File: expr.c

package info (click to toggle)
mksh 40.9.20120630-7
  • links: PTS, VCS
  • area: main
  • in suites: wheezy
  • size: 2,288 kB
  • sloc: ansic: 39,060; sh: 3,812; perl: 1,018; makefile: 158
file content (976 lines) | stat: -rw-r--r-- 25,313 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
/*	$OpenBSD: expr.c,v 1.21 2009/06/01 19:00:57 deraadt Exp $	*/

/*-
 * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
 *		 2011, 2012, 2013
 *	Thorsten Glaser <tg@mirbsd.org>
 *
 * Provided that these terms and disclaimer and all copyright notices
 * are retained or reproduced in an accompanying document, permission
 * is granted to deal in this work without restriction, including un-
 * limited rights to use, publicly perform, distribute, sell, modify,
 * merge, give away, or sublicence.
 *
 * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
 * the utmost extent permitted by applicable law, neither express nor
 * implied; without malicious intent or gross negligence. In no event
 * may a licensor, author or contributor be held liable for indirect,
 * direct, other damage, loss, or other issues arising in any way out
 * of dealing in the work, even if advised of the possibility of such
 * damage or existence of a defect, except proven that it results out
 * of said person's immediate fault when using the work as intended.
 */

#include "sh.h"

__RCSID("$MirOS: src/bin/mksh/expr.c,v 1.58.2.2 2013/02/15 18:54:53 tg Exp $");

#if !HAVE_SILENT_IDIVWRAPV
#if !defined(MKSH_LEGACY_MODE) || HAVE_LONG_32BIT
#define IDIVWRAPV_VL	(mksh_uari_t)0x80000000UL
#define IDIVWRAPV_VR	(mksh_uari_t)0xFFFFFFFFUL
#elif HAVE_LONG_64BIT
#define IDIVWRAPV_VL	(mksh_uari_t)0x8000000000000000UL
#define IDIVWRAPV_VR	(mksh_uari_t)0xFFFFFFFFFFFFFFFFUL
#else
# warning "cannot guarantee integer division wraparound"
#undef HAVE_SILENT_IDIVWRAPV
#define HAVE_SILENT_IDIVWRAPV 1
#endif
#endif

/* The order of these enums is constrained by the order of opinfo[] */
enum token {
	/* some (long) unary operators */
	O_PLUSPLUS = 0, O_MINUSMINUS,
	/* binary operators */
	O_EQ, O_NE,
	/* assignments are assumed to be in range O_ASN .. O_BORASN */
	O_ASN, O_TIMESASN, O_DIVASN, O_MODASN, O_PLUSASN, O_MINUSASN,
	O_LSHIFTASN, O_RSHIFTASN, O_BANDASN, O_BXORASN, O_BORASN,
	O_LSHIFT, O_RSHIFT,
	O_LE, O_GE, O_LT, O_GT,
	O_LAND,
	O_LOR,
	O_TIMES, O_DIV, O_MOD,
	O_PLUS, O_MINUS,
	O_BAND,
	O_BXOR,
	O_BOR,
	O_TERN,
	O_COMMA,
	/* things after this aren't used as binary operators */
	/* unary that are not also binaries */
	O_BNOT, O_LNOT,
	/* misc */
	OPEN_PAREN, CLOSE_PAREN, CTERN,
	/* things that don't appear in the opinfo[] table */
	VAR, LIT, END, BAD
};
#define IS_BINOP(op) (((int)op) >= (int)O_EQ && ((int)op) <= (int)O_COMMA)
#define IS_ASSIGNOP(op)	((int)(op) >= (int)O_ASN && (int)(op) <= (int)O_BORASN)

/* precisions; used to be enum prec but we do arithmetics on it */
#define P_PRIMARY	0	/* VAR, LIT, (), ~ ! - + */
#define P_MULT		1	/* * / % */
#define P_ADD		2	/* + - */
#define P_SHIFT		3	/* << >> */
#define P_RELATION	4	/* < <= > >= */
#define P_EQUALITY	5	/* == != */
#define P_BAND		6	/* & */
#define P_BXOR		7	/* ^ */
#define P_BOR		8	/* | */
#define P_LAND		9	/* && */
#define P_LOR		10	/* || */
#define P_TERN		11	/* ?: */
#define P_ASSIGN	12	/* = *= /= %= += -= <<= >>= &= ^= |= */
#define P_COMMA		13	/* , */
#define MAX_PREC	P_COMMA

struct opinfo {
	char		name[4];
	int		len;	/* name length */
	int		prec;	/* precedence: lower is higher */
};

