2000-02-22 16:59:20 +01:00
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/* An expandable hash tables datatype.
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2003-01-26 08:33:29 +01:00
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Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
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2000-02-22 16:59:20 +01:00
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Contributed by Vladimir Makarov (vmakarov@cygnus.com).
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This file is part of the libiberty library.
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Libiberty is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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Libiberty is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with libiberty; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* This package implements basic hash table functionality. It is possible
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to search for an entry, create an entry and destroy an entry.
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Elements in the table are generic pointers.
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The size of the table is not fixed; if the occupancy of the table
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grows too high the hash table will be expanded.
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The abstract data implementation is based on generalized Algorithm D
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from Knuth's book "The art of computer programming". Hash table is
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expanded by creation of new hash table and transferring elements from
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the old table to the new table. */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <sys/types.h>
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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2000-05-29 22:45:32 +02:00
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#ifdef HAVE_STRING_H
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#include <string.h>
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#endif
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2003-06-19 22:05:36 +02:00
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#ifdef HAVE_MALLOC_H
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#include <malloc.h>
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#endif
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2000-02-22 16:59:20 +01:00
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#include <stdio.h>
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#include "libiberty.h"
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#include "hashtab.h"
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/* This macro defines reserved value for empty table entry. */
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2000-11-03 21:55:25 +01:00
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#define EMPTY_ENTRY ((PTR) 0)
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2000-02-22 16:59:20 +01:00
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/* This macro defines reserved value for table entry which contained
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a deleted element. */
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2000-11-03 21:55:25 +01:00
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#define DELETED_ENTRY ((PTR) 1)
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2000-02-22 16:59:20 +01:00
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2000-06-15 22:56:25 +02:00
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static unsigned long higher_prime_number PARAMS ((unsigned long));
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static hashval_t hash_pointer PARAMS ((const void *));
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static int eq_pointer PARAMS ((const void *, const void *));
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2000-11-04 08:54:27 +01:00
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static int htab_expand PARAMS ((htab_t));
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2000-11-03 21:55:25 +01:00
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static PTR *find_empty_slot_for_expand PARAMS ((htab_t, hashval_t));
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2000-06-15 22:56:25 +02:00
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/* At some point, we could make these be NULL, and modify the
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hash-table routines to handle NULL specially; that would avoid
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function-call overhead for the common case of hashing pointers. */
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htab_hash htab_hash_pointer = hash_pointer;
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htab_eq htab_eq_pointer = eq_pointer;
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2000-11-29 20:19:10 +01:00
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/* The following function returns a nearest prime number which is
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greater than N, and near a power of two. */
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2000-02-22 16:59:20 +01:00
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static unsigned long
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2000-03-24 22:31:22 +01:00
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higher_prime_number (n)
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unsigned long n;
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2000-02-22 16:59:20 +01:00
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{
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2000-11-29 20:19:10 +01:00
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/* These are primes that are near, but slightly smaller than, a
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power of two. */
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2001-10-07 19:24:36 +02:00
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static const unsigned long primes[] = {
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2001-03-15 22:07:01 +01:00
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(unsigned long) 7,
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(unsigned long) 13,
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(unsigned long) 31,
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(unsigned long) 61,
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(unsigned long) 127,
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(unsigned long) 251,
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(unsigned long) 509,
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(unsigned long) 1021,
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(unsigned long) 2039,
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(unsigned long) 4093,
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(unsigned long) 8191,
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(unsigned long) 16381,
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(unsigned long) 32749,
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(unsigned long) 65521,
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(unsigned long) 131071,
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(unsigned long) 262139,
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(unsigned long) 524287,
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(unsigned long) 1048573,
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(unsigned long) 2097143,
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(unsigned long) 4194301,
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(unsigned long) 8388593,
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(unsigned long) 16777213,
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(unsigned long) 33554393,
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(unsigned long) 67108859,
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(unsigned long) 134217689,
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(unsigned long) 268435399,
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(unsigned long) 536870909,
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(unsigned long) 1073741789,
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(unsigned long) 2147483647,
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/* 4294967291L */
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2001-03-15 23:02:06 +01:00
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((unsigned long) 2147483647) + ((unsigned long) 2147483644),
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2000-11-29 20:19:10 +01:00
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};
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2001-10-07 19:24:36 +02:00
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const unsigned long *low = &primes[0];
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const unsigned long *high = &primes[sizeof(primes) / sizeof(primes[0])];
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2000-11-29 20:19:10 +01:00
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while (low != high)
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{
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2001-10-07 19:24:36 +02:00
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const unsigned long *mid = low + (high - low) / 2;
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2000-11-29 20:19:10 +01:00
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if (n > *mid)
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low = mid + 1;
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else
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high = mid;
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}
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/* If we've run out of primes, abort. */
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if (n > *low)
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{
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fprintf (stderr, "Cannot find prime bigger than %lu\n", n);
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abort ();
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}
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return *low;
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2000-02-22 16:59:20 +01:00
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}
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2000-06-15 22:56:25 +02:00
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/* Returns a hash code for P. */
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static hashval_t
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hash_pointer (p)
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2000-11-03 21:55:25 +01:00
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const PTR p;
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2000-06-15 22:56:25 +02:00
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{
