150 lines
4.4 KiB
C
150 lines
4.4 KiB
C
/* Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
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* SPDX-License-Identifier: GPL-3.0-or-later
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*/
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#pragma once
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#include <stdbool.h>
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#include <stdint.h>
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#include <libknot/mm_ctx.h>
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#include "lib/defines.h"
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/*!
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* \brief Native API of QP-tries:
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*
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* - keys are char strings, not necessarily zero-terminated,
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* the structure copies the contents of the passed keys
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* - values are void* pointers, typically you get an ephemeral pointer to it
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* - key lengths are limited by 2^32-1 ATM
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*
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* XXX EDITORS: trie.{h,c} are synced from
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* https://gitlab.nic.cz/knot/knot-dns/tree/68352fc969/src/contrib/qp-trie
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* only with simple adjustments, mostly include lines, KR_EXPORT and assertions.
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*/
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/*! \brief Element value. */
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typedef void* trie_val_t;
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/*! \brief Opaque structure holding a QP-trie. */
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typedef struct trie trie_t;
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/*! \brief Opaque type for holding a QP-trie iterator. */
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typedef struct trie_it trie_it_t;
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/*! \brief Create a trie instance. Pass NULL to use malloc+free. */
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KR_EXPORT
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trie_t* trie_create(knot_mm_t *mm);
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/*! \brief Free a trie instance. */
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KR_EXPORT
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void trie_free(trie_t *tbl);
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/*! \brief Clear a trie instance (make it empty). */
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KR_EXPORT
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void trie_clear(trie_t *tbl);
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/*! \brief Return the number of keys in the trie. */
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KR_EXPORT
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size_t trie_weight(const trie_t *tbl);
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/*! \brief Search the trie, returning NULL on failure. */
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KR_EXPORT
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trie_val_t* trie_get_try(trie_t *tbl, const char *key, uint32_t len);
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/*!
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* \brief Return pointer to the minimum. Optionally with key and its length. */
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KR_EXPORT
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trie_val_t* trie_get_first(trie_t *tbl, char **key, uint32_t *len);
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/*! \brief Search the trie, inserting NULL trie_val_t on failure. */
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KR_EXPORT
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trie_val_t* trie_get_ins(trie_t *tbl, const char *key, uint32_t len);
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/*!
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* \brief Search for less-or-equal element.
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*
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* \param tbl Trie.
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* \param key Searched key.
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* \param len Key length.
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* \param val Must be valid; it will be set to NULL if not found or errored.
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* \return KNOT_EOK for exact match, 1 for previous, KNOT_ENOENT for not-found,
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* or KNOT_E*.
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*/
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KR_EXPORT
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int trie_get_leq(trie_t *tbl, const char *key, uint32_t len, trie_val_t **val);
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/*!
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* \brief Apply a function to every trie_val_t, in order.
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*
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* \param d Parameter passed as the second argument to f().
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* \return First nonzero from f() or zero (i.e. KNOT_EOK).
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*/
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KR_EXPORT
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int trie_apply(trie_t *tbl, int (*f)(trie_val_t *, void *), void *d);
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/*!
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* \brief Apply a function to every trie_val_t, in order.
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*
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* It's like trie_apply() but additionally passes keys and their lengths.
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*
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* \param d Parameter passed as the second argument to f().
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* \return First nonzero from f() or zero (i.e. KNOT_EOK).
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*/
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KR_EXPORT
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int trie_apply_with_key(trie_t *tbl, int (*f)(const char *, uint32_t, trie_val_t *, void *), void *d);
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/*!
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* \brief Remove an item, returning KNOT_EOK if succeeded or KNOT_ENOENT if not found.
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*
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* If val!=NULL and deletion succeeded, the deleted value is set.
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*/
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KR_EXPORT
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int trie_del(trie_t *tbl, const char *key, uint32_t len, trie_val_t *val);
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/*!
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* \brief Remove the first item, returning KNOT_EOK on success.
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*
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* You may optionally get the key and/or value.
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* The key is copied, so you need to pass sufficient len,
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* otherwise kr_error(ENOSPC) is returned.
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*/
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KR_EXPORT
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int trie_del_first(trie_t *tbl, char *key, uint32_t *len, trie_val_t *val);
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/*! \brief Create a new iterator pointing to the first element (if any). */
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KR_EXPORT
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trie_it_t* trie_it_begin(trie_t *tbl);
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/*!
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* \brief Advance the iterator to the next element.
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*
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* Iteration is in ascending lexicographical order.
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* In particular, the empty string would be considered as the very first.
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*
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* \note You may not use this function if the trie's key-set has been modified
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* during the lifetime of the iterator (modifying values only is OK).
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*/
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KR_EXPORT
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void trie_it_next(trie_it_t *it);
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/*! \brief Test if the iterator has gone past the last element. */
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KR_EXPORT
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bool trie_it_finished(trie_it_t *it);
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/*! \brief Free any resources of the iterator. It's OK to call it on NULL. */
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KR_EXPORT
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void trie_it_free(trie_it_t *it);
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/*!
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* \brief Return pointer to the key of the current element.
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*
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* \note The optional len is uint32_t internally but size_t is better for our usage,
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* as it is without an additional type conversion.
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*/
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KR_EXPORT
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const char* trie_it_key(trie_it_t *it, size_t *len);
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/*! \brief Return pointer to the value of the current element (writable). */
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KR_EXPORT
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trie_val_t* trie_it_val(trie_it_t *it);
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