git.ozlabs.org Git - ccan/blob - ccan/opt/usage.c

   1 /* Licensed under GPLv3+ - see LICENSE file for details */
   2 #include <ccan/opt/opt.h>
   3 #include <string.h>
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6 #include <stdint.h>
   7 #include "private.h"
   8
   9 /* We only use this for pointer comparisons. */
  10 const char opt_hidden[1];
  11
  12 static unsigned write_short_options(char *str)
  13 {
  14         unsigned int i, num = 0;
  15         const char *p;
  16
  17         for (p = first_sopt(&i); p; p = next_sopt(p, &i)) {
  18                 if (opt_table[i].desc != opt_hidden)
  19                         str[num++] = *p;
  20         }
  21         return num;
  22 }
  23
  24 #define OPT_SPACE_PAD "                    "
  25
  26 /* FIXME: Get all purdy. */
  27 char *opt_usage(const char *argv0, const char *extra)
  28 {
  29         unsigned int i, num, len;
  30         char *ret, *p;
  31
  32         if (!extra) {
  33                 extra = "";
  34                 for (i = 0; i < opt_count; i++) {
  35                         if (opt_table[i].cb == (void *)opt_usage_and_exit
  36                             && opt_table[i].u.carg) {
  37                                 extra = opt_table[i].u.carg;
  38                                 break;
  39                         }
  40                 }
  41         }
  42
  43         /* An overestimate of our length. */
  44         len = strlen("Usage: %s ") + strlen(argv0)
  45                 + strlen("[-%.*s]") + opt_num_short + 1
  46                 + strlen(" ") + strlen(extra)
  47                 + strlen("\n");
  48
  49         for (i = 0; i < opt_count; i++) {
  50                 if (opt_table[i].type == OPT_SUBTABLE) {
  51                         len += strlen("\n") + strlen(opt_table[i].desc)
  52                                 + strlen(":\n");
  53                 } else if (opt_table[i].desc != opt_hidden) {
  54                         len += strlen(opt_table[i].names) + strlen(" <arg>");
  55                         len += strlen(OPT_SPACE_PAD)
  56                                 + strlen(opt_table[i].desc) + 1;
  57                         if (opt_table[i].show) {
  58                                 len += strlen("(default: %s)")
  59                                         + OPT_SHOW_LEN + sizeof("...");
  60                         }
  61                         len += strlen("\n");
  62                 }
  63         }
  64
  65         p = ret = malloc(len);
  66         if (!ret)
  67                 return NULL;
  68
  69         p += sprintf(p, "Usage: %s", argv0);
  70         p += sprintf(p, " [-");
  71         num = write_short_options(p);
  72         if (num) {
  73                 p += num;
  74                 p += sprintf(p, "]");
  75         } else {
  76                 /* Remove start of single-entry options */
  77                 p -= 3;
  78         }
  79         if (extra)
  80                 p += sprintf(p, " %s", extra);
  81         p += sprintf(p, "\n");
  82
  83         for (i = 0; i < opt_count; i++) {
  84                 if (opt_table[i].desc == opt_hidden)
  85                         continue;
  86                 if (opt_table[i].type == OPT_SUBTABLE) {
  87                         p += sprintf(p, "%s:\n", opt_table[i].desc);
  88                         continue;
  89                 }
  90                 len = sprintf(p, "%s", opt_table[i].names);
  91                 if (opt_table[i].type == OPT_HASARG
  92                     && !strchr(opt_table[i].names, ' ')
  93                     && !strchr(opt_table[i].names, '='))
  94                         len += sprintf(p + len, " <arg>");
  95                 len += sprintf(p + len, "%.*s",
  96                                len < strlen(OPT_SPACE_PAD)
  97                                ? (unsigned)strlen(OPT_SPACE_PAD) - len : 1,
  98                                OPT_SPACE_PAD);
  99
 100                 len += sprintf(p + len, "%s", opt_table[i].desc);
 101                 if (opt_table[i].show) {
 102                         char buf[OPT_SHOW_LEN + sizeof("...")];
 103                         strcpy(buf + OPT_SHOW_LEN, "...");
 104                         opt_table[i].show(buf, opt_table[i].u.arg);
 105                         len += sprintf(p + len, " (default: %s)", buf);
 106                 }
 107                 p += len;
 108                 p += sprintf(p, "\n");
 109         }
 110         *p = '\0';
 111         return ret;
 112 }