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 <search.h> 27 #include <stdlib.h> 28 29 #include "hsearch.h" 30 31 int 32 hcreate_r(size_t nel, struct hsearch_data *htab) 33 { 34 struct __hsearch *hsearch; 35 36 /* 37 * Allocate a hash table object. Ignore the provided hint and start 38 * off with a table of sixteen entries. In most cases this hint is 39 * just a wild guess. Resizing the table dynamically if the use 40 * increases a threshold does not affect the worst-case running time. 41 */ 42 hsearch = malloc(sizeof(*hsearch)); 43 if (hsearch == NULL) 44 return 0; 45 hsearch->entries = calloc(16, sizeof(ENTRY)); 46 if (hsearch->entries == NULL) { 47 free(hsearch); 48 return 0; 49 } 50 51 /* 52 * Pick a random initialization for the FNV-1a hashing. This makes it 53 * hard to come up with a fixed set of keys to force hash collisions. 54 */ 55 arc4random_buf(&hsearch->offset_basis, sizeof(hsearch->offset_basis)); 56 hsearch->index_mask = 0xf; 57 hsearch->entries_used = 0; 58 htab->__hsearch = hsearch; 59 return 1; 60 } 61