06a99fe36f
databases. - Make nsswitch support caching. Submitted by: Michael Bushkov <bushman__at__rsu.ru> Sponsored by: Google Summer of Code 2005
219 lines
7.5 KiB
C
219 lines
7.5 KiB
C
/*-
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* Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef __CACHELIB_HASHTABLE_H__
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#define __CACHELIB_HASHTABLE_H__
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#include <search.h>
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#include <string.h>
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#define HASHTABLE_INITIAL_ENTRIES_CAPACITY 8
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typedef int hashtable_index_t;
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/*
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* This file contains queue.h-like macro definitions for hash tables.
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* Hash table is organized as an array of the specified size of the user
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* defined (with HASTABLE_ENTRY_HEAD) structures. Each hash table
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* entry (user defined structure) stores its elements in the sorted array.
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* You can place elements into the hash table, retrieve elements with
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* specified key, traverse through all elements, and delete them.
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* New elements are placed into the hash table by using the compare and
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* hashing functions, provided by the user.
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*/
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/*
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* Defines the hash table entry structure, that uses specified type of
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* elements.
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*/
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#define HASHTABLE_ENTRY_HEAD(name, type) struct name { \
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type *values; \
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size_t capacity; \
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size_t size; \
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}
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/*
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* Defines the hash table structure, which uses the specified type of entries.
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* The only restriction for entries is that is that they should have the field,
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* defined with HASHTABLE_ENTRY_HEAD macro.
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*/
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#define HASHTABLE_HEAD(name, entry) struct name { \
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struct entry *entries; \
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size_t entries_size; \
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}
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#define HASHTABLE_ENTRIES_COUNT(table) ((table)->entries_size)
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/*
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* Unlike most of queue.h data types, hash tables can not be initialized
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* statically - so there is no HASHTABLE_HEAD_INITIALIZED macro.
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*/
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#define HASHTABLE_INIT(table, type, field, _entries_size) \
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do { \
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hashtable_index_t var; \
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(table)->entries = (void *)malloc( \
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sizeof(*(table)->entries) * (_entries_size)); \
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memset((table)->entries, 0, \
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sizeof(*(table)->entries) * (_entries_size)); \
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(table)->entries_size = (_entries_size); \
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for (var = 0; var < HASHTABLE_ENTRIES_COUNT(table); ++var) {\
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(table)->entries[var].field.capacity = \
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HASHTABLE_INITIAL_ENTRIES_CAPACITY; \
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(table)->entries[var].field.size = 0; \
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(table)->entries[var].field.values = (type *)malloc(\
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sizeof(type) * \
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HASHTABLE_INITIAL_ENTRIES_CAPACITY); \
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assert((table)->entries[var].field.values != NULL);\
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} \
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} while (0)
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/*
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* All initialized hashtables should be destroyed with this macro.
