1 %{
2 /* Written by Pace Willisson (pace@blitz.com)
3 * and placed in the public domain.
4 *
5 * Largely rewritten by J.T. Conklin (jtc@wimsey.com)
6 *
7 * $FreeBSD: src/bin/expr/expr.y,v 1.14.2.3 2001/08/01 02:37:46 obrien Exp $
8 */
9
10 #include <sys/types.h>
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <string.h>
14 #include <locale.h>
15 #include <ctype.h>
16 #include <err.h>
17 #include <errno.h>
18 #include <regex.h>
19 #include <limits.h>
20
21 #define yylex expr_yylex
22
23 enum valtype {
24 integer, numeric_string, string
25 } ;
26
27 struct val {
28 enum valtype type;
29 union {
30 char *s;
31 quad_t i;
32 } u;
33 } ;
34
35 static struct val *result;
36
37 int chk_div (quad_t, quad_t);
38 int chk_minus (quad_t, quad_t, quad_t);
39 int chk_plus (quad_t, quad_t, quad_t);
40 int chk_times (quad_t, quad_t, quad_t);
41 void free_value (struct val *);
42 int is_zero_or_null (struct val *);
43 int isstring (struct val *);
44 int main (int, char **);
45 struct val *make_integer (quad_t);
46 struct val *make_str (const char *);
47 struct val *op_and (struct val *, struct val *);
48 struct val *op_colon (struct val *, struct val *);
49 struct val *op_div (struct val *, struct val *);
50 struct val *op_eq (struct val *, struct val *);
51 struct val *op_ge (struct val *, struct val *);
52 struct val *op_gt (struct val *, struct val *);
53 struct val *op_le (struct val *, struct val *);
54 struct val *op_lt (struct val *, struct val *);
55 struct val *op_minus (struct val *, struct val *);
56 struct val *op_ne (struct val *, struct val *);
57 struct val *op_or (struct val *, struct val *);
58 struct val *op_plus (struct val *, struct val *);
59 struct val *op_rem (struct val *, struct val *);
60 struct val *op_times (struct val *, struct val *);
61 quad_t to_integer (struct val *);
62 void to_string (struct val *);
63 int yyerror (const char *) __dead2;
64 static int yylex (void);
65
66 static char **av;
67 %}
68
69 %union
70 {
71 struct val *val;
72 }
73
74 %left <val> '|'
75 %left <val> '&'
76 %left <val> '=' '>' '<' GE LE NE
77 %left <val> '+' '-'
78 %left <val> '*' '/' '%'
79 %left <val> ':'
80
81 %token <val> TOKEN
82 %type <val> start expr
83
84 %%
85
86 start: expr { result = $$; }
87
88 expr: TOKEN
89 | '(' expr ')' { $$ = $2; }
90 | expr '|' expr { $$ = op_or ($1, $3); }
91 | expr '&' expr { $$ = op_and ($1, $3); }
92 | expr '=' expr { $$ = op_eq ($1, $3); }
93 | expr '>' expr { $$ = op_gt ($1, $3); }
94 | expr '<' expr { $$ = op_lt ($1, $3); }
95 | expr GE expr { $$ = op_ge ($1, $3); }
96 | expr LE expr { $$ = op_le ($1, $3); }
97 | expr NE expr { $$ = op_ne ($1, $3); }
98 | expr '+' expr { $$ = op_plus ($1, $3); }
99 | expr '-' expr { $$ = op_minus ($1, $3); }
100 | expr '*' expr { $$ = op_times ($1, $3); }
101 | expr '/' expr { $$ = op_div ($1, $3); }
102 | expr '%' expr { $$ = op_rem ($1, $3); }
103 | expr ':' expr { $$ = op_colon ($1, $3); }
104 ;
105
106
107 %%
108
109 struct val *
110 make_integer(quad_t i)
111 {
112 struct val *vp;
113
114 vp = (struct val *) malloc (sizeof (*vp));
115 if (vp == NULL) {
116 errx (2, "malloc() failed");
117 }
118
119 vp->type = integer;
120 vp->u.i = i;
121 return vp;
122 }
123
124 struct val *
make_str(const char * s)125 make_str(const char *s)
126 {
127 struct val *vp;
128 size_t i;
129 int isint;
130
131 vp = (struct val *) malloc (sizeof (*vp));
132 if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
133 errx (2, "malloc() failed");
134 }
135
