LXR busybox/coreutils/seq.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * seq implementation for busybox
   4 *
   5 * Copyright (C) 2004, Glenn McGrath
   6 *
   7 * Licensed under GPLv2, see file LICENSE in this source tree.
   8 */
   9
  10//usage:#define seq_trivial_usage
  11//usage:       "[-w] [-s SEP] [FIRST [INC]] LAST"
  12//usage:#define seq_full_usage "\n\n"
  13//usage:       "Print numbers from FIRST to LAST, in steps of INC.\n"
  14//usage:       "FIRST, INC default to 1.\n"
  15//usage:     "\n        -w      Pad to last with leading zeros"
  16//usage:     "\n        -s SEP  String separator"
  17
  18#include "libbb.h"
  19
  20/* This is a NOFORK applet. Be very careful! */
  21
  22int seq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  23int seq_main(int argc, char **argv)
  24{
  25        enum {
  26                OPT_w = (1 << 0),
  27                OPT_s = (1 << 1),
  28        };
  29        double first, last, increment, v;
  30        unsigned n;
  31        unsigned width;
  32        unsigned frac_part;
  33        const char *sep, *opt_s = "\n";
  34        unsigned opt;
  35
  36#if ENABLE_LOCALE_SUPPORT
  37        /* Undo busybox.c: on input, we want to use dot
  38         * as fractional separator, regardless of current locale */
  39        setlocale(LC_NUMERIC, "C");
  40#endif
  41
  42        opt = getopt32(argv, "+ws:", &opt_s);
  43        argc -= optind;
  44        argv += optind;
  45        first = increment = 1;
  46        errno = 0;
  47        switch (argc) {
  48                        char *pp;
  49                case 3:
  50                        increment = strtod(argv[1], &pp);
  51                        errno |= *pp;
  52                case 2:
  53                        first = strtod(argv[0], &pp);
  54                        errno |= *pp;
  55                case 1:
  56                        last = strtod(argv[argc-1], &pp);
  57                        if (!errno && *pp == '\0')
  58                                break;
  59                default:
  60                        bb_show_usage();
  61        }
  62
  63#if ENABLE_LOCALE_SUPPORT
  64        setlocale(LC_NUMERIC, "");
  65#endif
  66
  67        /* Last checked to be compatible with: coreutils-6.10 */
  68        width = 0;
  69        frac_part = 0;
  70        while (1) {
  71                char *dot = strchrnul(*argv, '.');
  72                int w = (dot - *argv);
  73                int f = strlen(dot);
  74                if (width < w)
  75                        width = w;
  76                argv++;
  77                if (!*argv)
  78                        break;
  79                /* Why do the above _before_ frac check below?
  80                 * Try "seq 1 2.0" and "seq 1.0 2.0":
  81                 * coreutils never pay attention to the number
  82                 * of fractional digits in last arg. */
  83                if (frac_part < f)
  84                        frac_part = f;
  85        }
  86        if (frac_part) {
  87                frac_part--;
  88                if (frac_part)
  89                        width += frac_part + 1;
  90        }
  91        if (!(opt & OPT_w))
  92                width = 0;
  93
  94        sep = "";
  95        v = first;
  96        n = 0;
  97        while (increment >= 0 ? v <= last : v >= last) {
  98                if (printf("%s%0*.*f", sep, width, frac_part, v) < 0)
  99                        break; /* I/O error, bail out (yes, this really happens) */
 100                sep = opt_s;
 101                /* v += increment; - would accumulate floating point errors */
 102                n++;
 103                v = first + n * increment;
 104        }
 105        if (n) /* if while loop executed at least once */
 106                bb_putchar('\n');
 107
 108        return fflush_all();
 109}
 110