2 * CDE - Common Desktop Environment
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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
88 /****************************************************************************
89 Internal Macros and Utilities for Parser
90 ****************************************************************************/
92 #define DO(val) if (!(val)) return NULL
93 #define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
94 #define SKIPSPACE(ccc) while (isspace((int)*ccc)) ccc++
95 #define isvarfirstletter(ccc) (isalpha((int)ccc) || (ccc) == '_')
99 parse_variable (g, cp, varp)
106 if (!isvarfirstletter (*cp))
107 return CALLFUNC(g, handle_error) (g, cp, "variable name");
111 for (cp++; isalnum((int)*cp) || *cp == '_'; cp++) ;
117 parse_number (g, cp, valp)
125 if (!isdigit((int)*cp))
126 return CALLFUNC(g, handle_error) (g, cp, "number");
132 if ((*cp == 'x') || (*cp == 'X')) {
140 /* Ignore overflows and assume ASCII, what source is usually written in */
144 if ((*cp >= '0') && (*cp <= '7'))
145 increment = *cp++ - '0';
146 } else if (base == 16) {
147 if ((*cp >= '0') && (*cp <= '9'))
148 increment = *cp++ - '0';
149 else if ((*cp >= 'A') && (*cp <= 'F'))
150 increment = *cp++ - ('A' - 10);
151 else if ((*cp >= 'a') && (*cp <= 'f'))
152 increment = *cp++ - ('a' - 10);
153 } else { /* Decimal */
154 if ((*cp >= '0') && (*cp <= '9'))
155 increment = *cp++ - '0';
159 *valp = (*valp * base) + increment;
162 /* Skip trailing qualifiers */
163 while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++;
168 parse_character (g, cp, valp)
178 case 'n': val = '\n'; break;
179 case 't': val = '\t'; break;
180 case 'v': val = '\v'; break;
181 case 'b': val = '\b'; break;
182 case 'r': val = '\r'; break;
183 case 'f': val = '\f'; break;
184 case 'a': val = '\a'; break;
185 case '\\': val = '\\'; break;
186 case '?': val = '\?'; break;
187 case '\'': val = '\''; break;
188 case '\"': val = '\"'; break;
189 case 'x': val = (char) strtol (cp + 2, NULL, 16); break;
190 default: val = (char) strtol (cp + 1, NULL, 8); break;
194 while (*cp != '\'') cp++;
200 parse_value (g, cp, valp)
215 DO (cp = ParseIfExpression (g, cp + 1, valp));
218 return CALLFUNC(g, handle_error) (g, cp, ")");
220 return cp + 1; /* skip the right paren */
223 DO (cp = parse_value (g, cp + 1, valp));
228 DO (cp = parse_value (g, cp + 1, valp));
233 DO (cp = parse_variable (g, cp + 1, &var));
236 return CALLFUNC(g, handle_error) (g, cp, "(");
238 DO (cp = parse_variable (g, cp + 1, &var));
240 } while (*cp && *cp != ')');
242 return CALLFUNC(g, handle_error) (g, cp, ")");
247 DO (cp = parse_character (g, cp + 1, valp));
249 return CALLFUNC(g, handle_error) (g, cp, "'");
253 if (strncmp (cp, "defined", 7) == 0 && !isalnum((int)cp[7])) {
263 DO (cp = parse_variable (g, cp, &var));
266 if (paren && *cp != ')')
267 return CALLFUNC(g, handle_error) (g, cp, ")");
268 *valp = (*(g->funcs.eval_defined)) (g, var, len);
269 return cp + paren; /* skip the right paren */
274 if (isdigit((int)*cp)) {
275 DO (cp = parse_number (g, cp, valp));
276 } else if (!isvarfirstletter(*cp))
277 return CALLFUNC(g, handle_error) (g, cp, "variable or number");
279 DO (cp = parse_variable (g, cp, &var));
280 *valp = (*(g->funcs.eval_variable)) (g, var, cp - var);
289 parse_product (g, cp, valp)
296 DO (cp = parse_value (g, cp, valp));
301 DO (cp = parse_product (g, cp + 1, &rightval));
302 *valp = (*valp * rightval);
306 DO (cp = parse_product (g, cp + 1, &rightval));
308 *valp = (*valp / rightval);
314 DO (cp = parse_product (g, cp + 1, &rightval));
315 *valp = (*valp % rightval);
323 parse_sum (g, cp, valp)
330 DO (cp = parse_product (g, cp, valp));
335 DO (cp = parse_sum (g, cp + 1, &rightval));
336 *valp = (*valp + rightval);
340 DO (cp = parse_sum (g, cp + 1, &rightval));
341 *valp = (*valp - rightval);
349 parse_shift (g, cp, valp)
356 DO (cp = parse_sum (g, cp, valp));
362 DO (cp = parse_shift (g, cp + 2, &rightval));
363 *valp = (*valp << rightval);
369 DO (cp = parse_shift (g, cp + 2, &rightval));
370 *valp = (*valp >> rightval);
379 parse_inequality (g, cp, valp)
386 DO (cp = parse_shift (g, cp, valp));
392 DO (cp = parse_inequality (g, cp + 2, &rightval));
393 *valp = (*valp <= rightval);
395 DO (cp = parse_inequality (g, cp + 1, &rightval));
396 *valp = (*valp < rightval);
402 DO (cp = parse_inequality (g, cp + 2, &rightval));
403 *valp = (*valp >= rightval);
405 DO (cp = parse_inequality (g, cp + 1, &rightval));
406 *valp = (*valp > rightval);
415 parse_equality (g, cp, valp)
422 DO (cp = parse_inequality (g, cp, valp));
429 DO (cp = parse_equality (g, cp + 1, &rightval));
430 *valp = (*valp == rightval);
436 DO (cp = parse_equality (g, cp + 2, &rightval));
437 *valp = (*valp != rightval);
445 parse_band (g, cp, valp)
452 DO (cp = parse_equality (g, cp, valp));
458 DO (cp = parse_band (g, cp + 1, &rightval));
459 *valp = (*valp & rightval);
468 parse_bor (g, cp, valp)
475 DO (cp = parse_band (g, cp, valp));
481 DO (cp = parse_bor (g, cp + 1, &rightval));
482 *valp = (*valp | rightval);
491 parse_land (g, cp, valp)
498 DO (cp = parse_bor (g, cp, valp));
504 return CALLFUNC(g, handle_error) (g, cp, "&&");
505 DO (cp = parse_land (g, cp + 2, &rightval));
506 *valp = (*valp && rightval);
514 parse_lor (g, cp, valp)
521 DO (cp = parse_land (g, cp, valp));
527 return CALLFUNC(g, handle_error) (g, cp, "||");
528 DO (cp = parse_lor (g, cp + 2, &rightval));
529 *valp = (*valp || rightval);
536 /****************************************************************************
537 External Entry Points
538 ****************************************************************************/
541 ParseIfExpression (g, cp, valp)
546 return parse_lor (g, cp, valp);