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	"%Z%%M%	%I%	%E% SMI"
28
29#include <sys/types.h>
30#include <sys/sysmacros.h>
31#include <strings.h>
32#include <stdlib.h>
33#include <assert.h>
34
35#include <dt_strtab.h>
36#include <dt_impl.h>
37
38static int
39dt_strtab_grow(dt_strtab_t *sp)
40{
41	char *ptr, **bufs;
42
43	if ((ptr = malloc(sp->str_bufsz)) == NULL)
44		return (-1);
45
46	bufs = realloc(sp->str_bufs, (sp->str_nbufs + 1) * sizeof (char *));
47
48	if (bufs == NULL) {
49		free(ptr);
50		return (-1);
51	}
52
53	sp->str_nbufs++;
54	sp->str_bufs = bufs;
55	sp->str_ptr = ptr;
56	sp->str_bufs[sp->str_nbufs - 1] = sp->str_ptr;
57
58	return (0);
59}
60
61dt_strtab_t *
62dt_strtab_create(size_t bufsz)
63{
64	dt_strtab_t *sp = malloc(sizeof (dt_strtab_t));
65	uint_t nbuckets = _dtrace_strbuckets;
66
67	assert(bufsz != 0);
68
69	if (sp == NULL)
70		return (NULL);
71
72	bzero(sp, sizeof (dt_strtab_t));
73	sp->str_hash = malloc(nbuckets * sizeof (dt_strhash_t *));
74
75	if (sp->str_hash == NULL)
76		goto err;
77
78	bzero(sp->str_hash, nbuckets * sizeof (dt_strhash_t *));
79	sp->str_hashsz = nbuckets;
80	sp->str_bufs = NULL;
81	sp->str_ptr = NULL;
82	sp->str_nbufs = 0;
83	sp->str_bufsz = bufsz;
84	sp->str_nstrs = 1;
85	sp->str_size = 1;
86
87	if (dt_strtab_grow(sp) == -1)
88		goto err;
89
90	*sp->str_ptr++ = '\0';
91	return (sp);
92
93err:
94	dt_strtab_destroy(sp);
95	return (NULL);
96}
97
98void
99dt_strtab_destroy(dt_strtab_t *sp)
100{
101	dt_strhash_t *hp, *hq;
102	ulong_t i;
103
104	for (i = 0; i < sp->str_hashsz; i++) {
105		for (hp = sp->str_hash[i]; hp != NULL; hp = hq) {
106			hq = hp->str_next;
107			free(hp);
108		}
109	}
110
111	for (i = 0; i < sp->str_nbufs; i++)
112		free(sp->str_bufs[i]);
113
114	if (sp->str_hash != NULL)
115		free(sp->str_hash);
116	if (sp->str_bufs != NULL)
117		free(sp->str_bufs);
118
119	free(sp);
120}
121
122ulong_t
123dt_strtab_hash(const char *key, size_t *len)
124{
125	ulong_t g, h = 0;
126	const char *p;
127	size_t n = 0;
128
129	for (p = key; *p != '\0'; p++, n++) {
130		h = (h << 4) + *p;
131
132		if ((g = (h & 0xf0000000)) != 0) {
133			h ^= (g >> 24);
134			h ^= g;
135		}
136	}
137
138	if (len != NULL)
139		*len = n;
140
141	return (h);
142}
143
144static int
145dt_strtab_compare(dt_strtab_t *sp, dt_strhash_t *hp,
146    const char *str, size_t len)
147{
148	ulong_t b = hp->str_buf;
149	const char *buf = hp->str_data;
150	size_t resid, n;
151	int rv;
152
153	while (len != 0) {
154		if (buf == sp->str_bufs[b] + sp->str_bufsz)
155			buf = sp->str_bufs[++b];
156
157		resid = sp->str_bufs[b] + sp->str_bufsz - buf;
158		n = MIN(resid, len);
159
160		if ((rv = strncmp(buf, str, n)) != 0)
161			return (rv);
162
163		buf += n;
164		str += n;
165		len -= n;
166	}
167
168	return (0);
169}
170
