/*      $NetBSD: doscommain.c,v 1.1 2024/06/29 13:45:14 rin Exp $       */

/*
 * Copyright (c) 1996
 *      Matthias Drochner.  All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 */

/* argument line processing for DOS .COM programs */

#include <lib/libsa/stand.h>

/* The Program Segment Prefix */

static struct psp{
        char mist1[0x2c];
        short envseg;
        char mist2[0x80-2-0x2c];
        char cmdlen;
        char cmd[127];
} *PSP = (struct psp*)0;

static char* argv[64]; /* theor max */

static int whitespace(char);

static int
whitespace(char c)
{
        if ((c == '\0') || (c == ' ') || (c == '\t')
            || (c == '\r') || (c == '\n'))
                return (1);
        return 0;
}

enum state {skipping, doing_arg, doing_long_arg};

/* build argv/argc, start real main() */
int doscommain(void);
extern int main(int, char**);

int
doscommain(void)
{
        int argc, i;
        enum state s;

        argv[0] = "???"; /* we don't know */
        argc = 1;
        s = skipping;

        for (i = 0; i < PSP->cmdlen; i++){

                if (whitespace(PSP->cmd[i])) {
                        if (s == doing_arg) {
                                /* end of argument word */
                                PSP->cmd[i] = '\0';
                                s = skipping;
                        }
                        continue;
                }

                if (PSP->cmd[i] == '"') {
                        /* start or end long arg
                         * (end only if next char is whitespace)
                         *  XXX but '" ' cannot be in argument
                         */
                        switch (s) {
                        case skipping:
                                /* next char begins new argument word */
                                argv[argc++] = &PSP->cmd[i + 1];
                                s = doing_long_arg;
                                break;
                        case doing_long_arg:
                                if (whitespace(PSP->cmd[i + 1])) {
                                        PSP->cmd[i] = '\0';
                                        s = skipping;
                                }
                        case doing_arg:
                                /* ignore in the middle of arguments */
                        default:
                                break;
                        }
                        continue;
                }

                /* all other characters */
                if (s == skipping) {
                        /* begin new argument word */
                        argv[argc++] = &PSP->cmd[i];
                        s = doing_arg;
                }
        }
        if (s != skipping)
                PSP->cmd[i] = '\0'; /* to be sure */

        /* start real main() */
        return main(argc, argv);
}