/*      $NetBSD: asa.c,v 1.17 2016/09/05 00:40:28 sevan Exp $   */

/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 1993,94 Winning Strategies, Inc.
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Winning Strategies, Inc.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * 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.
 */

#include <err.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static void asa(FILE *);
static void usage(void) __dead2;

int
main(int argc, char *argv[])
{
        FILE *fp;
        int ch, exval;

        while ((ch = getopt(argc, argv, "")) != -1) {
                switch (ch) {
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        exval = 0;
        if (*argv == NULL) {
                asa(stdin);
        } else {
                do {
                        if (strcmp(*argv, "-") == 0) {
                                asa(stdin);
                        } else if ((fp = fopen(*argv, "r")) == NULL) {
                                warn("%s", *argv);
                                exval = 1;
                        } else {
                                asa(fp);
                                fclose(fp);
                        }
                } while (*++argv != NULL);
        }

        if (fflush(stdout) != 0)
                err(1, "stdout");

        exit(exval);
}

static void
usage(void)
{
        fprintf(stderr, "usage: asa [file ...]\n");
        exit(1);
}

static void
asa(FILE *f)
{
        char *buf;
        size_t len;
        bool eol = false;

        while ((buf = fgetln(f, &len)) != NULL) {
                /* in all cases but '+', terminate previous line, if any */
                if (buf[0] != '+' && eol)
                        putchar('\n');
                /* examine and translate the control character */
                switch (buf[0]) {
                default:
                        /*
                         * “It is suggested that implementations treat
                         * characters other than 0, 1, and '+' as <space>
                         * in the absence of any compelling reason to do
                         * otherwise” (POSIX.1-2017)
                         */
                case ' ':
                        /* nothing */
                        break;
                case '0':
                        putchar('\n');
                        break;
                case '1':
                        putchar('\f');
                        break;
                case '+':
                        /*
                         * “If the '+' is the first character in the
                         * input, it shall be equivalent to <space>.”
                         * (POSIX.1-2017)
                         */
                        if (eol)
                                putchar('\r');
                        break;
                }
                /* trim newline if there is one */
                if ((eol = (buf[len - 1] == '\n')))
                        --len;
                /* print the rest of the input line */
                if (len > 1 && buf[0] && buf[1])
                        fwrite(buf + 1, 1, len - 1, stdout);
        }
        /* terminate the last line, if any */
        if (eol)
                putchar('\n');
        /* check for output errors */
        if (ferror(stdout) != 0)
                err(1, "stdout");
}