sbase/seq.c

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2.8 KiB
C
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/* See LICENSE file for copyright and license details. */
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "util.h"
static int digitsleft(const char *);
static int digitsright(const char *);
static double estrtod(const char *);
static bool validfmt(const char *);
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static void
usage(void)
{
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eprintf("usage: %s [-f fmt] [-s separator] [-w width] [start"
" [step]] end\n", argv0);
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}
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int
main(int argc, char *argv[])
{
const char *starts = "1", *steps = "1", *ends = "1", *sep = "\n";
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bool wflag = false;
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char *tmp, ftmp[BUFSIZ], *fmt = ftmp;
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double start, step, end, out, dir;
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int left, right;
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ARGBEGIN {
case 'f':
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if(!validfmt(tmp=EARGF(usage())))
eprintf("%s: invalid format\n", tmp);
fmt = tmp;
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break;
case 's':
sep = EARGF(usage());
break;
case 'w':
wflag = true;
break;
default:
usage();
} ARGEND;
switch(argc) {
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case 3:
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steps = argv[1];
argv[1] = argv[2];
/* fallthrough */
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case 2:
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starts = argv[0];
argv++;
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/* fallthrough */
case 1:
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ends = argv[0];
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break;
default:
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usage();
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}
start = estrtod(starts);
step = estrtod(steps);
end = estrtod(ends);
dir = (step > 0) ? 1.0 : -1.0;
if(step == 0 || start * dir > end * dir)
return EXIT_FAILURE;
if(fmt == ftmp) {
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right = MAX(digitsright(starts),
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MAX(digitsright(ends),
digitsright(steps)));
if(wflag) {
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left = MAX(digitsleft(starts), digitsleft(ends));
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snprintf(ftmp, sizeof ftmp, "%%0%d.%df",
right+left+(right != 0), right);
} else
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snprintf(ftmp, sizeof ftmp, "%%.%df", right);
}
for(out = start; out * dir <= end * dir; out += step) {
if(out != start)
fputs(sep, stdout);
printf(fmt, out);
}
printf("\n");
return EXIT_SUCCESS;
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}
int
digitsleft(const char *d)
{
char *exp;
int shift;
if(*d == '+')
d++;
exp = strpbrk(d, "eE");
shift = exp ? atoi(&exp[1]) : 0;
return MAX(0, strspn(d, "-0123456789")+shift);
}
int
digitsright(const char *d)
{
char *exp;
int shift, after;
exp = strpbrk(d, "eE");
shift = exp ? atoi(&exp[1]) : 0;
after = (d = strchr(d, '.')) ? strspn(&d[1], "0123456789") : 0;
return MAX(0, after-shift);
}
double
estrtod(const char *s)
{
char *end;
double d;
d = strtod(s, &end);
if(end == s || *end != '\0')
eprintf("%s: not a real number\n", s);
return d;
}
bool
validfmt(const char *fmt)
{
int occur = 0;
literal:
while(*fmt)
if(*fmt++ == '%')
goto format;
return occur == 1;
format:
if(*fmt == '%') {
fmt++;
goto literal;
}
fmt += strspn(fmt, "-+#0 '");
fmt += strspn(fmt, "0123456789");
if(*fmt == '.') {
fmt++;
fmt += strspn(fmt, "0123456789");
}
if(*fmt == 'L')
fmt++;
switch(*fmt) {
case 'f': case 'F':
case 'g': case 'G':
case 'e': case 'E':
case 'a': case 'A':
occur++;
goto literal;
default:
return false;
}
}
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