136 for(i = 1, isint = isdigit(s[0]) || s[0] == '-';
137 isint && i < strlen(s);
138 i++)
139 {
140 if(!isdigit(s[i]))
141 isint = 0;
142 }
143
144 if (isint)
145 vp->type = numeric_string;
146 else
147 vp->type = string;
148
149 return vp;
150 }
151
152
153 void
free_value(struct val * vp)154 free_value(struct val *vp)
155 {
156 if (vp->type == string || vp->type == numeric_string)
157 free (vp->u.s);
158 }
159
160
161 quad_t
to_integer(struct val * vp)162 to_integer(struct val *vp)
163 {
164 quad_t i;
165
166 if (vp->type == integer)
167 return 1;
168
169 if (vp->type == string)
170 return 0;
171
172 /* vp->type == numeric_string, make it numeric */
173 errno = 0;
174 i = strtoll(vp->u.s, NULL, 10);
175 if (errno != 0) {
176 errx (2, "overflow");
177 }
178 free (vp->u.s);
179 vp->u.i = i;
180 vp->type = integer;
181 return 1;
182 }
183
184 void
to_string(struct val * vp)185 to_string(struct val *vp)
186 {
187 char *tmp;
188
189 if (vp->type == string || vp->type == numeric_string)
190 return;
191
192 tmp = malloc ((size_t)25);
193 if (tmp == NULL) {
194 errx (2, "malloc() failed");
195 }
196
197 sprintf (tmp, "%lld", (long long)vp->u.i);
198 vp->type = string;
199 vp->u.s = tmp;
200 }
201
202
203 int
isstring(struct val * vp)204 isstring(struct val *vp)
205 {
206 /* only TRUE if this string is not a valid integer */
207 return (vp->type == string);
208 }
209
210
211 static int
yylex(void)212 yylex(void)
213 {
214 char *p;
215
216 if (*av == NULL)
217 return (0);
218
219 p = *av++;
220
221 if (strlen (p) == 1) {
222 if (strchr ("|&=<>+-*/%:()", *p))
223 return (*p);
224 } else if (strlen (p) == 2 && p[1] == '=') {
225 switch (*p) {
226 case '>': return (GE);
227 case '<': return (LE);
228 case '!': return (NE);
229 }
230 }
231
232 yylval.val = make_str (p);
233 return (TOKEN);
234 }
235
236 int
is_zero_or_null(struct val * vp)237 is_zero_or_null(struct val *vp)
238 {
239 if (vp->type == integer) {
240 return (vp->u.i == 0);
241 } else {
242 return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));
243 }
244 /* NOTREACHED */
245 }
246
247 static void
usage(void)248 usage(void)
249 {
250 fprintf(stderr,
251 "usage: expr expression\n");
252 exit(EXIT_FAILURE);
253 }
254
255 int
main(int argc,char ** argv)256 main (int argc, char **argv)
257 {
258 setlocale (LC_ALL, "");
259
260 if (argc > 1 && strcmp(argv[1], "--"))
261 av = argv + 1;
262 else if (argc > 2)
263 av = argv + 2;
264 else
265 usage();
266
267 yyparse ();
268
269 if (result->type == integer)
270 printf ("%lld\n", (long long)result->u.i);
271 else
272 printf ("%s\n", result->u.s);
273
274 return (is_zero_or_null (result));
275 }
276
277 int
yyerror(const char * s __unused)278 yyerror(const char *s __unused)
279 {
280 errx (2, "syntax error");
281 }
282
283
284 struct val *
op_or(struct val * a,struct val * b)285 op_or(struct val *a, struct val *b)
286 {
287 if (is_zero_or_null (a)) {
288 free_value (a);
289 return (b);
290 } else {
291 free_value (b);
292 return (a);
293 }
294 }
295
296 struct val *
op_and(struct val * a,struct val * b)297 op_and(struct val *a, struct val *b)
298 {
299 if (is_zero_or_null (a) || is_zero_or_null (b)) {
300 free_value (a);
301 free_value (b);
302 return (make_integer ((quad_t)0));
303 } else {
304 free_value (b);
305 return (a);
306 }
307 }
308
309 struct val *
op_eq(struct val * a,struct val * b)310 op_eq(struct val *a, struct val *b)
311 {
312 struct val *r;
313
314 if (isstring (a) || isstring (b)) {
315 to_string (a);
316 to_string (b);