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return (hashval_t) ((long)p >> 3);
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}
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/* Returns non-zero if P1 and P2 are equal. */
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static int
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eq_pointer (p1, p2)
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2000-11-03 21:55:25 +01:00
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const PTR p1;
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const PTR p2;
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2000-06-15 22:56:25 +02:00
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{
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return p1 == p2;
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}
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2000-02-22 16:59:20 +01:00
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/* This function creates table with length slightly longer than given
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source length. Created hash table is initiated as empty (all the
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hash table entries are EMPTY_ENTRY). The function returns the
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2002-06-06 14:55:24 +02:00
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created hash table, or NULL if memory allocation fails. */
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2000-02-22 16:59:20 +01:00
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2000-03-24 22:31:22 +01:00
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htab_t
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2002-06-06 14:55:24 +02:00
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htab_create_alloc (size, hash_f, eq_f, del_f, alloc_f, free_f)
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2000-02-22 16:59:20 +01:00
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size_t size;
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2000-03-24 22:31:22 +01:00
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htab_hash hash_f;
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htab_eq eq_f;
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htab_del del_f;
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2002-06-06 14:55:24 +02:00
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htab_alloc alloc_f;
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htab_free free_f;
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2000-02-22 16:59:20 +01:00
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{
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2000-03-24 22:31:22 +01:00
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htab_t result;
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2000-02-22 16:59:20 +01:00
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size = higher_prime_number (size);
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2002-06-06 14:55:24 +02:00
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result = (htab_t) (*alloc_f) (1, sizeof (struct htab));
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if (result == NULL)
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return NULL;
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result->entries = (PTR *) (*alloc_f) (size, sizeof (PTR));
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if (result->entries == NULL)
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{
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if (free_f != NULL)
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(*free_f) (result);
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return NULL;
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}
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2000-02-22 16:59:20 +01:00
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result->size = size;
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2000-03-24 22:31:22 +01:00
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result->hash_f = hash_f;
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result->eq_f = eq_f;
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result->del_f = del_f;
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2002-06-06 14:55:24 +02:00
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result->alloc_f = alloc_f;
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result->free_f = free_f;
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2000-11-04 08:54:27 +01:00
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return result;
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}
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2003-01-26 08:33:29 +01:00
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/* As above, but use the variants of alloc_f and free_f which accept
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an extra argument. */
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htab_t
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htab_create_alloc_ex (size, hash_f, eq_f, del_f, alloc_arg, alloc_f,
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free_f)
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size_t size;
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htab_hash hash_f;
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htab_eq eq_f;
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htab_del del_f;
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PTR alloc_arg;
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htab_alloc_with_arg alloc_f;
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htab_free_with_arg free_f;
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{
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htab_t result;
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size = higher_prime_number (size);
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result = (htab_t) (*alloc_f) (alloc_arg, 1, sizeof (struct htab));
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if (result == NULL)
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return NULL;
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result->entries = (PTR *) (*alloc_f) (alloc_arg, size, sizeof (PTR));
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if (result->entries == NULL)
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{
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if (free_f != NULL)
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(*free_f) (alloc_arg, result);
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return NULL;
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}
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result->size = size;
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result->hash_f = hash_f;
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result->eq_f = eq_f;
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result->del_f = del_f;
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result->alloc_arg = alloc_arg;
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result->alloc_with_arg_f = alloc_f;
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result->free_with_arg_f = free_f;
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return result;
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}
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/* Update the function pointers and allocation parameter in the htab_t. */
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void
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htab_set_functions_ex (htab, hash_f, eq_f, del_f, alloc_arg, alloc_f, free_f)
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htab_t htab;
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htab_hash hash_f;
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htab_eq eq_f;
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htab_del del_f;
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PTR alloc_arg;
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htab_alloc_with_arg alloc_f;
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htab_free_with_arg free_f;
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{
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htab->hash_f = hash_f;
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htab->eq_f = eq_f;
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htab->del_f = del_f;
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htab->alloc_arg = alloc_arg;
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htab->alloc_with_arg_f = alloc_f;
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htab->free_with_arg_f = free_f;
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}
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2002-06-06 14:55:24 +02:00
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/* These functions exist solely for backward compatibility. */
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2000-11-04 08:54:27 +01:00
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2002-06-06 14:55:24 +02:00
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#undef htab_create
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2000-11-04 08:54:27 +01:00
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htab_t
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2002-06-06 14:55:24 +02:00
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htab_create (size, hash_f, eq_f, del_f)
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2000-11-04 08:54:27 +01:00
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size_t size;
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htab_hash hash_f;
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htab_eq eq_f;
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htab_del del_f;
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{
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2002-06-06 14:55:24 +02:00
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return htab_create_alloc (size, hash_f, eq_f, del_f, xcalloc, free);
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}
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2000-11-04 08:54:27 +01:00
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2002-06-06 14:55:24 +02:00
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htab_t
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htab_try_create (size, hash_f, eq_f, del_f)
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size_t size;
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htab_hash hash_f;
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htab_eq eq_f;
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htab_del del_f;
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{
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return htab_create_alloc (size, hash_f, eq_f, del_f, calloc, free);
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2000-02-22 16:59:20 +01:00
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}
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/* This function frees all memory allocated for given hash table.
