1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2004 Tim J. Robbins.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28 /*
29 * "Set of characters" ADT implemented as a splay tree of extents, with
30 * a lookup table cache to simplify looking up the first bunch of
31 * characters (which are presumably more common than others).
32 */
33
34 #include <sys/cdefs.h>
35 #include <assert.h>
36 #include <stdbool.h>
37 #include <stdlib.h>
38 #include <wchar.h>
39 #include <wctype.h>
40 #include "cset.h"
41
42 static struct csnode * cset_delete(struct csnode *, wchar_t);
43 static __inline int cset_rangecmp(struct csnode *, wchar_t);
44 static struct csnode * cset_splay(struct csnode *, wchar_t);
45
46 /*
47 * cset_alloc --
48 * Allocate a set of characters.
49 */
50 struct cset *
cset_alloc(void)51 cset_alloc(void)
52 {
53 struct cset *cs;
54
55 if ((cs = malloc(sizeof(*cs))) == NULL)
56 return (NULL);
57 cs->cs_root = NULL;
58 cs->cs_classes = NULL;
59 cs->cs_havecache = false;
60 cs->cs_invert = false;
61 return (cs);
62 }
63
64 /*
65 * cset_add --
66 * Add a character to the set.
67 */
68 bool
cset_add(struct cset * cs,wchar_t ch)69 cset_add(struct cset *cs, wchar_t ch)
70 {
71 struct csnode *csn, *ncsn;
72 wchar_t oval;
73
74 cs->cs_havecache = false;
75
76 /*
77 * Inserting into empty tree; new item becomes the root.
78 */
79 if (cs->cs_root == NULL) {
80 csn = malloc(sizeof(*cs->cs_root));
81 if (csn == NULL)
82 return (false);
83 csn->csn_left = csn->csn_right = NULL;
84 csn->csn_min = csn->csn_max = ch;
85 cs->cs_root = csn;
86 return (true);
87 }
88
89 /*
90 * Splay to check whether the item already exists, and otherwise,
91 * where we should put it.
92 */
93 csn = cs->cs_root = cset_splay(cs->cs_root, ch);
94
95 /*
96 * Avoid adding duplicate nodes.
97 */
98 if (cset_rangecmp(csn, ch) == 0)
99 return (true);
100
101 /*
102 * Allocate a new node and make it the new root.
103 */
104 ncsn = malloc(sizeof(*ncsn));
105 if (ncsn == NULL)
106 return (false);
107 ncsn->csn_min = ncsn->csn_max = ch;
108 if (cset_rangecmp(csn, ch) < 0) {
109 ncsn->csn_left = csn->csn_left;
110 ncsn->csn_right = csn;
111 csn->csn_left = NULL;
112 } else {
113 ncsn->csn_right = csn->csn_right;
114 ncsn->csn_left = csn;
115 csn->csn_right = NULL;
116 }
117 cs->cs_root = ncsn;
118
119 /*
120 * Coalesce with left and right neighbours if possible.
121 */
122 if (ncsn->csn_left != NULL) {
123 ncsn->csn_left = cset_splay(ncsn->csn_left, ncsn->csn_min - 1);
124 if (ncsn->csn_left->csn_max == ncsn->csn_min - 1) {
125 oval = ncsn->csn_left->csn_min;
126 ncsn->csn_left = cset_delete(ncsn->csn_left,
127 ncsn->csn_left->csn_min);
128 ncsn->csn_min = oval;
129 }
130 }
131 if (ncsn->csn_right != NULL) {
132 ncsn->csn_right = cset_splay(ncsn->csn_right,
133 ncsn->csn_max + 1);
134 if (ncsn->csn_right->csn_min == ncsn->csn_max + 1) {
135 oval = ncsn->csn_right->csn_max;
136 ncsn->csn_right = cset_delete(ncsn->csn_right,
137 ncsn->csn_right->csn_min);
138 ncsn->csn_max = oval;
139 }
140 }
141
142 return (true);
143 }
144
145 /*
146 * cset_in_hard --
147 * Determine whether a character is in the set without using
148 * the cache.
