t/helpopt.c

   1 /*
   2  * Test helper application to verify help_print_optstring operation.
   3  *
   4  * Copyright © 2021-2022, 2024 Nick Bowler
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  18  */
  19
  20 /*
  21  * Command-line arguments are collected to create the options to be formatted.
  22  * There are six basic forms:
  23  *
  24  *   --long-option-only
  25  *   --long-option-with-argument arg
  26  *   --long-option-with-optional-argument [arg]
  27  *   --short-option -s arg
  28  *   --short-option-with-argument -s arg
  29  *   --short-option-with-optional-argument -s [arg]
  30  *
  31  * Adding an argument of '&' to any form will set the "flag" member of
  32  * the option structure to a non-null value.
  33  *
  34  * Based on these arguments, a suitable 'struct option' is constructed and
  35  * passed to help_print_optstring.  Then a tab character is printed, followed
  36  * by the return value of help_print_optsring (via printf %d).  Then further
  37  * arguments are considered to output more options.
  38  *
  39  * Initially, the "l" value passed to help_print_optstring is 20.  This can be
  40  * changed at any point by a numeric command-line argument, which will set a
  41  * new value that applies to all subsequent calls until it is changed again.
  42  */
  43
  44 #include "help.h"
  45 #include "tap.h"
  46
  47 #include <stdio.h>
  48 #include <stdlib.h>
  49 #include <string.h>
  50 #include <limits.h>
  51 #include <errno.h>
  52
  53 #include "gnu_getopt.h"
  54
  55 int arg_to_int(const char *s)
  56 {
  57         char *end;
  58         long val;
  59
  60         errno = 0;
  61         val = strtol(s, &end, 0);
  62         if (*end != 0)
  63                 tap_bail_out("%s: numeric argument expected", s);
  64         else if (val < INT_MIN || val > INT_MAX || errno == ERANGE)
  65                 tap_bail_out("%s: %s", s, strerror(ERANGE));
  66         else if (errno)
  67                 tap_bail_out("%s: %s", s, strerror(errno));
  68
  69         return val;
  70 }
  71
  72 void print_opt(struct option *opt, const char *argname, int w)
  73 {
  74         w = help_print_optstring(opt, argname, w);
  75         printf("\t%d\n", w);
  76 }
  77
  78 int main(int argc, char **argv)
  79 {
  80         struct option opt = {0};
  81         const char *argname = 0;
  82         int i, w = 20;
  83
  84         for (i = 1; i < argc; i++) {
  85                 if (argv[i][0] == '-' && argv[i][1] == '-') {
  86                         if (opt.name)
  87                                 print_opt(&opt, argname, w);
  88                         opt.val = UCHAR_MAX+1;
  89                         opt.has_arg = 0;
  90                         opt.name = argv[i]+2;
  91                         opt.flag = NULL;
  92                 } else if (argv[i][0] == '-') {
  93                         opt.val = argv[i][1];
  94                 } else if (argv[i][0] == '[') {
  95                         char *c;
  96
  97                         argname = argv[i]+1;
  98                         if ((c = strchr(argname, ']')))
  99                                 *c = 0;
 100                         opt.has_arg = 2;
 101                 } else if (argv[i][0] == '&') {
 102                         static int dummy;
 103                         opt.flag = &dummy;
 104                 } else if (argv[i][0] >= '0' && argv[i][0] <= '9') {
 105                         w = arg_to_int(argv[i]);
 106                 } else {
 107                         argname = argv[i];
 108                         opt.has_arg = 1;
 109                 }
 110         }
 111
 112         if (opt.name)
 113                 print_opt(&opt, argname, w);
 114
 115         return 0;
 116 }