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

   1 // Print a file in reverse by using the ACE memory mapped file
   2 // wrapper.  It is SO easy to do compared with alternatives!
   3
   4 #include "ace/OS_main.h"
   5 #include "ace/Mem_Map.h"
   6 #include "ace/Log_Msg.h"
   7 #include "ace/Truncate.h"
   8
   9
  10 static void
  11 putline (const char *s)
  12 {
  13   while (putchar (*s++) != '\n')
  14     continue;
  15 }
  16
  17 static void
  18 print_array_in_reverse (char *array,
  19                         int size)
  20 {
  21   if (size <= 0)
  22     return;
  23
  24   size--;
  25
  26   if (array[size] == '\0')
  27     array[size] = '\n';
  28
  29   while (--size >= 0)
  30     if (array[size] == '\n')
  31       putline (array + size + 1);
  32
  33   putline (array);
  34 }
  35
  36 int
  37 ACE_TMAIN (int argc, ACE_TCHAR **argv)
  38 {
  39   ACE_LOG_MSG->open (argv[0]);
  40
  41   if (argc != 2)
  42     ACE_ERROR_RETURN ((LM_ERROR,
  43                        "usage: %n file\n"),
  44                       -1);
  45
  46   ACE_Mem_Map mmap;
  47
  48   if (mmap.map (argv[1], static_cast<size_t> (-1), O_RDWR) == -1)
  49     ACE_ERROR_RETURN ((LM_ERROR,
  50                        "%n: %p\n",
  51                        "mmap"),
  52                       -1);
  53
  54   print_array_in_reverse ((char *) mmap.addr (),
  55                           ACE_Utils::truncate_cast<int> (mmap.size ()));
  56   return 0;
  57 }