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Naturally the hash table must already exist. */
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void
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2000-03-24 22:31:22 +01:00
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htab_delete (htab)
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htab_t htab;
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2000-02-22 16:59:20 +01:00
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{
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2000-03-24 22:31:22 +01:00
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int i;
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2000-06-15 22:56:25 +02:00
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2000-03-24 22:31:22 +01:00
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if (htab->del_f)
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for (i = htab->size - 1; i >= 0; i--)
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2000-06-15 22:56:25 +02:00
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if (htab->entries[i] != EMPTY_ENTRY
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&& htab->entries[i] != DELETED_ENTRY)
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(*htab->del_f) (htab->entries[i]);
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2000-03-24 22:31:22 +01:00
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2002-06-06 14:55:24 +02:00
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if (htab->free_f != NULL)
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{
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(*htab->free_f) (htab->entries);
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(*htab->free_f) (htab);
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}
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2003-01-26 08:33:29 +01:00
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else if (htab->free_with_arg_f != NULL)
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{
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(*htab->free_with_arg_f) (htab->alloc_arg, htab->entries);
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(*htab->free_with_arg_f) (htab->alloc_arg, htab);
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}
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2000-02-22 16:59:20 +01:00
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}
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/* This function clears all entries in the given hash table. */
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void
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2000-03-24 22:31:22 +01:00
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htab_empty (htab)
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htab_t htab;
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{
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int i;
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2000-06-15 22:56:25 +02:00
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2000-03-24 22:31:22 +01:00
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if (htab->del_f)
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for (i = htab->size - 1; i >= 0; i--)
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2000-06-15 22:56:25 +02:00
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if (htab->entries[i] != EMPTY_ENTRY
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&& htab->entries[i] != DELETED_ENTRY)
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(*htab->del_f) (htab->entries[i]);
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2000-03-24 22:31:22 +01:00
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2000-11-03 21:55:25 +01:00
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memset (htab->entries, 0, htab->size * sizeof (PTR));
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2000-03-24 22:31:22 +01:00
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}
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/* Similar to htab_find_slot, but without several unwanted side effects:
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- Does not call htab->eq_f when it finds an existing entry.
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- Does not change the count of elements/searches/collisions in the
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|
|
hash table.
|
|
|
|
This function also assumes there are no deleted entries in the table.
|
|
|
|
HASH is the hash value for the element to be inserted. */
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-11-03 21:55:25 +01:00
|
|
|
static PTR *
|
2000-03-24 22:31:22 +01:00
|
|
|
find_empty_slot_for_expand (htab, hash)
|
|
|
|
htab_t htab;
|
2000-06-15 22:56:25 +02:00
|
|
|
hashval_t hash;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2000-03-24 22:31:22 +01:00
|
|
|
size_t size = htab->size;
|
|
|
|
unsigned int index = hash % size;
|
2002-04-10 02:43:27 +02:00
|
|
|
PTR *slot = htab->entries + index;
|
|
|
|
hashval_t hash2;
|
|
|
|
|
|
|
|
if (*slot == EMPTY_ENTRY)
|
|
|
|
return slot;
|
|
|
|
else if (*slot == DELETED_ENTRY)
|
|
|
|
abort ();
|
2000-03-24 22:31:22 +01:00
|
|
|
|
2002-04-10 02:43:27 +02:00
|
|
|
hash2 = 1 + hash % (size - 2);
|
2000-03-24 22:31:22 +01:00
|
|
|
for (;;)
|
|
|
|
{
|
2002-04-10 02:43:27 +02:00
|
|
|
index += hash2;
|
|
|
|
if (index >= size)
|
|
|
|
index -= size;
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2002-04-10 02:43:27 +02:00
|
|
|