149 */
150 bool
cset_in_hard(struct cset * cs,wchar_t ch)151 cset_in_hard(struct cset *cs, wchar_t ch)
152 {
153 struct csclass *csc;
154
155 for (csc = cs->cs_classes; csc != NULL; csc = csc->csc_next)
156 if (csc->csc_invert ^ (iswctype(ch, csc->csc_type) != 0))
157 return (cs->cs_invert ^ true);
158 if (cs->cs_root != NULL) {
159 cs->cs_root = cset_splay(cs->cs_root, ch);
160 return (cs->cs_invert ^ (cset_rangecmp(cs->cs_root, ch) == 0));
161 }
162 return (cs->cs_invert ^ false);
163 }
164
165 /*
166 * cset_cache --
167 * Update the cache.
168 */
169 void
cset_cache(struct cset * cs)170 cset_cache(struct cset *cs)
171 {
172 wchar_t i;
173
174 for (i = 0; i < CS_CACHE_SIZE; i++)
175 cs->cs_cache[i] = cset_in_hard(cs, i);
176
177 cs->cs_havecache = true;
178 }
179
180 /*
181 * cset_invert --
182 * Invert the character set.
183 */
184 void
cset_invert(struct cset * cs)185 cset_invert(struct cset *cs)
186 {
187
188 cs->cs_invert ^= true;
189 cs->cs_havecache = false;
190 }
191
192 /*
193 * cset_addclass --
194 * Add a wctype()-style character class to the set, optionally
195 * inverting it.
196 */
197 bool
cset_addclass(struct cset * cs,wctype_t type,bool invert)198 cset_addclass(struct cset *cs, wctype_t type, bool invert)
199 {
200 struct csclass *csc;
201
202 csc = malloc(sizeof(*csc));
203 if (csc == NULL)
204 return (false);
205 csc->csc_type = type;
206 csc->csc_invert = invert;
207 csc->csc_next = cs->cs_classes;
208 cs->cs_classes = csc;
209 cs->cs_havecache = false;
210 return (true);
211 }
212
213 static __inline int
cset_rangecmp(struct csnode * t,wchar_t ch)214 cset_rangecmp(struct csnode *t, wchar_t ch)
215 {
216
217 if (ch < t->csn_min)
218 return (-1);
219 if (ch > t->csn_max)
220 return (1);
221 return (0);
222 }
223
224 static struct csnode *
cset_splay(struct csnode * t,wchar_t ch)225 cset_splay(struct csnode *t, wchar_t ch)
226 {
227 struct csnode N, *l, *r, *y;
228
229 /*
230 * Based on public domain code from Sleator.
231 */
232
233 assert(t != NULL);
234
235 N.csn_left = N.csn_right = NULL;
236 l = r = &N;
237 for (;;) {
238 if (cset_rangecmp(t, ch) < 0) {
239 if (t->csn_left != NULL &&
240 cset_rangecmp(t->csn_left, ch) < 0) {
241 y = t->csn_left;
242 t->csn_left = y->csn_right;
243 y->csn_right = t;
244 t = y;
245 }
246 if (t->csn_left == NULL)
247 break;
248 r->csn_left = t;
249 r = t;
250 t = t->csn_left;
251 } else if (cset_rangecmp(t, ch) > 0) {
252 if (t->csn_right != NULL &&
253 cset_rangecmp(t->csn_right, ch) > 0) {
254 y = t->csn_right;
255 t->csn_right = y->csn_left;
256 y->csn_left = t;
257 t = y;
258 }
259 if (t->csn_right == NULL)
260 break;
261 l->csn_right = t;
262 l = t;
263 t = t->csn_right;
264 } else
265 break;
266 }
267 l->csn_right = t->csn_left;
268 r->csn_left = t->csn_right;
269 t->csn_left = N.csn_right;
270 t->csn_right = N.csn_left;
271 return (t);
272 }
273
274 static struct csnode *
cset_delete(struct csnode * t,wchar_t ch)275 cset_delete(struct csnode *t, wchar_t ch)
276 {
277 struct csnode *x;
278
279 assert(t != NULL);
280 t = cset_splay(t, ch);
281 assert(cset_rangecmp(t, ch) == 0);
282 if (t->csn_left == NULL)
283 x = t->csn_right;
284 else {
285 x = cset_splay(t->csn_left, ch);
286 x->csn_right = t->csn_right;
287 }
288 free(t);
289 return x;
290 }
291