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 //config:config SEQ
  10 //config:       bool "seq (4 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       print a sequence of numbers
  14
  15 //applet:IF_SEQ(APPLET_NOEXEC(seq, seq, BB_DIR_USR_BIN, BB_SUID_DROP, seq))
  16 /* was NOFORK, but then "seq 1 999999999" can't be ^C'ed if run by hush */
  17
  18 //kbuild:lib-$(CONFIG_SEQ) += seq.o
  19
  20 //usage:#define seq_trivial_usage
  21 //usage:       "[-w] [-s SEP] [FIRST [INC]] LAST"
  22 //usage:#define seq_full_usage "\n\n"
  23 //usage:       "Print numbers from FIRST to LAST, in steps of INC.\n"
  24 //usage:       "FIRST, INC default to 1.\n"
  25 //usage:     "\n        -w      Pad with leading zeros"
  26 //usage:     "\n        -s SEP  String separator"
  27
  28 #include "libbb.h"
  29
  30 /* This is a NOEXEC applet. Be very careful! */
  31
  32 int seq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  33 int seq_main(int argc, char **argv)
  34 {
  35         enum {
  36                 OPT_w = (1 << 0),
  37                 OPT_s = (1 << 1),
  38         };
  39         double first, last, increment, v;
  40         unsigned n;
  41         unsigned width;
  42         unsigned frac_part;
  43         const char *sep, *opt_s = "\n";
  44         char *saved;
  45         unsigned opt;
  46
  47 #if ENABLE_LOCALE_SUPPORT
  48         /* Undo busybox.c: on input, we want to use dot
  49          * as fractional separator, regardless of current locale */
  50         setlocale(LC_NUMERIC, "C");
  51 #endif
  52
  53         /* Cater for negative arguments: if we see one, truncate argv[] on it */
  54         n = 0;
  55         for (;;) {
  56                 char c;
  57                 saved = argv[++n];
  58                 if (!saved)
  59                         break;
  60                 if (saved[0] != '-') {
  61                         // break; // "seq -s : -1 1" won't be treated correctly
  62                         continue;
  63                 }
  64 // "seq -s -1 1 9" is not treated correctly, but such usage
  65 // (delimiter string which looks like negative number) is very unlikely
  66                 c = saved[1];
  67                 if (c == '.' || (c >= '0' && c <= '9')) {
  68                         argv[n] = NULL;
  69                         break;
  70                 }
  71         }
  72         opt = getopt32(argv, "+ws:", &opt_s); /* "+": stop at first non-option */
  73         /* Restore possibly truncated argv[] */
  74         argv[n] = saved;
  75
  76         argc -= optind;
  77         argv += optind;
  78         first = increment = 1;
  79         errno = 0;
  80         switch (argc) {
  81                         char *pp;
  82                 case 3:
  83                         increment = strtod(argv[1], &pp);
  84                         errno |= *pp;
  85                 case 2:
  86                         first = strtod(argv[0], &pp);
  87                         errno |= *pp;
  88                 case 1:
  89                         last = strtod(argv[argc-1], &pp);
  90                         if (!errno && *pp == '\0')
  91                                 break;
  92                 default:
  93                         bb_show_usage();
  94         }
  95
  96 #if ENABLE_LOCALE_SUPPORT
  97         setlocale(LC_NUMERIC, "");
  98 #endif
  99
 100         /* Last checked to be compatible with: coreutils-6.10 */
 101         width = 0;
 102         frac_part = 0;
 103         while (1) {
 104                 char *dot = strchrnul(*argv, '.');
 105                 int w = (dot - *argv);
 106                 int f = strlen(dot);
 107                 if (width < w)
 108                         width = w;
 109                 argv++;
 110                 if (!*argv)
 111                         break;
 112                 /* Why do the above _before_ frac check below?
 113                  * Try "seq 1 2.0" and "seq 1.0 2.0":
 114                  * coreutils never pay attention to the number
 115                  * of fractional digits in last arg. */
 116                 if (frac_part < f)
 117                         frac_part = f;
 118         }
 119         if (frac_part) {
 120                 frac_part--;
 121                 if (frac_part)
 122                         width += frac_part + 1;
 123         }
 124         if (!(opt & OPT_w))
 125                 width = 0;
 126
 127         sep = "";
 128         v = first;
 129         n = 0;
 130         while (increment >= 0 ? v <= last : v >= last) {
 131                 if (printf("%s%0*.*f", sep, width, frac_part, v) < 0)
 132                         break; /* I/O error, bail out (yes, this really happens) */
 133                 sep = opt_s;
 134                 /* v += increment; - would accumulate floating point errors */
 135                 n++;
 136                 v = first + n * increment;
 137         }
 138         if (n) /* if while loop executed at least once */
 139                 bb_putchar('\n');
 140
 141         return fflush_all();
 142 }