171static int
172dt_strtab_copyin(dt_strtab_t *sp, const char *str, size_t len)
173{
174	char *old_p = sp->str_ptr;
175	ulong_t old_n = sp->str_nbufs;
176
177	ulong_t b = sp->str_nbufs - 1;
178	size_t resid, n;
179
180	while (len != 0) {
181		if (sp->str_ptr == sp->str_bufs[b] + sp->str_bufsz) {
182			if (dt_strtab_grow(sp) == -1)
183				goto err;
184			b++;
185		}
186
187		resid = sp->str_bufs[b] + sp->str_bufsz - sp->str_ptr;
188		n = MIN(resid, len);
189		bcopy(str, sp->str_ptr, n);
190
191		sp->str_ptr += n;
192		str += n;
193		len -= n;
194	}
195
196	return (0);
197
198err:
199	while (sp->str_nbufs != old_n)
200		free(sp->str_bufs[--sp->str_nbufs]);
201
202	sp->str_ptr = old_p;
203	return (-1);
204}
205
206ssize_t
207dt_strtab_index(dt_strtab_t *sp, const char *str)
208{
209	dt_strhash_t *hp;
210	size_t len;
211	ulong_t h;
212
213	if (str == NULL || str[0] == '\0')
214		return (0); /* we keep a \0 at offset 0 to simplify things */
215
216	h = dt_strtab_hash(str, &len) % sp->str_hashsz;
217
218	for (hp = sp->str_hash[h]; hp != NULL; hp = hp->str_next) {
219		if (dt_strtab_compare(sp, hp, str, len + 1) == 0)
220			return (hp->str_off);
221	}
222
223	return (-1);
224}
225
226ssize_t
227dt_strtab_insert(dt_strtab_t *sp, const char *str)
228{
229	dt_strhash_t *hp;
230	size_t len;
231	ssize_t off;
232	ulong_t h;
233
234	if ((off = dt_strtab_index(sp, str)) != -1)
235		return (off);
236
237	h = dt_strtab_hash(str, &len) % sp->str_hashsz;
238
239	/*
240	 * Create a new hash bucket, initialize it, and insert it at the front
241	 * of the hash chain for the appropriate bucket.
242	 */
243	if ((hp = malloc(sizeof (dt_strhash_t))) == NULL)
244		return (-1L);
245
246	hp->str_data = sp->str_ptr;
247	hp->str_buf = sp->str_nbufs - 1;
248	hp->str_off = sp->str_size;
249	hp->str_len = len;
250	hp->str_next = sp->str_hash[h];
251
252	/*
253	 * Now copy the string data into our buffer list, and then update
254	 * the global counts of strings and bytes.  Return str's byte offset.
255	 */
256	if (dt_strtab_copyin(sp, str, len + 1) == -1)
257		return (-1L);
258
259	sp->str_nstrs++;
260	sp->str_size += len + 1;
261	sp->str_hash[h] = hp;
262
263	return (hp->str_off);
264}
265
266size_t
267dt_strtab_size(const dt_strtab_t *sp)
268{
269	return (sp->str_size);
270}
271
272ssize_t
273dt_strtab_write(const dt_strtab_t *sp, dt_strtab_write_f *func, void *private)
274{
275	ssize_t res, total = 0;
276	ulong_t i;
277	size_t n;
278
279	for (i = 0; i < sp->str_nbufs; i++, total += res) {
280		if (i == sp->str_nbufs - 1)
281			n = sp->str_ptr - sp->str_bufs[i];
282		else
283			n = sp->str_bufsz;
284
285		if ((res = func(sp->str_bufs[i], n, total, private)) <= 0)
286			break;
287	}
288
289	if (total == 0 && sp->str_size != 0)
290		return (-1);
291
292	return (total);
293}
294