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         /* An overestimate of our length. */
  32         len = strlen("Usage: %s ") + strlen(argv0)
  33                 + strlen("[-%.*s]") + opt_num_short + 1
  34                 + strlen(" ") + strlen(extra)
  35                 + strlen("\n");
  36
  37         for (i = 0; i < opt_count; i++) {
  38                 if (opt_table[i].flags == OPT_SUBTABLE) {
  39                         len += strlen("\n") + strlen(opt_table[i].desc)
  40                                 + strlen(":\n");
  41                 } else if (opt_table[i].desc != opt_hidden) {
  42                         len += strlen(opt_table[i].names) + strlen(" <arg>");
  43                         if (opt_table[i].desc) {
  44                                 len += strlen(OPT_SPACE_PAD)
  45                                         + strlen(opt_table[i].desc) + 1;
  46                         }
  47                         if (opt_table[i].show) {
  48                                 len += strlen("(default: %s)")
  49                                         + OPT_SHOW_LEN + sizeof("...");
  50                         }
  51                         len += strlen("\n");
  52                 }
  53         }
  54
  55         p = ret = malloc(len);
  56         if (!ret)
  57                 return NULL;
  58
  59         p += sprintf(p, "Usage: %s", argv0);
  60         p += sprintf(p, " [-");
  61         num = write_short_options(p);
  62         if (num) {
  63                 p += num;
  64                 p += sprintf(p, "]");
  65         } else {
  66                 /* Remove start of single-entry options */
  67                 p -= 3;
  68         }
  69         if (extra)
  70                 p += sprintf(p, " %s", extra);
  71         p += sprintf(p, "\n");
  72
  73         for (i = 0; i < opt_count; i++) {
  74                 if (opt_table[i].desc == opt_hidden)
  75                         continue;
  76                 if (opt_table[i].flags == OPT_SUBTABLE) {
  77                         p += sprintf(p, "%s:\n", opt_table[i].desc);
  78                         continue;
  79                 }
  80                 len = sprintf(p, "%s", opt_table[i].names);
  81                 if (opt_table[i].flags == OPT_HASARG)
  82                         len += sprintf(p + len, " <arg>");
  83                 if (opt_table[i].desc || opt_table[i].show)
  84                         len += sprintf(p + len, "%.*s",
  85                                        len < strlen(OPT_SPACE_PAD)
  86                                        ? strlen(OPT_SPACE_PAD) - len : 1,
  87                                        OPT_SPACE_PAD);
  88
  89                 if (opt_table[i].desc)
  90                         len += sprintf(p + len, "%s", opt_table[i].desc);
  91                 if (opt_table[i].show) {
  92                         char buf[OPT_SHOW_LEN + sizeof("...")];
  93                         strcpy(buf + OPT_SHOW_LEN, "...");
  94                         opt_table[i].show(buf, opt_table[i].arg);
  95                         len += sprintf(p + len, "%s(default: %s)",
  96                                        opt_table[i].desc ? " " : "", buf);
  97                 }
  98                 p += len;
  99                 p += sprintf(p, "\n");
 100         }
 101         *p = '\0';
 102         return ret;
 103 }