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_table_hidden[1];
  10
  11 static unsigned write_short_options(char *str)
  12 {
  13         unsigned int i, num = 0;
  14
  15         for (i = 0; i < opt_count; i++) {
  16                 if (opt_table[i].flags == OPT_SUBTABLE) {
  17                         if (opt_table[i].desc == opt_table_hidden) {
  18                                 /* Skip these options. */
  19                                 i += (intptr_t)opt_table[i].arg - 1;
  20                                 continue;
  21                         }
  22                 } else if (opt_table[i].shortopt)
  23                         str[num++] = opt_table[i].shortopt;
  24         }
  25         return num;
  26 }
  27
  28 /* FIXME: Get all purdy. */
  29 char *opt_usage(const char *argv0, const char *extra)
  30 {
  31         unsigned int i, num, len;
  32         char *ret, *p;
  33
  34         /* An overestimate of our length. */
  35         len = strlen("Usage: %s ") + strlen(argv0)
  36                 + strlen("[-%.*s]") + opt_count + 1
  37                 + strlen(" ") + strlen(extra)
  38                 + strlen("\n");
  39
  40         for (i = 0; i < opt_count; i++) {
  41                 if (opt_table[i].flags == OPT_SUBTABLE) {
  42                         len += strlen("\n") + strlen(opt_table[i].desc)
  43                                 + strlen(":\n");
  44                 } else {
  45                         len += strlen("--%s/-%c") + strlen(" <arg>");
  46                         if (opt_table[i].longopt)
  47                                 len += strlen(opt_table[i].longopt);
  48                         if (opt_table[i].desc)
  49                                 len += 20 + strlen(opt_table[i].desc);
  50                         len += strlen("\n");
  51                 }
  52         }
  53
  54         p = ret = malloc(len);
  55         if (!ret)
  56                 return NULL;
  57
  58         p += sprintf(p, "Usage: %s", argv0);
  59         p += sprintf(p, " [-");
  60         num = write_short_options(p);
  61         if (num) {
  62                 p += num;
  63                 p += sprintf(p, "]");
  64         } else {
  65                 /* Remove start of single-entry options */
  66                 p -= 3;
  67         }
  68         if (extra)
  69                 p += sprintf(p, " %s", extra);
  70         p += sprintf(p, "\n");
  71
  72         for (i = 0; i < opt_count; i++) {
  73                 if (opt_table[i].flags == OPT_SUBTABLE) {
  74                         if (opt_table[i].desc == opt_table_hidden) {
  75                                 /* Skip these options. */
  76                                 i += (intptr_t)opt_table[i].arg - 1;
  77                                 continue;
  78                         }
  79                         p += sprintf(p, "%s:\n", opt_table[i].desc);
  80                         continue;
  81                 }
  82                 if (opt_table[i].shortopt && opt_table[i].longopt)
  83                         len = sprintf(p, "--%s/-%c",
  84                                      opt_table[i].longopt,
  85                                       opt_table[i].shortopt);
  86                 else if (opt_table[i].shortopt)
  87                         len = sprintf(p, "-%c", opt_table[i].shortopt);
  88                 else
  89                         len = sprintf(p, "--%s", opt_table[i].longopt);
  90                 if (opt_table[i].flags == OPT_HASARG)
  91                         len += sprintf(p + len, " <arg>");
  92                 if (opt_table[i].desc) {
  93                         len += sprintf(p + len, "%.*s",
  94                                        len < 20 ? 20 - len : 1,
  95                                        "                    ");
  96                         len += sprintf(p + len, "%s", opt_table[i].desc);
  97                 }
  98                 p += len;
  99                 p += sprintf(p, "\n");
 100         }
 101         *p = '\0';
 102         return ret;
 103 }