/* Tokens in this table must be ordered so the longest are first
 * (eg, += before +). If you change something, change the order
 * of enum token too.
 */
static const struct opinfo opinfo[] = {
	{ "++",	 2, P_PRIMARY },	/* before + */
	{ "--",	 2, P_PRIMARY },	/* before - */
	{ "==",	 2, P_EQUALITY },	/* before = */
	{ "!=",	 2, P_EQUALITY },	/* before ! */
	{ "=",	 1, P_ASSIGN },		/* keep assigns in a block */
	{ "*=",	 2, P_ASSIGN },
	{ "/=",	 2, P_ASSIGN },
	{ "%=",	 2, P_ASSIGN },
	{ "+=",	 2, P_ASSIGN },
	{ "-=",	 2, P_ASSIGN },
	{ "<<=", 3, P_ASSIGN },
	{ ">>=", 3, P_ASSIGN },
	{ "&=",	 2, P_ASSIGN },
	{ "^=",	 2, P_ASSIGN },
	{ "|=",	 2, P_ASSIGN },
	{ "<<",	 2, P_SHIFT },
	{ ">>",	 2, P_SHIFT },
	{ "<=",	 2, P_RELATION },
	{ ">=",	 2, P_RELATION },
	{ "<",	 1, P_RELATION },
	{ ">",	 1, P_RELATION },
	{ "&&",	 2, P_LAND },
	{ "||",	 2, P_LOR },
	{ "*",	 1, P_MULT },
	{ "/",	 1, P_MULT },
	{ "%",	 1, P_MULT },
	{ "+",	 1, P_ADD },
	{ "-",	 1, P_ADD },
	{ "&",	 1, P_BAND },
	{ "^",	 1, P_BXOR },
	{ "|",	 1, P_BOR },
	{ "?",	 1, P_TERN },
	{ ",",	 1, P_COMMA },
	{ "~",	 1, P_PRIMARY },
	{ "!",	 1, P_PRIMARY },
	{ "(",	 1, P_PRIMARY },
	{ ")",	 1, P_PRIMARY },
	{ ":",	 1, P_PRIMARY },
	{ "",	 0, P_PRIMARY }
};

typedef struct expr_state Expr_state;
struct expr_state {
	const char *expression;		/* expression being evaluated */
	const char *tokp;		/* lexical position */
	struct tbl *val;		/* value from token() */
	struct tbl *evaling;		/* variable that is being recursively
					 * expanded (EXPRINEVAL flag set) */
	int noassign;			/* don't do assigns (for ?:,&&,||) */
	enum token tok;			/* token from token() */
	bool arith;			/* evaluating an $(()) expression? */
	bool natural;			/* unsigned arithmetic calculation */
};

#define bivui(x, op, y)	(es->natural ?			\
	(mksh_ari_t)((x)->val.u op (y)->val.u) :	\
	(mksh_ari_t)((x)->val.i op (y)->val.i)		\
)
#define stvui(x, n)	do {			\
	if (es->natural)			\
		(x)->val.u = (n);		\
	else					\
		(x)->val.i = (n);		\
} while (/* CONSTCOND */ 0)

enum error_type {
	ET_UNEXPECTED, ET_BADLIT, ET_RECURSIVE,
	ET_LVALUE, ET_RDONLY, ET_STR
};

static void evalerr(Expr_state *, enum error_type, const char *)
    MKSH_A_NORETURN;
static struct tbl *evalexpr(Expr_state *, int);
static void exprtoken(Expr_state *);
static struct tbl *do_ppmm(Expr_state *, enum token, struct tbl *, bool);
static void assign_check(Expr_state *, enum token, struct tbl *);
static struct tbl *intvar(Expr_state *, struct tbl *);

/*
 * parse and evaluate expression
 */
int
evaluate(const char *expr, mksh_ari_t *rval, int error_ok, bool arith)
{
	struct tbl v;
	int ret;

	v.flag = DEFINED|INTEGER;
	v.type = 0;
	ret = v_evaluate(&v, expr, error_ok, arith);
	*rval = v.val.i;
	return (ret);
}

/*
 * parse and evaluate expression, storing result in vp.
 */
int
v_evaluate(struct tbl *vp, const char *expr, volatile int error_ok,
    bool arith)
{
	struct tbl *v;
	Expr_state curstate;
	Expr_state * const es = &curstate;
	int i;

