expr.y revision 90109 
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: head/bin/expr/expr.y 90109 2002-02-02 06:36:49Z imp $
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
21enum valtype {
22	integer, numeric_string, string
23} ;
24
25struct val {
26	enum valtype type;
27	union {
28		char *s;
29		quad_t i;
30	} u;
31} ;
32
33struct val *result;
34
35int		chk_div(quad_t, quad_t);
36int		chk_minus(quad_t, quad_t, quad_t);
37int		chk_plus(quad_t, quad_t, quad_t);
38int		chk_times(quad_t, quad_t, quad_t);
39void		free_value(struct val *);
40int		is_zero_or_null(struct val *);
41int		isstring(struct val *);
42struct val	*make_integer(quad_t);
43struct val	*make_str(const char *);
44struct val	*op_and(struct val *, struct val *);
45struct val	*op_colon(struct val *, struct val *);
46struct val	*op_div(struct val *, struct val *);
47struct val	*op_eq(struct val *, struct val *);
48struct val	*op_ge(struct val *, struct val *);
49struct val	*op_gt(struct val *, struct val *);
50struct val	*op_le(struct val *, struct val *);
51struct val	*op_lt(struct val *, struct val *);
52struct val	*op_minus(struct val *, struct val *);
53struct val	*op_ne(struct val *, struct val *);
54struct val	*op_or(struct val *, struct val *);
55struct val	*op_plus(struct val *, struct val *);
56struct val	*op_rem(struct val *, struct val *);
57struct val	*op_times(struct val *, struct val *);
58quad_t		to_integer(struct val *);
59void		to_string(struct val *);
60int		yyerror(const char *);
61int		yylex(void);
62int		yyparse(void);
63
64char **av;
65%}
66
67%union
68{
69	struct val *val;
70}
71
72%left <val> '|'
73%left <val> '&'
74%left <val> '=' '>' '<' GE LE NE
75%left <val> '+' '-'
76%left <val> '*' '/' '%'
77%left <val> ':'
78
79%token <val> TOKEN
80%type <val> start expr
81
82%%
83
84start: expr { result = $$; }
85
86expr:	TOKEN
87	| '(' expr ')' { $$ = $2; }
88	| expr '|' expr { $$ = op_or ($1, $3); }
89	| expr '&' expr { $$ = op_and ($1, $3); }
90	| expr '=' expr { $$ = op_eq ($1, $3); }
91	| expr '>' expr { $$ = op_gt ($1, $3); }
92	| expr '<' expr { $$ = op_lt ($1, $3); }
93	| expr GE expr  { $$ = op_ge ($1, $3); }
94	| expr LE expr  { $$ = op_le ($1, $3); }
95	| expr NE expr  { $$ = op_ne ($1, $3); }
96	| expr '+' expr { $$ = op_plus ($1, $3); }
97	| expr '-' expr { $$ = op_minus ($1, $3); }
98	| expr '*' expr { $$ = op_times ($1, $3); }
99	| expr '/' expr { $$ = op_div ($1, $3); }
100	| expr '%' expr { $$ = op_rem ($1, $3); }
101	| expr ':' expr { $$ = op_colon ($1, $3); }
102	;
103
104
105%%
106
107struct val *
108make_integer(quad_t i)
109{
110	struct val *vp;
111
112	vp = (struct val *) malloc (sizeof (*vp));
113	if (vp == NULL) {
114		errx (2, "malloc() failed");
115	}
116
117	vp->type = integer;
118	vp->u.i  = i;
119	return vp;
120}
121
122struct val *
123make_str(const char *s)
124{
125	struct val *vp;
126	size_t i;
127	int isint;
128
129	vp = (struct val *) malloc (sizeof (*vp));
130	if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
131		errx (2, "malloc() failed");
132	}
133
134	for(i = 1, isint = isdigit(s[0]) || s[0] == '-';
135	    isint && i < strlen(s);
136	    i++)
137	{
138		if(!isdigit(s[i]))
139			 isint = 0;
140	}
141
142	if (isint)
143		vp->type = numeric_string;
144	else
145		vp->type = string;
146
147	return vp;
148}
149
150
151void
152free_value(struct val *vp)
153{
154	if (vp->type == string || vp->type == numeric_string)
155		free (vp->u.s);
156}
157
158
159quad_t
160to_integer(struct val *vp)
161{
162	quad_t i;
163
164	if (vp->type == integer)
165		return 1;
166
167	if (vp->type == string)
168		return 0;
169
170	/* vp->type == numeric_string, make it numeric */
171	errno = 0;
172	i  = strtoq(vp->u.s, (char**)NULL, 10);
173	if (errno != 0) {
174		errx (2, "overflow");
175	}
176	free (vp->u.s);
177	vp->u.i = i;
178	vp->type = integer;
179	return 1;
180}
181
182void
183to_string(struct val *vp)
184{
185	char *tmp;
186
187	if (vp->type == string || vp->type == numeric_string)
188		return;
189
190	tmp = malloc ((size_t)25);
191	if (tmp == NULL) {
192		errx (2, "malloc() failed");
193	}
194
195	sprintf (tmp, "%lld", (long long)vp->u.i);
196	vp->type = string;
197	vp->u.s  = tmp;
