1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27#pragma ident	"@(#)dt_strtab.c	1.4	06/09/19 SMI"
28
29#include <sys/types.h>
30#include <strings.h>
31#include <stdlib.h>
32#include <assert.h>
33
34#include <dt_strtab.h>
35#include <dt_impl.h>
36
37static int
38dt_strtab_grow(dt_strtab_t *sp)
39{
40	char *ptr, **bufs;
41
42	if ((ptr = malloc(sp->str_bufsz)) == NULL)
43		return (-1);
44
45	bufs = realloc(sp->str_bufs, (sp->str_nbufs + 1) * sizeof (char *));
46
47	if (bufs == NULL) {
48		free(ptr);
49		return (-1);
50	}
51
52	sp->str_nbufs++;
53	sp->str_bufs = bufs;
54	sp->str_ptr = ptr;
55	sp->str_bufs[sp->str_nbufs - 1] = sp->str_ptr;
56
57	return (0);
58}
59
60dt_strtab_t *
61dt_strtab_create(size_t bufsz)
62{
63	dt_strtab_t *sp = malloc(sizeof (dt_strtab_t));
64	uint_t nbuckets = _dtrace_strbuckets;
65
66	assert(bufsz != 0);
67
68	if (sp == NULL)
69		return (NULL);
70
71	bzero(sp, sizeof (dt_strtab_t));
72	sp->str_hash = malloc(nbuckets * sizeof (dt_strhash_t *));
73
74	if (sp->str_hash == NULL)
75		goto err;
76
77	bzero(sp->str_hash, nbuckets * sizeof (dt_strhash_t *));
78	sp->str_hashsz = nbuckets;
79	sp->str_bufs = NULL;
80	sp->str_ptr = NULL;
81	sp->str_nbufs = 0;
82	sp->str_bufsz = bufsz;
83	sp->str_nstrs = 1;
84	sp->str_size = 1;
85
86	if (dt_strtab_grow(sp) == -1)
87		goto err;
88
89	*sp->str_ptr++ = '\0';
90	return (sp);
91
92err:
93	dt_strtab_destroy(sp);
94	return (NULL);
95}
96
97void
98dt_strtab_destroy(dt_strtab_t *sp)
99{
100	dt_strhash_t *hp, *hq;
101	ulong_t i;
102
103	for (i = 0; i < sp->str_hashsz; i++) {
104		for (hp = sp->str_hash[i]; hp != NULL; hp = hq) {
105			hq = hp->str_next;
106			free(hp);
107		}
108	}
109
110	for (i = 0; i < sp->str_nbufs; i++)
111		free(sp->str_bufs[i]);
112
113	if (sp->str_hash != NULL)
114		free(sp->str_hash);
115	if (sp->str_bufs != NULL)
116		free(sp->str_bufs);
117
118	free(sp);
119}
120
121ulong_t
122dt_strtab_hash(const char *key, size_t *len)
123{
124	ulong_t g, h = 0;
125	const char *p;
126	size_t n = 0;
127
128	for (p = key; *p != '\0'; p++, n++) {
129		h = (h << 4) + *p;
130
131		if ((g = (h & 0xf0000000)) != 0) {
132			h ^= (g >> 24);
133			h ^= g;
134		}
135	}
136
137	if (len != NULL)
138		*len = n;
139
140	return (h);
141}
142
143static int
144dt_strtab_compare(dt_strtab_t *sp, dt_strhash_t *hp,
145    const char *str, size_t len)
146{
147	ulong_t b = hp->str_buf;
148	const char *buf = hp->str_data;
149	size_t resid, n;
150	int rv;
151
152	while (len != 0) {
153		if (buf == sp->str_bufs[b] + sp->str_bufsz)
154			buf = sp->str_bufs[++b];
155
156		resid = sp->str_bufs[b] + sp->str_bufsz - buf;
157		n = MIN(resid, len);
158
159		if ((rv = strncmp(buf, str, n)) != 0)
160			return (rv);
161
162		buf += n;
163		str += n;
164		len -= n;
165	}
166
167	return (0);
168}
169