	/* save state to allow recursive calls */
	memset(&curstate, 0, sizeof(curstate));
	curstate.expression = curstate.tokp = expr;
	curstate.tok = BAD;
	curstate.arith = arith;

	newenv(E_ERRH);
	if ((i = kshsetjmp(e->jbuf))) {
		/* Clear EXPRINEVAL in of any variables we were playing with */
		if (curstate.evaling)
			curstate.evaling->flag &= ~EXPRINEVAL;
		quitenv(NULL);
		if (i == LAEXPR) {
			if (error_ok == KSH_RETURN_ERROR)
				return (0);
			errorfz();
		}
		unwind(i);
		/* NOTREACHED */
	}

	exprtoken(es);
	if (es->tok == END) {
		es->tok = LIT;
		es->val = tempvar();
	}
	v = intvar(es, evalexpr(es, MAX_PREC));

	if (es->tok != END)
		evalerr(es, ET_UNEXPECTED, NULL);

	if (es->arith && es->natural)
		vp->flag |= INT_U;
	if (vp->flag & INTEGER)
		setint_v(vp, v, es->arith);
	else
		/* can fail if readonly */
		setstr(vp, str_val(v), error_ok);

	quitenv(NULL);

	return (1);
}

static void
evalerr(Expr_state *es, enum error_type type, const char *str)
{
	char tbuf[2];
	const char *s;

	es->arith = false;
	switch (type) {
	case ET_UNEXPECTED:
		switch (es->tok) {
		case VAR:
			s = es->val->name;
			break;
		case LIT:
			s = str_val(es->val);
			break;
		case END:
			s = "end of expression";
			break;
		case BAD:
			tbuf[0] = *es->tokp;
			tbuf[1] = '\0';
			s = tbuf;
			break;
		default:
			s = opinfo[(int)es->tok].name;
		}
		warningf(true, "%s: %s '%s'", es->expression,
		    "unexpected", s);
		break;

	case ET_BADLIT:
		warningf(true, "%s: %s '%s'", es->expression,
		    "bad number", str);
		break;

	case ET_RECURSIVE:
		warningf(true, "%s: %s '%s'", es->expression,
		    "expression recurses on parameter", str);
		break;

	case ET_LVALUE:
		warningf(true, "%s: %s %s",
		    es->expression, str, "requires lvalue");
		break;

	case ET_RDONLY:
		warningf(true, "%s: %s %s",
		    es->expression, str, "applied to read-only variable");
		break;

	default: /* keep gcc happy */
	case ET_STR:
		warningf(true, "%s: %s", es->expression, str);
		break;
	}
	unwind(LAEXPR);
}

static struct tbl *
evalexpr(Expr_state *es, int prec)
{
	struct tbl *vl, *vr = NULL, *vasn;
	enum token op;
	mksh_ari_t res = 0;

