monero/external/unbound/util/storage/slabhash.h
Erik de Castro Lopo a85b5759f3 Upgrade unbound library
These files were pulled from the 1.6.3 release tarball.

This new version builds against OpenSSL version 1.1 which will be
the default in the new Debian Stable which is due to be released
RealSoonNow (tm).
2017-06-17 23:04:00 +10:00

219 lines
7.5 KiB
C

/*
* util/storage/slabhash.h - hashtable consisting of several smaller tables.
*
* Copyright (c) 2007, NLnet Labs. All rights reserved.
*
* This software is open source.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the NLNET LABS nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file
*
* Hash table that consists of smaller hash tables.
* It cannot grow, but that gives it the ability to have multiple
* locks. Also this means there are multiple LRU lists.
*/
#ifndef UTIL_STORAGE_SLABHASH_H
#define UTIL_STORAGE_SLABHASH_H
#include "util/storage/lruhash.h"
/** default number of slabs */
#define HASH_DEFAULT_SLABS 4
/**
* Hash table formed from several smaller ones.
* This results in a partitioned lruhash table, a 'slashtable'.
* None of the data inside the slabhash may be altered.
* Therefore, no locks are needed to access the structure.
*/
struct slabhash {
/** the size of the array - must be power of 2 */
size_t size;
/** size bitmask - uses high bits. */
uint32_t mask;
/** shift right this many bits to get index into array. */
unsigned int shift;
/** lookup array of hash tables */
struct lruhash** array;
};
/**
* Create new slabbed hash table.
* @param numtables: number of hash tables to use, other parameters used to
* initialize these smaller hashtables.
* @param start_size: size of hashtable array at start, must be power of 2.
* @param maxmem: maximum amount of memory this table is allowed to use.
* so every table gets maxmem/numtables to use for itself.
* @param sizefunc: calculates memory usage of entries.
* @param compfunc: compares entries, 0 on equality.
* @param delkeyfunc: deletes key.
* @param deldatafunc: deletes data.
* @param arg: user argument that is passed to user function calls.
* @return: new hash table or NULL on malloc failure.
*/
struct slabhash* slabhash_create(size_t numtables, size_t start_size,
size_t maxmem, lruhash_sizefunc_type sizefunc,
lruhash_compfunc_type compfunc, lruhash_delkeyfunc_type delkeyfunc,
lruhash_deldatafunc_type deldatafunc, void* arg);
/**
* Delete hash table. Entries are all deleted.
* @param table: to delete.
*/
void slabhash_delete(struct slabhash* table);
/**
* Clear hash table. Entries are all deleted.
* @param table: to make empty.
*/
void slabhash_clear(struct slabhash* table);
/**
* Insert a new element into the hashtable, uses lruhash_insert.
* If key is already present data pointer in that entry is updated.
*
* @param table: hash table.
* @param hash: hash value. User calculates the hash.
* @param entry: identifies the entry.
* If key already present, this entry->key is deleted immediately.
* But entry->data is set to NULL before deletion, and put into
* the existing entry. The data is then freed.
* @param data: the data.
* @param cb_override: if not NULL overrides the cb_arg for deletfunc.
*/
void slabhash_insert(struct slabhash* table, hashvalue_type hash,
struct lruhash_entry* entry, void* data, void* cb_override);
/**
* Lookup an entry in the hashtable. Uses lruhash_lookup.
* At the end of the function you hold a (read/write)lock on the entry.
* The LRU is updated for the entry (if found).
* @param table: hash table.
* @param hash: hash of key.
* @param key: what to look for, compared against entries in overflow chain.
* the hash value must be set, and must work with compare function.
* @param wr: set to true if you desire a writelock on the entry.
* with a writelock you can update the data part.
* @return: pointer to the entry or NULL. The entry is locked.
* The user must unlock the entry when done.
*/
struct lruhash_entry* slabhash_lookup(struct slabhash* table,
hashvalue_type hash, void* key, int wr);
/**
* Remove entry from hashtable. Does nothing if not found in hashtable.
* Delfunc is called for the entry. Uses lruhash_remove.
* @param table: hash table.
* @param hash: hash of key.
* @param key: what to look for.
*/
void slabhash_remove(struct slabhash* table, hashvalue_type hash, void* key);
/**
* Output debug info to the log as to state of the hash table.
* @param table: hash table.
* @param id: string printed with table to identify the hash table.
* @param extended: set to true to print statistics on overflow bin lengths.
*/
void slabhash_status(struct slabhash* table, const char* id, int extended);
/**
* Retrieve slab hash total size.
* @param table: hash table.
* @return size configured as max.
*/
size_t slabhash_get_size(struct slabhash* table);
/**
* Retrieve slab hash current memory use.
* @param table: hash table.
* @return memory in use.
*/
size_t slabhash_get_mem(struct slabhash* table);
/**
* Get lruhash table for a given hash value
* @param table: slabbed hash table.
* @param hash: hash value.
* @return the lru hash table.
*/
struct lruhash* slabhash_gettable(struct slabhash* table, hashvalue_type hash);
/**
* Set markdel function
* @param table: slabbed hash table.
* @param md: markdel function ptr.
*/
void slabhash_setmarkdel(struct slabhash* table, lruhash_markdelfunc_type md);
/**
* Traverse a slabhash.
* @param table: slabbed hash table.
* @param wr: if true, writelock is obtained, otherwise readlock.
* @param func: function to call for every element.
* @param arg: user argument to function.
*/
void slabhash_traverse(struct slabhash* table, int wr,
void (*func)(struct lruhash_entry*, void*), void* arg);
/*
* Count entries in slabhash.
* @param table: slabbed hash table;
* @return the number of items
*/
size_t count_slabhash_entries(struct slabhash* table);
/* --- test representation --- */
/** test structure contains test key */
struct slabhash_testkey {
/** the key id */
int id;
/** the entry */
struct lruhash_entry entry;
};
/** test structure contains test data */
struct slabhash_testdata {
/** data value */
int data;
};
/** test sizefunc for lruhash */
size_t test_slabhash_sizefunc(void*, void*);
/** test comparefunc for lruhash */
int test_slabhash_compfunc(void*, void*);
/** test delkey for lruhash */
void test_slabhash_delkey(void*, void*);
/** test deldata for lruhash */
void test_slabhash_deldata(void*, void*);
/* --- end test representation --- */
#endif /* UTIL_STORAGE_SLABHASH_H */