/* Fixed size hash table with internal linking.
Copyright (C) 2000, 2001, 2002, 2004, 2005 Red Hat, Inc.
This file is part of elfutils.
Written by Ulrich Drepper <drepper@redhat.com>, 2000.
This file is free software; you can redistribute it and/or modify
it under the terms of either
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at
your option) any later version
or
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at
your option) any later version
or both in parallel, as here.
elfutils 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
General Public License for more details.
You should have received copies of the GNU General Public License and
the GNU Lesser General Public License along with this program. If
not, see <http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/cdefs.h>
#include <sys/param.h>
#include <system.h>
#define CONCAT(t1,t2) __CONCAT (t1,t2)
/* Before including this file the following macros must be defined:
TYPE data type of the hash table entries
HASHFCT name of the hashing function to use
HASHTYPE type used for the hashing value
COMPARE comparison function taking two pointers to TYPE objects
CLASS can be defined to `static' to avoid exporting the functions
PREFIX prefix to be used for function and data type names
STORE_POINTER if defined the table stores a pointer and not an element
of type TYPE
INSERT_HASH if defined alternate insert function which takes a hash
value is defined
NO_FINI_FCT if defined the fini function is not defined
*/
/* Defined separately. */
extern size_t next_prime (size_t seed);
/* Set default values. */
#ifndef HASHTYPE
# define HASHTYPE size_t
#endif
#ifndef CLASS
# define CLASS
#endif
#ifndef PREFIX
# define PREFIX
#endif
/* The data structure. */
struct CONCAT(PREFIX,fshash)
{
size_t nslots;
struct CONCAT(PREFIX,fshashent)
{
HASHTYPE hval;
#ifdef STORE_POINTER
# define ENTRYP(el) (el).entry
TYPE *entry;
#else
# define ENTRYP(el) &(el).entry
TYPE entry;
#endif
} table[0];
};
/* Constructor for the hashing table. */
CLASS struct CONCAT(PREFIX,fshash) *
CONCAT(PREFIX,fshash_init) (size_t nelems)
{
struct CONCAT(PREFIX,fshash) *result;
/* We choose a size for the hashing table 150% over the number of
entries. This will guarantee short medium search lengths. */
const size_t max_size_t = ~((size_t) 0);
if (nelems >= (max_size_t / 3) * 2)
{
errno = EINVAL;
return NULL;
}
/* Adjust the size to be used for the hashing table. */
nelems = next_prime (MAX ((nelems * 3) / 2, 10));
/* Allocate the data structure for the result. */
result = (struct CONCAT(PREFIX,fshash) *)
xcalloc (sizeof (struct CONCAT(PREFIX,fshash))
+ (nelems + 1) * sizeof (struct CONCAT(PREFIX,fshashent)), 1);
if (result == NULL)
return NULL;
result->nslots = nelems;
return result;
}
#ifndef NO_FINI_FCT
CLASS void
CONCAT(PREFIX,fshash_fini) (struct CONCAT(PREFIX,fshash) *htab)
{
free (htab);
}
#endif
static struct CONCAT(PREFIX,fshashent) *
CONCAT(PREFIX,fshash_lookup) (struct CONCAT(PREFIX,fshash) *htab,
HASHTYPE hval, TYPE *data)
{
size_t idx = 1 + hval % htab->nslots;
if (htab->table[idx].hval != 0)
{
HASHTYPE hash;
/* See whether this is the same entry. */
if (htab->table[idx].hval == hval
&& COMPARE (data, ENTRYP (htab->table[idx])) == 0)
return &htab->table[idx];
/* Second hash function as suggested in [Knuth]. */
hash = 1 + hval % (htab->nslots - 2);
do
{
if (idx <= hash)
idx = htab->nslots + idx - hash;
else
idx -= hash;
if (htab->table[idx].hval == hval
&& COMPARE (data, ENTRYP(htab->table[idx])) == 0)
return &htab->table[idx];
}
while (htab->table[idx].hval != 0);
}
return &htab->table[idx];
}
CLASS int
__attribute__ ((unused))
CONCAT(PREFIX,fshash_insert) (struct CONCAT(PREFIX,fshash) *htab,
const char *str,
size_t len __attribute__ ((unused)), TYPE *data)
{
HASHTYPE hval = HASHFCT (str, len ?: strlen (str));
struct CONCAT(PREFIX,fshashent) *slot;
slot = CONCAT(PREFIX,fshash_lookup) (htab, hval, data);
if (slot->hval != 0)
/* We don't want to overwrite the old value. */
return -1;
slot->hval = hval;
#ifdef STORE_POINTER
slot->entry = data;
#else
slot->entry = *data;
#endif
return 0;
}
#ifdef INSERT_HASH
CLASS int
__attribute__ ((unused))
CONCAT(PREFIX,fshash_insert_hash) (struct CONCAT(PREFIX,fshash) *htab,
HASHTYPE hval, TYPE *data)
{
struct CONCAT(PREFIX,fshashent) *slot;
slot = CONCAT(PREFIX,fshash_lookup) (htab, hval, data);
if (slot->hval != 0)
/* We don't want to overwrite the old value. */
return -1;
slot->hval = hval;
#ifdef STORE_POINTER
slot->entry = data;
#else
slot->entry = *data;
#endif
return 0;
}
#endif
CLASS int
__attribute__ ((unused))
CONCAT(PREFIX,fshash_overwrite) (struct CONCAT(PREFIX,fshash) *htab,
const char *str,
size_t len __attribute__ ((unused)),
TYPE *data)
{
HASHTYPE hval = HASHFCT (str, len ?: strlen (str));
struct CONCAT(PREFIX,fshashent) *slot;
slot = CONCAT(PREFIX,fshash_lookup) (htab, hval, data);
slot->hval = hval;
#ifdef STORE_POINTER
slot->entry = data;
#else
slot->entry = *data;
#endif
return 0;
}
CLASS const TYPE *
CONCAT(PREFIX,fshash_find) (const struct CONCAT(PREFIX,fshash) *htab,
const char *str,
size_t len __attribute__ ((unused)), TYPE *data)
{
HASHTYPE hval = HASHFCT (str, len ?: strlen (str));
struct CONCAT(PREFIX,fshashent) *slot;
slot = CONCAT(PREFIX,fshash_lookup) ((struct CONCAT(PREFIX,fshash) *) htab,
hval, data);
if (slot->hval == 0)
/* Not found. */
return NULL;
return ENTRYP(*slot);
}
/* Unset the macros we expect. */
#undef TYPE
#undef HASHFCT
#undef HASHTYPE
#undef COMPARE
#undef CLASS
#undef PREFIX
#undef INSERT_HASH
#undef STORE_POINTER
#undef NO_FINI_FCT