1 /* ccl - routines for character classes */
2
3 /* Copyright (c) 1990 The Regents of the University of California. */
4 /* All rights reserved. */
5
6 /* This code is derived from software contributed to Berkeley by */
7 /* Vern Paxson. */
8
9 /* The United States Government has rights in this work pursuant */
10 /* to contract no. DE-AC03-76SF00098 between the United States */
11 /* Department of Energy and the University of California. */
12
13 /* This file is part of flex. */
14
15 /* Redistribution and use in source and binary forms, with or without */
16 /* modification, are permitted provided that the following conditions */
17 /* are met: */
18
19 /* 1. Redistributions of source code must retain the above copyright */
20 /* notice, this list of conditions and the following disclaimer. */
21 /* 2. Redistributions in binary form must reproduce the above copyright */
22 /* notice, this list of conditions and the following disclaimer in the */
23 /* documentation and/or other materials provided with the distribution. */
24
25 /* Neither the name of the University nor the names of its contributors */
26 /* may be used to endorse or promote products derived from this software */
27 /* without specific prior written permission. */
28
29 /* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR */
30 /* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED */
31 /* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
32 /* PURPOSE. */
33
34 #include "flexdef.h"
35
36 /* return true if the chr is in the ccl. Takes negation into account. */
37 static bool
38 ccl_contains (const int cclp, const int ch)
39 {
40 int ind, len, i;
41
42 len = ccllen[cclp];
43 ind = cclmap[cclp];
44
45 for (i = 0; i < len; ++i)
46 if (ccltbl[ind + i] == ch)
47 return !cclng[cclp];
48
49 return cclng[cclp];
50 }
51
52
53 /* ccladd - add a single character to a ccl */
54
55 void ccladd (int cclp, int ch)
56 {
57 int ind, len, newpos, i;
58
59 check_char (ch);
60
61 len = ccllen[cclp];
62 ind = cclmap[cclp];
63
64 /* check to see if the character is already in the ccl */
65
66 for (i = 0; i < len; ++i)
67 if (ccltbl[ind + i] == ch)
68 return;
69
70 /* mark newlines */
71 if (ch == nlch)
72 ccl_has_nl[cclp] = true;
73
74 newpos = ind + len;
75
76 if (newpos >= current_max_ccl_tbl_size) {
77 current_max_ccl_tbl_size += MAX_CCL_TBL_SIZE_INCREMENT;
78
79 ++num_reallocs;
80
81 ccltbl = reallocate_Character_array (ccltbl,
82 current_max_ccl_tbl_size);
83 }
84
85 ccllen[cclp] = len + 1;
86 ccltbl[newpos] = (unsigned char) ch;
87 }
88
89 /* dump_cclp - same thing as list_character_set, but for cclps. */
90
91 static void dump_cclp (FILE* file, int cclp)
92 {
93 int i;
94
95 putc ('[', file);
96
97 for (i = 0; i < csize; ++i) {
98 if (ccl_contains(cclp, i)){
99 int start_char = i;
100
101 putc (' ', file);
102
103 fputs (readable_form (i), file);
104
105 while (++i < csize && ccl_contains(cclp,i)) ;
106
107 if (i - 1 > start_char)
108 /* this was a run */
109 fprintf (file, "-%s",
110 readable_form (i - 1));
111
112 putc (' ', file);
113 }
114 }
115
116 putc (']', file);
117 }
118
119
120
121 /* ccl_set_diff - create a new ccl as the set difference of the two given ccls. */
122 int
123 ccl_set_diff (int a, int b)
124 {
125 int d, ch;
126
127 /* create new class */
128 d = cclinit();
129
130 /* In order to handle negation, we spin through all possible chars,
131 * addding each char in a that is not in b.
132 * (This could be O(n^2), but n is small and bounded.)
