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/cdefs.h>
28 #include <sys/types.h>
29 #include <sys/cpuset.h>
30 #include <sys/param.h>
31 #include <sys/stat.h>
32 #include <sys/pmc.h>
33
34 #include <assert.h>
35 #include <err.h>
36 #include <errno.h>
37 #include <pmc.h>
38 #include <pmclog.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <sysexits.h>
43
44 #include "libpmcstat.h"
45
46 static LIST_HEAD(,pmcstat_string) pmcstat_string_hash[PMCSTAT_NHASH];
47
48 /*
49 * Intern a copy of string 's', and return a pointer to the
50 * interned structure.
51 */
52
53 pmcstat_interned_string
pmcstat_string_intern(const char * s)54 pmcstat_string_intern(const char *s)
55 {
56 struct pmcstat_string *ps;
57 const struct pmcstat_string *cps;
58 int hash, len;
59
60 if ((cps = pmcstat_string_lookup(s)) != NULL)
61 return (cps);
62
63 hash = pmcstat_string_compute_hash(s);
64 len = strlen(s);
65
66 if ((ps = malloc(sizeof(*ps))) == NULL)
67 err(EX_OSERR, "ERROR: Could not intern string");
68 ps->ps_len = len;
69 ps->ps_hash = hash;
70 ps->ps_string = strdup(s);
71 LIST_INSERT_HEAD(&pmcstat_string_hash[hash], ps, ps_next);
72 return ((pmcstat_interned_string) ps);
73 }
74
75 const char *
pmcstat_string_unintern(pmcstat_interned_string str)76 pmcstat_string_unintern(pmcstat_interned_string str)
77 {
78 const char *s;
79
80 s = ((const struct pmcstat_string *) str)->ps_string;
81 return (s);
82 }
83
84 /*
85 * Compute a 'hash' value for a string.
86 */
87
88 int
pmcstat_string_compute_hash(const char * s)89 pmcstat_string_compute_hash(const char *s)
90 {
91 unsigned hash;
92
93 for (hash = 2166136261; *s; s++)
94 hash = (hash ^ *s) * 16777619;
95
96 return (hash & PMCSTAT_HASH_MASK);
97 }
98
99 pmcstat_interned_string
pmcstat_string_lookup(const char * s)100 pmcstat_string_lookup(const char *s)
101 {
102 struct pmcstat_string *ps;
103 int hash, len;
104
105 hash = pmcstat_string_compute_hash(s);
106 len = strlen(s);
107
108 LIST_FOREACH(ps, &pmcstat_string_hash[hash], ps_next)
109 if (ps->ps_len == len && ps->ps_hash == hash &&
110 strcmp(ps->ps_string, s) == 0)
111 return (ps);
112 return (NULL);
113 }
114
115 int
pmcstat_string_lookup_hash(pmcstat_interned_string s)116 pmcstat_string_lookup_hash(pmcstat_interned_string s)
117 {
118 const struct pmcstat_string *ps;
119
120 ps = (const struct pmcstat_string *) s;
121 return (ps->ps_hash);
122 }
123
124 /*
125 * Destroy the string table, free'ing up space.
126 */
127
128 void
pmcstat_string_shutdown(void)129 pmcstat_string_shutdown(void)
130 {
131 int i;
132 struct pmcstat_string *ps, *pstmp;
133
134 for (i = 0; i < PMCSTAT_NHASH; i++)
135 LIST_FOREACH_SAFE(ps, &pmcstat_string_hash[i], ps_next,
136 pstmp) {
137 LIST_REMOVE(ps, ps_next);
138 free(ps->ps_string);
139 free(ps);
140 }
141 }
142
143 /*
144 * Initialize the string interning facility.
145 */
146
147 void
pmcstat_string_initialize(void)148 pmcstat_string_initialize(void)
149 {
150 int i;
151
152 for (i = 0; i < PMCSTAT_NHASH; i++)
153 LIST_INIT(&pmcstat_string_hash[i]);
154 }
155