	if (prec == P_PRIMARY) {
		op = es->tok;
		if (op == O_BNOT || op == O_LNOT || op == O_MINUS ||
		    op == O_PLUS) {
			exprtoken(es);
			vl = intvar(es, evalexpr(es, P_PRIMARY));
			if (op == O_BNOT)
				vl->val.i = ~vl->val.i;
			else if (op == O_LNOT)
				vl->val.i = !vl->val.i;
			else if (op == O_MINUS)
				vl->val.i = -vl->val.i;
			/* op == O_PLUS is a no-op */
		} else if (op == OPEN_PAREN) {
			exprtoken(es);
			vl = evalexpr(es, MAX_PREC);
			if (es->tok != CLOSE_PAREN)
				evalerr(es, ET_STR, "missing )");
			exprtoken(es);
		} else if (op == O_PLUSPLUS || op == O_MINUSMINUS) {
			exprtoken(es);
			vl = do_ppmm(es, op, es->val, true);
			exprtoken(es);
		} else if (op == VAR || op == LIT) {
			vl = es->val;
			exprtoken(es);
		} else {
			evalerr(es, ET_UNEXPECTED, NULL);
			/* NOTREACHED */
		}
		if (es->tok == O_PLUSPLUS || es->tok == O_MINUSMINUS) {
			vl = do_ppmm(es, es->tok, vl, false);
			exprtoken(es);
		}
		return (vl);
	}
	vl = evalexpr(es, prec - 1);
	for (op = es->tok; IS_BINOP(op) && opinfo[(int)op].prec == prec;
	    op = es->tok) {
		exprtoken(es);
		vasn = vl;
		if (op != O_ASN)
			/* vl may not have a value yet */
			vl = intvar(es, vl);
		if (IS_ASSIGNOP(op)) {
			if (!es->noassign)
				assign_check(es, op, vasn);
			vr = intvar(es, evalexpr(es, P_ASSIGN));
		} else if (op != O_TERN && op != O_LAND && op != O_LOR)
			vr = intvar(es, evalexpr(es, prec - 1));
		if ((op == O_DIV || op == O_MOD || op == O_DIVASN ||
		    op == O_MODASN) && vr->val.i == 0) {
			if (es->noassign)
				vr->val.i = 1;
			else
				evalerr(es, ET_STR, "zero divisor");
		}
		switch ((int)op) {
		case O_TIMES:
		case O_TIMESASN:
			res = bivui(vl, *, vr);
			break;
		case O_DIV:
		case O_DIVASN:
#if !HAVE_SILENT_IDIVWRAPV
			/*
			 * we are doing the comparisons here for the
			 * signed arithmetics (!es->natural) case,
			 * but the exact value checks and the bypass
			 * case assignments are done unsignedly as
			 * several compilers bitch around otherwise
			 */
			if (!es->natural &&
			    vl->val.u == IDIVWRAPV_VL &&
			    vr->val.u == IDIVWRAPV_VR) {
				/* -2147483648 / -1 = 2147483648 */
				/* this ^ is really (1 << 31) though */
				res = (mksh_ari_t)IDIVWRAPV_VL;
			} else
#endif
				res = bivui(vl, /, vr);
			break;
		case O_MOD:
		case O_MODASN:
#if !HAVE_SILENT_IDIVWRAPV
			/* see O_DIV / O_DIVASN for the reason behind this */
			if (!es->natural &&
			    vl->val.u == IDIVWRAPV_VL &&
			    vr->val.u == IDIVWRAPV_VR) {
				/* -2147483648 % -1 = 0 */
				res = 0;
			} else
#endif
				res = bivui(vl, %, vr);
			break;
		case O_PLUS:
		case O_PLUSASN:
			res = bivui(vl, +, vr);
			break;
		case O_MINUS:
		case O_MINUSASN:
			res = bivui(vl, -, vr);
			break;
		case O_LSHIFT:
		case O_LSHIFTASN:
			res = bivui(vl, <<, vr);
			break;
		case O_RSHIFT:
		case O_RSHIFTASN:
			res = bivui(vl, >>, vr);
			break;
		case O_LT:
			res = bivui(vl, <, vr);
			break;
		case O_LE:
			res = bivui(vl, <=, vr);
			break;
		case O_GT:
			res = bivui(vl, >, vr);
			break;
		case O_GE:
			res = bivui(vl, >=, vr);
			break;
		case O_EQ:
			res = bivui(vl, ==, vr);
			break;
		case O_NE:
			res = bivui(vl, !=, vr);
			break;
		case O_BAND:
		case O_BANDASN:
			res = bivui(vl, &, vr);
			break;
		case O_BXOR:
		case O_BXORASN:
			res = bivui(vl, ^, vr);
			break;
		case O_BOR:
		case O_BORASN:
			res = bivui(vl, |, vr);
			break;
		case O_LAND:
			if (!vl->val.i)
				es->noassign++;
			vr = intvar(es, evalexpr(es, prec - 1));
			res = bivui(vl, &&, vr);
			if (!vl->val.i)
				es->noassign--;
			break;
		case O_LOR:
			if (vl->val.i)
				es->noassign++;
			vr = intvar(es, evalexpr(es, prec - 1));
			res = bivui(vl, ||, vr);
			if (vl->val.i)
				es->noassign--;
			break;
		case O_TERN:
			{
				bool ev = vl->val.i != 0;

				if (!ev)
					es->noassign++;
				vl = evalexpr(es, MAX_PREC);
				if (!ev)
					es->noassign--;
				if (es->tok != CTERN)
					evalerr(es, ET_STR, "missing :");
				exprtoken(es);
				if (ev)
					es->noassign++;
				vr = evalexpr(es, P_TERN);
				if (ev)
					es->noassign--;
				vl = ev ? vl : vr;
			}
			break;
		case O_ASN:
			res = vr->val.i;
			break;
		case O_COMMA:
			res = vr->val.i;
			break;
		}
		if (IS_ASSIGNOP(op)) {
			stvui(vr, res);
			if (!es->noassign) {
				if (vasn->flag & INTEGER)
					setint_v(vasn, vr, es->arith);
				else
					setint(vasn, res);
			}
			vl = vr;
		} else if (op != O_TERN)
			stvui(vl, res);
	}
	return (vl);
}

static void
exprtoken(Expr_state *es)
{
	const char *cp = es->tokp;
	int c;
	char *tvar;

	/* skip white space */
 skip_spaces:
	while ((c = *cp), ksh_isspace(c))
		++cp;
	if (es->tokp == es->expression && c == '#') {
		/* expression begins with # */
		es->natural = true;	/* switch to unsigned */
		++cp;
		goto skip_spaces;
	}
	es->tokp = cp;

	if (c == '\0')
		es->tok = END;
	else if (ksh_isalphx(c)) {
		for (; ksh_isalnux(c); c = *cp)
			cp++;
		if (c == '[') {
			size_t len;

