/*      $OpenBSD: unvis.c,v 1.15 2022/12/04 23:50:50 cheloha Exp $      */

/*-
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  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. 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 <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <vis.h>

void process(FILE *fp, const char *filename);

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

        if (pledge("stdio rpath", NULL) == -1)
                err(1, "pledge");

        while ((ch = getopt(argc, argv, "")) != -1)
                switch(ch) {
                default:
                        (void) fprintf(stderr, "usage: unvis [file ...]\n");
                        exit(1);
                }
        argc -= optind;
        argv += optind;

        if (*argv)
                while (*argv) {
                        if ((fp=fopen(*argv, "r")) != NULL) {
                                process(fp, *argv);
                                fclose(fp);
                        } else
                                warn("%s", *argv);
                        argv++;
                }
        else {
                if (pledge("stdio", NULL) == -1)
                        err(1, "pledge");

                process(stdin, "<stdin>");
        }
        exit(0);
}

void
process(FILE *fp, const char *filename)
{
        int offset = 0, c, ret;
        int state = 0;
        char outc;

        while ((c = getc(fp)) != EOF) {
                offset++;
        again:
                switch(ret = unvis(&outc, (char)c, &state, 0)) {
                case UNVIS_VALID:
                        putchar(outc);
                        break;
                case UNVIS_VALIDPUSH:
                        putchar(outc);
                        goto again;
                case UNVIS_SYNBAD:
                        warnx("%s: offset: %d: can't decode", filename, offset);
                        state = 0;
                        break;
                case 0:
                case UNVIS_NOCHAR:
                        break;
                default:
                        errx(1, "bad return value (%d), can't happen", ret);
                        /* NOTREACHED */
                }
        }
        if (unvis(&outc, (char)0, &state, UNVIS_END) == UNVIS_VALID)
                putchar(outc);
}