2 * CDE - Common Desktop Environment
4 * Copyright (c) 1993-2012, The Open Group. All rights reserved.
6 * These libraries and programs are free software; you can
7 * redistribute them and/or modify them under the terms of the GNU
8 * Lesser General Public License as published by the Free Software
9 * Foundation; either version 2 of the License, or (at your option)
12 * These libraries and programs are distributed in the hope that
13 * they will be useful, but WITHOUT ANY WARRANTY; without even the
14 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
15 * PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with these libraries and programs; if not, write
20 * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
21 * Floor, Boston, MA 02110-1301 USA
24 * $XConsortium: ifparser.c /main/10 1996/09/28 16:15:18 rws $
26 * Copyright 1992 Network Computing Devices, Inc.
28 * Permission to use, copy, modify, and distribute this software and its
29 * documentation for any purpose and without fee is hereby granted, provided
30 * that the above copyright notice appear in all copies and that both that
31 * copyright notice and this permission notice appear in supporting
32 * documentation, and that the name of Network Computing Devices may not be
33 * used in advertising or publicity pertaining to distribution of the software
34 * without specific, written prior permission. Network Computing Devices makes
35 * no representations about the suitability of this software for any purpose.
36 * It is provided ``as is'' without express or implied warranty.
38 * NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
39 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
40 * IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL,
41 * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
42 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
43 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
44 * PERFORMANCE OF THIS SOFTWARE.
47 * Network Computing Devices, Inc.
49 * Simple if statement processor
51 * This module can be used to evaluate string representations of C language
52 * if constructs. It accepts the following grammar:
55 * | VALUE BINOP EXPRESSION
57 * VALUE := '(' EXPRESSION ')'
60 * | 'defined' '(' variable ')'
61 * | 'defined' variable
62 * | # variable '(' variable-list ')'
66 * BINOP := '*' | '/' | '%'
69 * | '<' | '>' | '<=' | '>='
74 * The normal C order of precidence is supported.
77 * External Entry Points:
79 * ParseIfExpression parse a string for #if
87 /****************************************************************************
88 Internal Macros and Utilities for Parser
89 ****************************************************************************/
91 #define DO(val) if (!(val)) return NULL
92 #define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
93 #define SKIPSPACE(ccc) while (isspace((int)*ccc)) ccc++
94 #define isvarfirstletter(ccc) (isalpha((int)ccc) || (ccc) == '_')
98 parse_variable (g, cp, varp)
105 if (!isvarfirstletter (*cp))
106 return CALLFUNC(g, handle_error) (g, cp, "variable name");
110 for (cp++; isalnum((int)*cp) || *cp == '_'; cp++) ;
116 parse_number (g, cp, valp)
124 if (!isdigit((int)*cp))
125 return CALLFUNC(g, handle_error) (g, cp, "number");
131 if ((*cp == 'x') || (*cp == 'X')) {
139 /* Ignore overflows and assume ASCII, what source is usually written in */
143 if ((*cp >= '0') && (*cp <= '7'))
144 increment = *cp++ - '0';
145 } else if (base == 16) {
146 if ((*cp >= '0') && (*cp <= '9'))
147 increment = *cp++ - '0';
148 else if ((*cp >= 'A') && (*cp <= 'F'))
149 increment = *cp++ - ('A' - 10);
150 else if ((*cp >= 'a') && (*cp <= 'f'))
151 increment = *cp++ - ('a' - 10);
152 } else { /* Decimal */
153 if ((*cp >= '0') && (*cp <= '9'))
154 increment = *cp++ - '0';
158 *valp = (*valp * base) + increment;
161 /* Skip trailing qualifiers */
162 while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++;
167 parse_character (g, cp, valp)
177 case 'n': val = '\n'; break;
178 case 't': val = '\t'; break;
179 case 'v': val = '\v'; break;
