/*      $OpenBSD: egetopt.c,v 1.9 2013/11/26 13:19:07 deraadt Exp $     */

/*-
 * Copyright (c) 1991 Keith Muller.
 * Copyright (c) 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Keith Muller of the University of California, San Diego.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

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

#include "extern.h"

/*
 * egetopt:     get option letter from argument vector (an extended
 *              version of getopt).
 *
 * Non standard additions to the ostr specs are:
 * 1) '?': immediate value following arg is optional (no white space
 *    between the arg and the value)
 * 2) '#': +/- followed by a number (with an optional sign but
 *    no white space between the arg and the number). The - may be
 *    combined with other options, but the + cannot.
 */

int     eopterr = 1;            /* if error message should be printed */
int     eoptind = 1;            /* index into parent argv vector */
int     eoptopt;                /* character checked for validity */
char    *eoptarg;               /* argument associated with option */

#define BADCH   (int)'?'
#define EMSG    ""

int
egetopt(int nargc, char * const *nargv, const char *ostr)
{
        static char *place = EMSG;      /* option letter processing */
        char *oli;                      /* option letter list index */
        static int delim;               /* which option delimiter */
        char *p;
        static char savec = '\0';

        if (savec != '\0') {
                *place = savec;
                savec = '\0';
        }

        if (!*place) {
                /*
                 * update scanning pointer
                 */
                if ((eoptind >= nargc) ||
                    ((*(place = nargv[eoptind]) != '-') && (*place != '+'))) {
                        place = EMSG;
                        return (-1);
                }

                delim = (int)*place;
                if (place[1] && *++place == '-' && !place[1]) {
                        /*
                         * found "--"
                         */
                        ++eoptind;
                        place = EMSG;
                        return (-1);
                }
        }

        /*
         * check option letter
         */
        if ((eoptopt = (int)*place++) == (int)':' || (eoptopt == (int)'?') ||
            !(oli = strchr(ostr, eoptopt))) {
                /*
                 * if the user didn't specify '-' as an option,
                 * assume it means EOF when by itself.
                 */
                if ((eoptopt == (int)'-') && !*place)
                        return (-1);
                if (strchr(ostr, '#') && (isdigit((unsigned char)eoptopt) ||
                    (((eoptopt == (int)'-') || (eoptopt == (int)'+')) &&
                      isdigit((unsigned char)*place)))) {
                        /*
                         * # option: +/- with a number is ok
                         */
                        for (p = place; *p != '\0'; ++p) {
                                if (!isdigit((unsigned char)*p))
                                        break;
                        }
                        eoptarg = place-1;

                        if (*p == '\0') {
                                place = EMSG;
                                ++eoptind;
                        } else {
                                place = p;
                                savec = *p;
                                *place = '\0';
                        }
                        return (delim);
                }

                if (!*place)
                        ++eoptind;
                if (eopterr) {
                        if (!(p = strrchr(*nargv, '/')))
                                p = *nargv;
                        else
                                ++p;
                        (void)fprintf(stderr, "%s: illegal option -- %c\n",
                            p, eoptopt);
                }
                return (BADCH);
        }
        if (delim == (int)'+') {
                /*
                 * '+' is only allowed with numbers
                 */
                if (!*place)
                        ++eoptind;
                if (eopterr) {
                        if (!(p = strrchr(*nargv, '/')))
                                p = *nargv;
                        else
                                ++p;
                        (void)fprintf(stderr,
                                "%s: illegal '+' delimiter with option -- %c\n",
                                p, eoptopt);
                }
                return (BADCH);
        }
        ++oli;
        if ((*oli != ':') && (*oli != '?')) {
                /*
                 * don't need argument
                 */
                eoptarg = NULL;
                if (!*place)
                        ++eoptind;
                return (eoptopt);
        }

        if (*place) {
                /*
                 * no white space
                 */
                eoptarg = place;
        } else if (*oli == '?') {
                /*
                 * no arg, but NOT required
                 */
                eoptarg = NULL;
        } else if (nargc <= ++eoptind) {
                /*
                 * no arg, but IS required
                 */
                place = EMSG;
                if (eopterr) {
                        if (!(p = strrchr(*nargv, '/')))
                                p = *nargv;
                        else
                                ++p;
                        (void)fprintf(stderr,
                            "%s: option requires an argument -- %c\n", p,
                            eoptopt);
                }
                return (BADCH);
        } else {
                /*
                 * arg has white space
                 */
                eoptarg = nargv[eoptind];
        }
        place = EMSG;
        ++eoptind;
        return (eoptopt);
}