/* Copyright (C) 2000, 2001, 2002 Red Hat, Inc.
Written by Ulrich Drepper <drepper@redhat.com>, 2000.
This program is Open Source software; you can redistribute it and/or
modify it under the terms of the Open Software License version 1.0 as
published by the Open Source Initiative.
You should have received a copy of the Open Software License along
with this program; if not, you may obtain a copy of the Open Software
License version 1.0 from http://www.opensource.org/licenses/osl.php or
by writing the Open Source Initiative c/o Lawrence Rosen, Esq.,
3001 King Ranch Road, Ukiah, CA 95482. */
#include <assert.h>
#include <stdlib.h>
#include <system.h>
/* Before including this file the following macros must be defined:
NAME name of the hash table structure.
TYPE data type of the hash table entries
COMPARE comparison function taking two pointers to TYPE objects
The following macros if present select features:
ITERATE iterating over the table entries is possible
REVERSE iterate in reverse order of insert
*/
static size_t
lookup (htab, hval, val)
NAME *htab;
unsigned long int hval;
TYPE val;
{
/* First hash function: simply take the modul but prevent zero. */
size_t idx = 1 + hval % htab->size;
if (htab->table[idx].hashval != 0)
{
unsigned long int hash;
if (htab->table[idx].hashval == hval
&& COMPARE (htab->table[idx].data, val) == 0)
return idx;
/* Second hash function as suggested in [Knuth]. */
hash = 1 + hval % (htab->size - 2);
do
{
if (idx <= hash)
idx = htab->size + idx - hash;
else
idx -= hash;
/* If entry is found use it. */
if (htab->table[idx].hashval == hval
&& COMPARE (htab->table[idx].data, val) == 0)
return idx;
}
while (htab->table[idx].hashval);
}
return idx;
}
static void
insert_entry_2 (NAME *htab, unsigned long int hval, size_t idx, TYPE data)
{
#ifdef ITERATE
if (htab->table[idx].hashval == 0)
{
# ifdef REVERSE
htab->table[idx].next = htab->first;
htab->first = &htab->table[idx];
# else
/* Add the new value to the list. */
if (htab->first == NULL)
htab->first = htab->table[idx].next = &htab->table[idx];
else
{
htab->table[idx].next = htab->first->next;
htab->first = htab->first->next = &htab->table[idx];
}
# endif
}
#endif
htab->table[idx].hashval = hval;
htab->table[idx].data = data;
++htab->filled;
if (100 * htab->filled > 90 * htab->size)
{
/* Table is filled more than 90%. Resize the table. */
#ifdef ITERATE
__typeof__ (htab->first) first;
# ifndef REVERSE
__typeof__ (htab->first) runp;
# endif
#else
unsigned long int old_size = htab->size;
#endif
#define _TABLE(name) \
name##_ent *table = htab->table
#define TABLE(name) _TABLE (name)
TABLE(NAME);
htab->size = next_prime (htab->size * 2);
htab->filled = 0;
#ifdef ITERATE
first = htab->first;
htab->first = NULL;
#endif
htab->table = calloc ((1 + htab->size), sizeof (htab->table[0]));
if (htab->table == NULL)
{
/* We cannot enlarge the table. Live with what we got. This
might lead to an infinite loop at some point, though. */
htab->table = table;
return;
}
/* Add the old entries to the new table. When iteration is
supported we maintain the order. */
#ifdef ITERATE
# ifdef REVERSE
while (first != NULL)
{
insert_entry_2 (htab, first->hashval,
lookup (htab, first->hashval, first->data),
first->data);
first = first->next;
}
# else
assert (first != NULL);
runp = first = first->next;
do
insert_entry_2 (htab, runp->hashval,
lookup (htab, runp->hashval, runp->data), runp->data);
while ((runp = runp->next) != first);
# endif
#else
for (idx = 1; idx <= old_size; ++idx)
if (table[idx].hashval != 0)
insert_entry_2 (htab, table[idx].hashval,
lookup (htab, table[idx].hashval, table[idx].data),
table[idx].data);
#endif
free (table);
}
}
int
#define INIT(name) _INIT (name)
#define _INIT(name) \
name##_init
INIT(NAME) (htab, init_size)
NAME *htab;
unsigned long int init_size;
{
/* We need the size to be a prime. */
init_size = next_prime (init_size);
/* Initialize the data structure. */
htab->size = init_size;
htab->filled = 0;
#ifdef ITERATE
htab->first = NULL;
#endif
htab->table = (void *) calloc ((init_size + 1), sizeof (htab->table[0]));
if (htab->table == NULL)
return -1;
return 0;
}
int
#define FREE(name) _FREE (name)
#define _FREE(name) \
name##_free
FREE(NAME) (htab)
NAME *htab;
{
free (htab->table);
return 0;
}
int
#define INSERT(name) _INSERT (name)
#define _INSERT(name) \
name##_insert
INSERT(NAME) (htab, hval, data)
NAME *htab;
unsigned long int hval;
TYPE data;
{
size_t idx;
/* Make the hash value nonzero. */
hval = hval ?: 1;
idx = lookup (htab, hval, data);
if (htab->table[idx].hashval != 0)
/* We don't want to overwrite the old value. */
return -1;
/* An empty bucket has been found. */
insert_entry_2 (htab, hval, idx, data);
return 0;
}
#ifdef OVERWRITE
int
#define INSERT(name) _INSERT (name)
#define _INSERT(name) \
name##_overwrite
INSERT(NAME) (htab, hval, data)
NAME *htab;
unsigned long int hval;
TYPE data;
{
size_t idx;
/* Make the hash value nonzero. */
hval = hval ?: 1;
idx = lookup (htab, hval, data);
/* The correct bucket has been found. */
insert_entry_2 (htab, hval, idx, data);
return 0;
}
#endif
TYPE
#define FIND(name) _FIND (name)
#define _FIND(name) \
name##_find
FIND(NAME) (htab, hval, val)
NAME *htab;
unsigned long int hval;
TYPE val;
{
size_t idx;
/* Make the hash value nonzero. */
hval = hval ?: 1;
idx = lookup (htab, hval, val);
if (htab->table[idx].hashval == 0)
return NULL;
return htab->table[idx].data;
}
#ifdef ITERATE
# define ITERATEFCT(name) _ITERATEFCT (name)
# define _ITERATEFCT(name) \
name##_iterate
TYPE
ITERATEFCT(NAME) (htab, ptr)
NAME *htab;
void **ptr;
{
void *p = *ptr;
# define TYPENAME(name) _TYPENAME (name)
# define _TYPENAME(name) name##_ent
# ifdef REVERSE
if (p == NULL)
p = htab->first;
else
p = ((TYPENAME(NAME) *) p)->next;
if (p == NULL)
{
*ptr = NULL;
return NULL;
}
# else
if (p == NULL)
{
if (htab->first == NULL)
return NULL;
p = htab->first->next;
}
else
{
if (p == htab->first)
return NULL;
p = ((TYPENAME(NAME) *) p)->next;
}
# endif
/* Prepare the next element. If possible this will pull the data
into the cache, for reading. */
__builtin_prefetch (((TYPENAME(NAME) *) p)->next, 0, 2);
return ((TYPENAME(NAME) *) (*ptr = p))->data;
}
#endif