expr.y revision 77244 
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 77244 2001-05-26 20:45:25Z kris $
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 __P((quad_t, quad_t));
36int		chk_minus __P((quad_t, quad_t, quad_t));
37int		chk_plus __P((quad_t, quad_t, quad_t));
38int		chk_times __P((quad_t, quad_t, quad_t));
39void		free_value __P((struct val *));
40int		is_zero_or_null __P((struct val *));
41int		isstring __P((struct val *));
42int		main __P((int, char **));
43struct val	*make_integer __P((quad_t));
44struct val	*make_str __P((const char *));
45struct val	*op_and __P((struct val *, struct val *));
46struct val	*op_colon __P((struct val *, struct val *));
47struct val	*op_div __P((struct val *, struct val *));
48struct val	*op_eq __P((struct val *, struct val *));
49struct val	*op_ge __P((struct val *, struct val *));
50struct val	*op_gt __P((struct val *, struct val *));
51struct val	*op_le __P((struct val *, struct val *));
52struct val	*op_lt __P((struct val *, struct val *));
53struct val	*op_minus __P((struct val *, struct val *));
54struct val	*op_ne __P((struct val *, struct val *));
55struct val	*op_or __P((struct val *, struct val *));
56struct val	*op_plus __P((struct val *, struct val *));
57struct val	*op_rem __P((struct val *, struct val *));
58struct val	*op_times __P((struct val *, struct val *));
59quad_t		to_integer __P((struct val *));
60void		to_string __P((struct val *));
61int		yyerror __P((const char *));
62int		yylex __P((void));
63int		yyparse __P((void));
64
65char **av;
66%}
67
68%union
69{
70	struct val *val;
71}
72
73%left <val> '|'
74%left <val> '&'
75%left <val> '=' '>' '<' GE LE NE
76%left <val> '+' '-'
77%left <val> '*' '/' '%'
78%left <val> ':'
79
80%token <val> TOKEN
81%type <val> start expr
82
83%%
84
85start: expr { result = $$; }
86
87expr:	TOKEN
88	| '(' expr ')' { $$ = $2; }
89	| expr '|' expr { $$ = op_or ($1, $3); }
90	| expr '&' expr { $$ = op_and ($1, $3); }
91	| expr '=' expr { $$ = op_eq ($1, $3); }
92	| expr '>' expr { $$ = op_gt ($1, $3); }
93	| expr '<' expr { $$ = op_lt ($1, $3); }
94	| expr GE expr  { $$ = op_ge ($1, $3); }
95	| expr LE expr  { $$ = op_le ($1, $3); }
96	| expr NE expr  { $$ = op_ne ($1, $3); }
97	| expr '+' expr { $$ = op_plus ($1, $3); }
98	| expr '-' expr { $$ = op_minus ($1, $3); }
99	| expr '*' expr { $$ = op_times ($1, $3); }
100	| expr '/' expr { $$ = op_div ($1, $3); }
101	| expr '%' expr { $$ = op_rem ($1, $3); }
102	| expr ':' expr { $$ = op_colon ($1, $3); }
103	;
104
105
106%%
107
108struct val *
109make_integer (i)
110quad_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
124struct val *
125make_str (s)
126const char *s;
127{
128	struct val *vp;
129	size_t i;
130	int isint;
131
132	vp = (struct val *) malloc (sizeof (*vp));
133	if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
134		errx (2, "malloc() failed");
135	}
136
137	for(i = 1, isint = isdigit(s[0]) || s[0] == '-';
138	    isint && i < strlen(s);
139	    i++)
140	{
141		if(!isdigit(s[i]))
142			 isint = 0;
143	}
144
145	if (isint)
146		vp->type = numeric_string;
147	else
148		vp->type = string;
149
150	return vp;
151}
152
153
154void
155free_value (vp)
156struct val *vp;
157{
158	if (vp->type == string || vp->type == numeric_string)
159		free (vp->u.s);
160}
161
162
163quad_t
164to_integer (vp)
165struct val *vp;
166{
167	quad_t i;
168
169	if (vp->type == integer)
170		return 1;
171
172	if (vp->type == string)
173		return 0;
174
175	/* vp->type == numeric_string, make it numeric */
176	errno = 0;
177	i  = strtoq(vp->u.s, (char**)NULL, 10);
178	if (errno != 0) {
179		errx (2, "overflow");
180	}
181	free (vp->u.s);
182	vp->u.i = i;
183	vp->type = integer;
184	return 1;
185}
186
187void
188to_string (vp)
189struct val *vp;
190{
191	char *tmp;
192
193	if (vp->type == string || vp->type == numeric_string)
194		return;
195
196	tmp = malloc ((size_t)25);
197	if (tmp == NULL) {
198		errx (2, "malloc() failed");
199	}
200
201	sprintf (tmp, "%lld", (long long)vp->u.i);
202	vp->type = string;
203	vp->u.s  = tmp;
204}
205
206