			len = array_ref_len(cp);
			if (len == 0)
				evalerr(es, ET_STR, "missing ]");
			cp += len;
		} else if (c == '(' /*)*/ ) {
			/* todo: add math functions (all take single argument):
			 * abs acos asin atan cos cosh exp int log sin sinh sqrt
			 * tan tanh
			 */
			;
		}
		if (es->noassign) {
			es->val = tempvar();
			es->val->flag |= EXPRLVALUE;
		} else {
			strndupx(tvar, es->tokp, cp - es->tokp, ATEMP);
			es->val = global(tvar);
			afree(tvar, ATEMP);
		}
		es->tok = VAR;
	} else if (c == '1' && cp[1] == '#') {
		cp += 2;
		cp += utf_ptradj(cp);
		strndupx(tvar, es->tokp, cp - es->tokp, ATEMP);
		goto process_tvar;
#ifndef MKSH_SMALL
	} else if (c == '\'') {
		++cp;
		cp += utf_ptradj(cp);
		if (*cp++ != '\'')
			evalerr(es, ET_STR,
			    "multi-character character constant");
		/* 'x' -> 1#x (x = one multibyte character) */
		c = cp - es->tokp;
		tvar = alloc(c + /* NUL */ 1, ATEMP);
		tvar[0] = '1';
		tvar[1] = '#';
		memcpy(tvar + 2, es->tokp + 1, c - 2);
		tvar[c] = '\0';
		goto process_tvar;
#endif
	} else if (ksh_isdigit(c)) {
		while (c != '_' && (ksh_isalnux(c) || c == '#'))
			c = *cp++;
		strndupx(tvar, es->tokp, --cp - es->tokp, ATEMP);
 process_tvar:
		es->val = tempvar();
		es->val->flag &= ~INTEGER;
		es->val->type = 0;
		es->val->val.s = tvar;
		if (setint_v(es->val, es->val, es->arith) == NULL)
			evalerr(es, ET_BADLIT, tvar);
		afree(tvar, ATEMP);
		es->tok = LIT;
	} else {
		int i, n0;

		for (i = 0; (n0 = opinfo[i].name[0]); i++)
			if (c == n0 && strncmp(cp, opinfo[i].name,
			    (size_t)opinfo[i].len) == 0) {
				es->tok = (enum token)i;
				cp += opinfo[i].len;
				break;
			}
		if (!n0)
			es->tok = BAD;
	}
	es->tokp = cp;
}

/* Do a ++ or -- operation */
static struct tbl *
do_ppmm(Expr_state *es, enum token op, struct tbl *vasn, bool is_prefix)
{
	struct tbl *vl;
	mksh_ari_t oval;

	assign_check(es, op, vasn);

	vl = intvar(es, vasn);
	oval = vl->val.i;
	if (op == O_PLUSPLUS) {
		if (es->natural)
			++vl->val.u;
		else
			++vl->val.i;
	} else {
		if (es->natural)
			--vl->val.u;
		else
			--vl->val.i;
	}
	if (vasn->flag & INTEGER)
		setint_v(vasn, vl, es->arith);
	else
		setint(vasn, vl->val.i);
	if (!is_prefix)
		/* undo the increment/decrement */
		vl->val.i = oval;

	return (vl);
}

static void
assign_check(Expr_state *es, enum token op, struct tbl *vasn)
{
	if (es->tok == END || !vasn ||
	    (vasn->name[0] == '\0' && !(vasn->flag & EXPRLVALUE)))
		evalerr(es, ET_LVALUE, opinfo[(int)op].name);
	else if (vasn->flag & RDONLY)
		evalerr(es, ET_RDONLY, opinfo[(int)op].name);
}

struct tbl *
tempvar(void)
{
	struct tbl *vp;

	vp = alloc(sizeof(struct tbl), ATEMP);
	vp->flag = ISSET|INTEGER;
	vp->type = 0;
	vp->areap = ATEMP;
	vp->ua.hval = 0;
	vp->val.i = 0;
	vp->name[0] = '\0';
	return (vp);
}

/* cast (string) variable to temporary integer variable */
static struct tbl *
intvar(Expr_state *es, struct tbl *vp)
{
	struct tbl *vq;

	/* try to avoid replacing a temp var with another temp var */
	if (vp->name[0] == '\0' &&
	    (vp->flag & (ISSET|INTEGER|EXPRLVALUE)) == (ISSET|INTEGER))
		return (vp);

	vq = tempvar();
	if (setint_v(vq, vp, es->arith) == NULL) {
		if (vp->flag & EXPRINEVAL)
			evalerr(es, ET_RECURSIVE, vp->name);
		es->evaling = vp;
		vp->flag |= EXPRINEVAL;
		v_evaluate(vq, str_val(vp), KSH_UNWIND_ERROR, es->arith);
		vp->flag &= ~EXPRINEVAL;
		es->evaling = NULL;
	}
	return (vq);
}


