2 * Copyright (c) 2004 Tim J. Robbins.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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
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12 * documentation and/or other materials provided with the distribution.
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17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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26 * $FreeBSD: head/usr.bin/tr/cset.c 226363 2011-10-14 10:43:55Z ed $
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).
41 static struct csnode * cset_delete(struct csnode *, wchar_t);
42 static __inline int cset_rangecmp(struct csnode *, wchar_t);
43 static struct csnode * cset_splay(struct csnode *, wchar_t);
47 * Allocate a set of characters.
54 if ((cs = malloc(sizeof(*cs))) == NULL)
57 cs->cs_classes = NULL;
58 cs->cs_havecache = false;
59 cs->cs_invert = false;
65 * Add a character to the set.
68 cset_add(struct cset *cs, wchar_t ch)
70 struct csnode *csn, *ncsn;
73 cs->cs_havecache = false;
76 * Inserting into empty tree; new item becomes the root.
78 if (cs->cs_root == NULL) {
79 csn = malloc(sizeof(*cs->cs_root));
82 csn->csn_left = csn->csn_right = NULL;
83 csn->csn_min = csn->csn_max = ch;
89 * Splay to check whether the item already exists, and otherwise,
90 * where we should put it.
92 csn = cs->cs_root = cset_splay(cs->cs_root, ch);
95 * Avoid adding duplicate nodes.
97 if (cset_rangecmp(csn, ch) == 0)
101 * Allocate a new node and make it the new root.
103 ncsn = malloc(sizeof(*ncsn));
106 ncsn->csn_min = ncsn->csn_max = ch;
107 if (cset_rangecmp(csn, ch) < 0) {
108 ncsn->csn_left = csn->csn_left;
109 ncsn->csn_right = csn;
110 csn->csn_left = NULL;
112 ncsn->csn_right = csn->csn_right;
113 ncsn->csn_left = csn;
114 csn->csn_right = NULL;
119 * Coalesce with left and right neighbours if possible.
121 if (ncsn->csn_left != NULL) {
122 ncsn->csn_left = cset_splay(ncsn->csn_left, ncsn->csn_min - 1);
123 if (ncsn->csn_left->csn_max == ncsn->csn_min - 1) {
124 oval = ncsn->csn_left->csn_min;
125 ncsn->csn_left = cset_delete(ncsn->csn_left,
126 ncsn->csn_left->csn_min);
127 ncsn->csn_min = oval;
130 if (ncsn->csn_right != NULL) {
131 ncsn->csn_right = cset_splay(ncsn->csn_right,
133 if (ncsn->csn_right->csn_min == ncsn->csn_max + 1) {
134 oval = ncsn->csn_right->csn_max;
135 ncsn->csn_right = cset_delete(ncsn->csn_right,
136 ncsn->csn_right->csn_min);
137 ncsn->csn_max = oval;
146 * Determine whether a character is in the set without using
150 cset_in_hard(struct cset *cs, wchar_t ch)
154 for (csc = cs->cs_classes; csc != NULL; csc = csc->csc_next)
155 if (csc->csc_invert ^ (iswctype(ch, csc->csc_type) != 0))
156 return (cs->cs_invert ^ true);
157 if (cs->cs_root != NULL) {
158 cs->cs_root = cset_splay(cs->cs_root, ch);
159 return (cs->cs_invert ^ (cset_rangecmp(cs->cs_root, ch) == 0));
161 return (cs->cs_invert ^ false);
169 cset_cache(struct cset *cs)
173 for (i = 0; i < CS_CACHE_SIZE; i++)
174 cs->cs_cache[i] = cset_in_hard(cs, i);
176 cs->cs_havecache = true;
181 * Invert the character set.
184 cset_invert(struct cset *cs)
187 cs->cs_invert ^= true;
188 cs->cs_havecache = false;
193 * Add a wctype()-style character class to the set, optionally
197 cset_addclass(struct cset *cs, wctype_t type, bool invert)
201 csc = malloc(sizeof(*csc));
204 csc->csc_type = type;
205 csc->csc_invert = invert;
206 csc->csc_next = cs->cs_classes;
207 cs->cs_classes = csc;
208 cs->cs_havecache = false;
213 cset_rangecmp(struct csnode *t, wchar_t ch)
223 static struct csnode *
224 cset_splay(struct csnode *t, wchar_t ch)
226 struct csnode N, *l, *r, *y;
229 * Based on public domain code from Sleator.
234 N.csn_left = N.csn_right = NULL;
237 if (cset_rangecmp(t, ch) < 0) {
238 if (t->csn_left != NULL &&
239 cset_rangecmp(t->csn_left, ch) < 0) {
241 t->csn_left = y->csn_right;
245 if (t->csn_left == NULL)
250 } else if (cset_rangecmp(t, ch) > 0) {
251 if (t->csn_right != NULL &&
252 cset_rangecmp(t->csn_right, ch) > 0) {
254 t->csn_right = y->csn_left;
258 if (t->csn_right == NULL)
266 l->csn_right = t->csn_left;
267 r->csn_left = t->csn_right;
268 t->csn_left = N.csn_right;
269 t->csn_right = N.csn_left;
273 static struct csnode *
274 cset_delete(struct csnode *t, wchar_t ch)
279 t = cset_splay(t, ch);
280 assert(cset_rangecmp(t, ch) == 0);
281 if (t->csn_left == NULL)
284 x = cset_splay(t->csn_left, ch);
285 x->csn_right = t->csn_right;