//
// Here's something you've all been waiting for:  the AT&T public domain
// source for getopt(3).  It is the code which was given out at the 1985
// UNIFORUM conference in Dallas.  I obtained it by electronic mail
// directly from AT&T.  The people there assure me that it is indeed
// in the public domain.
//
// There is no manual page.  That is because the one they gave out at
// UNIFORUM was slightly different from the current System V Release 2
// manual page.  The difference apparently involved a note about the
// famous rules 5 and 6, recommending using white space between an option
// and its first argument, and not grouping options that have arguments.
// Getopt itself is currently lenient about both of these things White
// space is allowed, but not mandatory, and the last option in a group can
// have an argument.  That particular version of the man page evidently
// has no official existence, and my source at AT&T did not send a copy.
// The current SVR2 man page reflects the actual behavor of this getopt.
// However, I am not about to post a copy of anything licensed by AT&T.
//
//    -- Andrew Derbyshire
//
#include <stdio.h>
#include <string.h>
#define  index strchr

#include "getopt.h"

#define ERR(s,c) fprintf(stderr,"%s%s%c\n", argv[0],s,c)

//
// Globals used by the caller
//
int   optind = 1;
int   optopt;
char  *optarg;

int getopts(int argc, char **argv, char *opts)
{
   static int sp = 1;
   register int c;
   register char *cp;

   if (optind < argc && argv[optind][0] == '-' && argv[optind][1] == '\0')
	   if((cp=index(opts, '-')) != NULL) {
		   optind++;
		   return('-');
	   } else {
		   optind++;
           return('?');
       }

   if(sp == 1)
      if(optind >= argc || argv[optind][0] != '-' || argv[optind][1] == '\0')
         return(EOF);
      else if(strcmp(argv[optind], "--") == 0) {
         optind++;
         return(EOF);
      }

   optopt = c = argv[optind][sp];

   if(c == ':' || (cp=index(opts, c)) == NULL) {
      ERR(": illegal option -- ", c);
      if(argv[optind][++sp] == '\0') {
         optind++;
         sp = 1;
      }
      return('?');
   }

   if(*++cp == ':') {
      if(argv[optind][sp+1] != '\0')
         optarg = &argv[optind++][sp+1];
      else if(++optind >= argc) {
         ERR(": option requires an argument -- ", c);
         sp = 1;
         return('?');
      } else
         optarg = argv[optind++];
      sp = 1;
   } else {
      if(argv[optind][++sp] == '\0') {
         sp = 1;
         optind++;
      }
      optarg = NULL;
   }
   return(c);
}