expr.y revision 63755 
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 63755 2000-07-22 10:59:36Z se $
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;
34struct val *op_or ();
35struct val *op_and ();
36struct val *op_eq ();
37struct val *op_gt ();
38struct val *op_lt ();
39struct val *op_ge ();
40struct val *op_le ();
41struct val *op_ne ();
42struct val *op_plus ();
43struct val *op_minus ();
44struct val *op_times ();
45struct val *op_div ();
46struct val *op_rem ();
47struct val *op_colon ();
48
49char **av;
50%}
51
52%union
53{
54	struct val *val;
55}
56
57%left <val> '|'
58%left <val> '&'
59%left <val> '=' '>' '<' GE LE NE
60%left <val> '+' '-'
61%left <val> '*' '/' '%'
62%left <val> ':'
63
64%token <val> TOKEN
65%type <val> start expr
66
67%%
68
69start: expr { result = $$; }
70
71expr:	TOKEN
72	| '(' expr ')' { $$ = $2; }
73	| expr '|' expr { $$ = op_or ($1, $3); }
74	| expr '&' expr { $$ = op_and ($1, $3); }
75	| expr '=' expr { $$ = op_eq ($1, $3); }
76	| expr '>' expr { $$ = op_gt ($1, $3); }
77	| expr '<' expr { $$ = op_lt ($1, $3); }
78	| expr GE expr  { $$ = op_ge ($1, $3); }
79	| expr LE expr  { $$ = op_le ($1, $3); }
80	| expr NE expr  { $$ = op_ne ($1, $3); }
81	| expr '+' expr { $$ = op_plus ($1, $3); }
82	| expr '-' expr { $$ = op_minus ($1, $3); }
83	| expr '*' expr { $$ = op_times ($1, $3); }
84	| expr '/' expr { $$ = op_div ($1, $3); }
85	| expr '%' expr { $$ = op_rem ($1, $3); }
86	| expr ':' expr { $$ = op_colon ($1, $3); }
87	;
88
89
90%%
91
92struct val *
93make_integer (i)
94quad_t i;
95{
96	struct val *vp;
97
98	vp = (struct val *) malloc (sizeof (*vp));
99	if (vp == NULL) {
100		errx (2, "malloc() failed");
101	}
102
103	vp->type = integer;
104	vp->u.i  = i;
105	return vp;
106}
107
108struct val *
109make_str (s)
110char *s;
111{
112	struct val *vp;
113	int i, isint;
114
115	vp = (struct val *) malloc (sizeof (*vp));
116	if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
117		errx (2, "malloc() failed");
118	}
119
120	for(i = 1, isint = isdigit(s[0]) || s[0] == '-';
121	    isint && i < strlen(s);
122	    i++)
123	{
124		if(!isdigit(s[i]))
125			 isint = 0;
126	}
127
128	if (isint)
129		vp->type = numeric_string;
130	else
131		vp->type = string;
132
133	return vp;
134}
135
136
137void
138free_value (vp)
139struct val *vp;
140{
141	if (vp->type == string || vp->type == numeric_string)
142		free (vp->u.s);
143}
144
145
146quad_t
147to_integer (vp)
148struct val *vp;
149{
150	quad_t i;
151
152	if (vp->type == integer)
153		return 1;
154
155	if (vp->type == string)
156		return 0;
157
158	/* vp->type == numeric_string, make it numeric */
159	errno = 0;
160	i  = strtoq(vp->u.s, (char**)NULL, 10);
161	if (errno != 0) {
162		errx (2, "overflow");
163	}
164	free (vp->u.s);
165	vp->u.i = i;
166	vp->type = integer;
167	return 1;
168}
169
170void
171to_string (vp)
172struct val *vp;
173{
174	char *tmp;
175
176	if (vp->type == string || vp->type == numeric_string)
177		return;
178
179	tmp = malloc (25);
180	if (tmp == NULL) {
181		errx (2, "malloc() failed");
182	}
183
184	sprintf (tmp, "%qd", vp->u.i);
185	vp->type = string;
186	vp->u.s  = tmp;
187}
188
189
190int
191isstring (vp)
192struct val *vp;
193{
194	/* only TRUE if this string is not a valid integer */
195	return (vp->type == string);
196}
197
198
199int
200yylex ()
201{
202	char *p;
203
204	if (*av == NULL)
205		return (0);
206
207	p = *av++;
208
209	if (strlen (p) == 1) {
210		if (strchr ("|&=<>+-*/%:()", *p))
211			return (*p);
212	} else if (strlen (p) == 2 && p[1] == '=') {
213		switch (*p) {
214		case '>': return (GE);
215		case '<': return (LE);
216		case '!': return (NE);
217		}
218	}
219
220	yylval.val = make_str (p);
221	return (TOKEN);
