sbase/seq.c

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2.8 KiB
C
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2012-06-09 13:53:05 -04:00
/* 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 *);
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 c, ftmp[BUFSIZ], *fmt = ftmp;
double start, step, end, out, dir;
while((c = getopt(argc, argv, "f:s:w")) != -1)
switch(c) {
case 'f':
if(!validfmt(optarg))
eprintf("%s: invalid format\n", optarg);
fmt = optarg;
break;
case 's':
sep = optarg;
break;
case 'w':
wflag = true;
break;
}
switch(argc-optind) {
case 3:
starts = argv[optind++];
steps = argv[optind++];
ends = argv[optind++];
break;
case 2:
starts = argv[optind++];
/* fallthrough */
case 1:
ends = argv[optind++];
break;
default:
eprintf("usage: %s [-w] [-f fmt] [-s separator] [start [step]] end\n", argv[0]);
}
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) {
int right = MAX(digitsright(starts),
MAX(digitsright(ends),
digitsright(steps)));
if(wflag) {
int left = MAX(digitsleft(starts), digitsleft(ends));
snprintf(ftmp, sizeof ftmp, "%%0%d.%df", right+left+(right != 0), right);
}
else
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;
}
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;
}
}