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/****************************************************************************
* bfs *
* Copyright (C) 2019-2022 Tavian Barnes <tavianator@tavianator.com> *
* *
* Permission to use, copy, modify, and/or distribute this software for any *
* purpose with or without fee is hereby granted. *
* *
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES *
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF *
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR *
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES *
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN *
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF *
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. *
****************************************************************************/
#ifndef BFS_TRIE_H
#define BFS_TRIE_H
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
/**
* A leaf of a trie.
*/
struct trie_leaf {
/**
* Linked list of leaves, in insertion order.
*/
struct trie_leaf *prev, *next;
/**
* An arbitrary value associated with this leaf.
*/
void *value;
/**
* The length of the key in bytes.
*/
size_t length;
/**
* The key itself, stored inline.
*/
char key[];
};
/**
* A trie that holds a set of fixed- or variable-length strings.
*/
struct trie {
/** Pointer to the root node/leaf. */
uintptr_t root;
/** Linked list of leaves. */
struct trie_leaf *head, *tail;
};
/**
* Initialize an empty trie.
*/
void trie_init(struct trie *trie);
/**
* Find the leaf for a string key.
*
* @param trie
* The trie to search.
* @param key
* The key to look up.
* @return
* The found leaf, or NULL if the key is not present.
*/
struct trie_leaf *trie_find_str(const struct trie *trie, const char *key);
/**
* Find the leaf for a fixed-size key.
*
* @param trie
* The trie to search.
* @param key
* The key to look up.
* @param length
* The length of the key in bytes.
* @return
* The found leaf, or NULL if the key is not present.
*/
struct trie_leaf *trie_find_mem(const struct trie *trie, const void *key, size_t length);
/**
* Find the shortest leaf that starts with a given key.
*
* @param trie
* The trie to search.
* @param key
* The key to look up.
* @return
* A leaf that starts with the given key, or NULL.
*/
struct trie_leaf *trie_find_postfix(const struct trie *trie, const char *key);
/**
* Find the leaf that is the longest prefix of the given key.
*
* @param trie
* The trie to search.
* @param key
* The key to look up.
* @return
* The longest prefix match for the given key, or NULL.
*/
struct trie_leaf *trie_find_prefix(const struct trie *trie, const char *key);
/**
* Insert a string key into the trie.
*
* @param trie
* The trie to modify.
* @param key
* The key to insert.
* @return
* The inserted leaf, or NULL on failure.
*/
struct trie_leaf *trie_insert_str(struct trie *trie, const char *key);
/**
* Insert a fixed-size key into the trie.
*
* @param trie
* The trie to modify.
* @param key
* The key to insert.
* @param length
* The length of the key in bytes.
* @return
* The inserted leaf, or NULL on failure.
*/
struct trie_leaf *trie_insert_mem(struct trie *trie, const void *key, size_t length);
/**
* Remove a leaf from a trie.
*
* @param trie
* The trie to modify.
* @param leaf
* The leaf to remove.
*/
void trie_remove(struct trie *trie, struct trie_leaf *leaf);
/**
* Destroy a trie and its contents.
*/
void trie_destroy(struct trie *trie);
/**
* Iterate over the leaves of a trie.
*/
#define TRIE_FOR_EACH(trie, leaf) \
for (struct trie_leaf *leaf = (trie)->head, *_next; \
leaf && (_next = leaf->next, true); \
leaf = _next)
#endif // BFS_TRIE_H
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