getopt.c

柏林科技大学开发的gsm编码程序

/*
**	@(#)getopt.c	2.2 (smail) 1/26/87
*/

/*
 * 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.
 */

#ifdef BSD
#define INDEX index
#include <strings.h>
#else
#define INDEX strchr
#include <string.h>
/* #include <io.h> */
#endif
#include "getopt.h"

/*LINTLIBRARY*/
#define NULL	0
#define EOF	(-1)
#define ERR(s, c)	if(opterr){\
	extern int write();\
	char errbuf[2];\
	errbuf[0] = c; errbuf[1] = '\n';\
	(void) write(2, argv[0], (unsigned)strlen(argv[0]));\
	(void) write(2, s, (unsigned)strlen(s));\
	(void) write(2, errbuf, 2);}

extern char *INDEX();

int opterr = 1;
int optind = 1;
int optopt;
char *optarg;

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

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