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