ack/lang/cem/libcc.ansi/misc/getopt.c

/*
 * getopt - parse command-line options
 */
/* $Id$ */

#include <stdio.h>
#include <string.h>

#define ERR(s, c)               \
	if (opterr)                 \
	{                           \
		fputs(argv[0], stderr); \
		fputs(s, stderr);       \
		fputc(c, stderr);       \
		fputc('\n', stderr);    \
	}

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

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

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