180 case 'b': val = '\b'; break;
181 case 'r': val = '\r'; break;
182 case 'f': val = '\f'; break;
183 case 'a': val = '\a'; break;
184 case '\\': val = '\\'; break;
185 case '?': val = '\?'; break;
186 case '\'': val = '\''; break;
187 case '\"': val = '\"'; break;
188 case 'x': val = (char) strtol (cp + 2, NULL, 16); break;
189 default: val = (char) strtol (cp + 1, NULL, 8); break;
193 while (*cp != '\'') cp++;
199 parse_value (g, cp, valp)
214 DO (cp = ParseIfExpression (g, cp + 1, valp));
217 return CALLFUNC(g, handle_error) (g, cp, ")");
219 return cp + 1; /* skip the right paren */
222 DO (cp = parse_value (g, cp + 1, valp));
227 DO (cp = parse_value (g, cp + 1, valp));
232 DO (cp = parse_variable (g, cp + 1, &var));
235 return CALLFUNC(g, handle_error) (g, cp, "(");
237 DO (cp = parse_variable (g, cp + 1, &var));
239 } while (*cp && *cp != ')');
241 return CALLFUNC(g, handle_error) (g, cp, ")");
246 DO (cp = parse_character (g, cp + 1, valp));
248 return CALLFUNC(g, handle_error) (g, cp, "'");
252 if (strncmp (cp, "defined", 7) == 0 && !isalnum((int)cp[7])) {
262 DO (cp = parse_variable (g, cp, &var));
265 if (paren && *cp != ')')
266 return CALLFUNC(g, handle_error) (g, cp, ")");
267 *valp = (*(g->funcs.eval_defined)) (g, var, len);
268 return cp + paren; /* skip the right paren */
273 if (isdigit((int)*cp)) {
274 DO (cp = parse_number (g, cp, valp));
275 } else if (!isvarfirstletter(*cp))
276 return CALLFUNC(g, handle_error) (g, cp, "variable or number");
278 DO (cp = parse_variable (g, cp, &var));
279 *valp = (*(g->funcs.eval_variable)) (g, var, cp - var);
288 parse_product (g, cp, valp)
295 DO (cp = parse_value (g, cp, valp));
300 DO (cp = parse_product (g, cp + 1, &rightval));
301 *valp = (*valp * rightval);
305 DO (cp = parse_product (g, cp + 1, &rightval));
307 *valp = (*valp / rightval);
313 DO (cp = parse_product (g, cp + 1, &rightval));
314 *valp = (*valp % rightval);
322 parse_sum (g, cp, valp)
329 DO (cp = parse_product (g, cp, valp));
334 DO (cp = parse_sum (g, cp + 1, &rightval));
335 *valp = (*valp + rightval);
339 DO (cp = parse_sum (g, cp + 1, &rightval));
340 *valp = (*valp - rightval);
348 parse_shift (g, cp, valp)
355 DO (cp = parse_sum (g, cp, valp));
361 DO (cp = parse_shift (g, cp + 2, &rightval));
362 *valp = (*valp << rightval);
368 DO (cp = parse_shift (g, cp + 2, &rightval));
369 *valp = (*valp >> rightval);
378 parse_inequality (g, cp, valp)
385 DO (cp = parse_shift (g, cp, valp));
391 DO (cp = parse_inequality (g, cp + 2, &rightval));
392 *valp = (*valp <= rightval);
394 DO (cp = parse_inequality (g, cp + 1, &rightval));
395 *valp = (*valp < rightval);
401 DO (cp = parse_inequality (g, cp + 2, &rightval));
402 *valp = (*valp >= rightval);
404 DO (cp = parse_inequality (g, cp + 1, &rightval));
405 *valp = (*valp > rightval);
414 parse_equality (g, cp, valp)
421 DO (cp = parse_inequality (g, cp, valp));
428 DO (cp = parse_equality (g, cp + 1, &rightval));
429 *valp = (*valp == rightval);
435 DO (cp = parse_equality (g, cp + 2, &rightval));
436 *valp = (*valp != rightval);
444 parse_band (g, cp, valp)
451 DO (cp = parse_equality (g, cp, valp));
457 DO (cp = parse_band (g, cp + 1, &rightval));
458 *valp = (*valp & rightval);
467 parse_bor (g, cp, valp)
474 DO (cp = parse_band (g, cp, valp));
480 DO (cp = parse_bor (g, cp + 1, &rightval));
481 *valp = (*valp | rightval);
490 parse_land (g, cp, valp)
497 DO (cp = parse_bor (g, cp, valp));
503 return CALLFUNC(g, handle_error) (g, cp, "&&");
504 DO (cp = parse_land (g, cp + 2, &rightval));
505 *valp = (*valp && rightval);
513 parse_lor (g, cp, valp)
520 DO (cp = parse_land (g, cp, valp));
526 return CALLFUNC(g, handle_error) (g, cp, "||");
527 DO (cp = parse_lor (g, cp + 2, &rightval));
528 *valp = (*valp || rightval);
535 /****************************************************************************
536 External Entry Points
537 ****************************************************************************/
540 ParseIfExpression (g, cp, valp)
545 return parse_lor (g, cp, valp);