Ondřej Surý
f46ce447a6
Add new isc_hashmap API that differs from the current isc_ht API in several aspects: 1. It implements Robin Hood Hashing which is open-addressing hash table algorithm (e.g. no linked-lists) 2. No memory allocations - the array to store the nodes is made of isc_hashmap_node_t structures instead of just pointers, so there's only allocation on resize. 3. The key is not copied into the hashmap node and must be also stored externally, either as part of the stored value or in any other location that's valid as long the value is stored in the hashmap. This makes the isc_hashmap_t a little less universal because of the key storage requirements, but the inserts and deletes are faster because they don't require memory allocation on isc_hashmap_add() and memory deallocation on isc_hashmap_delete().
199 lines
4.7 KiB
C
199 lines
4.7 KiB
C
/*
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* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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*
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* SPDX-License-Identifier: MPL-2.0
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, you can obtain one at https://mozilla.org/MPL/2.0/.
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*
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* See the COPYRIGHT file distributed with this work for additional
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* information regarding copyright ownership.
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*/
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/* ! \file */
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#pragma once
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#include <inttypes.h>
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#include <string.h>
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#include <isc/result.h>
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#include <isc/types.h>
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typedef struct isc_hashmap isc_hashmap_t;
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typedef struct isc_hashmap_iter isc_hashmap_iter_t;
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enum { ISC_HASHMAP_CASE_SENSITIVE = 0x00, ISC_HASHMAP_CASE_INSENSITIVE = 0x01 };
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/*%
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* Create hashmap at *hashmapp, using memory context and size of (1<<bits)
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*
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* Requires:
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* \li 'hashmapp' is not NULL and '*hashmapp' is NULL.
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* \li 'mctx' is a valid memory context.
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* \li 'bits' >=1 and 'bits' <=32
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*
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*/
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void
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isc_hashmap_create(isc_mem_t *mctx, uint8_t bits, unsigned int options,
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isc_hashmap_t **hashmapp);
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/*%
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* Destroy hashmap, freeing everything
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*
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* Requires:
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* \li '*hashmapp' is valid hashmap
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*/
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void
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isc_hashmap_destroy(isc_hashmap_t **hashmapp);
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/*%
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* Return current hashed value for 'key' of size 'keysize';
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*/
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uint32_t
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isc_hashmap_hash(const isc_hashmap_t *hashmap, const void *key,
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uint32_t keysize);
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/*%
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* Add a node to hashmap, pointed by binary key 'key' of size 'keysize';
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* set its value to 'value'
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*
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* Requires:
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* \li 'hashmap' is a valid hashmap
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* \li 'hashval' is optional precomputed hash value of 'key'
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* \li 'key' is non-null key of size 'keysize'
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*
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* Returns:
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* \li #ISC_R_EXISTS -- node of the same key already exists
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* \li #ISC_R_SUCCESS -- all is well.
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*/
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isc_result_t
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isc_hashmap_add(isc_hashmap_t *hashmap, const uint32_t *hashvalp,
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const void *key, uint32_t keysize, void *value);
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/*%
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* Find a node matching 'key'/'keysize' in hashmap 'hashmap';
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* if found, set '*valuep' to its value. (If 'valuep' is NULL,
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* then simply return SUCCESS or NOTFOUND to indicate whether the
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* key exists in the hashmap.)
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*
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* Requires:
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* \li 'hashmap' is a valid hashmap
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* \li 'hashval' is optional precomputed hash value of 'key'
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* \li 'key' is non-null key of size 'keysize'
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*
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* Returns:
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* \li #ISC_R_SUCCESS -- success
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* \li #ISC_R_NOTFOUND -- key not found
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*/
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isc_result_t
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isc_hashmap_find(const isc_hashmap_t *hashmap, const uint32_t *hashvalp,
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const void *key, uint32_t keysize, void **valuep);
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/*%
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* Delete node from hashmap
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*
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* Requires:
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* \li 'hashmap' is a valid hashmap
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* \li 'hashval' is optional precomputed hash value of 'key'
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* \li 'key' is non-null key of size 'keysize'
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*
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* Returns:
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* \li #ISC_R_NOTFOUND -- key not found
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* \li #ISC_R_SUCCESS -- all is well
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*/
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isc_result_t
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isc_hashmap_delete(isc_hashmap_t *hashmap, const uint32_t *hashvalp,
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const void *key, uint32_t keysize);
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/*%
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* Create an iterator for the hashmap; point '*itp' to it.
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*
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* Requires:
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* \li 'hashmap' is a valid hashmap
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* \li 'itp' is non NULL and '*itp' is NULL.
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*/
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void
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isc_hashmap_iter_create(isc_hashmap_t *hashmap, isc_hashmap_iter_t **itp);
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/*%
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* Destroy the iterator '*itp', set it to NULL
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*
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* Requires:
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* \li 'itp' is non NULL and '*itp' is non NULL.
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*/
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void
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isc_hashmap_iter_destroy(isc_hashmap_iter_t **itp);
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/*%
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* Set an iterator to the first entry.
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*
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* Requires:
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* \li 'it' is non NULL.
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*
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* Returns:
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* \li #ISC_R_SUCCESS -- success
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* \li #ISC_R_NOMORE -- no data in the hashmap
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*/
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isc_result_t
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isc_hashmap_iter_first(isc_hashmap_iter_t *it);
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/*%
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* Set an iterator to the next entry.
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*
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* Requires:
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* \li 'it' is non NULL.
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*
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* Returns:
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* \li #ISC_R_SUCCESS -- success
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* \li #ISC_R_NOMORE -- end of hashmap reached
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*/
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isc_result_t
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isc_hashmap_iter_next(isc_hashmap_iter_t *it);
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/*%
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* Delete current entry and set an iterator to the next entry.
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*
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* Requires:
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* \li 'it' is non NULL.
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*
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* Returns:
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* \li #ISC_R_SUCCESS -- success
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* \li #ISC_R_NOMORE -- end of hashmap reached
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*/
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isc_result_t
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isc_hashmap_iter_delcurrent_next(isc_hashmap_iter_t *it);
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/*%
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* Set 'value' to the current value under the iterator
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*
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* Requires:
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* \li 'it' is non NULL.
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* \li 'valuep' is non NULL and '*valuep' is NULL.
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*/
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void
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isc_hashmap_iter_current(isc_hashmap_iter_t *it, void **valuep);
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/*%
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* Set 'key' and 'keysize to the current key and keysize for the value
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* under the iterator
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*
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* Requires:
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* \li 'it' is non NULL.
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* \li 'key' is non NULL and '*key' is NULL.
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* \li 'keysize' is non NULL.
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*/
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void
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isc_hashmap_iter_currentkey(isc_hashmap_iter_t *it, const unsigned char **key,
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size_t *keysize);
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/*%
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* Returns the number of items in the hashmap.
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*
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* Requires:
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* \li 'hashmap' is a valid hashmap
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*/
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unsigned int
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isc_hashmap_count(isc_hashmap_t *hashmap);
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