198}
199
200
201int
202isstring(struct val *vp)
203{
204	/* only TRUE if this string is not a valid integer */
205	return (vp->type == string);
206}
207
208
209int
210yylex(void)
211{
212	char *p;
213
214	if (*av == NULL)
215		return (0);
216
217	p = *av++;
218
219	if (strlen (p) == 1) {
220		if (strchr ("|&=<>+-*/%:()", *p))
221			return (*p);
222	} else if (strlen (p) == 2 && p[1] == '=') {
223		switch (*p) {
224		case '>': return (GE);
225		case '<': return (LE);
226		case '!': return (NE);
227		}
228	}
229
230	yylval.val = make_str (p);
231	return (TOKEN);
232}
233
234int
235is_zero_or_null(struct val *vp)
236{
237	if (vp->type == integer) {
238		return (vp->u.i == 0);
239	} else {
240		return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));
241	}
242	/* NOTREACHED */
243}
244
245int
246main(int argc __unused, char *argv[])
247{
248	setlocale (LC_ALL, "");
249
250	av = argv + 1;
251
252	yyparse ();
253
254	if (result->type == integer)
255		printf ("%lld\n", (long long)result->u.i);
256	else
257		printf ("%s\n", result->u.s);
258
259	return (is_zero_or_null (result));
260}
261
262int
263yyerror(const char *s __unused)
264{
265	errx (2, "syntax error");
266}
267
268
269struct val *
270op_or(struct val *a, struct val *b)
271{
272	if (is_zero_or_null (a)) {
273		free_value (a);
274		return (b);
275	} else {
276		free_value (b);
277		return (a);
278	}
279}
280
281struct val *
282op_and(struct val *a, struct val *b)
283{
284	if (is_zero_or_null (a) || is_zero_or_null (b)) {
285		free_value (a);
286		free_value (b);
287		return (make_integer ((quad_t)0));
288	} else {
289		free_value (b);
290		return (a);
291	}
292}
293
294struct val *
295op_eq(struct val *a, struct val *b)
296{
297	struct val *r;
298
299	if (isstring (a) || isstring (b)) {
300		to_string (a);
301		to_string (b);
302		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) == 0));
303	} else {
304		(void)to_integer(a);
305		(void)to_integer(b);
306		r = make_integer ((quad_t)(a->u.i == b->u.i));
307	}
308
309	free_value (a);
310	free_value (b);
311	return r;
312}
313
314struct val *
315op_gt(struct val *a, struct val *b)
316{
317	struct val *r;
318
319	if (isstring (a) || isstring (b)) {
320		to_string (a);
321		to_string (b);
322		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) > 0));
323	} else {
324		(void)to_integer(a);
325		(void)to_integer(b);
326		r = make_integer ((quad_t)(a->u.i > b->u.i));
327	}
328
329	free_value (a);
330	free_value (b);
331	return r;
332}
333
334struct val *
335op_lt(struct val *a, struct val *b)
336{
337	struct val *r;
338
339	if (isstring (a) || isstring (b)) {
340		to_string (a);
341		to_string (b);
342		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) < 0));
343	} else {
344		(void)to_integer(a);
345		(void)to_integer(b);
346		r = make_integer ((quad_t)(a->u.i < b->u.i));
347	}
348
349	free_value (a);
350	free_value (b);
351	return r;
352}
353
354struct val *
355op_ge(struct val *a, struct val *b)
356{
357	struct val *r;
358
359	if (isstring (a) || isstring (b)) {
360		to_string (a);
361		to_string (b);
362		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) >= 0));
363	} else {
364		(void)to_integer(a);
365		(void)to_integer(b);
366		r = make_integer ((quad_t)(a->u.i >= b->u.i));
367	}
368
369	free_value (a);
370	free_value (b);
371	return r;
372}
373
374struct val *
375op_le(struct val *a, struct val *b)
376{
377	struct val *r;
378
379	if (isstring (a) || isstring (b)) {
380		to_string (a);
381		to_string (b);
382		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) <= 0));
383	} else {
384		(void)to_integer(a);
385		(void)to_integer(b);
386		r = make_integer ((quad_t)(a->u.i <= b->u.i));
387	}
388
389	free_value (a);
390	free_value (b);
391	return r;
392}
393
394struct val *
395op_ne(struct val *a, struct val *b)
396{
397	struct val *r;
398
399	if (isstring (a) || isstring (b)) {
400		to_string (a);
401		to_string (b);
402		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) != 0));
403	} else {
404		(void)to_integer(a);
405		(void)to_integer(b);
406		r = make_integer ((quad_t)(a->u.i != b->u.i));
407	}
408
409	free_value (a);
410	free_value (b);
411	return r;