317 r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) == 0));
318 } else {
319 to_integer(a);
320 to_integer(b);
321 r = make_integer ((quad_t)(a->u.i == b->u.i));
322 }
323
324 free_value (a);
325 free_value (b);
326 return r;
327 }
328
329 struct val *
op_gt(struct val * a,struct val * b)330 op_gt(struct val *a, struct val *b)
331 {
332 struct val *r;
333
334 if (isstring (a) || isstring (b)) {
335 to_string (a);
336 to_string (b);
337 r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) > 0));
338 } else {
339 to_integer(a);
340 to_integer(b);
341 r = make_integer ((quad_t)(a->u.i > b->u.i));
342 }
343
344 free_value (a);
345 free_value (b);
346 return r;
347 }
348
349 struct val *
op_lt(struct val * a,struct val * b)350 op_lt(struct val *a, struct val *b)
351 {
352 struct val *r;
353
354 if (isstring (a) || isstring (b)) {
355 to_string (a);
356 to_string (b);
357 r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) < 0));
358 } else {
359 to_integer(a);
360 to_integer(b);
361 r = make_integer ((quad_t)(a->u.i < b->u.i));
362 }
363
364 free_value (a);
365 free_value (b);
366 return r;
367 }
368
369 struct val *
op_ge(struct val * a,struct val * b)370 op_ge(struct val *a, struct val *b)
371 {
372 struct val *r;
373
374 if (isstring (a) || isstring (b)) {
375 to_string (a);
376 to_string (b);
377 r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) >= 0));
378 } else {
379 to_integer(a);
380 to_integer(b);
381 r = make_integer ((quad_t)(a->u.i >= b->u.i));
382 }
383
384 free_value (a);
385 free_value (b);
386 return r;
387 }
388
389 struct val *
op_le(struct val * a,struct val * b)390 op_le(struct val *a, struct val *b)
391 {
392 struct val *r;
393
394 if (isstring (a) || isstring (b)) {
395 to_string (a);
396 to_string (b);
397 r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) <= 0));
398 } else {
399 to_integer(a);
400 to_integer(b);
401 r = make_integer ((quad_t)(a->u.i <= b->u.i));
402 }
403
404 free_value (a);
405 free_value (b);
406 return r;
407 }
408
409 struct val *
op_ne(struct val * a,struct val * b)410 op_ne(struct val *a, struct val *b)
411 {
412 struct val *r;
413
414 if (isstring (a) || isstring (b)) {
415 to_string (a);
416 to_string (b);
417 r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) != 0));
418 } else {
419 to_integer(a);
420 to_integer(b);
421 r = make_integer ((quad_t)(a->u.i != b->u.i));
422 }
423
424 free_value (a);
425 free_value (b);
426 return r;
427 }
428
429 int
chk_plus(quad_t a,quad_t b,quad_t r)430 chk_plus(quad_t a, quad_t b, quad_t r)
431 {
432 /* sum of two positive numbers must be positive */
433 if (a > 0 && b > 0 && r <= 0)
434 return 1;
435 /* sum of two negative numbers must be negative */
436 if (a < 0 && b < 0 && r >= 0)
437 return 1;
438 /* all other cases are OK */
439 return 0;
440 }
441
442 struct val *
op_plus(struct val * a,struct val * b)443 op_plus(struct val *a, struct val *b)
444 {
445 struct val *r;
446
447 if (!to_integer (a) || !to_integer (b)) {
448 errx (2, "non-numeric argument");
449 }
450
451 r = make_integer (/*(quad_t)*/(a->u.i + b->u.i));
452 if (chk_plus (a->u.i, b->u.i, r->u.i)) {
453 errx (2, "overflow");
454 }
455 free_value (a);
456 free_value (b);
457 return r;
458 }
459
460 int
chk_minus(quad_t a,quad_t b,quad_t r)461 chk_minus(quad_t a, quad_t b, quad_t r)
462 {
463 /* special case subtraction of QUAD_MIN */
464 if (b == QUAD_MIN) {
465 if (a >= 0)
466 return 1;
467 else
468 return 0;
469 }
470 /* this is allowed for b != QUAD_MIN */