slot = htab->entries + index;
|
2000-03-24 22:31:22 +01:00
|
|
|
if (*slot == EMPTY_ENTRY)
|
|
|
|
return slot;
|
2000-06-15 22:56:25 +02:00
|
|
|
else if (*slot == DELETED_ENTRY)
|
2000-03-24 22:31:22 +01:00
|
|
|
abort ();
|
|
|
|
}
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/* The following function changes size of memory allocated for the
|
|
|
|
entries and repeatedly inserts the table elements. The occupancy
|
|
|
|
of the table after the call will be about 50%. Naturally the hash
|
|
|
|
table must already exist. Remember also that the place of the
|
2000-11-04 08:54:27 +01:00
|
|
|
table entries is changed. If memory allocation failures are allowed,
|
|
|
|
this function will return zero, indicating that the table could not be
|
|
|
|
expanded. If all goes well, it will return a non-zero value. */
|
2000-02-22 16:59:20 +01:00
|
|
|
|
2000-11-04 08:54:27 +01:00
|
|
|
static int
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_expand (htab)
|
|
|
|
htab_t htab;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR *oentries;
|
|
|
|
PTR *olimit;
|
|
|
|
PTR *p;
|
2002-06-06 14:55:24 +02:00
|
|
|
PTR *nentries;
|
2003-01-20 20:03:56 +01:00
|
|
|
size_t nsize;
|
2000-03-24 22:31:22 +01:00
|
|
|
|
|
|
|
oentries = htab->entries;
|
|
|
|
olimit = oentries + htab->size;
|
|
|
|
|
2003-03-12 16:08:02 +01:00
|
|
|
/* Resize only when table after removal of unused elements is either
|
|
|
|
too full or too empty. */
|
|
|
|
if ((htab->n_elements - htab->n_deleted) * 2 > htab->size
|
2003-03-12 18:28:10 +01:00
|
|
|
|| ((htab->n_elements - htab->n_deleted) * 8 < htab->size
|
|
|
|
&& htab->size > 32))
|
2003-03-12 16:08:02 +01:00
|
|
|
nsize = higher_prime_number ((htab->n_elements - htab->n_deleted) * 2);
|
|
|
|
else
|
|
|
|
nsize = htab->size;
|
2000-11-04 08:54:27 +01:00
|
|
|
|
2003-01-26 08:33:29 +01:00
|
|
|
if (htab->alloc_with_arg_f != NULL)
|
|
|
|
nentries = (PTR *) (*htab->alloc_with_arg_f) (htab->alloc_arg, nsize,
|
|
|
|
sizeof (PTR *));
|
|
|
|
else
|
|
|
|
nentries = (PTR *) (*htab->alloc_f) (nsize, sizeof (PTR *));
|
2002-06-06 14:55:24 +02:00
|
|
|
if (nentries == NULL)
|
|
|
|
return 0;
|
|
|
|
htab->entries = nentries;
|
2003-01-20 20:03:56 +01:00
|
|
|
htab->size = nsize;
|
2000-03-24 22:31:22 +01:00
|
|
|
|
|
|
|
htab->n_elements -= htab->n_deleted;
|
|
|
|
htab->n_deleted = 0;
|
|
|
|
|
|
|
|
p = oentries;
|
|
|
|
do
|
|
|
|
{
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR x = *p;
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
if (x != EMPTY_ENTRY && x != DELETED_ENTRY)
|
|
|
|
{
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR *q = find_empty_slot_for_expand (htab, (*htab->hash_f) (x));
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
*q = x;
|
|
|
|
}
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
p++;
|
|
|
|
}
|
|
|
|
while (p < olimit);
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2002-06-06 14:55:24 +02:00
|
|
|
if (htab->free_f != NULL)
|
|
|
|
(*htab->free_f) (oentries);
|
2003-01-26 08:33:29 +01:00
|
|
|
else if (htab->free_with_arg_f != NULL)
|
|
|
|
(*htab->free_with_arg_f) (htab->alloc_arg, oentries);
|
2000-11-04 08:54:27 +01:00
|
|
|
return 1;
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
/* This function searches for a hash table entry equal to the given
|
|
|
|
element. It cannot be used to insert or delete an element. */
|
|
|
|
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_find_with_hash (htab, element, hash)
|
|
|
|
htab_t htab;
|
2000-11-03 21:55:25 +01:00
|
|
|
const PTR element;
|
2000-06-15 22:56:25 +02:00
|
|
|
hashval_t hash;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2000-06-15 22:56:25 +02:00
|
|
|
unsigned int index;
|
|
|
|
hashval_t hash2;
|
2000-03-24 22:31:22 +01:00
|
|
|
size_t size;
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR entry;
|
2000-02-22 16:59:20 +01:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
htab->searches++;
|
|
|
|
size = htab->size;
|
|
|
|
index = hash % size;
|
|
|
|
|
2000-06-15 22:56:25 +02:00
|
|
|
entry = htab->entries[index];
|
|
|
|
if (entry == EMPTY_ENTRY
|
|
|
|
|| (entry != DELETED_ENTRY && (*htab->eq_f) (entry, element)))
|
|
|
|
return entry;
|
|
|
|
|
|
|
|
hash2 = 1 + hash % (size - 2);
|
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
for (;;)
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2000-03-24 22:31:22 +01:00
|
|
|
htab->collisions++;
|
|
|
|
index += hash2;
|
|
|
|
if (index >= size)
|
|
|
|
index -= size;
|
2000-06-15 22:56:25 +02:00
|
|
|
|
|
|
|
entry = htab->entries[index];
|
|
|
|
if (entry == EMPTY_ENTRY
|
|
|
|
|| (entry != DELETED_ENTRY && (*htab->eq_f) (entry, element)))
|
|
|
|
return entry;
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
2000-03-24 22:31:22 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/* Like htab_find_slot_with_hash, but compute the hash value from the
|
|
|
|
element. */
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_find (htab, element)
|
|
|
|
htab_t htab;
|
2000-11-03 21:55:25 +01:00
|
|
|
const PTR element;
|
2000-03-24 22:31:22 +01:00
|
|
|
{
|
|
|
|
return htab_find_with_hash (htab, element, (*htab->hash_f) (element));
|
|
|
|
}
|
|
|
|
|
|
|
|
/* This function searches for a hash table slot containing an entry
|
|
|
|
equal to the given element. To delete an entry, call this with
|
|
|
|
INSERT = 0, then call htab_clear_slot on the slot returned (possibly
|
|
|
|
after doing some checks). To insert an entry, call this with
|
2000-11-04 08:54:27 +01:00
|
|
|
INSERT = 1, then write the value you want into the returned slot.
