examples/Mem_Map/file-reverse/file-reverse.cpp


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57

// $Id$

// Print a file in reverse by using the ACE memory mapped file
// wrapper.  It is SO easy to do compared with alternatives!

#include "ace/Mem_Map.h"

ACE_RCSID(file_reverse, file_reverse, "$Id$")

static void
putline (const char *s)
{
  while (putchar (*s++) != '\n')
    continue;
}

static void
print_array_in_reverse (char *array,
                        int size)
{
  if (size <= 0)
    return;

  size--;

  if (array[size] == '\0')
    array[size] = '\n';

  while (--size >= 0)
    if (array[size] == '\n')
      putline (array + size + 1);

  putline (array);
}

int
main (int argc, char **argv)
{
  ACE_LOG_MSG->open (argv[0]);

  if (argc != 2)
    ACE_ERROR_RETURN ((LM_ERROR,
                       "usage: %n file\n"),
                      -1);

  ACE_Mem_Map mmap;
  
  if (mmap.map (argv[1], -1, O_RDWR) == -1)
    ACE_ERROR_RETURN ((LM_ERROR, 
                       "%n: %p\n",
                       "mmap"),
                      -1);

  print_array_in_reverse ((char *) mmap.addr (),
                          mmap.size ());
  return 0;
}