207int
208isstring (vp)
209struct val *vp;
210{
211	/* only TRUE if this string is not a valid integer */
212	return (vp->type == string);
213}
214
215
216int
217yylex ()
218{
219	char *p;
220
221	if (*av == NULL)
222		return (0);
223
224	p = *av++;
225
226	if (strlen (p) == 1) {
227		if (strchr ("|&=<>+-*/%:()", *p))
228			return (*p);
229	} else if (strlen (p) == 2 && p[1] == '=') {
230		switch (*p) {
231		case '>': return (GE);
232		case '<': return (LE);
233		case '!': return (NE);
234		}
235	}
236
237	yylval.val = make_str (p);
238	return (TOKEN);
239}
240
241int
242is_zero_or_null (vp)
243struct val *vp;
244{
245	if (vp->type == integer) {
246		return (vp->u.i == 0);
247	} else {
248		return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));
249	}
250	/* NOTREACHED */
251}
252
253int
254main (argc, argv)
255int argc __unused;
256char **argv;
257{
258	setlocale (LC_ALL, "");
259
260	av = argv + 1;
261
262	yyparse ();
263
264	if (result->type == integer)
265		printf ("%lld\n", (long long)result->u.i);
266	else
267		printf ("%s\n", result->u.s);
268
269	return (is_zero_or_null (result));
270}
271
272int
273yyerror (s)
274const char *s __unused;
275{
276	errx (2, "syntax error");
277}
278
279
280struct val *
281op_or (a, b)
282struct val *a, *b;
283{
284	if (is_zero_or_null (a)) {
285		free_value (a);
286		return (b);
287	} else {
288		free_value (b);
289		return (a);
290	}
291}
292
293struct val *
294op_and (a, b)
295struct val *a, *b;
296{
297	if (is_zero_or_null (a) || is_zero_or_null (b)) {
298		free_value (a);
299		free_value (b);
300		return (make_integer ((quad_t)0));
301	} else {
302		free_value (b);
303		return (a);
304	}
305}
306
307struct val *
308op_eq (a, b)
309struct val *a, *b;
310{
311	struct val *r;
312
313	if (isstring (a) || isstring (b)) {
314		to_string (a);
315		to_string (b);
316		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) == 0));
317	} else {
318		(void)to_integer(a);
319		(void)to_integer(b);
320		r = make_integer ((quad_t)(a->u.i == b->u.i));
321	}
322
323	free_value (a);
324	free_value (b);
325	return r;
326}
327
328struct val *
329op_gt (a, b)
330struct val *a, *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		(void)to_integer(a);
340		(void)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
349struct val *
350op_lt (a, b)
351struct val *a, *b;
352{
353	struct val *r;
354
355	if (isstring (a) || isstring (b)) {
356		to_string (a);
357		to_string (b);
358		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) < 0));
359	} else {
360		(void)to_integer(a);
361		(void)to_integer(b);
362		r = make_integer ((quad_t)(a->u.i < b->u.i));
363	}
364
365	free_value (a);
366	free_value (b);
367	return r;
368}
369
370struct val *
371op_ge (a, b)
372struct val *a, *b;
373{
374	struct val *r;
375
376	if (isstring (a) || isstring (b)) {
377		to_string (a);
378		to_string (b);
379		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) >= 0));
380	} else {
381		(void)to_integer(a);
382		(void)to_integer(b);
383		r = make_integer ((quad_t)(a->u.i >= b->u.i));
384	}
385
386	free_value (a);
387	free_value (b);
388	return r;
389}
390
391struct val *
392op_le (a, b)
393struct val *a, *b;
394{
395	struct val *r;
396
397	if (isstring (a) || isstring (b)) {
398		to_string (a);
399		to_string (b);
400		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) <= 0));
401	} else {
402		(void)to_integer(a);
403		(void)to_integer(b);
404		r = make_integer ((quad_t)(a->u.i <= b->u.i));
405	}
406
407	free_value (a);
408	free_value (b);
409	return r;
410}
411
412struct val *
413op_ne (a, b)
414struct val *a, *b;
415{
416	struct val *r;
417
418	if (isstring (a) || isstring (b)) {
419		to_string (a);
420		to_string (b);
421		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) != 0));
422	} else {
423		(void)to_integer(a);
424		(void)to_integer(b);
425		r = make_integer ((quad_t)(a->u.i != b->u.i));
426	}
427
428	free_value (a);
429	free_value (b);
430	return r;
431}
432
433int
434chk_plus (a, b, r)
435quad_t a, b, r;
436{
437	/* sum of two positive numbers must be positive */