|
|
|
|
When inserting an entry, NULL may be returned if memory allocation
|
|
|
|
fails. */
|
2000-03-24 22:31:22 +01:00
|
|
|
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR *
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_find_slot_with_hash (htab, element, hash, insert)
|
|
|
|
htab_t htab;
|
2000-11-03 21:55:25 +01:00
|
|
|
const PTR element;
|
2000-06-15 22:56:25 +02:00
|
|
|
hashval_t hash;
|
|
|
|
enum insert_option insert;
|
2000-03-24 22:31:22 +01:00
|
|
|
{
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR *first_deleted_slot;
|
2000-06-15 22:56:25 +02:00
|
|
|
unsigned int index;
|
|
|
|
hashval_t hash2;
|
2000-03-24 22:31:22 +01:00
|
|
|
size_t size;
|
2002-04-10 02:43:27 +02:00
|
|
|
PTR entry;
|
2000-03-24 22:31:22 +01:00
|
|
|
|
2000-11-04 08:54:27 +01:00
|
|
|
if (insert == INSERT && htab->size * 3 <= htab->n_elements * 4
|
|
|
|
&& htab_expand (htab) == 0)
|
|
|
|
return NULL;
|
2000-03-24 22:31:22 +01:00
|
|
|
|
|
|
|
size = htab->size;
|
|
|
|
index = hash % size;
|
|
|
|
|
2000-02-22 16:59:20 +01:00
|
|
|
htab->searches++;
|
2000-03-24 22:31:22 +01:00
|
|
|
first_deleted_slot = NULL;
|
|
|
|
|
2002-04-10 02:43:27 +02:00
|
|
|
entry = htab->entries[index];
|
|
|
|
if (entry == EMPTY_ENTRY)
|
|
|
|
goto empty_entry;
|
|
|
|
else if (entry == DELETED_ENTRY)
|
|
|
|
first_deleted_slot = &htab->entries[index];
|
|
|
|
else if ((*htab->eq_f) (entry, element))
|
|
|
|
return &htab->entries[index];
|
|
|
|
|
|
|
|
hash2 = 1 + hash % (size - 2);
|
2000-03-24 22:31:22 +01:00
|
|
|
for (;;)
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2002-04-10 02:43:27 +02:00
|
|
|
htab->collisions++;
|
|
|
|
index += hash2;
|
|
|
|
if (index >= size)
|
|
|
|
index -= size;
|
|
|
|
|
|
|
|
entry = htab->entries[index];
|
2000-03-24 22:31:22 +01:00
|
|
|
if (entry == EMPTY_ENTRY)
|
2002-04-10 02:43:27 +02:00
|
|
|
goto empty_entry;
|
|
|
|
else if (entry == DELETED_ENTRY)
|
2000-03-24 22:31:22 +01:00
|
|
|
{
|
|
|
|
if (!first_deleted_slot)
|
|
|
|
first_deleted_slot = &htab->entries[index];
|
|
|
|
}
|
2002-04-10 02:43:27 +02:00
|
|
|
else if ((*htab->eq_f) (entry, element))
|
2000-06-15 22:56:25 +02:00
|
|
|
return &htab->entries[index];
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
2002-04-10 02:43:27 +02:00
|
|
|
|
|
|
|
empty_entry:
|
|
|
|
if (insert == NO_INSERT)
|
|
|
|
return NULL;
|
|
|
|
|
|
|
|
htab->n_elements++;
|
|
|
|
|
|
|
|
if (first_deleted_slot)
|
|
|
|
{
|
|
|
|
*first_deleted_slot = EMPTY_ENTRY;
|
|
|
|
return first_deleted_slot;
|
|
|
|
}
|
|
|
|
|
|
|
|
return &htab->entries[index];
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
/* Like htab_find_slot_with_hash, but compute the hash value from the
|
|
|
|
element. */
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR *
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_find_slot (htab, element, insert)
|
|
|
|
htab_t htab;
|
2000-11-03 21:55:25 +01:00
|
|
|
const PTR element;
|
2000-06-15 22:56:25 +02:00
|
|
|
enum insert_option insert;
|
2000-03-24 22:31:22 +01:00
|
|
|
{
|
|
|
|
return htab_find_slot_with_hash (htab, element, (*htab->hash_f) (element),
|
|
|
|
insert);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* This function deletes an element with the given value from hash
|
|
|
|
table. If there is no matching element in the hash table, this
|
|
|
|
function does nothing. */
|
2000-02-22 16:59:20 +01:00
|
|
|
|
|
|
|
void
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_remove_elt (htab, element)
|
|
|
|
htab_t htab;
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR element;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR *slot;
|
2000-03-24 22:31:22 +01:00
|
|
|
|
2000-06-15 22:56:25 +02:00
|
|
|
slot = htab_find_slot (htab, element, NO_INSERT);
|
2000-03-24 22:31:22 +01:00
|
|
|
if (*slot == EMPTY_ENTRY)
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (htab->del_f)
|
|
|
|
(*htab->del_f) (*slot);
|
2000-02-22 16:59:20 +01:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
*slot = DELETED_ENTRY;
|
|
|
|
htab->n_deleted++;