170static int
171dt_strtab_copyin(dt_strtab_t *sp, const char *str, size_t len)
172{
173	char *old_p = sp->str_ptr;
174	ulong_t old_n = sp->str_nbufs;
175
176	ulong_t b = sp->str_nbufs - 1;
177	size_t resid, n;
178
179	while (len != 0) {
180		if (sp->str_ptr == sp->str_bufs[b] + sp->str_bufsz) {
181			if (dt_strtab_grow(sp) == -1)
182				goto err;
183			b++;
184		}
185
186		resid = sp->str_bufs[b] + sp->str_bufsz - sp->str_ptr;
187		n = MIN(resid, len);
188		bcopy(str, sp->str_ptr, n);
189
190		sp->str_ptr += n;
191		str += n;
192		len -= n;
193	}
194
195	return (0);
196
197err:
198	while (sp->str_nbufs != old_n)
199		free(sp->str_bufs[--sp->str_nbufs]);
200
201	sp->str_ptr = old_p;
202	return (-1);
203}
204
205ssize_t
206dt_strtab_index(dt_strtab_t *sp, const char *str)
207{
208	dt_strhash_t *hp;
209	size_t len;
210	ulong_t h;
211
212	if (str == NULL || str[0] == '\0')
213		return (0); /* we keep a \0 at offset 0 to simplify things */
214
215	h = dt_strtab_hash(str, &len) % sp->str_hashsz;
216
217	for (hp = sp->str_hash[h]; hp != NULL; hp = hp->str_next) {
218		if (dt_strtab_compare(sp, hp, str, len + 1) == 0)
219			return (hp->str_off);
220	}
221
222	return (-1);
223}
224
225ssize_t
226dt_strtab_insert(dt_strtab_t *sp, const char *str)
227{
228	dt_strhash_t *hp;
229	size_t len;
230	ssize_t off;
231	ulong_t h;
232
233	if ((off = dt_strtab_index(sp, str)) != -1)
234		return (off);
235
236	h = dt_strtab_hash(str, &len) % sp->str_hashsz;
237
238	/*
239	 * Create a new hash bucket, initialize it, and insert it at the front
240	 * of the hash chain for the appropriate bucket.
241	 */
242	if ((hp = malloc(sizeof (dt_strhash_t))) == NULL)
243		return (-1L);
244
245	hp->str_data = sp->str_ptr;
246	hp->str_buf = sp->str_nbufs - 1;
247	hp->str_off = sp->str_size;
248	hp->str_len = len;
249	hp->str_next = sp->str_hash[h];
250
251	/*
252	 * Now copy the string data into our buffer list, and then update
253	 * the global counts of strings and bytes.  Return str's byte offset.
254	 */
255	if (dt_strtab_copyin(sp, str, len + 1) == -1)
256		return (-1L);
257
258	sp->str_nstrs++;
259	sp->str_size += len + 1;
260	sp->str_hash[h] = hp;
261
262	return (hp->str_off);
263}
264
265size_t
266dt_strtab_size(const dt_strtab_t *sp)
267{
268	return (sp->str_size);
269}
270
271ssize_t
272dt_strtab_write(const dt_strtab_t *sp, dt_strtab_write_f *func, void *private)
273{
274	ssize_t res, total = 0;
275	ulong_t i;
276	size_t n;
277
278	for (i = 0; i < sp->str_nbufs; i++, total += res) {
279		if (i == sp->str_nbufs - 1)
280			n = sp->str_ptr - sp->str_bufs[i];
281		else
282			n = sp->str_bufsz;
283
284		if ((res = func(sp->str_bufs[i], n, total, private)) <= 0)
285			break;
286	}
287
288	if (total == 0 && sp->str_size != 0)
289		return (-1);
290
291	return (total);
292}
293