1*2747eff1SEd Schouten /*-
2*2747eff1SEd Schouten * Copyright (c) 2015 Nuxi, https://nuxi.nl/
3*2747eff1SEd Schouten *
4*2747eff1SEd Schouten * Redistribution and use in source and binary forms, with or without
5*2747eff1SEd Schouten * modification, are permitted provided that the following conditions
6*2747eff1SEd Schouten * are met:
7*2747eff1SEd Schouten * 1. Redistributions of source code must retain the above copyright
8*2747eff1SEd Schouten * notice, this list of conditions and the following disclaimer.
9*2747eff1SEd Schouten * 2. Redistributions in binary form must reproduce the above copyright
10*2747eff1SEd Schouten * notice, this list of conditions and the following disclaimer in the
11*2747eff1SEd Schouten * documentation and/or other materials provided with the distribution.
12*2747eff1SEd Schouten *
13*2747eff1SEd Schouten * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14*2747eff1SEd Schouten * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15*2747eff1SEd Schouten * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16*2747eff1SEd Schouten * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17*2747eff1SEd Schouten * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18*2747eff1SEd Schouten * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19*2747eff1SEd Schouten * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20*2747eff1SEd Schouten * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21*2747eff1SEd Schouten * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22*2747eff1SEd Schouten * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23*2747eff1SEd Schouten * SUCH DAMAGE.
24*2747eff1SEd Schouten */
25*2747eff1SEd Schouten
26*2747eff1SEd Schouten #include <search.h>
27*2747eff1SEd Schouten #include <stdlib.h>
28*2747eff1SEd Schouten
29*2747eff1SEd Schouten #include "hsearch.h"
30*2747eff1SEd Schouten
31*2747eff1SEd Schouten int
hcreate_r(size_t nel,struct hsearch_data * htab)32*2747eff1SEd Schouten hcreate_r(size_t nel, struct hsearch_data *htab)
33*2747eff1SEd Schouten {
34*2747eff1SEd Schouten struct __hsearch *hsearch;
35*2747eff1SEd Schouten
36*2747eff1SEd Schouten /*
37*2747eff1SEd Schouten * Allocate a hash table object. Ignore the provided hint and start
38*2747eff1SEd Schouten * off with a table of sixteen entries. In most cases this hint is
39*2747eff1SEd Schouten * just a wild guess. Resizing the table dynamically if the use
40*2747eff1SEd Schouten * increases a threshold does not affect the worst-case running time.
41*2747eff1SEd Schouten */
42*2747eff1SEd Schouten hsearch = malloc(sizeof(*hsearch));
43*2747eff1SEd Schouten if (hsearch == NULL)
44*2747eff1SEd Schouten return 0;
45*2747eff1SEd Schouten hsearch->entries = calloc(16, sizeof(ENTRY));
46*2747eff1SEd Schouten if (hsearch->entries == NULL) {
47*2747eff1SEd Schouten free(hsearch);
48*2747eff1SEd Schouten return 0;
49*2747eff1SEd Schouten }
50*2747eff1SEd Schouten
51*2747eff1SEd Schouten /*
52*2747eff1SEd Schouten * Pick a random initialization for the FNV-1a hashing. This makes it
53*2747eff1SEd Schouten * hard to come up with a fixed set of keys to force hash collisions.
54*2747eff1SEd Schouten */
55*2747eff1SEd Schouten arc4random_buf(&hsearch->offset_basis, sizeof(hsearch->offset_basis));
56*2747eff1SEd Schouten hsearch->index_mask = 0xf;
57*2747eff1SEd Schouten hsearch->entries_used = 0;
58*2747eff1SEd Schouten htab->__hsearch = hsearch;
59*2747eff1SEd Schouten return 1;
60*2747eff1SEd Schouten }
61