222}
223
224int
225is_zero_or_null (vp)
226struct val *vp;
227{
228	if (vp->type == integer) {
229		return (vp->u.i == 0);
230	} else {
231		return (*vp->u.s == 0 || (to_integer (vp) && vp->u.i == 0));
232	}
233	/* NOTREACHED */
234}
235
236int yyparse ();
237
238int
239main (argc, argv)
240int argc;
241char **argv;
242{
243	setlocale (LC_ALL, "");
244
245	av = argv + 1;
246
247	yyparse ();
248
249	if (result->type == integer)
250		printf ("%qd\n", result->u.i);
251	else
252		printf ("%s\n", result->u.s);
253
254	return (is_zero_or_null (result));
255}
256
257int
258yyerror (s)
259char *s;
260{
261	errx (2, "syntax error");
262}
263
264
265struct val *
266op_or (a, b)
267struct val *a, *b;
268{
269	if (is_zero_or_null (a)) {
270		free_value (a);
271		return (b);
272	} else {
273		free_value (b);
274		return (a);
275	}
276}
277
278struct val *
279op_and (a, b)
280struct val *a, *b;
281{
282	if (is_zero_or_null (a) || is_zero_or_null (b)) {
283		free_value (a);
284		free_value (b);
285		return (make_integer ((quad_t)0));
286	} else {
287		free_value (b);
288		return (a);
289	}
290}
291
292struct val *
293op_eq (a, b)
294struct val *a, *b;
295{
296	struct val *r;
297
298	if (isstring (a) || isstring (b)) {
299		to_string (a);
300		to_string (b);
301		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) == 0));
302	} else {
303		(void)to_integer(a);
304		(void)to_integer(b);
305		r = make_integer ((quad_t)(a->u.i == b->u.i));
306	}
307
308	free_value (a);
309	free_value (b);
310	return r;
311}
312
313struct val *
314op_gt (a, b)
315struct val *a, *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 (a, b)
336struct val *a, *b;
337{
338	struct val *r;
339
340	if (isstring (a) || isstring (b)) {
341		to_string (a);
342		to_string (b);
343		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) < 0));
344	} else {
345		(void)to_integer(a);
346		(void)to_integer(b);
347		r = make_integer ((quad_t)(a->u.i < b->u.i));
348	}
349
350	free_value (a);
351	free_value (b);
352	return r;
353}
354
355struct val *
356op_ge (a, b)
357struct val *a, *b;
358{
359	struct val *r;
360
361	if (isstring (a) || isstring (b)) {
362		to_string (a);
363		to_string (b);
364		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) >= 0));
365	} else {
366		(void)to_integer(a);
367		(void)to_integer(b);
368		r = make_integer ((quad_t)(a->u.i >= b->u.i));
369	}
370
371	free_value (a);
372	free_value (b);
373	return r;
374}
375
376struct val *
377op_le (a, b)
378struct val *a, *b;
379{
380	struct val *r;
381
382	if (isstring (a) || isstring (b)) {
383		to_string (a);
384		to_string (b);
385		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) <= 0));
386	} else {
387		(void)to_integer(a);
388		(void)to_integer(b);
389		r = make_integer ((quad_t)(a->u.i <= b->u.i));
390	}
391
392	free_value (a);
393	free_value (b);
394	return r;
395}
396
397struct val *
398op_ne (a, b)
399struct val *a, *b;
400{
401	struct val *r;
402
403	if (isstring (a) || isstring (b)) {
404		to_string (a);
405		to_string (b);
406		r = make_integer ((quad_t)(strcoll (a->u.s, b->u.s) != 0));
407	} else {
408		(void)to_integer(a);
409		(void)to_integer(b);
410		r = make_integer ((quad_t)(a->u.i != b->u.i));
411	}
412
413	free_value (a);
414	free_value (b);
415	return r;
416}
417
418int
419chk_plus (a, b, r)
420quad_t a, b, r;
421{
422	/* sum of two positive numbers must be positive */
423	if (a > 0 && b > 0 && r <= 0)
424		return 1;
425	/* sum of two negative numbers must be negative */
426	if (a < 0 && b < 0 && r >= 0)
427		return 1;
428	/* all other cases are OK */
429	return 0;
430}
431
432struct val *
433op_plus (a, b)
434struct val *a, *b;
435{
436	struct val *r;
437
438	if (!to_integer (a) || !to_integer (b)) {
