75 lines
2.7 KiB
C
75 lines
2.7 KiB
C
/*
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* Copyright 2006 Rob Kendrick <rjek@rjek.com>
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*
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* This file is part of NetSurf, http://www.netsurf-browser.org/
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*
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* NetSurf is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* NetSurf is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* \file
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* Interface to Write-Once hash table for string to string mapping
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*/
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#ifndef _NETSURF_UTILS_HASHTABLE_H_
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#define _NETSURF_UTILS_HASHTABLE_H_
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#include <stdbool.h>
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struct hash_table;
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/**
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* Create a new hash table, and return a context for it. The memory consumption
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* of a hash table is approximately 8 + (nchains * 12) bytes if it is empty.
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*
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* \param chains Number of chains/buckets this hash table will have. This
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* should be a prime number, and ideally a prime number just
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* over a power of two, for best performance and distribution.
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* \return struct hash_table containing the context of this hash table or NULL
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* if there is insufficent memory to create it and its chains.
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*/
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struct hash_table *hash_create(unsigned int chains);
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/**
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* Destroys a hash table, freeing all memory associated with it.
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*
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* \param ht Hash table to destroy. After the function returns, this
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* will nolonger be valid.
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*/
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void hash_destroy(struct hash_table *ht);
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/**
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* Adds a key/value pair to a hash table. If the key you're adding is already
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* in the hash table, it does not replace it, but it does take precedent over
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* it. The old key/value pair will be inaccessable but still in memory until
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* hash_destroy() is called on the hash table.
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*
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* \param ht The hash table context to add the key/value pair to.
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* \param key The key to associate the value with. A copy is made.
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* \param value The value to associate the key with. A copy is made.
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* \return true if the add succeeded, false otherwise. (Failure most likely
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* indicates insufficent memory to make copies of the key and value.
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*/
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bool hash_add(struct hash_table *ht, const char *key, const char *value);
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/**
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* Looks up a the value associated with with a key from a specific hash table.
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*
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* \param ht The hash table context to look up the key in.
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* \param key The key to search for.
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* \return The value associated with the key, or NULL if it was not found.
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*/
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const char *hash_get(struct hash_table *ht, const char *key);
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#endif
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