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 #define OPT_SPACE_PAD "                    "
  29
  30 /* FIXME: Get all purdy. */
  31 char *opt_usage(const char *argv0, const char *extra)
  32 {
  33         unsigned int i, num, len;
  34         char *ret, *p;
  35
  36         /* An overestimate of our length. */
  37         len = strlen("Usage: %s ") + strlen(argv0)
  38                 + strlen("[-%.*s]") + opt_count + 1
  39                 + strlen(" ") + strlen(extra)
  40                 + strlen("\n");
  41
  42         for (i = 0; i < opt_count; i++) {
  43                 if (opt_table[i].flags == OPT_SUBTABLE) {
  44                         len += strlen("\n") + strlen(opt_table[i].desc)
  45                                 + strlen(":\n");
  46                 } else {
  47                         len += strlen("--%s/-%c") + strlen(" <arg>");
  48                         if (opt_table[i].longopt)
  49                                 len += strlen(opt_table[i].longopt);
  50                         if (opt_table[i].desc) {
  51                                 len += strlen(OPT_SPACE_PAD)
  52                                         + strlen(opt_table[i].desc) + 1;
  53                         }
  54                         if (opt_table[i].show) {
  55                                 len += strlen("(default: %s)")
  56                                         + OPT_SHOW_LEN + sizeof("...");
  57                         }
  58                         len += strlen("\n");
  59                 }
  60         }
  61
  62         p = ret = malloc(len);
  63         if (!ret)
  64                 return NULL;
  65
  66         p += sprintf(p, "Usage: %s", argv0);
  67         p += sprintf(p, " [-");
  68         num = write_short_options(p);
  69         if (num) {
  70                 p += num;
  71                 p += sprintf(p, "]");
  72         } else {
  73                 /* Remove start of single-entry options */
  74                 p -= 3;
  75         }
  76         if (extra)
  77                 p += sprintf(p, " %s", extra);
  78         p += sprintf(p, "\n");
  79
  80         for (i = 0; i < opt_count; i++) {
  81                 if (opt_table[i].flags == OPT_SUBTABLE) {
  82                         if (opt_table[i].desc == opt_table_hidden) {
  83                                 /* Skip these options. */
  84                                 i += (intptr_t)opt_table[i].arg - 1;
  85                                 continue;
  86                         }
  87                         p += sprintf(p, "%s:\n", opt_table[i].desc);
  88                         continue;
  89                 }
  90                 if (opt_table[i].shortopt && opt_table[i].longopt)
  91                         len = sprintf(p, "--%s/-%c",
  92                                      opt_table[i].longopt,
  93                                       opt_table[i].shortopt);
  94                 else if (opt_table[i].shortopt)
  95                         len = sprintf(p, "-%c", opt_table[i].shortopt);
  96                 else
  97                         len = sprintf(p, "--%s", opt_table[i].longopt);
  98                 if (opt_table[i].flags == OPT_HASARG)
  99                         len += sprintf(p + len, " <arg>");
 100                 if (opt_table[i].desc || opt_table[i].show)
 101                         len += sprintf(p + len, "%.*s",
 102                                        len < strlen(OPT_SPACE_PAD)
 103                                        ? strlen(OPT_SPACE_PAD) - len : 1,
 104                                        OPT_SPACE_PAD);
 105
 106                 if (opt_table[i].desc)
 107                         len += sprintf(p + len, "%s", opt_table[i].desc);
 108                 if (opt_table[i].show) {
 109                         char buf[OPT_SHOW_LEN + sizeof("...")];
 110                         strcpy(buf + OPT_SHOW_LEN, "...");
 111                         opt_table[i].show(buf, opt_table[i].arg);
 112                         len += sprintf(p + len, "%s(default: %s)",
 113                                        opt_table[i].desc ? " " : "", buf);
 114                 }
 115                 p += len;
 116                 p += sprintf(p, "\n");
 117         }
 118         *p = '\0';
 119         return ret;
 120 }