/*
 * UTF-8 support code: high-level functions
 */

int
utf_widthadj(const char *src, const char **dst)
{
	size_t len;
	unsigned int wc;
	int width;

	if (!UTFMODE || (len = utf_mbtowc(&wc, src)) == (size_t)-1 ||
	    wc == 0)
		len = width = 1;
	else if ((width = utf_wcwidth(wc)) < 0)
		/* XXX use 2 for x_zotc3 here? */
		width = 1;

	if (dst)
		*dst = src + len;
	return (width);
}

size_t
utf_mbswidth(const char *s)
{
	size_t len, width = 0;
	unsigned int wc;
	int cw;

	if (!UTFMODE)
		return (strlen(s));

	while (*s)
		if (((len = utf_mbtowc(&wc, s)) == (size_t)-1) ||
		    ((cw = utf_wcwidth(wc)) == -1)) {
			s++;
			width += 1;
		} else {
			s += len;
			width += cw;
		}
	return (width);
}

const char *
utf_skipcols(const char *p, int cols)
{
	int c = 0;

	while (c < cols) {
		if (!*p)
			return (p + cols - c);
		c += utf_widthadj(p, &p);
	}
	return (p);
}

size_t
utf_ptradj(const char *src)
{
	register size_t n;

	if (!UTFMODE ||
	    *(const unsigned char *)(src) < 0xC2 ||
	    (n = utf_mbtowc(NULL, src)) == (size_t)-1)
		n = 1;
	return (n);
}

/*
 * UTF-8 support code: low-level functions
 */

/* CESU-8 multibyte and wide character conversion crafted for mksh */

size_t
utf_mbtowc(unsigned int *dst, const char *src)
{
	const unsigned char *s = (const unsigned char *)src;
	unsigned int c, wc;

	if ((wc = *s++) < 0x80) {
 out:
		if (dst != NULL)
			*dst = wc;
		return (wc ? ((const char *)s - src) : 0);
	}
	if (wc < 0xC2 || wc >= 0xF0)
		/* < 0xC0: spurious second byte */
		/* < 0xC2: non-minimalistic mapping error in 2-byte seqs */
		/* > 0xEF: beyond BMP */
		goto ilseq;

	if (wc < 0xE0) {
		wc = (wc & 0x1F) << 6;
		if (((c = *s++) & 0xC0) != 0x80)
			goto ilseq;
		wc |= c & 0x3F;
		goto out;
	}

	wc = (wc & 0x0F) << 12;

	if (((c = *s++) & 0xC0) != 0x80)
		goto ilseq;
	wc |= (c & 0x3F) << 6;

	if (((c = *s++) & 0xC0) != 0x80)
		goto ilseq;
	wc |= c & 0x3F;

	/* Check for non-minimalistic mapping error in 3-byte seqs */
	if (wc >= 0x0800 && wc <= 0xFFFD)
		goto out;
 ilseq:
	return ((size_t)(-1));
}

size_t
utf_wctomb(char *dst, unsigned int wc)
{
	unsigned char *d;

	if (wc < 0x80) {
		*dst = wc;
		return (1);
	}

	d = (unsigned char *)dst;
	if (wc < 0x0800)
		*d++ = (wc >> 6) | 0xC0;
	else {
		*d++ = ((wc = wc > 0xFFFD ? 0xFFFD : wc) >> 12) | 0xE0;
		*d++ = ((wc >> 6) & 0x3F) | 0x80;
	}
	*d++ = (wc & 0x3F) | 0x80;
	return ((char *)d - dst);
}


#ifndef MKSH_mirbsd_wcwidth
/* --- begin of wcwidth.c excerpt --- */
/*-
 * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
 *
 * Permission to use, copy, modify, and distribute this software
 * for any purpose and without fee is hereby granted. The author
 * disclaims all warranties with regard to this software.
 */