439		errx (2, "non-numeric argument");
440	}
441
442	r = make_integer (/*(quad_t)*/(a->u.i + b->u.i));
443	if (chk_plus (a->u.i, b->u.i, r->u.i)) {
444		errx (2, "overflow");
445	}
446	free_value (a);
447	free_value (b);
448	return r;
449}
450
451int
452chk_minus (a, b, r)
453quad_t a, b, r;
454{
455	/* special case subtraction of QUAD_MIN */
456	if (b == QUAD_MIN) {
457		if (a >= 0)
458			return 1;
459		else
460			return 0;
461	}
462	/* this is allowed for b != QUAD_MIN */
463	return chk_plus (a, -b, r);
464}
465
466struct val *
467op_minus (a, b)
468struct val *a, *b;
469{
470	struct val *r;
471
472	if (!to_integer (a) || !to_integer (b)) {
473		errx (2, "non-numeric argument");
474	}
475
476	r = make_integer (/*(quad_t)*/(a->u.i - b->u.i));
477	if (chk_minus (a->u.i, b->u.i, r->u.i)) {
478		errx (2, "overflow");
479	}
480	free_value (a);
481	free_value (b);
482	return r;
483}
484
485int
486chk_times (a, b, r)
487quad_t a, b, r;
488{
489	/* special case: first operand is 0, no overflow possible */
490	if (a == 0)
491		return 0;
492	/* cerify that result of division matches second operand */
493	if (r / a != b)
494		return 1;
495	return 0;
496}
497
498struct val *
499op_times (a, b)
500struct val *a, *b;
501{
502	struct val *r;
503
504	if (!to_integer (a) || !to_integer (b)) {
505		errx (2, "non-numeric argument");
506	}
507
508	r = make_integer (/*(quad_t)*/(a->u.i * b->u.i));
509	if (chk_times (a->u.i, b->u.i, r->u.i)) {
510		errx (2, "overflow");
511	}
512	free_value (a);
513	free_value (b);
514	return (r);
515}
516
517int
518chk_div (a, b, r)
519quad_t a, b, r;
520{
521	/* div by zero has been taken care of before */
522	/* only QUAD_MIN / -1 causes overflow */
523	if (a == QUAD_MIN && b == -1)
524		return 1;
525	/* everything else is OK */
526	return 0;
527}
528
529struct val *
530op_div (a, b)
531struct val *a, *b;
532{
533	struct val *r;
534
535	if (!to_integer (a) || !to_integer (b)) {
536		errx (2, "non-numeric argument");
537	}
538
539	if (b->u.i == 0) {
540		errx (2, "division by zero");
541	}
542
543	r = make_integer (/*(quad_t)*/(a->u.i / b->u.i));
544	if (chk_div (a->u.i, b->u.i, r->u.i)) {
545		errx (2, "overflow");
546	}
547	free_value (a);
548	free_value (b);
549	return r;
550}
551
552struct val *
553op_rem (a, b)
554struct val *a, *b;
555{
556	struct val *r;
557
558	if (!to_integer (a) || !to_integer (b)) {
559		errx (2, "non-numeric argument");
560	}
561
562	if (b->u.i == 0) {
563		errx (2, "division by zero");
564	}
565
566	r = make_integer (/*(quad_t)*/(a->u.i % b->u.i));
567	/* chk_rem necessary ??? */
568	free_value (a);
569	free_value (b);
570	return r;
571}
572
573struct val *
574op_colon (a, b)
575struct val *a, *b;
576{
577	regex_t rp;
578	regmatch_t rm[2];
579	char errbuf[256];
580	int eval;
581	struct val *v;
582
583	/* coerce to both arguments to strings */
584	to_string(a);
585	to_string(b);
586
587	/* compile regular expression */
588	if ((eval = regcomp (&rp, b->u.s, 0)) != 0) {
589		regerror (eval, &rp, errbuf, sizeof(errbuf));
590		errx (2, "%s", errbuf);
591	}
592
593	/* compare string against pattern */
594	/* remember that patterns are anchored to the beginning of the line */
595	if (regexec(&rp, a->u.s, 2, rm, 0) == 0 && rm[0].rm_so == 0) {
596		if (rm[1].rm_so >= 0) {
597			*(a->u.s + rm[1].rm_eo) = '\0';
598			v = make_str (a->u.s + rm[1].rm_so);
599
600		} else {
601			v = make_integer ((quad_t)(rm[0].rm_eo - rm[0].rm_so));
602		}
603	} else {
604		if (rp.re_nsub == 0) {
605			v = make_integer ((quad_t)0);
606		} else {
607			v = make_str ("");
608		}
609	}
610
611	/* free arguments and pattern buffer */
612	free_value (a);
613	free_value (b);
614	regfree (&rp);
615
616	return v;
617}
618