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*/
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#define HASHTABLE_DESTROY(table, field) \
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do { \
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hashtable_index_t var; \
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for (var = 0; var < HASHTABLE_ENTRIES_COUNT(table); ++var) {\
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free((table)->entries[var].field.values); \
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} \
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} while (0)
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#define HASHTABLE_GET_ENTRY(table, hash) (&((table)->entries[hash]))
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/*
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* Traverses through all hash table entries
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*/
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#define HASHTABLE_FOREACH(table, var) \
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for ((var) = &((table)->entries[0]); \
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(var) < &((table)->entries[HASHTABLE_ENTRIES_COUNT(table)]);\
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++(var))
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/*
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* Traverses through all elements of the specified hash table entry
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*/
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#define HASHTABLE_ENTRY_FOREACH(entry, field, var) \
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for ((var) = &((entry)->field.values[0]); \
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(var) < &((entry)->field.values[(entry)->field.size]); \
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++(var))
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#define HASHTABLE_ENTRY_CLEAR(entry, field) \
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((entry)->field.size = 0)
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#define HASHTABLE_ENTRY_SIZE(entry, field) \
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((entry)->field.size)
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#define HASHTABLE_ENTRY_CAPACITY(entry, field) \
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((entry)->field.capacity)
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#define HASHTABLE_ENTRY_CAPACITY_INCREASE(entry, field, type) \
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(entry)->field.capacity *= 2; \
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(entry)->field.values = (type *)realloc((entry)->field.values, \
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(entry)->field.capacity * sizeof(type));
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#define HASHTABLE_ENTRY_CAPACITY_DECREASE(entry, field, type) \
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(entry)->field.capacity /= 2; \
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(entry)->field.values = (type *)realloc((entry)->field.values, \
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(entry)->field.capacity * sizeof(type));
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/*
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* Generates prototypes for the hash table functions
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*/
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#define HASHTABLE_PROTOTYPE(name, entry_, type) \
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hashtable_index_t name##_CALCULATE_HASH(struct name *, type *); \
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void name##_ENTRY_STORE(struct entry_*, type *); \
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type *name##_ENTRY_FIND(struct entry_*, type *); \
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type *name##_ENTRY_FIND_SPECIAL(struct entry_ *, type *, \
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int (*) (const void *, const void *)); \
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void name##_ENTRY_REMOVE(struct entry_*, type *);
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/*
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* Generates implementations of the hash table functions
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*/
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#define HASHTABLE_GENERATE(name, entry_, type, field, HASH, CMP) \
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hashtable_index_t name##_CALCULATE_HASH(struct name *table, type *data) \
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{ \
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\
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return HASH(data, table->entries_size); \
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} \
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\
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void name##_ENTRY_STORE(struct entry_ *the_entry, type *data) \
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{ \
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\
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if (the_entry->field.size == the_entry->field.capacity) \
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HASHTABLE_ENTRY_CAPACITY_INCREASE(the_entry, field, type);\
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\
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memcpy(&(the_entry->field.values[the_entry->field.size++]), \
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data, \
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sizeof(type)); \
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qsort(the_entry->field.values, the_entry->field.size, \
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sizeof(type), CMP); \
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} \
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\
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type *name##_ENTRY_FIND(struct entry_ *the_entry, type *key) \
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{ \
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\
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return ((type *)bsearch(key, the_entry->field.values, \
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the_entry->field.size, sizeof(type), CMP)); \
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} \
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\
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type *name##_ENTRY_FIND_SPECIAL(struct entry_ *the_entry, type *key, \
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int (*compar) (const void *, const void *)) \
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{ \
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return ((type *)bsearch(key, the_entry->field.values, \
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the_entry->field.size, sizeof(type), compar)); \
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} \
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\
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void name##_ENTRY_REMOVE(struct entry_ *the_entry, type *del_elm) \
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{ \
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\
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memmove(del_elm, del_elm + 1, \
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(&the_entry->field.values[--the_entry->field.size] - del_elm) *\
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sizeof(type)); \
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}
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/*
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* Macro definitions below wrap the functions, generaed with
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* HASHTABLE_GENERATE macro. You should use them and avoid using generated
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* functions directly.
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*/
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#define HASHTABLE_CALCULATE_HASH(name, table, data) \
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(name##_CALCULATE_HASH((table), data))
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#define HASHTABLE_ENTRY_STORE(name, entry, data) \
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name##_ENTRY_STORE((entry), data)
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#define HASHTABLE_ENTRY_FIND(name, entry, key) \
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(name##_ENTRY_FIND((entry), (key)))
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#define HASHTABLE_ENTRY_FIND_SPECIAL(name, entry, key, cmp) \
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(name##_ENTRY_FIND_SPECIAL((entry), (key), (cmp)))
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#define HASHTABLE_ENTRY_REMOVE(name, entry, del_elm) \
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name##_ENTRY_REMOVE((entry), (del_elm))
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#endif
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