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
45 static 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
52 pmcstat_interned_string
pmcstat_string_intern(const char * s)53 pmcstat_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
74 const char *
pmcstat_string_unintern(pmcstat_interned_string str)75 pmcstat_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
87 int
pmcstat_string_compute_hash(const char * s)88 pmcstat_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
98 pmcstat_interned_string
pmcstat_string_lookup(const char * s)99 pmcstat_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
114 int
pmcstat_string_lookup_hash(pmcstat_interned_string s)115 pmcstat_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
127 void
pmcstat_string_shutdown(void)128 pmcstat_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
146 void
pmcstat_string_initialize(void)147 pmcstat_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