.
*/
#ifdef HAVE_CONFIG_H
#include "../config.h"
#endif
#include "util.h"
#include "libisofs.h"
#include <stdlib.h>
/*
* This implementation of Red-Black tree is based on the public domain
* implementation of Julienne Walker.
*/
struct iso_rbnode
{
void *data;
struct iso_rbnode *ch[2];
unsigned int red :1;
};
struct iso_rbtree
{
struct iso_rbnode *root;
size_t size;
int (*compare)(const void *a, const void *b);
};
/**
* Create a new binary tree. libisofs binary trees allow you to add any data
* passing it as a pointer. You must provide a function suitable for compare
* two elements.
*
* @param compare
* A function to compare two elements. It takes a pointer to both elements
* and return 0, -1 or 1 if the first element is equal, less or greater
* than the second one.
* @param tree
* Location where the tree structure will be stored.
*/
int iso_rbtree_new(int (*compare)(const void*, const void*), IsoRBTree **tree)
{
if (compare == NULL || tree == NULL) {
return ISO_NULL_POINTER;
}
*tree = calloc(1, sizeof(IsoRBTree));
if (*tree == NULL) {
return ISO_OUT_OF_MEM;
}
(*tree)->compare = compare;
return ISO_SUCCESS;
}
static
void rbtree_destroy_aux(struct iso_rbnode *root, void (*free_data)(void *))
{
if (root == NULL) {
return;
}
if (free_data != NULL) {
free_data(root->data);
}
rbtree_destroy_aux(root->ch[0], free_data);
rbtree_destroy_aux(root->ch[1], free_data);
free(root);
}
/**
* Destroy a given tree.
*
* Note that only the structure itself is deleted. To delete the elements, you
* should provide a valid free_data function. It will be called for each
* element of the tree, so you can use it to free any related data.
*/
void iso_rbtree_destroy(IsoRBTree *tree, void (*free_data)(void *))
{
if (tree == NULL) {
return;
}
rbtree_destroy_aux(tree->root, free_data);
free(tree);
}
static inline
int is_red(struct iso_rbnode *root)
{
return root != NULL && root->red;
}
static
struct iso_rbnode *iso_rbtree_single(struct iso_rbnode *root, int dir)
{
struct iso_rbnode *save = root->ch[!dir];
root->ch[!dir] = save->ch[dir];
save->ch[dir] = root;
root->red = 1;
save->red = 0;
return save;
}
static
struct iso_rbnode *iso_rbtree_double(struct iso_rbnode *root, int dir)
{
root->ch[!dir] = iso_rbtree_single(root->ch[!dir], !dir);
return iso_rbtree_single(root, dir);
}
static
struct iso_rbnode *iso_rbnode_new(void *data)
{
struct iso_rbnode *rn = malloc(sizeof(struct iso_rbnode));
if (rn != NULL) {
rn->data = data;
rn->red = 1;
rn->ch[0] = NULL;
rn->ch[1] = NULL;
}
return rn;
}
/**
* Inserts a given element in a Red-Black tree.
*
* @param tree
* the tree where to insert
* @param data
* element to be inserted on the tree. It can't be NULL
* @param item
* if not NULL, it will point to a location where the tree element ptr
* will be stored. If data was inserted, *item == data. If data was
* already on the tree, *item points to the previously inserted object
* that is equal to data.
