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freeswitch/libs/sofia-sip/libsofia-sip-ua/su/sofia-sip/htable2.h

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/*
* This file is part of the Sofia-SIP package
*
* Copyright (C) 2005 Nokia Corporation.
*
* Contact: Pekka Pessi <pekka.pessi@nokia.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
*/
#ifndef HTABLE2_H
/** Defined when <sofia-sip/htable2.h> has been included. */
#define HTABLE2_H
/**@file sofia-sip/htable2.h
*
* Hash tables templates, take 2.
*
* Note: this version can handle structures as entries, and it can be used
* without <su_alloc.h>.
*
* This file contain a hash table template for C. The hash tables are
* resizeable, and they usually contain pointers to entries. The
* declaration for template datatypes is instantiated with macro
* HTABLE2_DECLARE(). The prototypes for hashing functions are instantiated
* with macro HTABLE2_PROTOS(). The implementation is instantiated with
* macro HTABLE2_BODIES().
*
* The hash table template is most efficient when the hash value is
* precalculated and stored in each entry. The hash "function" given to the
* HTABLE2_BODIES() would then be something like macro
* @code
* #define HTABLE2_ENTRY_HASH(e) ((e).e_hash_value)
* @endcode
*
* When a entry with new identical hash key is added to the table, it can be
* either @e inserted (before any other entry with same key value) or
* @e appended.
*
* Example code can be found from <htable_test.c>.
*
* @author Pekka Pessi <Pekka.Pessi@nokia.com>.
*
* @date Created: Tue Sep 25 17:42:40 2001 ppessi
*
*/
typedef unsigned long hash_value_t;
/** Minimum size of hash table */
#define HTABLE2_MIN_SIZE 31
/** Declare hash table structure type.
*
* The macro HTABLE2_DECLARE() expands to a declaration for hash table
* structure. The its typedef will be <em>prefix</em><code>_t</code>, the
* field names start with @a pr. The entry type is @a entrytype.
*
* @param sname name of struct
* @param prefix hash table type and function prefix
* @param pr hash table field prefix
* @param entrytype entry type
*/
#define HTABLE2_DECLARE(sname, prefix, pr, entrytype) \
struct sname { \
unsigned pr##size; \
unsigned pr##used; \
entrytype *pr##table; /**< Hash table itself */ \
}
#ifndef HTABLE2_SCOPE
/** Default scope for hash table functions. */
#define HTABLE2_SCOPE su_inline
#endif
/** Prototypes for hash table
*
* The macro HTABLE2_PROTOS() expands to the prototypes of hash table
* functions. The function and type names start with @a prefix, the field
* names start with @a pr. The entry type is @a entrytype.
* @param type hash table typedef
* @param prefix function prefix
* @param pr hash table field prefix
* @param entrytype entry type
*/
#define HTABLE2_PROTOS(type, prefix, pr, entrytype) \
HTABLE2_SCOPE int prefix##_resize(void *a, type pr[1], unsigned); \
HTABLE2_SCOPE int prefix##_is_full(type const *); \
HTABLE2_SCOPE entrytype *prefix##_hash(type const *, hash_value_t hv); \
HTABLE2_SCOPE entrytype *prefix##_next(type const *, entrytype *ee); \
HTABLE2_SCOPE void prefix##_append(type *pr, entrytype e); \
HTABLE2_SCOPE void prefix##_insert(type *pr, entrytype e); \
HTABLE2_SCOPE int prefix##_remove(type *, entrytype const e)
/** Hash table implementation.
*
* The macro HTABLE2_BODIES() expands the hash table functions. The function
* and type names start with @a prefix, the field names start with @a pr.
* The entry type is @a entrytype. The function (or macro) name returning
* hash value of each entry is given as @a hfun.