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
/* This function clears a specified slot in a hash table. It is
|
|
|
|
useful when you've already done the lookup and don't want to do it
|
|
|
|
again. */
|
2000-02-22 16:59:20 +01:00
|
|
|
|
|
|
|
void
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_clear_slot (htab, slot)
|
|
|
|
htab_t htab;
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR *slot;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
|
|
|
if (slot < htab->entries || slot >= htab->entries + htab->size
|
|
|
|
|| *slot == EMPTY_ENTRY || *slot == DELETED_ENTRY)
|
|
|
|
abort ();
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
if (htab->del_f)
|
|
|
|
(*htab->del_f) (*slot);
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-02-22 16:59:20 +01:00
|
|
|
*slot = DELETED_ENTRY;
|
2000-03-24 22:31:22 +01:00
|
|
|
htab->n_deleted++;
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
/* This function scans over the entire hash table calling
|
|
|
|
CALLBACK for each live entry. If CALLBACK returns false,
|
|
|
|
the iteration stops. INFO is passed as CALLBACK's second
|
|
|
|
argument. */
|
|
|
|
|
|
|
|
void
|
2003-03-17 19:01:07 +01:00
|
|
|
htab_traverse_noresize (htab, callback, info)
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_t htab;
|
|
|
|
htab_trav callback;
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR info;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2003-03-12 16:08:02 +01:00
|
|
|
PTR *slot;
|
|
|
|
PTR *limit;
|
|
|
|
|
|
|
|
slot = htab->entries;
|
|
|
|
limit = slot + htab->size;
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
do
|
|
|
|
{
|
2000-11-03 21:55:25 +01:00
|
|
|
PTR x = *slot;
|
2000-06-15 22:56:25 +02:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
if (x != EMPTY_ENTRY && x != DELETED_ENTRY)
|
|
|
|
if (!(*callback) (slot, info))
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
while (++slot < limit);
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
|
|
|
|
2003-03-17 19:01:07 +01:00
|
|
|
/* Like htab_traverse_noresize, but does resize the table when it is
|
|
|
|
too empty to improve effectivity of subsequent calls. */
|
|
|
|
|
|
|
|
void
|
|
|
|
htab_traverse (htab, callback, info)
|
|
|
|
htab_t htab;
|
|
|
|
htab_trav callback;
|
|
|
|
PTR info;
|
|
|
|
{
|
|
|
|
if ((htab->n_elements - htab->n_deleted) * 8 < htab->size)
|
|
|
|
htab_expand (htab);
|
|
|
|
|
|
|
|
htab_traverse_noresize (htab, callback, info);
|
|
|
|
}
|
|
|
|
|
2000-06-15 22:56:25 +02:00
|
|
|
/* Return the current size of given hash table. */
|
2000-02-22 16:59:20 +01:00
|
|
|
|
|
|
|
size_t
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_size (htab)
|
|
|
|
htab_t htab;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
|
|
|
return htab->size;
|
|
|
|
}
|
|
|
|
|
2000-06-15 22:56:25 +02:00
|
|
|
/* Return the current number of elements in given hash table. */
|
2000-02-22 16:59:20 +01:00
|
|
|
|
|
|
|
size_t
|
2000-03-24 22:31:22 +01:00
|
|
|
htab_elements (htab)
|
|
|
|
htab_t htab;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2000-03-24 22:31:22 +01:00
|
|
|
return htab->n_elements - htab->n_deleted;
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
|
|
|
|
2000-06-15 22:56:25 +02:00
|
|
|
/* Return the fraction of fixed collisions during all work with given
|
|
|
|
hash table. */
|
2000-02-22 16:59:20 +01:00
|
|
|
|
2000-03-24 22:31:22 +01:00
|
|
|
double
|
|
|
|
htab_collisions (htab)
|
|
|
|
htab_t htab;
|
2000-02-22 16:59:20 +01:00
|
|
|
{
|
2000-06-15 22:56:25 +02:00
|
|
|
if (htab->searches == 0)
|
2000-03-24 22:31:22 +01:00
|
|
|
return 0.0;
|
2000-06-15 22:56:25 +02:00
|
|
|
|
|
|
|
return (double) htab->collisions / (double) htab->searches;
|
2000-02-22 16:59:20 +01:00
|
|
|
}
|
2001-08-17 08:33:05 +02:00
|
|
|
|
2001-08-17 23:14:20 +02:00
|
|
|
/* Hash P as a null-terminated string.
|
|
|
|
|
|
|
|
Copied from gcc/hashtable.c. Zack had the following to say with respect
|
|
|
|
to applicability, though note that unlike hashtable.c, this hash table
|
|
|
|
implementation re-hashes rather than chain buckets.
