/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * James W. Williams of NASA Goddard Space Flight Center.
 *
 * 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 <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "extern.h"

static void usage(void) __dead2;

int
main(int argc, char **argv)
{
        uint32_t val;
        int ch, fd, rval;
        off_t len;
        char *fn, *p;
        int (*cfncn)(int, uint32_t *, off_t *);
        void (*pfncn)(char *, uint32_t, off_t);

        if ((p = strrchr(argv[0], '/')) == NULL)
                p = argv[0];
        else
                ++p;
        if (!strcmp(p, "sum")) {
                cfncn = csum1;
                pfncn = psum1;
                ++argv;
        } else {
                cfncn = crc;
                pfncn = pcrc;

                while ((ch = getopt(argc, argv, "o:")) != -1)
                        switch (ch) {
                        case 'o':
                                if (!strcmp(optarg, "1")) {
                                        cfncn = csum1;
                                        pfncn = psum1;
                                } else if (!strcmp(optarg, "2")) {
                                        cfncn = csum2;
                                        pfncn = psum2;
                                } else if (!strcmp(optarg, "3")) {
                                        cfncn = crc32;
                                        pfncn = pcrc;
                                } else {
                                        warnx("illegal argument to -o option");
                                        usage();
                                }
                                break;
                        case '?':
                        default:
                                usage();
                        }
                argc -= optind;
                argv += optind;
        }

        fd = STDIN_FILENO;
        fn = NULL;
        rval = 0;
        do {
                if (*argv) {
                        fn = *argv++;
                        if ((fd = open(fn, O_RDONLY, 0)) < 0) {
                                warn("%s", fn);
                                rval = 1;
                                continue;
                        }
                }
                if (cfncn(fd, &val, &len)) {
                        warn("%s", fn ? fn : "stdin");
                        rval = 1;
                } else
                        pfncn(fn, val, len);
                (void)close(fd);
        } while (*argv);
        exit(rval);
}

static void
usage(void)
{
        (void)fprintf(stderr, "usage: cksum [-o 1 | 2 | 3] [file ...]\n");
        (void)fprintf(stderr, "       sum [file ...]\n");
        exit(1);
}