1/*-
2 * Copyright (c) 2003-2008 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/types.h>
28#include <sys/cpuset.h>
29#include <sys/param.h>
30#include <sys/stat.h>
31#include <sys/pmc.h>
32
33#include <assert.h>
34#include <err.h>
35#include <errno.h>
36#include <pmc.h>
37#include <pmclog.h>
38#include <stdio.h>
39#include <stdlib.h>
40#include <string.h>
41#include <sysexits.h>
42
43#include "libpmcstat.h"
44
45static LIST_HEAD(,pmcstat_string)	pmcstat_string_hash[PMCSTAT_NHASH];
46
47/*
48 * Intern a copy of string 's', and return a pointer to the
49 * interned structure.
50 */
51
52pmcstat_interned_string
53pmcstat_string_intern(const char *s)
54{
55	struct pmcstat_string *ps;
56	const struct pmcstat_string *cps;
57	int hash, len;
58
59	if ((cps = pmcstat_string_lookup(s)) != NULL)
60		return (cps);
61
62	hash = pmcstat_string_compute_hash(s);
63	len  = strlen(s);
64
65	if ((ps = malloc(sizeof(*ps))) == NULL)
66		err(EX_OSERR, "ERROR: Could not intern string");
67	ps->ps_len = len;
68	ps->ps_hash = hash;
69	ps->ps_string = strdup(s);
70	LIST_INSERT_HEAD(&pmcstat_string_hash[hash], ps, ps_next);
71	return ((pmcstat_interned_string) ps);
72}
73
74const char *
75pmcstat_string_unintern(pmcstat_interned_string str)
76{
77	const char *s;
78
79	s = ((const struct pmcstat_string *) str)->ps_string;
80	return (s);
81}
82
83/*
84 * Compute a 'hash' value for a string.
85 */
86
87int
88pmcstat_string_compute_hash(const char *s)
89{
90	unsigned hash;
91
92	for (hash = 2166136261; *s; s++)
93		hash = (hash ^ *s) * 16777619;
94
95	return (hash & PMCSTAT_HASH_MASK);
96}
97
98pmcstat_interned_string
99pmcstat_string_lookup(const char *s)
100{
101	struct pmcstat_string *ps;
102	int hash, len;
103
104	hash = pmcstat_string_compute_hash(s);
105	len = strlen(s);
106
107	LIST_FOREACH(ps, &pmcstat_string_hash[hash], ps_next)
108	    if (ps->ps_len == len && ps->ps_hash == hash &&
109		strcmp(ps->ps_string, s) == 0)
110		    return (ps);
111	return (NULL);
112}
113
114int
115pmcstat_string_lookup_hash(pmcstat_interned_string s)
116{
117	const struct pmcstat_string *ps;
118
119	ps = (const struct pmcstat_string *) s;
120	return (ps->ps_hash);
121}
122
123/*
124 * Destroy the string table, free'ing up space.
125 */
126
127void
128pmcstat_string_shutdown(void)
129{
130	int i;
131	struct pmcstat_string *ps, *pstmp;
132
133	for (i = 0; i < PMCSTAT_NHASH; i++)
134		LIST_FOREACH_SAFE(ps, &pmcstat_string_hash[i], ps_next,
135		    pstmp) {
136			LIST_REMOVE(ps, ps_next);
137			free(ps->ps_string);
138			free(ps);
139		}
140}
141
142/*
143 * Initialize the string interning facility.
144 */
145
146void
147pmcstat_string_initialize(void)
148{
149	int i;
150
151	for (i = 0; i < PMCSTAT_NHASH; i++)
152		LIST_INIT(&pmcstat_string_hash[i]);
153}
154