|
|
|
|
|
|
|
|
http://gcc.gnu.org/ml/gcc-patches/2001-08/msg01021.html
|
|
|
|
From: Zack Weinberg <zackw@panix.com>
|
|
|
|
Date: Fri, 17 Aug 2001 02:15:56 -0400
|
|
|
|
|
|
|
|
I got it by extracting all the identifiers from all the source code
|
|
|
|
I had lying around in mid-1999, and testing many recurrences of
|
|
|
|
the form "H_n = H_{n-1} * K + c_n * L + M" where K, L, M were either
|
|
|
|
prime numbers or the appropriate identity. This was the best one.
|
|
|
|
I don't remember exactly what constituted "best", except I was
|
|
|
|
looking at bucket-length distributions mostly.
|
|
|
|
|
|
|
|
So it should be very good at hashing identifiers, but might not be
|
|
|
|
as good at arbitrary strings.
|
|
|
|
|
|
|
|
I'll add that it thoroughly trounces the hash functions recommended
|
|
|
|
for this use at http://burtleburtle.net/bob/hash/index.html, both
|
|
|
|
on speed and bucket distribution. I haven't tried it against the
|
|
|
|
function they just started using for Perl's hashes. */
|
2001-08-17 08:33:05 +02:00
|
|
|
|
|
|
|
hashval_t
|
|
|
|
htab_hash_string (p)
|
|
|
|
const PTR p;
|
|
|
|
{
|
|
|
|
const unsigned char *str = (const unsigned char *) p;
|
|
|
|
hashval_t r = 0;
|
|
|
|
unsigned char c;
|
|
|
|
|
|
|
|
while ((c = *str++) != 0)
|
|
|
|
r = r * 67 + c - 113;
|
|
|
|
|
|
|
|
return r;
|
|
|
|
}
|
2003-05-07 20:07:53 +02:00
|
|
|
|
|
|
|
/* DERIVED FROM:
|
|
|
|
--------------------------------------------------------------------
|
|
|
|
lookup2.c, by Bob Jenkins, December 1996, Public Domain.
|
|
|
|
hash(), hash2(), hash3, and mix() are externally useful functions.
|
|
|
|
Routines to test the hash are included if SELF_TEST is defined.
|
|
|
|
You can use this free for any purpose. It has no warranty.
|
|
|
|
--------------------------------------------------------------------
|
|
|
|
*/
|
|
|
|
|
|
|
|
/*
|
|
|
|
--------------------------------------------------------------------
|
|
|
|
mix -- mix 3 32-bit values reversibly.
|
|
|
|
For every delta with one or two bit set, and the deltas of all three
|
|
|
|
high bits or all three low bits, whether the original value of a,b,c
|
|
|
|
is almost all zero or is uniformly distributed,
|
|
|
|
* If mix() is run forward or backward, at least 32 bits in a,b,c
|
|
|
|
have at least 1/4 probability of changing.
|
|
|
|
* If mix() is run forward, every bit of c will change between 1/3 and
|
|
|
|
2/3 of the time. (Well, 22/100 and 78/100 for some 2-bit deltas.)
|
|
|
|
mix() was built out of 36 single-cycle latency instructions in a
|
|
|
|
structure that could supported 2x parallelism, like so:
|
|
|
|
a -= b;
|
|
|
|
a -= c; x = (c>>13);
|
|
|
|
b -= c; a ^= x;
|
|
|
|
b -= a; x = (a<<8);
|
|
|
|
c -= a; b ^= x;
|
|
|
|
c -= b; x = (b>>13);
|
|
|
|
...
|
|
|
|
Unfortunately, superscalar Pentiums and Sparcs can't take advantage
|
|
|
|
of that parallelism. They've also turned some of those single-cycle
|
|
|
|
latency instructions into multi-cycle latency instructions. Still,
|
|
|
|
this is the fastest good hash I could find. There were about 2^^68
|
|
|
|
to choose from. I only looked at a billion or so.
|
|
|
|
--------------------------------------------------------------------
|
|
|
|
*/
|
|
|
|
/* same, but slower, works on systems that might have 8 byte hashval_t's */
|
|
|
|
#define mix(a,b,c) \
|
|
|
|
{ \
|
|
|
|
a -= b; a -= c; a ^= (c>>13); \
|
|
|
|
b -= c; b -= a; b ^= (a<< 8); \
|
|
|
|
c -= a; c -= b; c ^= ((b&0xffffffff)>>13); \
|
|
|
|
a -= b; a -= c; a ^= ((c&0xffffffff)>>12); \
|
|
|
|
b -= c; b -= a; b = (b ^ (a<<16)) & 0xffffffff; \
|
|
|
|
c -= a; c -= b; c = (c ^ (b>> 5)) & 0xffffffff; \
|
|
|
|
a -= b; a -= c; a = (a ^ (c>> 3)) & 0xffffffff; \
|
|
|
|
b -= c; b -= a; b = (b ^ (a<<10)) & 0xffffffff; \
|
|
|
|
c -= a; c -= b; c = (c ^ (b>>15)) & 0xffffffff; \
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
--------------------------------------------------------------------
|
|
|
|
hash() -- hash a variable-length key into a 32-bit value
|
|
|
|
k : the key (the unaligned variable-length array of bytes)
|
|
|
|
len : the length of the key, counting by bytes
|
|
|
|
level : can be any 4-byte value
|
|
|
|
Returns a 32-bit value. Every bit of the key affects every bit of
|
|
|
|
the return value. Every 1-bit and 2-bit delta achieves avalanche.
