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	seq.c - sbase - suckless unix tools
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	---
	seq.c (2581B)
	---
	1 /* See LICENSE file for copyright and license details. */
	2 #include <stdio.h>
	3 #include <stdlib.h>
	4 #include <string.h>
	5
	6 #include "util.h"
	7
	8 static int
	9 digitsleft(const char *d)
	10 {
	11 int shift;
	12 char *exp;
	13
	14 if (*d == '+')
	15 d++;
	16 exp = strpbrk(d, "eE");
	17 shift = exp ? estrtonum(exp + 1, INT_MIN, INT_MAX) : 0;
	18
	19 return MAX(0, strspn(d, "-0123456789") + shift);
	20 }
	21
	22 static int
	23 digitsright(const char *d)
	24 {
	25 int shift, after;
	26 char *exp;
	27
	28 exp = strpbrk(d, "eE");
	29 shift = exp ? estrtonum(&exp[1], INT_MIN, INT_MAX) : 0;
	30 after = (d = strchr(d, '.')) ? strspn(&d[1], "0123456789") : 0;
	31
	32 return MAX(0, after - shift);
	33 }
	34
	35 static int
	36 validfmt(const char *fmt)
	37 {
	38 int occur = 0;
	39
	40 literal:
	41 while (*fmt)
	42 if (*fmt++ == '%')
	43 goto format;
	44 return occur == 1;
	45
	46 format:
	47 if (*fmt == '%') {
	48 fmt++;
	49 goto literal;
	50 }
	51 fmt += strspn(fmt, "-+#0 '");
	52 fmt += strspn(fmt, "0123456789");
	53 if (*fmt == '.') {
	54 fmt++;
	55 fmt += strspn(fmt, "0123456789");
	56 }
	57 if (*fmt == 'L')
	58 fmt++;
	59
	60 switch (*fmt) {
	61 case 'f': case 'F':
	62 case 'g': case 'G':
	63 case 'e': case 'E':
	64 case 'a': case 'A':
	65 occur++;
	66 goto literal;
	67 default:
	68 return 0;
	69 }
	70 }
	71
	72 static void
	73 usage(void)
	74 {
	75 eprintf("usage: %s [-f fmt] [-s sep] [-w] "
	76 "[startnum [step]] endnum\n", argv0);
	77 }
	78
	79 int
	80 main(int argc, char *argv[])
	81 {
	82 double start, step, end, out, dir;
	83 int wflag = 0, left, right;
	84 char tmp, ftmp[BUFSIZ], fmt = ftmp;
	85 const char starts = "1", steps = "1", ends = "1", sep = "\n";
	86
	87 ARGBEGIN {
	88 case 'f':
	89 if (!validfmt(tmp=EARGF(usage())))
	90 eprintf("%s: invalid format\n", tmp);
	91 fmt = tmp;
	92 break;
	93 case 's':
	94 sep = EARGF(usage());
	95 break;
	96 case 'w':
	97 wflag = 1;
	98 break;
	99 default:
	100 usage();
	101 } ARGEND
	102
	103 switch (argc) {
	104 case 3:
	105 steps = argv[1];
	106 argv[1] = argv[2];
	107 /* fallthrough */
	108 case 2:
	109 starts = argv[0];
	110 argv++;
	111 /* fallthrough */
	112 case 1:
	113 ends = argv[0];
	114 break;
	115 default:
	116 usage();
	117 }
	118 start = estrtod(starts);
	119 step = estrtod(steps);
	120 end = estrtod(ends);
	121
	122 dir = (step > 0) ? 1.0 : -1.0;
	123 if (step == 0 \|\| start * dir > end * dir)
	124 return 1;
	125
	126 if (fmt == ftmp) {
	127 right = MAX(digitsright(starts),
	128 MAX(digitsright(ends),
	129 digitsright(steps)));
	130
	131 if (wflag) {
	132 left = MAX(digitsleft(starts), digitsleft(ends));
	133
	134 snprintf(ftmp, sizeof ftmp, "%%0%d.%df",
	135 right + left + (right != 0), rig…
	136 } else
	137 snprintf(ftmp, sizeof ftmp, "%%.%df", right);
	138 }
	139 for (out = start; out * dir <= end * dir; out += step) {
	140 if (out != start)
	141 fputs(sep, stdout);
	142 printf(fmt, out);
	143 }
	144 putchar('\n');
	145
	146 return fshut(stdout, "<stdout>");
	147 }