133 */
134 for ( ch = 0; ch < csize; ++ch )
135 if (ccl_contains (a, ch) && !ccl_contains(b, ch))
136 ccladd (d, ch);
137
138 /* debug */
139 if (0){
140 fprintf(stderr, "ccl_set_diff (");
141 fprintf(stderr, "\n ");
142 dump_cclp (stderr, a);
143 fprintf(stderr, "\n ");
144 dump_cclp (stderr, b);
145 fprintf(stderr, "\n ");
146 dump_cclp (stderr, d);
147 fprintf(stderr, "\n)\n");
148 }
149 return d;
150 }
151
152 /* ccl_set_union - create a new ccl as the set union of the two given ccls. */
153 int
154 ccl_set_union (int a, int b)
155 {
156 int d, i;
157
158 /* create new class */
159 d = cclinit();
160
161 /* Add all of a */
162 for (i = 0; i < ccllen[a]; ++i)
163 ccladd (d, ccltbl[cclmap[a] + i]);
164
165 /* Add all of b */
166 for (i = 0; i < ccllen[b]; ++i)
167 ccladd (d, ccltbl[cclmap[b] + i]);
168
169 /* debug */
170 if (0){
171 fprintf(stderr, "ccl_set_union (%d + %d = %d", a, b, d);
172 fprintf(stderr, "\n ");
173 dump_cclp (stderr, a);
174 fprintf(stderr, "\n ");
175 dump_cclp (stderr, b);
176 fprintf(stderr, "\n ");
177 dump_cclp (stderr, d);
178 fprintf(stderr, "\n)\n");
179 }
180 return d;
181 }
182
183
184 /* cclinit - return an empty ccl */
185
186 int cclinit (void)
187 {
188 if (++lastccl >= current_maxccls) {
189 current_maxccls += MAX_CCLS_INCREMENT;
190
191 ++num_reallocs;
192
193 cclmap =
194 reallocate_integer_array (cclmap, current_maxccls);
195 ccllen =
196 reallocate_integer_array (ccllen, current_maxccls);
197 cclng = reallocate_integer_array (cclng, current_maxccls);
198 ccl_has_nl =
199 reallocate_bool_array (ccl_has_nl,
200 current_maxccls);
201 }
202
203 if (lastccl == 1)
204 /* we're making the first ccl */
205 cclmap[lastccl] = 0;
206
207 else
208 /* The new pointer is just past the end of the last ccl.
209 * Since the cclmap points to the \first/ character of a
210 * ccl, adding the length of the ccl to the cclmap pointer
211 * will produce a cursor to the first free space.
212 */
213 cclmap[lastccl] =
214 cclmap[lastccl - 1] + ccllen[lastccl - 1];
215
216 ccllen[lastccl] = 0;
217 cclng[lastccl] = 0; /* ccl's start out life un-negated */
218 ccl_has_nl[lastccl] = false;
219
220 return lastccl;
221 }
222
223
224 /* cclnegate - negate the given ccl */
225
226 void cclnegate (int cclp)
227 {
228 cclng[cclp] = 1;
229 ccl_has_nl[cclp] = !ccl_has_nl[cclp];
230 }
231
232
233 /* list_character_set - list the members of a set of characters in CCL form
234 *
235 * Writes to the given file a character-class representation of those
236 * characters present in the given CCL. A character is present if it
237 * has a non-zero value in the cset array.
238 */
239
240 void list_character_set (FILE *file, int cset[])
241 {
242 int i;
243
244 putc ('[', file);
245
246 for (i = 0; i < csize; ++i) {
247 if (cset[i]) {
248 int start_char = i;
249
250 putc (' ', file);
251
252 fputs (readable_form (i), file);
253
254 while (++i < csize && cset[i]) ;
255
256 if (i - 1 > start_char)
257 /* this was a run */
258 fprintf (file, "-%s",
259 readable_form (i - 1));
260
261 putc (' ', file);
262 }
263 }
264
265 putc (']', file);
266 }
267
268 /** Determines if the range [c1-c2] is unambiguous in a case-insensitive
269 * scanner. Specifically, if a lowercase or uppercase character, x, is in the
270 * range [c1-c2], then we require that UPPERCASE(x) and LOWERCASE(x) must also
271 * be in the range. If not, then this range is ambiguous, and the function
272 * returns false. For example, [@-_] spans [a-z] but not [A-Z]. Beware that
273 * [a-z] will be labeled ambiguous because it does not include [A-Z].
274 *
275 * @param c1 the lower end of the range
276 * @param c2 the upper end of the range
277 * @return true if [c1-c2] is not ambiguous for a caseless scanner.
278 */
279 bool range_covers_case (int c1, int c2)
280 {
281 int i, o;
282
283 for (i = c1; i <= c2; i++) {
284 if (has_case (i)) {
285 o = reverse_case (i);
286 if (o < c1 || c2 < o)
287 return false;
288 }
289 }
290 return true;
291 }
292
293 /** Reverse the case of a character, if possible.
294 * @return c if case-reversal does not apply.
295 */
296 int reverse_case (int c)
297 {
298 return isupper (c) ? tolower (c) : (islower (c) ? toupper (c) : c);
299 }
300
301 /** Return true if c is uppercase or lowercase. */
302 bool has_case (int c)
303 {
304 return (isupper (c) || islower (c)) ? true : false;
305 }