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
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 *
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
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
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
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
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
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