* @return
* 1 success, 0 element already inserted, < 0 error
*/
int iso_rbtree_insert(IsoRBTree *tree, void *data, void **item)
{
struct iso_rbnode *new;
int added = 0; /* has a new node been added? */
if (tree == NULL || data == NULL) {
return ISO_NULL_POINTER;
}
if (tree->root == NULL) {
/* Empty tree case */
tree->root = iso_rbnode_new(data);
if (tree->root == NULL) {
return ISO_OUT_OF_MEM;
}
new = data;
added = 1;
} else {
struct iso_rbnode head = { 0, {NULL, NULL}, 0 }; /* False tree root */
struct iso_rbnode *g, *t; /* Grandparent & parent */
struct iso_rbnode *p, *q; /* Iterator & parent */
int dir = 0, last = 0;
int comp;
/* Set up helpers */
t = &head;
g = p = NULL;
q = t->ch[1] = tree->root;
/* Search down the tree */
while (1) {
if (q == NULL) {
/* Insert new node at the bottom */
p->ch[dir] = q = iso_rbnode_new(data);
if (q == NULL) {
return ISO_OUT_OF_MEM;
}
added = 1;
} else if (is_red(q->ch[0]) && is_red(q->ch[1])) {
/* Color flip */
q->red = 1;
q->ch[0]->red = 0;
q->ch[1]->red = 0;
}
/* Fix red violation */
if (is_red(q) && is_red(p)) {
int dir2 = (t->ch[1] == g);
if (q == p->ch[last]) {
t->ch[dir2] = iso_rbtree_single(g, !last);
} else {
t->ch[dir2] = iso_rbtree_double(g, !last);
}
}
if (q->data == data) {
comp = 0;
} else {
comp = tree->compare(q->data, data);
}
/* Stop if found */
if (comp == 0) {
new = q->data;
break;
}
last = dir;
dir = (comp < 0);
/* Update helpers */
if (g != NULL)
t = g;
g = p, p = q;
q = q->ch[dir];
}
/* Update root */
tree->root = head.ch[1];
}
/* Make root black */
tree->root->red = 0;
if (item != NULL) {
*item = new;
}
if (added) {
/* a new element has been added */
tree->size++;
return 1;
} else {
return 0;
}
}
/**
* Get the number of elements in a given tree.
*/
size_t iso_rbtree_get_size(IsoRBTree *tree)
{
return tree->size;
}
static
size_t rbtree_to_array_aux(struct iso_rbnode *root, void **array, size_t pos,
int (*include_item)(void *))
{
if (root == NULL) {
return pos;
}
pos = rbtree_to_array_aux(root->ch[0], array, pos, include_item);
if (include_item == NULL || include_item(root->data)) {
array[pos++] = root->data;
}
pos = rbtree_to_array_aux(root->ch[1], array, pos, include_item);
return pos;
}
/**
* Get an array view of the elements of the tree.
*
* @param include_item
* Function to select which elements to include in the array. It that takes
* a pointer to an element and returns 1 if the element should be included,
* 0 if not. If you want to add all elements to the array, you can pass a
* NULL pointer.
* @return
* A sorted array with the contents of the tree, or NULL if there is not
* enought memory to allocate the array. You should free(3) the array when
* no more needed. Note that the array is NULL-terminated, and thus it
* has size + 1 length.
*/
void ** iso_rbtree_to_array(IsoRBTree *tree, int (*include_item)(void *),
size_t *size)
{
size_t pos;
void **array, **new_array;
array = malloc((tree->size + 1) * sizeof(void*));
if (array == NULL) {
return NULL;
}
/* fill array */
pos = rbtree_to_array_aux(tree->root, array, 0, include_item);
array[pos] = NULL;
new_array = realloc(array, (pos + 1) * sizeof(void*));
if (new_array == NULL) {
free((char *) array);
return NULL;
}
array= new_array;
if (size) {
*size = pos;
}
return array;
}
static
size_t rbtree_count_array_aux(struct iso_rbnode *root, size_t pos,
int (*include_item)(void *))
{
if (root == NULL) {
return pos;
}
pos = rbtree_count_array_aux(root->ch[0], pos, include_item);
if (include_item == NULL || include_item(root->data)) {
/*
{
IsoFileSrc* src = (IsoFileSrc*) root->data;
fprintf(stderr, "libisofs_DEBUG: rbtree_count_array_aux : not taken : '%s'\n",
iso_stream_get_source_path(src->stream, 0));
}
*/
pos++;
}
pos = rbtree_count_array_aux(root->ch[1], pos, include_item);
return pos;
}
size_t iso_rbtree_count_array(IsoRBTree *tree, size_t initial_count,
int (*include_item)(void *))
{
size_t pos;
pos = rbtree_count_array_aux(tree->root, initial_count, include_item);
return pos;
}