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Diffstat (limited to 'src/trie.h')
| -rw-r--r-- | src/trie.h | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/src/trie.h b/src/trie.h new file mode 100644 index 0000000..2d29ac7 --- /dev/null +++ b/src/trie.h @@ -0,0 +1,156 @@ +/**************************************************************************** + * bfs * + * Copyright (C) 2019 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 <stddef.h> +#include <stdint.h> + +/** + * A trie that holds a set of fixed- or variable-length strings. + */ +struct trie { + uintptr_t root; +}; + +/** + * A leaf of a trie. + */ +struct trie_leaf { + /** + * 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[]; +}; + +/** + * Initialize an empty trie. + */ +void trie_init(struct trie *trie); + +/** + * Get the first (lexicographically earliest) leaf in the trie. + * + * @param trie + * The trie to search. + * @return + * The first leaf, or NULL if the trie is empty. + */ +struct trie_leaf *trie_first_leaf(const 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); + +#endif // BFS_TRIE_H |