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hash.c revision 1.18 
      1 /*	$NetBSD: hash.c,v 1.18 2021/08/28 17:11:19 rillig Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1994, 1995 Jochen Pohl
      5  * All Rights Reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *      This product includes software developed by Jochen Pohl for
     18  *	The NetBSD Project.
     19  * 4. The name of the author may not be used to endorse or promote products
     20  *    derived from this software without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     32  */
     33 
     34 #if HAVE_NBTOOL_CONFIG_H
     35 #include "nbtool_config.h"
     36 #endif
     37 
     38 #include <sys/cdefs.h>
     39 #if defined(__RCSID) && !defined(lint)
     40 __RCSID("$NetBSD: hash.c,v 1.18 2021/08/28 17:11:19 rillig Exp $");
     41 #endif
     42 
     43 /*
     44  * XXX Really need a generalized hash table package
     45  */
     46 
     47 #include <limits.h>
     48 #include <stddef.h>
     49 #include <stdlib.h>
     50 #include <string.h>
     51 
     52 #include "lint2.h"
     53 
     54 /* pointer to hash table, initialized in inithash() */
     55 static	hte_t	**htab;
     56 
     57 static	unsigned int hash(const char *);
     58 
     59 /*
     60  * Initialize hash table.
     61  */
     62 void
     63 _inithash(hte_t ***tablep)
     64 {
     65 
     66 	if (tablep == NULL)
     67 		tablep = &htab;
     68 
     69 	*tablep = xcalloc(HSHSIZ2, sizeof(**tablep));
     70 }
     71 
     72 /*
     73  * Compute hash value from a string.
     74  */
     75 static unsigned int
     76 hash(const char *s)
     77 {
     78 	unsigned int v;
     79 	const unsigned char *us;
     80 
     81 	v = 0;
     82 	for (us = (const unsigned char *)s; *us != '\0'; us++) {
     83 		v = (v << sizeof(v)) + *us;
     84 		v ^= v >> (sizeof(v) * CHAR_BIT - sizeof(v));
     85 	}
     86 	return v % HSHSIZ2;
     87 }
     88 
     89 /*
     90  * Look for a hash table entry. If no hash table entry for the
     91  * given name exists and mknew is set, create a new one.
     92  */
     93 hte_t *
     94 _hsearch(hte_t **table, const char *s, bool mknew)
     95 {
     96 	unsigned int h;
     97 	hte_t	*hte;
     98 
     99 	if (table == NULL)
    100 		table = htab;
    101 
    102 	h = hash(s);
    103 	for (hte = table[h]; hte != NULL; hte = hte->h_link) {
    104 		if (strcmp(hte->h_name, s) == 0)
    105 			break;
    106 	}
    107 
    108 	if (hte != NULL || !mknew)
    109 		return hte;
    110 
    111 	/* create a new hte */
    112 	hte = xmalloc(sizeof(*hte));
    113 	hte->h_name = xstrdup(s);
    114 	hte->h_used = false;
    115 	hte->h_def = false;
    116 	hte->h_static = false;
    117 	hte->h_syms = NULL;
    118 	hte->h_lsym = &hte->h_syms;
    119 	hte->h_calls = NULL;
    120 	hte->h_lcall = &hte->h_calls;
    121 	hte->h_usyms = NULL;
    122 	hte->h_lusym = &hte->h_usyms;
    123 	hte->h_link = table[h];
    124 	hte->h_hte = NULL;
    125 	table[h] = hte;
    126 
    127 	return hte;
    128 }
    129 
    130 /*
    131  * Call the action for each name in the hash table.
    132  */
    133 void
    134 symtab_forall(void (*action)(hte_t *))
    135 {
    136 	int	i;
    137 	hte_t	*hte;
    138 	hte_t	**table = htab;
    139 
    140 	for (i = 0; i < HSHSIZ2; i++) {
    141 		for (hte = table[i]; hte != NULL; hte = hte->h_link)
    142 			action(hte);
    143 	}
    144 }
    145 
    146 /*
    147  * Free all contents of the hash table that this module allocated.
    148  */
    149 void
    150 _destroyhash(hte_t **table)
    151 {
    152 	int	i;
    153 	hte_t	*hte, *nexthte;
    154 
    155 	if (table == NULL)
    156 		err(1, "_destroyhash called on main hash table");
    157 
    158 	for (i = 0; i < HSHSIZ2; i++) {
    159 		for (hte = table[i]; hte != NULL; hte = nexthte) {
    160 			free(__UNCONST(hte->h_name));
    161 			nexthte = hte->h_link;
    162 			free(hte);
    163 		}
    164 	}
    165 	free(table);
    166 }
    167