exiv2/app/getopt.cpp

// SPDX-License-Identifier: GPL-2.0-or-later

// included header files
#include "getopt.hpp"

#include <cstdio>
#include <cstring>
#include <filesystem>

namespace fs = std::filesystem;

namespace Util {

    // https://raw.githubusercontent.com/skeeto/getopt/master/getopt.h
    int optind = 0;
    int opterr = 1;
    int optopt;
    int optpos = 1;
    const char* optarg;

	/* A minimal POSIX getopt() implementation in ANSI C
	 *
	 * This is free and unencumbered software released into the public domain.
	 *
	 * This implementation supports the convention of resetting the option
	 * parser by assigning optind to 0. This resets the internal state
	 * appropriately.
	 *
	 * Ref: http://pubs.opengroup.org/onlinepubs/9699919799/functions/getopt.html
	 */

	int getopt(int argc, char * const argv[], const char *optstring)
	{
		const char *arg;
		(void)argc;

		/* Reset? */
		if (optind == 0) {
			optind = 1;
			optpos = 1;
		}

		arg = argv[optind];
		if (arg && strcmp(arg, "--") == 0) {
			optind++;
			return -1;
        }
        if (!arg || arg[0] != '-' || !isalnum(arg[1])) {
            return -1;
        }
        const char *opt = strchr(optstring, arg[optpos]);
        optopt = arg[optpos];
        if (!opt) {
            if (opterr && *optstring != ':')
                fprintf(stderr, "%s: illegal option: %c\n", argv[0], optopt);
            return '?';
        }
        if (opt[1] == ':') {
            if (arg[optpos + 1]) {
                optarg = const_cast<char*>(arg) + optpos + 1;
                optind++;
                optpos = 1;
                return optopt;
            }
            if (argv[optind + 1]) {
                optarg = argv[optind + 1];
                optind += 2;
                optpos = 1;
                return optopt;
            }
            if (opterr && *optstring != ':')
                fprintf(stderr, "%s: option requires an argument: %c\n", argv[0], optopt);
            return *optstring == ':' ? ':' : '?';
        }
        if (!arg[++optpos]) {
            optind++;
            optpos = 1;
        }
        return optopt;
    }

// *****************************************************************************
// class Getopt
    Getopt::Getopt()
        : errcnt_(0)
    {
    }

    int Getopt::getopt(int argc, char* const argv[], const std::string& optstring)
    {
        progname_ = fs::path(argv[0]).filename().string();
        Util::optind = 0; // reset the Util::Getopt scanner

        for (;!errcnt_;) {
            int c = Util::getopt(argc, argv, optstring.c_str());
            if (c == -1) {
                break;
            }
            errcnt_ += option(c, Util::optarg ? Util::optarg : "", Util::optopt);
            if (c == '?' ) {
                break;
            }
        }
        for (int i = Util::optind; i < argc; i++) {
            errcnt_ += nonoption(argv[i]);
        }

        return errcnt_;
    }

    int Getopt::nonoption(const std::string& /*argv*/)
    {
        return 0;
    }

} // namespace Util