dist/ntp/libntp/getopt.c

   1 /*      $NetBSD$        */
   2
   3 /*
   4  * getopt - get option letter from argv
   5  *
   6  * This is a version of the public domain getopt() implementation by
   7  * Henry Spencer, changed for 4.3BSD compatibility (in addition to System V).
   8  * It allows rescanning of an option list by setting optind to 0 before
   9  * calling, which is why we use it even if the system has its own (in fact,
  10  * this one has a unique name so as not to conflict with the system's).
  11  * Thanks to Dennis Ferguson for the appropriate modifications.
  12  *
  13  * This file is in the Public Domain.
  14  */
  15
  16 /*LINTLIBRARY*/
  17
  18 #include <stdio.h>
  19
  20 #include "ntp_stdlib.h"
  21
  22 #ifdef  lint
  23 #undef  putc
  24 #define putc    fputc
  25 #endif  /* lint */
  26
  27 char    *ntp_optarg;    /* Global argument pointer. */
  28 int     ntp_optind = 0; /* Global argv index. */
  29 int     ntp_opterr = 1; /* for compatibility, should error be printed? */
  30 int     ntp_optopt;     /* for compatibility, option character checked */
  31
  32 static char     *scan = NULL;   /* Private scan pointer. */
  33 static const char       *prog = "amnesia";
  34
  35 /*
  36  * Print message about a bad option.
  37  */
  38 static int
  39 badopt(
  40         const char *mess,
  41         int ch
  42         )
  43 {
  44         if (ntp_opterr) {
  45                 fputs(prog, stderr);
  46                 fputs(mess, stderr);
  47                 (void) putc(ch, stderr);
  48                 (void) putc('\n', stderr);
  49         }
  50         return ('?');
  51 }
  52
  53 int
  54 ntp_getopt(
  55         int argc,
  56         char *argv[],
  57         const char *optstring
  58         )
  59 {
  60         register char c;
  61         register const char *place;
  62
  63         prog = argv[0];
  64         ntp_optarg = NULL;
  65
  66         if (ntp_optind == 0) {
  67                 scan = NULL;
  68                 ntp_optind++;
  69         }
  70
  71         if (scan == NULL || *scan == '\0') {
  72                 if (ntp_optind >= argc
  73                     || argv[ntp_optind][0] != '-'
  74                     || argv[ntp_optind][1] == '\0') {
  75                         return (EOF);
  76                 }
  77                 if (argv[ntp_optind][1] == '-'
  78                     && argv[ntp_optind][2] == '\0') {
  79                         ntp_optind++;
  80                         return (EOF);
  81                 }
  82
  83                 scan = argv[ntp_optind++]+1;
  84         }
  85
  86         c = *scan++;
  87         ntp_optopt = c & 0377;
  88         for (place = optstring; place != NULL && *place != '\0'; ++place)
  89             if (*place == c)
  90                 break;
  91
  92         if (place == NULL || *place == '\0' || c == ':' || c == '?') {
  93                 return (badopt(": unknown option -", c));
  94         }
  95
  96         place++;
  97         if (*place == ':') {
  98                 if (*scan != '\0') {
  99                         ntp_optarg = scan;
 100                         scan = NULL;
 101                 } else if (ntp_optind >= argc) {
 102                         return (badopt(": option requires argument -", c));
 103                 } else {
 104                         ntp_optarg = argv[ntp_optind++];
 105                 }
 106         }
 107
 108         return (c & 0377);
 109 }