438	if (a > 0 && b > 0 && r <= 0)
439		return 1;
440	/* sum of two negative numbers must be negative */
441	if (a < 0 && b < 0 && r >= 0)
442		return 1;
443	/* all other cases are OK */
444	return 0;
445}
446
447struct val *
448op_plus (a, b)
449struct val *a, *b;
450{
451	struct val *r;
452
453	if (!to_integer (a) || !to_integer (b)) {
454		errx (2, "non-numeric argument");
455	}
456
457	r = make_integer (/*(quad_t)*/(a->u.i + b->u.i));
458	if (chk_plus (a->u.i, b->u.i, r->u.i)) {
459		errx (2, "overflow");
460	}
461	free_value (a);
462	free_value (b);
463	return r;
464}
465
466int
467chk_minus (a, b, r)
468quad_t a, b, r;
469{
470	/* special case subtraction of QUAD_MIN */
471	if (b == QUAD_MIN) {
472		if (a >= 0)
473			return 1;
474		else
475			return 0;
476	}
477	/* this is allowed for b != QUAD_MIN */
478	return chk_plus (a, -b, r);
479}
480
481struct val *
482op_minus (a, b)
483struct val *a, *b;
484{
485	struct val *r;
486
487	if (!to_integer (a) || !to_integer (b)) {
488		errx (2, "non-numeric argument");
489	}
490
491	r = make_integer (/*(quad_t)*/(a->u.i - b->u.i));
492	if (chk_minus (a->u.i, b->u.i, r->u.i)) {
493		errx (2, "overflow");
494	}
495	free_value (a);
496	free_value (b);
497	return r;
498}
499
500int
501chk_times (a, b, r)
502quad_t a, b, r;
503{
504	/* special case: first operand is 0, no overflow possible */
505	if (a == 0)
506		return 0;
507	/* cerify that result of division matches second operand */
508	if (r / a != b)
509		return 1;
510	return 0;
511}
512
513struct val *
514op_times (a, b)
515struct val *a, *b;
516{
517	struct val *r;
518
519	if (!to_integer (a) || !to_integer (b)) {
520		errx (2, "non-numeric argument");
521	}
522
523	r = make_integer (/*(quad_t)*/(a->u.i * b->u.i));
524	if (chk_times (a->u.i, b->u.i, r->u.i)) {
525		errx (2, "overflow");
526	}
527	free_value (a);
528	free_value (b);
529	return (r);
530}
531
532int
533chk_div (a, b)
534quad_t a, b;
535{
536	/* div by zero has been taken care of before */
537	/* only QUAD_MIN / -1 causes overflow */
538	if (a == QUAD_MIN && b == -1)
539		return 1;
540	/* everything else is OK */
541	return 0;
542}
543
544struct val *
545op_div (a, b)
546struct val *a, *b;
547{
548	struct val *r;
549
550	if (!to_integer (a) || !to_integer (b)) {
551		errx (2, "non-numeric argument");
552	}
553
554	if (b->u.i == 0) {
555		errx (2, "division by zero");
556	}
557
558	r = make_integer (/*(quad_t)*/(a->u.i / b->u.i));
559	if (chk_div (a->u.i, b->u.i)) {
560		errx (2, "overflow");
561	}
562	free_value (a);
563	free_value (b);
564	return r;
565}
566
567struct val *
568op_rem (a, b)
569struct val *a, *b;
570{
571	struct val *r;
572
573	if (!to_integer (a) || !to_integer (b)) {
574		errx (2, "non-numeric argument");
575	}
576
577	if (b->u.i == 0) {
578		errx (2, "division by zero");
579	}
580
581	r = make_integer (/*(quad_t)*/(a->u.i % b->u.i));
582	/* chk_rem necessary ??? */
583	free_value (a);
584	free_value (b);
585	return r;
586}
587
588struct val *
589op_colon (a, b)
590struct val *a, *b;
591{
592	regex_t rp;
593	regmatch_t rm[2];
594	char errbuf[256];
595	int eval;
596	struct val *v;
597
598	/* coerce to both arguments to strings */
599	to_string(a);
600	to_string(b);
601
602	/* compile regular expression */
603	if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
604		regerror (eval, &rp, errbuf, sizeof(errbuf));
605		errx (2, "%s", errbuf);
606	}
607
608	/* compare string against pattern */
609	/* remember that patterns are anchored to the beginning of the line */
610	if (regexec(&rp, a->u.s, (size_t)2, rm, 0) == 0 && rm[0].rm_so == 0) {
611		if (rm[1].rm_so >= 0) {
612			*(a->u.s + rm[1].rm_eo) = '\0';
613			v = make_str (a->u.s + rm[1].rm_so);
614
615		} else {
616			v = make_integer ((quad_t)(rm[0].rm_eo - rm[0].rm_so));
617		}
618	} else {
619		if (rp.re_nsub == 0) {
620			v = make_integer ((quad_t)0);
621		} else {
622			v = make_str ("");
623		}
624	}
625
626	/* free arguments and pattern buffer */
627	free_value (a);
628	free_value (b);
629	regfree (&rp);
630
631	return v;
632}
633