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
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 *
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
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
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
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
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
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