412}
413
414int
415chk_plus(quad_t a, quad_t b, quad_t r)
416{
417	/* sum of two positive numbers must be positive */
418	if (a > 0 && b > 0 && r <= 0)
419		return 1;
420	/* sum of two negative numbers must be negative */
421	if (a < 0 && b < 0 && r >= 0)
422		return 1;
423	/* all other cases are OK */
424	return 0;
425}
426
427struct val *
428op_plus(struct val *a, struct val *b)
429{
430	struct val *r;
431
432	if (!to_integer (a) || !to_integer (b)) {
433		errx (2, "non-numeric argument");
434	}
435
436	r = make_integer (/*(quad_t)*/(a->u.i + b->u.i));
437	if (chk_plus (a->u.i, b->u.i, r->u.i)) {
438		errx (2, "overflow");
439	}
440	free_value (a);
441	free_value (b);
442	return r;
443}
444
445int
446chk_minus(quad_t a, quad_t b, quad_t r)
447{
448	/* special case subtraction of QUAD_MIN */
449	if (b == QUAD_MIN) {
450		if (a >= 0)
451			return 1;
452		else
453			return 0;
454	}
455	/* this is allowed for b != QUAD_MIN */
456	return chk_plus (a, -b, r);
457}
458
459struct val *
460op_minus(struct val *a, struct val *b)
461{
462	struct val *r;
463
464	if (!to_integer (a) || !to_integer (b)) {
465		errx (2, "non-numeric argument");
466	}
467
468	r = make_integer (/*(quad_t)*/(a->u.i - b->u.i));
469	if (chk_minus (a->u.i, b->u.i, r->u.i)) {
470		errx (2, "overflow");
471	}
472	free_value (a);
473	free_value (b);
474	return r;
475}
476
477int
478chk_times(quad_t a, quad_t b, quad_t r)
479{
480	/* special case: first operand is 0, no overflow possible */
481	if (a == 0)
482		return 0;
483	/* cerify that result of division matches second operand */
484	if (r / a != b)
485		return 1;
486	return 0;
487}
488
489struct val *
490op_times(struct val *a, struct val *b)
491{
492	struct val *r;
493
494	if (!to_integer (a) || !to_integer (b)) {
495		errx (2, "non-numeric argument");
496	}
497
498	r = make_integer (/*(quad_t)*/(a->u.i * b->u.i));
499	if (chk_times (a->u.i, b->u.i, r->u.i)) {
500		errx (2, "overflow");
501	}
502	free_value (a);
503	free_value (b);
504	return (r);
505}
506
507int
508chk_div(quad_t a, quad_t b)
509{
510	/* div by zero has been taken care of before */
511	/* only QUAD_MIN / -1 causes overflow */
512	if (a == QUAD_MIN && b == -1)
513		return 1;
514	/* everything else is OK */
515	return 0;
516}
517
518struct val *
519op_div(struct val *a, struct val *b)
520{
521	struct val *r;
522
523	if (!to_integer (a) || !to_integer (b)) {
524		errx (2, "non-numeric argument");
525	}
526
527	if (b->u.i == 0) {
528		errx (2, "division by zero");
529	}
530
531	r = make_integer (/*(quad_t)*/(a->u.i / b->u.i));
532	if (chk_div (a->u.i, b->u.i)) {
533		errx (2, "overflow");
534	}
535	free_value (a);
536	free_value (b);
537	return r;
538}
539
540struct val *
541op_rem(struct val *a, struct val *b)
542{
543	struct val *r;
544
545	if (!to_integer (a) || !to_integer (b)) {
546		errx (2, "non-numeric argument");
547	}
548
549	if (b->u.i == 0) {
550		errx (2, "division by zero");
551	}
552
553	r = make_integer (/*(quad_t)*/(a->u.i % b->u.i));
554	/* chk_rem necessary ??? */
555	free_value (a);
556	free_value (b);
557	return r;
558}
559
560struct val *
561op_colon(struct val *a, struct val *b)
562{
563	regex_t rp;
564	regmatch_t rm[2];
565	char errbuf[256];
566	int eval;
567	struct val *v;
568
569	/* coerce to both arguments to strings */
570	to_string(a);
571	to_string(b);
572
573	/* compile regular expression */
574	if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
575		regerror (eval, &rp, errbuf, sizeof(errbuf));
576		errx (2, "%s", errbuf);
577	}
578
579	/* compare string against pattern */
580	/* remember that patterns are anchored to the beginning of the line */
581	if (regexec(&rp, a->u.s, (size_t)2, rm, 0) == 0 && rm[0].rm_so == 0) {
582		if (rm[1].rm_so >= 0) {
583			*(a->u.s + rm[1].rm_eo) = '\0';
584			v = make_str (a->u.s + rm[1].rm_so);
585
586		} else {
587			v = make_integer ((quad_t)(rm[0].rm_eo - rm[0].rm_so));
588		}
589	} else {
590		if (rp.re_nsub == 0) {
591			v = make_integer ((quad_t)0);
592		} else {
593			v = make_str ("");
594		}
595	}
596
597	/* free arguments and pattern buffer */
598	free_value (a);
599	free_value (b);
600	regfree (&rp);
601
602	return v;
603}
604