*
* @param type hash table type
* @param prefix function prefix for hash table
* @param pr field prefix for hash table
* @param entrytype type of entry element
* @param hfun function or macro returning hash value of entry
* @param is_used function or macro returning true if entry is occupied
* @param reclaim function or macro zeroing entry
* @param is_equal equality test
* @param halloc function allocating or freeing memory
*/
#define HTABLE2_BODIES(type, prefix, pr, entrytype, \
hfun, is_used, reclaim, is_equal, halloc) \
/** Reallocate new hash table */ \
HTABLE2_SCOPE \
int prefix##_resize(void *realloc_arg, \
type pr[1], \
unsigned new_size) \
{ \
entrytype *new_hash; \
entrytype *old_hash = pr->pr##table; \
unsigned old_size; \
unsigned i, j, i0; \
unsigned again = 0, used = 0, collisions = 0; \
\
(void)realloc_arg; \
\
if (new_size == 0) \
new_size = 2 * pr->pr##size + 1; \
if (new_size < HTABLE2_MIN_SIZE) \
new_size = HTABLE2_MIN_SIZE; \
\
if (!(new_hash = halloc(realloc_arg, NULL, sizeof(*new_hash) * new_size))) \
return -1; \
\
memset(new_hash, 0, sizeof(*new_hash) * new_size); \
old_size = pr->pr##size; \
\
do for (j = 0; j < old_size; j++) { \
if (!is_used(old_hash[j])) \
continue; \
\
if (again < 2 && hfun(old_hash[j]) % old_size > j) { \
/* Wrapped, leave entry for second pass */ \
again = 1; continue; \
} \
\
i0 = hfun(old_hash[j]) % new_size; \
\
for (i = i0; is_used(new_hash[i]); \
i = (i + 1) % new_size, assert(i != i0)) \
collisions++; \
\
new_hash[i] = old_hash[j]; reclaim(&old_hash[j]); \
used++; \
} \
while (again++ == 1); \
\
pr->pr##table = new_hash, pr->pr##size = new_size; \
\
if (old_hash) old_hash = halloc(realloc_arg, old_hash, 0); \
\
assert(pr->pr##used == used);\
\
return 0; \
} \
\
HTABLE2_SCOPE \
int prefix##_is_full(type const *pr) \
{ \
return pr->pr##table == NULL || 3 * pr->pr##used > 2 * pr->pr##size; \
} \
\
HTABLE2_SCOPE \
entrytype *prefix##_hash(type const *pr, hash_value_t hv) \
{ \
return pr->pr##table + hv % pr->pr##size; \
} \
\
HTABLE2_SCOPE \
entrytype *prefix##_next(type const *pr, entrytype *ee) \
{ \
if (++ee < pr->pr##table + pr->pr##size && ee >= pr->pr##table) \
return ee; \
else \
return pr->pr##table; \
} \
\
HTABLE2_SCOPE \
void prefix##_append(type *pr, entrytype e) \
{ \
entrytype *ee; \
\
pr->pr##used++; \
for (ee = prefix##_hash(pr, hfun(e)); \
is_used(*ee); \
ee = prefix##_next(pr, ee)) \
; \
*ee = e; \
} \
\
HTABLE2_SCOPE \
void prefix##_insert(type *pr, entrytype e) \
{ \
entrytype e0; \
entrytype *ee; \
\
pr->pr##used++; \
/* Insert entry into hash table (before other entries with same hash) */ \
for (ee = prefix##_hash(pr, hfun(e)); \
is_used((*ee)); \
ee = prefix##_next(pr, ee)) \
*ee = e, e = e0; \
*ee = e; \
} \
\
HTABLE2_SCOPE \
int prefix##_remove(type *pr, entrytype const e) \
{ \
unsigned i, j, k, size = pr->pr##size; \
entrytype *htable = pr->pr##table; \
\
/* Search for entry */ \
for (i = hfun(e) % size; is_used(htable[i]); i = (i + 1) % size) \
if (is_equal(e, htable[i])) \
break; \
\
if (!is_used(htable[i])) return -1; \
\
/* Move table entries towards their primary place */ \
for (j = (i + 1) % size; is_used(htable[j]); j = (j + 1) % size) { \
/* k is primary place for entry */ \
k = hfun(htable[j]) % size; \
if (k == j) /* entry is in its primary place? */ \
continue; \
/* primary place is between i and j - do not move this to i */ \
if (j > i ? (i < k && k < j) : (i < k || k < j)) \
continue; \
\
htable[i] = htable[j], i = j; \
} \
\
pr->pr##used--; \
\
reclaim(&htable[i]); \
\
return 0; \
} \
extern int const prefix##_dummy
#endif /** !defined(HTABLE2_H) */
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