1 /*
2 * $Xorg: ifparser.c,v 1.3 2000/08/17 19:41:50 cpqbld Exp $
3 *
4 * Copyright 1992 Network Computing Devices, Inc.
5 *
6 * Permission to use, copy, modify, and distribute this software and its
7 * documentation for any purpose and without fee is hereby granted, provided
8 * that the above copyright notice appear in all copies and that both that
9 * copyright notice and this permission notice appear in supporting
10 * documentation, and that the name of Network Computing Devices may not be
11 * used in advertising or publicity pertaining to distribution of the software
12 * without specific, written prior permission. Network Computing Devices makes
13 * no representations about the suitability of this software for any purpose.
14 * It is provided ``as is'' without express or implied warranty.
15 *
16 * NETWORK COMPUTING DEVICES DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
17 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
18 * IN NO EVENT SHALL NETWORK COMPUTING DEVICES BE LIABLE FOR ANY SPECIAL,
19 * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
20 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
21 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
22 * PERFORMANCE OF THIS SOFTWARE.
23 *
24 * Author: Jim Fulton
25 * Network Computing Devices, Inc.
26 *
27 * Simple if statement processor
28 *
29 * This module can be used to evaluate string representations of C language
30 * if constructs. It accepts the following grammar:
31 *
32 * EXPRESSION := VALUE
33 * | VALUE BINOP EXPRESSION
34 * | VALUE '?' EXPRESSION ':' EXPRESSION
35 *
36 * VALUE := '(' EXPRESSION ')'
37 * | '!' VALUE
38 * | '-' VALUE
39 * | '+' VALUE
40 * | '~' VALUE
41 * | 'defined' '(' variable ')'
42 * | 'defined' variable
43 * | # variable '(' variable-list ')'
44 * | variable
45 * | number
46 *
47 * BINOP := '*' | '/' | '%'
48 * | '+' | '-'
49 * | '<<' | '>>'
50 * | '<' | '>' | '<=' | '>='
51 * | '==' | '!='
52 * | '&' | '^' | '|'
53 * | '&&' | '||'
54 *
55 * The normal C order of precedence is supported.
56 *
57 *
58 * External Entry Points:
59 *
60 * ParseIfExpression parse a string for #if
61 */
62 /* $XFree86: xc/config/makedepend/ifparser.c,v 3.11 2002/09/23 01:48:08 tsi Exp $ */
63
64 #include "ifparser.h"
65 #include <ctype.h>
66 #include <stdlib.h>
67 #include <string.h>
68
69 /****************************************************************************
70 Internal Macros and Utilities for Parser
71 ****************************************************************************/
72
73 #define DO(val) if (!(val)) return NULL
74 #define CALLFUNC(ggg,fff) (*((ggg)->funcs.fff))
75 #define SKIPSPACE(ccc) while (isspace(*ccc)) ccc++
76 #define isvarfirstletter(ccc) (isalpha(ccc) || (ccc) == '_')
77
78
79 static const char *
parse_variable(IfParser * g,const char * cp,const char ** varp)80 parse_variable (IfParser *g, const char *cp, const char **varp)
81 {
82 SKIPSPACE (cp);
83
84 if (!isvarfirstletter (*cp))
85 return CALLFUNC(g, handle_error) (g, cp, "variable name");
86
87 *varp = cp;
88 /* EMPTY */
89 for (cp++; isalnum(*cp) || *cp == '_'; cp++) ;
90 return cp;
91 }
92
93
94 static const char *
parse_number(IfParser * g,const char * cp,long * valp)95 parse_number (IfParser *g, const char *cp, long *valp)
96 {
97 long base = 10;
98 SKIPSPACE (cp);
99
100 if (!isdigit(*cp))
101 return CALLFUNC(g, handle_error) (g, cp, "number");
102
103 *valp = 0;
104
105 if (*cp == '0') {
106 cp++;
107 if ((*cp == 'x') || (*cp == 'X')) {
