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

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