__RCSID("$miros: src/lib/libc/i18n/wcwidth.c,v 1.11 2012/09/01 23:46:43 tg Exp $");

int
utf_wcwidth(unsigned int c)
{
	static const struct cbset {
		unsigned short first;
		unsigned short last;
	} comb[] = {
		/* Unicode 6.1.0 BMP */
		{ 0x0300, 0x036F }, { 0x0483, 0x0489 }, { 0x0591, 0x05BD },
		{ 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 }, { 0x05C4, 0x05C5 },
		{ 0x05C7, 0x05C7 }, { 0x0600, 0x0604 }, { 0x0610, 0x061A },
		{ 0x064B, 0x065F }, { 0x0670, 0x0670 }, { 0x06D6, 0x06DD },
		{ 0x06DF, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED },
		{ 0x070F, 0x070F }, { 0x0711, 0x0711 }, { 0x0730, 0x074A },
		{ 0x07A6, 0x07B0 }, { 0x07EB, 0x07F3 }, { 0x0816, 0x0819 },
		{ 0x081B, 0x0823 }, { 0x0825, 0x0827 }, { 0x0829, 0x082D },
		{ 0x0859, 0x085B }, { 0x08E4, 0x08FE }, { 0x0900, 0x0902 },
		{ 0x093A, 0x093A }, { 0x093C, 0x093C }, { 0x0941, 0x0948 },
		{ 0x094D, 0x094D }, { 0x0951, 0x0957 }, { 0x0962, 0x0963 },
		{ 0x0981, 0x0981 }, { 0x09BC, 0x09BC }, { 0x09C1, 0x09C4 },
		{ 0x09CD, 0x09CD }, { 0x09E2, 0x09E3 }, { 0x0A01, 0x0A02 },
		{ 0x0A3C, 0x0A3C }, { 0x0A41, 0x0A42 }, { 0x0A47, 0x0A48 },
		{ 0x0A4B, 0x0A4D }, { 0x0A51, 0x0A51 }, { 0x0A70, 0x0A71 },
		{ 0x0A75, 0x0A75 }, { 0x0A81, 0x0A82 }, { 0x0ABC, 0x0ABC },
		{ 0x0AC1, 0x0AC5 }, { 0x0AC7, 0x0AC8 }, { 0x0ACD, 0x0ACD },
		{ 0x0AE2, 0x0AE3 }, { 0x0B01, 0x0B01 }, { 0x0B3C, 0x0B3C },
		{ 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B44 }, { 0x0B4D, 0x0B4D },
		{ 0x0B56, 0x0B56 }, { 0x0B62, 0x0B63 }, { 0x0B82, 0x0B82 },
		{ 0x0BC0, 0x0BC0 }, { 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 },
		{ 0x0C46, 0x0C48 }, { 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 },
		{ 0x0C62, 0x0C63 }, { 0x0CBC, 0x0CBC }, { 0x0CBF, 0x0CBF },
		{ 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD }, { 0x0CE2, 0x0CE3 },
		{ 0x0D41, 0x0D44 }, { 0x0D4D, 0x0D4D }, { 0x0D62, 0x0D63 },
		{ 0x0DCA, 0x0DCA }, { 0x0DD2, 0x0DD4 }, { 0x0DD6, 0x0DD6 },
		{ 0x0E31, 0x0E31 }, { 0x0E34, 0x0E3A }, { 0x0E47, 0x0E4E },
		{ 0x0EB1, 0x0EB1 }, { 0x0EB4, 0x0EB9 }, { 0x0EBB, 0x0EBC },
		{ 0x0EC8, 0x0ECD }, { 0x0F18, 0x0F19 }, { 0x0F35, 0x0F35 },
		{ 0x0F37, 0x0F37 }, { 0x0F39, 0x0F39 }, { 0x0F71, 0x0F7E },
		{ 0x0F80, 0x0F84 }, { 0x0F86, 0x0F87 }, { 0x0F8D, 0x0F97 },
		{ 0x0F99, 0x0FBC }, { 0x0FC6, 0x0FC6 }, { 0x102D, 0x1030 },
		{ 0x1032, 0x1037 }, { 0x1039, 0x103A }, { 0x103D, 0x103E },
		{ 0x1058, 0x1059 }, { 0x105E, 0x1060 }, { 0x1071, 0x1074 },
		{ 0x1082, 0x1082 }, { 0x1085, 0x1086 }, { 0x108D, 0x108D },
		{ 0x109D, 0x109D }, { 0x1160, 0x11FF }, { 0x135D, 0x135F },
		{ 0x1712, 0x1714 }, { 0x1732, 0x1734 }, { 0x1752, 0x1753 },
		{ 0x1772, 0x1773 }, { 0x17B4, 0x17B5 }, { 0x17B7, 0x17BD },
		{ 0x17C6, 0x17C6 }, { 0x17C9, 0x17D3 }, { 0x17DD, 0x17DD },
		{ 0x180B, 0x180D }, { 0x18A9, 0x18A9 }, { 0x1920, 0x1922 },
		{ 0x1927, 0x1928 }, { 0x1932, 0x1932 }, { 0x1939, 0x193B },
		{ 0x1A17, 0x1A18 }, { 0x1A56, 0x1A56 }, { 0x1A58, 0x1A5E },
		{ 0x1A60, 0x1A60 }, { 0x1A62, 0x1A62 }, { 0x1A65, 0x1A6C },
		{ 0x1A73, 0x1A7C }, { 0x1A7F, 0x1A7F }, { 0x1B00, 0x1B03 },
		{ 0x1B34, 0x1B34 }, { 0x1B36, 0x1B3A }, { 0x1B3C, 0x1B3C },
		{ 0x1B42, 0x1B42 }, { 0x1B6B, 0x1B73 }, { 0x1B80, 0x1B81 },
		{ 0x1BA2, 0x1BA5 }, { 0x1BA8, 0x1BA9 }, { 0x1BAB, 0x1BAB },
		{ 0x1BE6, 0x1BE6 }, { 0x1BE8, 0x1BE9 }, { 0x1BED, 0x1BED },
		{ 0x1BEF, 0x1BF1 }, { 0x1C2C, 0x1C33 }, { 0x1C36, 0x1C37 },
		{ 0x1CD0, 0x1CD2 }, { 0x1CD4, 0x1CE0 }, { 0x1CE2, 0x1CE8 },
		{ 0x1CED, 0x1CED }, { 0x1CF4, 0x1CF4 }, { 0x1DC0, 0x1DE6 },
		{ 0x1DFC, 0x1DFF }, { 0x200B, 0x200F }, { 0x202A, 0x202E },
		{ 0x2060, 0x2064 }, { 0x206A, 0x206F }, { 0x20D0, 0x20F0 },
		{ 0x2CEF, 0x2CF1 }, { 0x2D7F, 0x2D7F }, { 0x2DE0, 0x2DFF },
		{ 0x302A, 0x302D }, { 0x3099, 0x309A }, { 0xA66F, 0xA672 },
		{ 0xA674, 0xA67D }, { 0xA69F, 0xA69F }, { 0xA6F0, 0xA6F1 },
		{ 0xA802, 0xA802 }, { 0xA806, 0xA806 }, { 0xA80B, 0xA80B },
		{ 0xA825, 0xA826 }, { 0xA8C4, 0xA8C4 }, { 0xA8E0, 0xA8F1 },
		{ 0xA926, 0xA92D }, { 0xA947, 0xA951 }, { 0xA980, 0xA982 },
		{ 0xA9B3, 0xA9B3 }, { 0xA9B6, 0xA9B9 }, { 0xA9BC, 0xA9BC },
		{ 0xAA29, 0xAA2E }, { 0xAA31, 0xAA32 }, { 0xAA35, 0xAA36 },
		{ 0xAA43, 0xAA43 }, { 0xAA4C, 0xAA4C }, { 0xAAB0, 0xAAB0 },
		{ 0xAAB2, 0xAAB4 }, { 0xAAB7, 0xAAB8 }, { 0xAABE, 0xAABF },
		{ 0xAAC1, 0xAAC1 }, { 0xAAEC, 0xAAED }, { 0xAAF6, 0xAAF6 },
		{ 0xABE5, 0xABE5 }, { 0xABE8, 0xABE8 }, { 0xABED, 0xABED },
		{ 0xFB1E, 0xFB1E }, { 0xFE00, 0xFE0F }, { 0xFE20, 0xFE26 },
		{ 0xFEFF, 0xFEFF }, { 0xFFF9, 0xFFFB }
	};
	size_t min = 0, mid, max = NELEM(comb) - 1;