108 base = 16;
109 cp++;
110 } else {
111 base = 8;
112 }
113 }
114
115 /* Ignore overflows and assume ASCII, what source is usually written in */
116 while (1) {
117 int increment = -1;
118 if (base == 8) {
119 if ((*cp >= '0') && (*cp <= '7'))
120 increment = *cp++ - '0';
121 } else if (base == 16) {
122 if ((*cp >= '0') && (*cp <= '9'))
123 increment = *cp++ - '0';
124 else if ((*cp >= 'A') && (*cp <= 'F'))
125 increment = *cp++ - ('A' - 10);
126 else if ((*cp >= 'a') && (*cp <= 'f'))
127 increment = *cp++ - ('a' - 10);
128 } else { /* Decimal */
129 if ((*cp >= '0') && (*cp <= '9'))
130 increment = *cp++ - '0';
131 }
132 if (increment < 0)
133 break;
134 *valp = (*valp * base) + increment;
135 }
136
137 /* Skip trailing qualifiers */
138 while (*cp == 'U' || *cp == 'u' || *cp == 'L' || *cp == 'l') cp++;
139 return cp;
140 }
141
142 static const char *
parse_character(IfParser * g,const char * cp,long * valp)143 parse_character (IfParser *g, const char *cp, long *valp)
144 {
145 char val;
146
147 SKIPSPACE (cp);
148 if (*cp == '\\')
149 switch (cp[1]) {
150 case 'n': val = '\n'; break;
151 case 't': val = '\t'; break;
152 case 'v': val = '\v'; break;
153 case 'b': val = '\b'; break;
154 case 'r': val = '\r'; break;
155 case 'f': val = '\f'; break;
156 case 'a': val = '\a'; break;
157 case '\\': val = '\\'; break;
158 case '?': val = '\?'; break;
159 case '\'': val = '\''; break;
160 case '\"': val = '\"'; break;
161 case 'x': val = (char) strtol (cp + 2, NULL, 16); break;
162 default: val = (char) strtol (cp + 1, NULL, 8); break;
163 }
164 else
165 val = *cp;
166 while (*cp != '\'') cp++;
167 *valp = (long) val;
168 return cp;
169 }
170
171 static const char *
parse_value(IfParser * g,const char * cp,long * valp)172 parse_value (IfParser *g, const char *cp, long *valp)
173 {
174 const char *var, *varend;
175
176 *valp = 0;
177
178 SKIPSPACE (cp);
179 if (!*cp)
180 return cp;
181
182 switch (*cp) {
183 case '(':
184 DO (cp = ParseIfExpression (g, cp + 1, valp));
185 SKIPSPACE (cp);
186 if (*cp != ')')
187 return CALLFUNC(g, handle_error) (g, cp, ")");
188
189 return cp + 1; /* skip the right paren */
190
191 case '!':
192 DO (cp = parse_value (g, cp + 1, valp));
193 *valp = !(*valp);
194 return cp;
195
196 case '-':
197 DO (cp = parse_value (g, cp + 1, valp));
198 *valp = -(*valp);
199 return cp;
200
201 case '+':
202 DO (cp = parse_value (g, cp + 1, valp));
203 return cp;
204
205 case '~':
206 DO (cp = parse_value (g, cp + 1, valp));
207 *valp = ~(*valp);
208 return cp;
209
210 case '#':
211 DO (cp = parse_variable (g, cp + 1, &var));
212 SKIPSPACE (cp);
213 if (*cp != '(')
214 return CALLFUNC(g, handle_error) (g, cp, "(");
215 do {
216 DO (cp = parse_variable (g, cp + 1, &var));
217 SKIPSPACE (cp);
218 } while (*cp && *cp != ')');
219 if (*cp != ')')
220 return CALLFUNC(g, handle_error) (g, cp, ")");
221 *valp = 1; /* XXX */
222 return cp + 1;
223
224 case '\'':
225 DO (cp = parse_character (g, cp + 1, valp));
226 if (*cp != '\'')
227 return CALLFUNC(g, handle_error) (g, cp, "'");
228 return cp + 1;
229
230 case 'd':
231 if (strncmp (cp, "defined", 7) == 0 && !isalnum(cp[7])) {
232 int paren = 0;
233 int len;
234
235 cp += 7;
236 SKIPSPACE (cp);
237 if (*cp == '(') {
238 paren = 1;
239 cp++;
240 }
241 DO (cp = parse_variable (g, cp, &var));
242 len = cp - var;
243 SKIPSPACE (cp);
244 if (paren && *cp != ')')
245 return CALLFUNC(g, handle_error) (g, cp, ")");
246 *valp = (*(g->funcs.eval_defined)) (g, var, len);
