/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1991, 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 <sys/types.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>

#include <capsicum_helpers.h>

#define TAB     8

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

int
main(int argc, char *argv[])
{
        u_long column, start, stop;
        int ch, width;
        char *p;

        setlocale(LC_ALL, "");

        caph_cache_catpages();
        if (caph_limit_stdio() < 0 || caph_enter() < 0)
                err(EXIT_FAILURE, "capsicum");

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

        start = stop = 0;
        switch(argc) {
        case 2:
                stop = strtol(argv[1], &p, 10);
                if (stop <= 0 || *p)
                        errx(EXIT_FAILURE, "illegal column -- %s", argv[1]);
                /* FALLTHROUGH */
        case 1:
                start = strtol(argv[0], &p, 10);
                if (start <= 0 || *p)
                        errx(EXIT_FAILURE, "illegal column -- %s", argv[0]);
                break;
        case 0:
                break;
        default:
                usage();
        }

        if (stop && start > stop)
                errx(EXIT_FAILURE, "illegal start and stop columns");

        for (column = 0;;) {
                switch (ch = getwchar()) {
                case WEOF:
                        check(stdin);
                        break;
                case '\b':
                        if (column)
                                --column;
                        break;
                case '\n':
                        column = 0;
                        break;
                case '\t':
                        column = (column + TAB) & ~(TAB - 1);
                        break;
                default:
                        if ((width = wcwidth(ch)) > 0)
                                column += width;
                        break;
                }

                if ((!start || column < start || (stop && column > stop)) &&
                    putwchar(ch) == WEOF)
                        check(stdout);
        }
}

void
check(FILE *stream)
{
        if (feof(stream))
                exit(EXIT_SUCCESS);
        if (ferror(stream))
                err(EXIT_FAILURE, "%s", stream == stdin ? "stdin" : "stdout");
}

void
usage(void)
{
        (void)fprintf(stderr, "usage: colrm [start [stop]]\n");
        exit(EXIT_FAILURE);
}