	/* test for 8-bit control characters */
	if (c < 32 || (c >= 0x7F && c < 0xA0))
		return (c ? -1 : 0);

	/* binary search in table of non-spacing characters */
	if (c >= comb[0].first && c <= comb[max].last)
		while (max >= min) {
			mid = (min + max) / 2;
			if (c > comb[mid].last)
				min = mid + 1;
			else if (c < comb[mid].first)
				max = mid - 1;
			else
				return (0);
		}

	/* if we arrive here, c is not a combining or C0/C1 control char */

	return ((c >= 0x1100 && (
	    c <= 0x115F || /* Hangul Jamo init. consonants */
	    c == 0x2329 || c == 0x232A ||
	    (c >= 0x2E80 && c <= 0xA4CF && c != 0x303F) || /* CJK ... Yi */
	    (c >= 0xAC00 && c <= 0xD7A3) || /* Hangul Syllables */
	    (c >= 0xF900 && c <= 0xFAFF) || /* CJK Compatibility Ideographs */
	    (c >= 0xFE10 && c <= 0xFE19) || /* Vertical forms */
	    (c >= 0xFE30 && c <= 0xFE6F) || /* CJK Compatibility Forms */
	    (c >= 0xFF00 && c <= 0xFF60) || /* Fullwidth Forms */
	    (c >= 0xFFE0 && c <= 0xFFE6))) ? 2 : 1);
}
/* --- end of wcwidth.c excerpt --- */
#endif

/*
 * Wrapper around access(2) because it says root can execute everything
 * on some operating systems. Does not set errno, no user needs it. Use
 * this iff mode can have the X_OK bit set, access otherwise.
 */
int
ksh_access(const char *fn, int mode)
{
	int rv;
	struct stat sb;

	if ((rv = access(fn, mode)) == 0 && kshuid == 0 && (mode & X_OK) &&
	    (rv = stat(fn, &sb)) == 0 && !S_ISDIR(sb.st_mode) &&
	    (sb.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
		rv = -1;

	return (rv);
}