getopt.c revision 285612 
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 <config.h>
17#include <stdio.h>
18
19#include "ntp_stdlib.h"
20
21#ifdef	lint
22#undef	putc
23#define	putc	fputc
24#endif	/* lint */
25
26char	*ntp_optarg;	/* Global argument pointer. */
27int	ntp_optind = 0;	/* Global argv index. */
28int	ntp_opterr = 1;	/* for compatibility, should error be printed? */
29int	ntp_optopt;	/* for compatibility, option character checked */
30
31static char	*scan = NULL;	/* Private scan pointer. */
32static const char	*prog = "amnesia";
33
34/*
35 * Print message about a bad option.
36 */
37static int
38badopt(
39	const char *mess,
40	int ch
41	)
42{
43	if (ntp_opterr) {
44		fputs(prog, stderr);
45		fputs(mess, stderr);
46		(void) putc(ch, stderr);
47		(void) putc('\n', stderr);
48	}
49	return ('?');
50}
51
52int
53ntp_getopt(
54	int argc,
55	char *argv[],
56	const char *optstring
57	)
58{
59	register char c;
60	register const char *place;
61
62	prog = argv[0];
63	ntp_optarg = NULL;
64
65	if (ntp_optind == 0) {
66		scan = NULL;
67		ntp_optind++;
68	}
69
70	if (scan == NULL || *scan == '\0') {
71		if (ntp_optind >= argc
72		    || argv[ntp_optind][0] != '-'
73		    || argv[ntp_optind][1] == '\0') {
74			return (EOF);
75		}
76		if (argv[ntp_optind][1] == '-'
77		    && argv[ntp_optind][2] == '\0') {
78			ntp_optind++;
79			return (EOF);
80		}
81
82		scan = argv[ntp_optind++]+1;
83	}
84
85	c = *scan++;
86	ntp_optopt = c & 0377;
87	for (place = optstring; place != NULL && *place != '\0'; ++place)
88	    if (*place == c)
89		break;
90
91	if (place == NULL || *place == '\0' || c == ':' || c == '?') {
92		return (badopt(": unknown option -", c));
93	}
94
95	place++;
96	if (*place == ':') {
97		if (*scan != '\0') {
98			ntp_optarg = scan;
99			scan = NULL;
100		} else if (ntp_optind >= argc) {
101			return (badopt(": option requires argument -", c));
102		} else {
103			ntp_optarg = argv[ntp_optind++];
104		}
105	}
106
107	return (c & 0377);
108}
109