|
|
|
|
About 36+6len instructions.
|
|
|
|
|
|
|
|
The best hash table sizes are powers of 2. There is no need to do
|
|
|
|
mod a prime (mod is sooo slow!). If you need less than 32 bits,
|
|
|
|
use a bitmask. For example, if you need only 10 bits, do
|
|
|
|
h = (h & hashmask(10));
|
|
|
|
In which case, the hash table should have hashsize(10) elements.
|
|
|
|
|
|
|
|
If you are hashing n strings (ub1 **)k, do it like this:
|
|
|
|
for (i=0, h=0; i<n; ++i) h = hash( k[i], len[i], h);
|
|
|
|
|
|
|
|
By Bob Jenkins, 1996. bob_jenkins@burtleburtle.net. You may use this
|
|
|
|
code any way you wish, private, educational, or commercial. It's free.
|
|
|
|
|
|
|
|
See http://burtleburtle.net/bob/hash/evahash.html
|
|
|
|
Use for hash table lookup, or anything where one collision in 2^32 is
|
|
|
|
acceptable. Do NOT use for cryptographic purposes.
|
|
|
|
--------------------------------------------------------------------
|
|
|
|
*/
|
|
|
|
|
2003-05-07 22:30:13 +02:00
|
|
|
hashval_t iterative_hash (k_in, length, initval)
|
2003-05-07 20:07:53 +02:00
|
|
|
const PTR k_in; /* the key */
|
|
|
|
register size_t length; /* the length of the key */
|
|
|
|
register hashval_t initval; /* the previous hash, or an arbitrary value */
|
|
|
|
{
|
|
|
|
register const unsigned char *k = (const unsigned char *)k_in;
|
|
|
|
register hashval_t a,b,c,len;
|
|
|
|
|
|
|
|
/* Set up the internal state */
|
|
|
|
len = length;
|
|
|
|
a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
|
|
|
|
c = initval; /* the previous hash value */
|
|
|
|
|
|
|
|
/*---------------------------------------- handle most of the key */
|
|
|
|
#ifndef WORDS_BIGENDIAN
|
|
|
|
/* On a little-endian machine, if the data is 4-byte aligned we can hash
|
|
|
|
by word for better speed. This gives nondeterministic results on
|
|
|
|
big-endian machines. */
|
|
|
|
if (sizeof (hashval_t) == 4 && (((size_t)k)&3) == 0)
|
|
|
|
while (len >= 12) /* aligned */
|
|
|
|
{
|
|
|
|
a += *(hashval_t *)(k+0);
|
|
|
|
b += *(hashval_t *)(k+4);
|
|
|
|
c += *(hashval_t *)(k+8);
|
|
|
|
mix(a,b,c);
|
|
|
|
k += 12; len -= 12;
|
|
|
|
}
|
|
|
|
else /* unaligned */
|
|
|
|
#endif
|
|
|
|
while (len >= 12)
|
|
|
|
{
|
|
|
|
a += (k[0] +((hashval_t)k[1]<<8) +((hashval_t)k[2]<<16) +((hashval_t)k[3]<<24));
|
|
|
|
b += (k[4] +((hashval_t)k[5]<<8) +((hashval_t)k[6]<<16) +((hashval_t)k[7]<<24));
|
|
|
|
c += (k[8] +((hashval_t)k[9]<<8) +((hashval_t)k[10]<<16)+((hashval_t)k[11]<<24));
|
|
|
|
mix(a,b,c);
|
|
|
|
k += 12; len -= 12;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*------------------------------------- handle the last 11 bytes */
|
|
|
|
c += length;
|
|
|
|
switch(len) /* all the case statements fall through */
|
|
|
|
{
|
|
|
|
case 11: c+=((hashval_t)k[10]<<24);
|
|
|
|
case 10: c+=((hashval_t)k[9]<<16);
|
|
|
|
case 9 : c+=((hashval_t)k[8]<<8);
|
|
|
|
/* the first byte of c is reserved for the length */
|
|
|
|
case 8 : b+=((hashval_t)k[7]<<24);
|
|
|
|
case 7 : b+=((hashval_t)k[6]<<16);
|
|
|
|
case 6 : b+=((hashval_t)k[5]<<8);
|
|
|
|
case 5 : b+=k[4];
|
|
|
|
case 4 : a+=((hashval_t)k[3]<<24);
|
|
|
|
case 3 : a+=((hashval_t)k[2]<<16);
|
|
|
|
case 2 : a+=((hashval_t)k[1]<<8);
|
|
|
|
case 1 : a+=k[0];
|
|
|
|
/* case 0: nothing left to add */
|
|
|
|
}
|
|
|
|
mix(a,b,c);
|
|
|
|
/*-------------------------------------------- report the result */
|
|
|
|
return c;
|
|
|
|
}
|