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/* Copyright (C) 2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
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
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <stdbool.h>
#include <stdint.h>
#include "libknot/mm_ctx.h"
/*!
* \brief Native API of QP-tries:
*
* - keys are char strings, not necessarily zero-terminated,
* the structure copies the contents of the passed keys
* - values are void* pointers, typically you get an ephemeral pointer to it
* - key lengths are limited by 2^32-1 ATM
*/
/*! \brief Element value. */
typedef void* trie_val_t;
/*! \brief Opaque structure holding a QP-trie. */
typedef struct trie trie_t;
/*! \brief Opaque type for holding a QP-trie iterator. */
typedef struct trie_it trie_it_t;
/*! \brief Create a trie instance. */
trie_t* trie_create(knot_mm_t *mm);
/*! \brief Free a trie instance. */
void trie_free(trie_t *tbl);
/*! \brief Clear a trie instance (make it empty). */
void trie_clear(trie_t *tbl);
/*! \brief Return the number of keys in the trie. */
size_t trie_weight(const trie_t *tbl);
/*! \brief Search the trie, returning NULL on failure. */
trie_val_t* trie_get_try(trie_t *tbl, const char *key, uint32_t len);
/*! \brief Search the trie, inserting NULL trie_val_t on failure. */
trie_val_t* trie_get_ins(trie_t *tbl, const char *key, uint32_t len);
/*!
* \brief Search for less-or-equal element.
*
* \param tbl Trie.
* \param key Searched key.
* \param len Key length.
* \param val Must be valid; it will be set to NULL if not found or errored.
* \return KNOT_EOK for exact match, 1 for previous, KNOT_ENOENT for not-found,
* or KNOT_E*.
*/
int trie_get_leq(trie_t *tbl, const char *key, uint32_t len, trie_val_t **val);
/*!
* \brief Apply a function to every trie_val_t, in order.
*
* \return KNOT_EOK if success or KNOT_E* if error.
*/
int trie_apply(trie_t *tbl, int (*f)(trie_val_t *, void *), void *d);
/*!
* \brief Remove an item, returning KNOT_EOK if succeeded or KNOT_ENOENT if not found.
*
* If val!=NULL and deletion succeeded, the deleted value is set.
*/
int trie_del(trie_t *tbl, const char *key, uint32_t len, trie_val_t *val);
/*! \brief Create a new iterator pointing to the first element (if any). */
trie_it_t* trie_it_begin(trie_t *tbl);
/*!
* \brief Advance the iterator to the next element.
*
* Iteration is in ascending lexicographical order.
* In particular, the empty string would be considered as the very first.
*/
void trie_it_next(trie_it_t *it);
/*! \brief Test if the iterator has gone past the last element. */
bool trie_it_finished(trie_it_t *it);
/*! \brief Free any resources of the iterator. It's OK to call it on NULL. */
void trie_it_free(trie_it_t *it);
/*!
* \brief Return pointer to the key of the current element.
*
* \note The len is uint32_t internally but size_t is better for our usage
* as it is without an additional type conversion.
*/
const char* trie_it_key(trie_it_t *it, size_t *len);
/*! \brief Return pointer to the value of the current element (writable). */
trie_val_t* trie_it_val(trie_it_t *it);
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