471 return chk_plus (a, -b, r);
472 }
473
474 struct val *
op_minus(struct val * a,struct val * b)475 op_minus(struct val *a, struct val *b)
476 {
477 struct val *r;
478
479 if (!to_integer (a) || !to_integer (b)) {
480 errx (2, "non-numeric argument");
481 }
482
483 r = make_integer (/*(quad_t)*/(a->u.i - b->u.i));
484 if (chk_minus (a->u.i, b->u.i, r->u.i)) {
485 errx (2, "overflow");
486 }
487 free_value (a);
488 free_value (b);
489 return r;
490 }
491
492 int
chk_times(quad_t a,quad_t b,quad_t r)493 chk_times(quad_t a, quad_t b, quad_t r)
494 {
495 /* special case: first operand is 0, no overflow possible */
496 if (a == 0)
497 return 0;
498 /* cerify that result of division matches second operand */
499 if (r / a != b)
500 return 1;
501 return 0;
502 }
503
504 struct val *
op_times(struct val * a,struct val * b)505 op_times(struct val *a, struct val *b)
506 {
507 struct val *r;
508
509 if (!to_integer (a) || !to_integer (b)) {
510 errx (2, "non-numeric argument");
511 }
512
513 r = make_integer (/*(quad_t)*/(a->u.i * b->u.i));
514 if (chk_times (a->u.i, b->u.i, r->u.i)) {
515 errx (2, "overflow");
516 }
517 free_value (a);
518 free_value (b);
519 return (r);
520 }
521
522 int
chk_div(quad_t a,quad_t b)523 chk_div(quad_t a, quad_t b)
524 {
525 /* div by zero has been taken care of before */
526 /* only QUAD_MIN / -1 causes overflow */
527 if (a == QUAD_MIN && b == -1)
528 return 1;
529 /* everything else is OK */
530 return 0;
531 }
532
533 struct val *
op_div(struct val * a,struct val * b)534 op_div(struct val *a, struct val *b)
535 {
536 struct val *r;
537
538 if (!to_integer (a) || !to_integer (b)) {
539 errx (2, "non-numeric argument");
540 }
541
542 if (b->u.i == 0) {
543 errx (2, "division by zero");
544 }
545
546 r = make_integer (/*(quad_t)*/(a->u.i / b->u.i));
547 if (chk_div (a->u.i, b->u.i)) {
548 errx (2, "overflow");
549 }
550 free_value (a);
551 free_value (b);
552 return r;
553 }
554
555 struct val *
op_rem(struct val * a,struct val * b)556 op_rem(struct val *a, struct val *b)
557 {
558 struct val *r;
559
560 if (!to_integer (a) || !to_integer (b)) {
561 errx (2, "non-numeric argument");
562 }
563
564 if (b->u.i == 0) {
565 errx (2, "division by zero");
566 }
567
568 r = make_integer (/*(quad_t)*/(a->u.i % b->u.i));
569 /* chk_rem necessary ??? */
570 free_value (a);
571 free_value (b);
572 return r;
573 }
574
575 struct val *
op_colon(struct val * a,struct val * b)576 op_colon(struct val *a, struct val *b)
577 {
578 regex_t rp;
579 regmatch_t rm[2];
580 char errbuf[256];
581 int eval;
582 struct val *v;
583
584 /* coerce to both arguments to strings */
585 to_string(a);
586 to_string(b);
587
588 /* compile regular expression */
589 if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
590 regerror (eval, &rp, errbuf, sizeof(errbuf));
591 errx (2, "%s", errbuf);
592 }
593
594 /* compare string against pattern */
595 /* remember that patterns are anchored to the beginning of the line */
596 if (regexec(&rp, a->u.s, (size_t)2, rm, 0) == 0 && rm[0].rm_so == 0) {
597 if (rm[1].rm_so >= 0) {
598 *(a->u.s + rm[1].rm_eo) = '\0';
599 v = make_str (a->u.s + rm[1].rm_so);
600
601 } else {
602 v = make_integer ((quad_t)(rm[0].rm_eo - rm[0].rm_so));
603 }
604 } else {
605 if (rp.re_nsub == 0) {
606 v = make_integer ((quad_t)0);
607 } else {
608 v = make_str ("");
609 }
610 }
611
612 /* free arguments and pattern buffer */
613 free_value (a);
614 free_value (b);
615 regfree (&rp);
616
617 return v;
618 }
619