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scrypt-1.2.1/libcperciva/util/getopt.c  view on Meta::CPAN

const char *
getopt(int argc, char * const argv[])
{
	const char * os = NULL;
	const char * canonical_os = NULL;

	/* No argument yet. */
	optarg = NULL;

	/* Reset the getopt state if needed. */
	if (optreset)
		reset(argc, argv);

	/* If not initialized, return dummy option. */
	if (!getopt_initialized)
		return (GETOPT_DUMMY);

	/* If we've run out of arguments, we're done. */
	if (optind >= argc)
		return (NULL);

	/*
	 * If we're not already in the middle of a packed single-character
	 * options, see if we should start.
	 */
	if ((packedopts == NULL) && (argv[optind][0] == '-') &&
	    (argv[optind][1] != '-') && (argv[optind][1] != '\0')) {
		/* We have one or more single-character options. */
		packedopts = &argv[optind][1];
	}

	/* If we're processing single-character options, fish one out. */
	if (packedopts != NULL) {
		/* Construct the option string. */
		popt[0] = '-';
		popt[1] = *packedopts;
		popt[2] = '\0';
		os = popt;

		/* We've done this character. */
		packedopts++;

		/* Are we done with this string? */
		if (*packedopts == '\0') {
			packedopts = NULL;
			optind++;
		}
	}

	/* If we don't have an option yet, do we have dash-dash? */
	if ((os == NULL) && (argv[optind][0] == '-') &&
	    (argv[optind][1] == '-')) {
		/* If this is not "--\0", it's an option. */
		if (argv[optind][2] != '\0')
			os = argv[optind];

		/* Either way, we want to eat the string. */
		optind++;
	}

	/* If we have found nothing which looks like an option, we're done. */
	if (os == NULL)
		return (NULL);

	/* Search for the potential option. */
	opt_found = searchopt(os);

	/* If the option is not registered, give up now. */
	if (opt_found == opt_default) {
		WARN("unknown option: %s", os);
		return (os);
	}

	/* The canonical option string is the one registered. */
	canonical_os = opts[opt_found].os;

	/* Does the option take an argument? */
	if (opts[opt_found].hasarg) {
		/*
		 * If we're processing packed single-character options, the
		 * rest of the string is the argument to this option.
		 */
		if (packedopts != NULL) {
			optarg = packedopts;
			packedopts = NULL;
			optind++;
		}

		/*
		 * If the option string is <option>=<value>, extract that
		 * value as the option argument.
		 */
		if (os[opts[opt_found].olen] == '=')
			optarg = &os[opts[opt_found].olen + 1];

		/*
		 * If we don't have an argument yet, take one from the
		 * remaining command line.
		 */
		if ((optarg == NULL) && (optind < argc))
			optarg = argv[optind++];

		/* If we still have no option, declare it MIA. */
		if (optarg == NULL) {
			WARN("option requires an argument: %s",
			    opts[opt_found].os);
			opt_found = opt_missing;
		}
	} else {
		/* If we have --foo=bar, something went wrong. */
		if (os[opts[opt_found].olen] == '=') {
			WARN("option doesn't take an argument: %s",
			    opts[opt_found].os);
			opt_found = opt_default;
		}
	}

	/* Return the canonical option string. */
	return (canonical_os);
}