247 return cp + paren; /* skip the right paren */
248 }
249 /* fall out */
250 }
251
252 if (isdigit(*cp)) {
253 DO (cp = parse_number (g, cp, valp));
254 } else if (!isvarfirstletter(*cp))
255 return CALLFUNC(g, handle_error) (g, cp, "variable or number");
256 else {
257 DO (cp = parse_variable (g, cp, &var));
258 varend = cp;
259 SKIPSPACE(cp);
260 if (*cp != '(') {
261 *valp = (*(g->funcs.eval_variable)) (g, var, varend - var);
262 } else {
263 do {
264 long dummy;
265 DO (cp = ParseIfExpression (g, cp + 1, &dummy));
266 SKIPSPACE(cp);
267 if (*cp == ')')
268 break;
269 if (*cp != ',')
270 return CALLFUNC(g, handle_error) (g, cp, ",");
271 } while (1);
272
273 *valp = 1; /* XXX */
274 cp++;
275 }
276 }
277
278 return cp;
279 }
280
281
282
283 static const char *
parse_product(IfParser * g,const char * cp,long * valp)284 parse_product (IfParser *g, const char *cp, long *valp)
285 {
286 long rightval;
287
288 DO (cp = parse_value (g, cp, valp));
289 SKIPSPACE (cp);
290
291 switch (*cp) {
292 case '*':
293 DO (cp = parse_product (g, cp + 1, &rightval));
294 *valp = (*valp * rightval);
295 break;
296
297 case '/':
298 DO (cp = parse_product (g, cp + 1, &rightval));
299 if (rightval == 0)
300 return CALLFUNC(g, handle_error) (g, cp, "0");
301 *valp = (*valp / rightval);
302 break;
303
304 case '%':
305 DO (cp = parse_product (g, cp + 1, &rightval));
306 *valp = (*valp % rightval);
307 break;
308 }
309 return cp;
310 }
311
312
313 static const char *
parse_sum(IfParser * g,const char * cp,long * valp)314 parse_sum (IfParser *g, const char *cp, long *valp)
315 {
316 long rightval;
317
318 DO (cp = parse_product (g, cp, valp));
319 SKIPSPACE (cp);
320
321 switch (*cp) {
322 case '+':
323 DO (cp = parse_sum (g, cp + 1, &rightval));
324 *valp = (*valp + rightval);
325 break;
326
327 case '-':
328 DO (cp = parse_sum (g, cp + 1, &rightval));
329 *valp = (*valp - rightval);
330 break;
331 }
332 return cp;
333 }
334
335
336 static const char *
parse_shift(IfParser * g,const char * cp,long * valp)337 parse_shift (IfParser *g, const char *cp, long *valp)
338 {
339 long rightval;
340
341 DO (cp = parse_sum (g, cp, valp));
342 SKIPSPACE (cp);
343
344 switch (*cp) {
345 case '<':
346 if (cp[1] == '<') {
347 DO (cp = parse_shift (g, cp + 2, &rightval));
348 *valp = (*valp << rightval);
349 }
350 break;
351
352 case '>':
353 if (cp[1] == '>') {
354 DO (cp = parse_shift (g, cp + 2, &rightval));
355 *valp = (*valp >> rightval);
356 }
357 break;
358 }
359 return cp;
360 }
361
362
363 static const char *
parse_inequality(IfParser * g,const char * cp,long * valp)364 parse_inequality (IfParser *g, const char *cp, long *valp)
365 {
366 long rightval;
367
368 DO (cp = parse_shift (g, cp, valp));
369 SKIPSPACE (cp);
370
371 switch (*cp) {
372 case '<':
373 if (cp[1] == '=') {
374 DO (cp = parse_inequality (g, cp + 2, &rightval));
375 *valp = (*valp <= rightval);
376 } else {
377 DO (cp = parse_inequality (g, cp + 1, &rightval));
378 *valp = (*valp < rightval);
379 }
380 break;
381
382 case '>':
383 if (cp[1] == '=') {
384 DO (cp = parse_inequality (g, cp + 2, &rightval));
385 *valp = (*valp >= rightval);
386 } else {
387 DO (cp = parse_inequality (g, cp + 1, &rightval));
388 *valp = (*valp > rightval);
389 }
390 break;
391 }
392 return cp;
393 }
394
395
396 static const char *
parse_equality(IfParser * g,const char * cp,long * valp)397 parse_equality (IfParser *g, const char *cp, long *valp)
398 {
399 long rightval;
400
