/*	$NetBSD: regular.c,v 1.24 2013/11/20 17:19:14 kleink 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.
 */

#define _DEFAULT_SOURCE

#include <sys/mman.h>
#include <sys/param.h>
#include <sys/stat.h>

#include <err.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#include "extern.h"

typedef unsigned char u_char;

void c_regular(int fd1, const char *file1, off_t skip1, off_t len1, int fd2,
               const char *file2, off_t skip2, off_t len2) {
  u_char ch, *p1, *p2;
  off_t byte, length, line;
  int dfound;
  size_t blk_sz, blk_cnt;

  if (sflag && len1 != len2)
    exit(1);

  if (skip1 > len1)
    eofmsg(file1, len1 + 1, 0);
  len1 -= skip1;
  if (skip2 > len2)
    eofmsg(file2, len2 + 1, 0);
  len2 -= skip2;

  byte = line = 1;
  dfound = 0;
  length = MIN(len1, len2);
  for (blk_sz = 1024 * 1024; length != 0; length -= blk_sz) {
    if ((uintmax_t)blk_sz > (uintmax_t)length)
      blk_sz = length;
    p1 = mmap(NULL, blk_sz, PROT_READ, MAP_FILE | MAP_SHARED, fd1, skip1);
    if (p1 == MAP_FAILED)
      goto mmap_failed;

    p2 = mmap(NULL, blk_sz, PROT_READ, MAP_FILE | MAP_SHARED, fd2, skip2);
    if (p2 == MAP_FAILED) {
      munmap(p1, blk_sz);
      goto mmap_failed;
    }

    blk_cnt = blk_sz;
    for (; blk_cnt--; ++p1, ++p2, ++byte) {
      if ((ch = *p1) != *p2) {
        if (!lflag) {
          diffmsg(file1, file2, byte, line);
          /* NOTREACHED */
        }
        dfound = 1;
        (void)printf("%6lld %3o %3o\n", (long long)byte, ch, *p2);
      }
      if (ch == '\n')
        ++line;
    }
    munmap(p1 - blk_sz, blk_sz);
    munmap(p2 - blk_sz, blk_sz);
    skip1 += blk_sz;
    skip2 += blk_sz;
  }

  if (len1 != len2)
    eofmsg(len1 > len2 ? file2 : file1, byte, line);
  if (dfound)
    exit(DIFF_EXIT);
  return;

mmap_failed:
  c_special(fd1, file1, skip1, fd2, file2, skip2);
}
