/contrib/ntp/libntp/getopt.c

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