1 /*- 2 * Copyright (c) 2015 Nuxi, https://nuxi.nl/ 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26 #include <sys/cdefs.h> 27 __FBSDID("$FreeBSD$"); 28 29 #include <search.h> 30 #include <stdlib.h> 31 32 #include "hsearch.h" 33 34 int 35 hcreate_r(size_t nel, struct hsearch_data *htab) 36 { 37 struct __hsearch *hsearch; 38 39 /* 40 * Allocate a hash table object. Ignore the provided hint and start 41 * off with a table of sixteen entries. In most cases this hint is 42 * just a wild guess. Resizing the table dynamically if the use 43 * increases a threshold does not affect the worst-case running time. 44 */ 45 hsearch = malloc(sizeof(*hsearch)); 46 if (hsearch == NULL) 47 return 0; 48 hsearch->entries = calloc(16, sizeof(ENTRY)); 49 if (hsearch->entries == NULL) { 50 free(hsearch); 51 return 0; 52 } 53 54 /* 55 * Pick a random initialization for the FNV-1a hashing. This makes it 56 * hard to come up with a fixed set of keys to force hash collisions. 57 */ 58 arc4random_buf(&hsearch->offset_basis, sizeof(hsearch->offset_basis)); 59 hsearch->index_mask = 0xf; 60 hsearch->entries_used = 0; 61 htab->__hsearch = hsearch; 62 return 1; 63 } 64