busybox/coreutils/seq.c

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/* vi: set sw=4 ts=4: */
/*
* seq implementation for busybox
*
* Copyright (C) 2004, Glenn McGrath
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config SEQ
//config: bool "seq (3.6 kb)"
//config: default y
//config: help
//config: print a sequence of numbers
//applet:IF_SEQ(APPLET_NOFORK(seq, seq, BB_DIR_USR_BIN, BB_SUID_DROP, seq))
//kbuild:lib-$(CONFIG_SEQ) += seq.o
//usage:#define seq_trivial_usage
//usage: "[-w] [-s SEP] [FIRST [INC]] LAST"
//usage:#define seq_full_usage "\n\n"
//usage: "Print numbers from FIRST to LAST, in steps of INC.\n"
//usage: "FIRST, INC default to 1.\n"
//usage: "\n -w Pad to last with leading zeros"
//usage: "\n -s SEP String separator"
#include "libbb.h"
/* This is a NOFORK applet. Be very careful! */
int seq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int seq_main(int argc, char **argv)
{
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enum {
OPT_w = (1 << 0),
OPT_s = (1 << 1),
};
double first, last, increment, v;
unsigned n;
unsigned width;
unsigned frac_part;
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const char *sep, *opt_s = "\n";
unsigned opt;
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#if ENABLE_LOCALE_SUPPORT
/* Undo busybox.c: on input, we want to use dot
* as fractional separator, regardless of current locale */
setlocale(LC_NUMERIC, "C");
#endif
opt = getopt32(argv, "+ws:", &opt_s);
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argc -= optind;
argv += optind;
first = increment = 1;
errno = 0;
switch (argc) {
char *pp;
case 3:
increment = strtod(argv[1], &pp);
errno |= *pp;
case 2:
first = strtod(argv[0], &pp);
errno |= *pp;
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case 1:
last = strtod(argv[argc-1], &pp);
if (!errno && *pp == '\0')
break;
default:
bb_show_usage();
}
#if ENABLE_LOCALE_SUPPORT
setlocale(LC_NUMERIC, "");
#endif
/* Last checked to be compatible with: coreutils-6.10 */
width = 0;
frac_part = 0;
while (1) {
char *dot = strchrnul(*argv, '.');
int w = (dot - *argv);
int f = strlen(dot);
if (width < w)
width = w;
argv++;
if (!*argv)
break;
/* Why do the above _before_ frac check below?
* Try "seq 1 2.0" and "seq 1.0 2.0":
* coreutils never pay attention to the number
* of fractional digits in last arg. */
if (frac_part < f)
frac_part = f;
}
if (frac_part) {
frac_part--;
if (frac_part)
width += frac_part + 1;
}
if (!(opt & OPT_w))
width = 0;
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sep = "";
v = first;
n = 0;
while (increment >= 0 ? v <= last : v >= last) {
if (printf("%s%0*.*f", sep, width, frac_part, v) < 0)
break; /* I/O error, bail out (yes, this really happens) */
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sep = opt_s;
/* v += increment; - would accumulate floating point errors */
n++;
v = first + n * increment;
}
if (n) /* if while loop executed at least once */
bb_putchar('\n');
return fflush_all();
}