/*      $OpenBSD: special.c,v 1.8 2018/03/05 16:53:39 cheloha Exp $      */
/*      $NetBSD: special.c,v 1.2 1995/09/08 03:23:00 tls Exp $      */

/*-
 * Copyright (c) 1991, 1993, 1994
 *      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 <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "extern.h"

void
c_special(int fd1, char *file1, off_t skip1, int fd2, char *file2, off_t skip2)
{
        int ch1, ch2;
        off_t byte, line;
        FILE *fp1, *fp2;
        int dfound;

        if ((fp1 = fdopen(fd1, "r")) == NULL)
                fatal("%s", file1);
        if ((fp2 = fdopen(fd2, "r")) == NULL)
                fatal("%s", file2);

        dfound = 0;
        while (skip1--)
                if (getc(fp1) == EOF)
                        goto eof;
        while (skip2--)
                if (getc(fp2) == EOF)
                        goto eof;

        for (byte = line = 1;; ++byte) {
                ch1 = getc(fp1);
                ch2 = getc(fp2);
                if (ch1 == EOF || ch2 == EOF)
                        break;
                if (ch1 != ch2) {
                        if (lflag) {
                                dfound = 1;
                                (void)printf("%6lld %3o %3o\n", (long long)byte,
                                    ch1, ch2);
                        } else
                                diffmsg(file1, file2, byte, line);
                                /* NOTREACHED */
                }
                if (ch1 == '\n')
                        ++line;
        }

eof:    if (ferror(fp1))
                fatal("%s", file1);
        if (ferror(fp2))
                fatal("%s", file2);
        if (feof(fp1)) {
                if (!feof(fp2))
                        eofmsg(file1);
        } else
                if (feof(fp2))
                        eofmsg(file2);
        if (dfound)
                exit(DIFF_EXIT);
}