118 lines
3.5 KiB
C
118 lines
3.5 KiB
C
/*
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* Copyright © 2008 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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/**
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* \file hash_table.h
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* \brief Implementation of a generic, opaque hash table data type.
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*
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* \author Ian Romanick <ian.d.romanick@intel.com>
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*/
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#ifndef HASH_TABLE_H
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#define HASH_TABLE_H
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#include <string.h>
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struct hash_table;
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typedef unsigned (*hash_func_t)(const void *key);
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typedef int (*hash_compare_func_t)(const void *key1, const void *key2);
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/**
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* Hash table constructor
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*
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* Creates a hash table with the specified number of buckets. The supplied
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* \c hash and \c compare routines are used when adding elements to the table
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* and when searching for elements in the table.
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*
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* \param num_buckets Number of buckets (bins) in the hash table.
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* \param hash Function used to compute hash value of input keys.
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* \param compare Function used to compare keys.
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*/
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extern struct hash_table *hash_table_ctor(unsigned num_buckets,
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hash_func_t hash, hash_compare_func_t compare);
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/**
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* Release all memory associated with a hash table
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*
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* \warning
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* This function cannot release memory occupied either by keys or data.
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*/
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extern void hash_table_dtor(struct hash_table *ht);
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/**
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* Flush all entries from a hash table
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*
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* \param ht Table to be cleared of its entries.
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*/
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extern void hash_table_clear(struct hash_table *ht);
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/**
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* Search a hash table for a specific element
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*
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* \param ht Table to be searched
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* \param key Key of the desired element
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*
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* \return
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* The \c data value supplied to \c hash_table_insert when the element with
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* the matching key was added. If no matching key exists in the table,
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* \c NULL is returned.
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*/
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extern void *hash_table_find(struct hash_table *ht, const void *key);
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/**
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* Add an element to a hash table
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*/
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extern void hash_table_insert(struct hash_table *ht, void *data,
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const void *key);
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/**
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* Compute hash value of a string
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*
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* Computes the hash value of a string using the DJB2 algorithm developed by
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* Professor Daniel J. Bernstein. It was published on comp.lang.c once upon
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* a time. I was unable to find the original posting in the archives.
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*
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* \param key Pointer to a NUL terminated string to be hashed.
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*
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* \sa hash_table_string_compare
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*/
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extern unsigned hash_table_string_hash(const void *key);
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/**
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* Compare two strings used as keys
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*
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* This is just a macro wrapper around \c strcmp.
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*
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* \sa hash_table_string_hash
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*/
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#define hash_table_string_compare ((hash_compare_func_t) strcmp)
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#endif /* HASH_TABLE_H */
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