401 DO (cp = parse_inequality (g, cp, valp));
402 SKIPSPACE (cp);
403
404 switch (*cp) {
405 case '=':
406 if (cp[1] == '=')
407 cp++;
408 DO (cp = parse_equality (g, cp + 1, &rightval));
409 *valp = (*valp == rightval);
410 break;
411
412 case '!':
413 if (cp[1] != '=')
414 break;
415 DO (cp = parse_equality (g, cp + 2, &rightval));
416 *valp = (*valp != rightval);
417 break;
418 }
419 return cp;
420 }
421
422
423 static const char *
parse_band(IfParser * g,const char * cp,long * valp)424 parse_band (IfParser *g, const char *cp, long *valp)
425 {
426 long rightval;
427
428 DO (cp = parse_equality (g, cp, valp));
429 SKIPSPACE (cp);
430
431 switch (*cp) {
432 case '&':
433 if (cp[1] != '&') {
434 DO (cp = parse_band (g, cp + 1, &rightval));
435 *valp = (*valp & rightval);
436 }
437 break;
438 }
439 return cp;
440 }
441
442
443 static const char *
parse_bxor(IfParser * g,const char * cp,long * valp)444 parse_bxor (IfParser *g, const char *cp, long *valp)
445 {
446 long rightval;
447
448 DO (cp = parse_band (g, cp, valp));
449 SKIPSPACE (cp);
450
451 switch (*cp) {
452 case '^':
453 DO (cp = parse_bxor (g, cp + 1, &rightval));
454 *valp = (*valp ^ rightval);
455 break;
456 }
457 return cp;
458 }
459
460
461 static const char *
parse_bor(IfParser * g,const char * cp,long * valp)462 parse_bor (IfParser *g, const char *cp, long *valp)
463 {
464 long rightval;
465
466 DO (cp = parse_bxor (g, cp, valp));
467 SKIPSPACE (cp);
468
469 switch (*cp) {
470 case '|':
471 if (cp[1] != '|') {
472 DO (cp = parse_bor (g, cp + 1, &rightval));
473 *valp = (*valp | rightval);
474 }
475 break;
476 }
477 return cp;
478 }
479
480
481 static const char *
parse_land(IfParser * g,const char * cp,long * valp)482 parse_land (IfParser *g, const char *cp, long *valp)
483 {
484 long rightval;
485
486 DO (cp = parse_bor (g, cp, valp));
487 SKIPSPACE (cp);
488
489 switch (*cp) {
490 case '&':
491 if (cp[1] != '&')
492 return CALLFUNC(g, handle_error) (g, cp, "&&");
493 DO (cp = parse_land (g, cp + 2, &rightval));
494 *valp = (*valp && rightval);
495 break;
496 }
497 return cp;
498 }
499
500
501 static const char *
parse_lor(IfParser * g,const char * cp,long * valp)502 parse_lor (IfParser *g, const char *cp, long *valp)
503 {
504 long rightval;
505
506 DO (cp = parse_land (g, cp, valp));
507 SKIPSPACE (cp);
508
509 switch (*cp) {
510 case '|':
511 if (cp[1] != '|')
512 return CALLFUNC(g, handle_error) (g, cp, "||");
513 DO (cp = parse_lor (g, cp + 2, &rightval));
514 *valp = (*valp || rightval);
515 break;
516 }
517 return cp;
518 }
519
520
521 static const char *
parse_cond(IfParser * g,const char * cp,long * valp)522 parse_cond(IfParser *g, const char *cp, long *valp)
523 {
524 long trueval, falseval;
525
526 DO (cp = parse_lor (g, cp, valp));
527 SKIPSPACE (cp);
528
529 switch (*cp) {
530 case '?':
531 DO (cp = parse_cond (g, cp + 1, &trueval));
532 SKIPSPACE (cp);
533 if (*cp != ':')
534 return CALLFUNC(g, handle_error) (g, cp, ":");
535 DO (cp = parse_cond (g, cp + 1, &falseval));
536 *valp = (*valp ? trueval : falseval);
537 break;
538 }
539 return cp;
540 }
541
542
543 /****************************************************************************
544 External Entry Points
545 ****************************************************************************/
546
547 const char *
ParseIfExpression(IfParser * g,const char * cp,long * valp)548 ParseIfExpression (IfParser *g, const char *cp, long *valp)
549 {
550 return parse_cond (g, cp, valp);
551 }
552