/*
 *  Empire - A multi-player, client/server Internet based war game.
 *  Copyright (C) 1986-2021, Dave Pare, Jeff Bailey, Thomas Ruschak,
 *                Ken Stevens, Steve McClure, Markus Armbruster
 *
 *  Empire is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *  ---
 *
 *  See files README, COPYING and CREDITS in the root of the source
 *  tree for related information and legal notices.  It is expected
 *  that future projects/authors will amend these files as needed.
 *
 *  ---
 *
 *  parse.c: Parse an Empire command line
 *
 *  Known contributors to this file:
 *
 */

#include <config.h>

#include <ctype.h>
#include "prototypes.h"

/*
 * Parse user command in @buf.
 * @buf is UTF-8.
 * Command name and arguments are copied into @space[], whose size must
 * be at least strlen(@buf) + 1.
 * Set @arg[0] to the zero-terminated command name.
 * Set @arg[1..N] to the zero-terminated arguments, where N is the
 * number of arguments.  Set @arg[N+1..127] to NULL.
 * Set @tail[0..N] to beginning of @arg[0] in @buf[].
 * If @condp is not null, recognize conditional argument syntax, and
 * set *@condp to the conditional argument if present, else NULL.
 * If @redir is not null, recognize redirection syntax, and set *@redir
 * to UTF-8 redirection string if present, else NULL.
 * Return number of slots used in @arg[], or -1 on error.
 */
int
parse(char *buf, char *space, char **arg,
      char **tail, char **condp, char **redir)
{
    int i, quoted, argnum;

    if (redir)
	*redir = NULL;
    if (condp)
	*condp = NULL;

    for (argnum = 0; argnum < 127;) {
	for (; isspace(*(unsigned char *)buf); buf++) ;
	if (!*buf)
	    break;

	/* recognize redirection syntax */
	if (redir && (*buf == '>' || *buf == '|')) {
	    *redir = buf;
	    break;
	}

	if (condp && *buf == '?') {
	    buf++;
	    *condp = space;
	} else {
	    if (tail)
		tail[argnum] = buf;
	    arg[argnum++] = space;
	}

	/* copy argument */
	quoted = 0;
	for (; *buf && (quoted || !isspace(*(unsigned char *)buf)); buf++) {
	    if (*buf == '"')
		quoted = !quoted;
	    else if ((*buf >= 0x20 && *buf <= 0x7e) || *buf == '\t')
		*space++ = *buf;
	    /* else funny character; ignore */
	}
	*space++ = 0;
    }

    for (i = argnum; i < 128; i++) {
	arg[i] = NULL;
	if (tail)
	    tail[i] = NULL;
    }

    return argnum;
}
