2 * CDE - Common Desktop Environment
4 * Copyright (c) 1993-2012, The Open Group. All rights reserved.
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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
86 /****************************************************************************
87 Internal Macros and Utilities for Parser
88 ****************************************************************************/
90 #define DO(val) if (!(val)) return NULL
91 #define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
92 #define SKIPSPACE(ccc) while (isspace(*ccc)) ccc++
93 #define isvarfirstletter(ccc) (isalpha(ccc) || (ccc) == '_')
97 parse_variable (g, cp, varp)
104 if (!isvarfirstletter (*cp))
105 return CALLFUNC(g, handle_error) (g, cp, "variable name");
109 for (cp++; isalnum(*cp) || *cp == '_'; cp++) ;
115 parse_number (g, cp, valp)
124 return CALLFUNC(g, handle_error) (g, cp, "number");
130 if ((*cp == 'x') || (*cp == 'X')) {
138 /* Ignore overflows and assume ASCII, what source is usually written in */
142 if ((*cp >= '0') && (*cp <= '7'))
143 increment = *cp++ - '0';
144 } else if (base == 16) {
145 if ((*cp >= '0') && (*cp <= '9'))
146 increment = *cp++ - '0';
147 else if ((*cp >= 'A') && (*cp <= 'F'))
148 increment = *cp++ - ('A' - 10);
149 else if ((*cp >= 'a') && (*cp <= 'f'))
150 increment = *cp++ - ('a' - 10);
151 } else { /* Decimal */
152 if ((*cp >= '0') && (*cp <= '9'))
153 increment = *cp++ - '0';
157 *valp = (*valp * base) + increment;
160 /* Skip trailing qualifiers */
161 while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++;
166 parse_character (g, cp, valp)
176 case 'n': val = '\n'; break;
177 case 't': val = '\t'; break;
178 case 'v': val = '\v'; break;
179 case 'b': val = '\b'; break;
180 case 'r': val = '\r'; break;
181 case 'f': val = '\f'; break;
182 case 'a': val = '\a'; break;
183 case '\\': val = '\\'; break;
184 case '?': val = '\?'; break;
185 case '\'': val = '\''; break;
186 case '\"': val = '\"'; break;
187 case 'x': val = (char) strtol (cp + 2, NULL, 16); break;
188 default: val = (char) strtol (cp + 1, NULL, 8); break;
192 while (*cp != '\'') cp++;
198 parse_value (g, cp, valp)
213 DO (cp = ParseIfExpression (g, cp + 1, valp));
216 return CALLFUNC(g, handle_error) (g, cp, ")");
218 return cp + 1; /* skip the right paren */
221 DO (cp = parse_value (g, cp + 1, valp));
226 DO (cp = parse_value (g, cp + 1, valp));
231 DO (cp = parse_variable (g, cp + 1, &var));
234 return CALLFUNC(g, handle_error) (g, cp, "(");
236 DO (cp = parse_variable (g, cp + 1, &var));
238 } while (*cp && *cp != ')');
240 return CALLFUNC(g, handle_error) (g, cp, ")");
245 DO (cp = parse_character (g, cp + 1, valp));
247 return CALLFUNC(g, handle_error) (g, cp, "'");
251 if (strncmp (cp, "defined", 7) == 0 && !isalnum(cp[7])) {
261 DO (cp = parse_variable (g, cp, &var));
264 if (paren && *cp != ')')
265 return CALLFUNC(g, handle_error) (g, cp, ")");
266 *valp = (*(g->funcs.eval_defined)) (g, var, len);
267 return cp + paren; /* skip the right paren */
273 DO (cp = parse_number (g, cp, valp));
274 } else if (!isvarfirstletter(*cp))
275 return CALLFUNC(g, handle_error) (g, cp, "variable or number");
277 DO (cp = parse_variable (g, cp, &var));
278 *valp = (*(g->funcs.eval_variable)) (g, var, cp - var);
287 parse_product (g, cp, valp)
294 DO (cp = parse_value (g, cp, valp));
299 DO (cp = parse_product (g, cp + 1, &rightval));
300 *valp = (*valp * rightval);
304 DO (cp = parse_product (g, cp + 1, &rightval));
306 *valp = (*valp / rightval);
312 DO (cp = parse_product (g, cp + 1, &rightval));
313 *valp = (*valp % rightval);
321 parse_sum (g, cp, valp)
328 DO (cp = parse_product (g, cp, valp));
333 DO (cp = parse_sum (g, cp + 1, &rightval));
334 *valp = (*valp + rightval);
338 DO (cp = parse_sum (g, cp + 1, &rightval));
339 *valp = (*valp - rightval);
347 parse_shift (g, cp, valp)
354 DO (cp = parse_sum (g, cp, valp));
360 DO (cp = parse_shift (g, cp + 2, &rightval));
361 *valp = (*valp << rightval);
367 DO (cp = parse_shift (g, cp + 2, &rightval));
368 *valp = (*valp >> rightval);
377 parse_inequality (g, cp, valp)
384 DO (cp = parse_shift (g, cp, valp));
390 DO (cp = parse_inequality (g, cp + 2, &rightval));
391 *valp = (*valp <= rightval);
393 DO (cp = parse_inequality (g, cp + 1, &rightval));
394 *valp = (*valp < rightval);
400 DO (cp = parse_inequality (g, cp + 2, &rightval));
401 *valp = (*valp >= rightval);
403 DO (cp = parse_inequality (g, cp + 1, &rightval));
404 *valp = (*valp > rightval);
413 parse_equality (g, cp, valp)
420 DO (cp = parse_inequality (g, cp, valp));
427 DO (cp = parse_equality (g, cp + 1, &rightval));
428 *valp = (*valp == rightval);
434 DO (cp = parse_equality (g, cp + 2, &rightval));
435 *valp = (*valp != rightval);
443 parse_band (g, cp, valp)
450 DO (cp = parse_equality (g, cp, valp));
456 DO (cp = parse_band (g, cp + 1, &rightval));
457 *valp = (*valp & rightval);
466 parse_bor (g, cp, valp)
473 DO (cp = parse_band (g, cp, valp));
479 DO (cp = parse_bor (g, cp + 1, &rightval));
480 *valp = (*valp | rightval);
489 parse_land (g, cp, valp)
496 DO (cp = parse_bor (g, cp, valp));
502 return CALLFUNC(g, handle_error) (g, cp, "&&");
503 DO (cp = parse_land (g, cp + 2, &rightval));
504 *valp = (*valp && rightval);
512 parse_lor (g, cp, valp)
519 DO (cp = parse_land (g, cp, valp));
525 return CALLFUNC(g, handle_error) (g, cp, "||");
526 DO (cp = parse_lor (g, cp + 2, &rightval));
527 *valp = (*valp || rightval);
534 /****************************************************************************
535 External Entry Points
536 ****************************************************************************/
539 ParseIfExpression (g, cp, valp)
544 return parse_lor (g, cp, valp);