reactos/lib/sdk/crt/stdio/_flsbuf.c

   1 /*
   2  * COPYRIGHT:       GNU GPL, see COPYING in the top level directory
   3  * PROJECT:         ReactOS crt library
   4  * FILE:            lib/sdk/crt/stdio/_flsbuf.c
   5  * PURPOSE:         Implementation of _flsbuf / _flswbuf
   6  * PROGRAMMER:      Timo Kreuzer
   7  */
   8
   9 #include <stdio.h>
  10 #include <io.h>
  11 #include <tchar.h>
  12
  13 void __cdecl alloc_buffer(FILE *stream);
  14
  15 int __cdecl
  16 _flsbuf(int ch, FILE *stream)
  17 {
  18     int count, written;
  19
  20     /* Check if the stream supports flushing */
  21     if ((stream->_flag & _IOSTRG) || !(stream->_flag & (_IORW|_IOWRT)))
  22     {
  23         stream->_flag |= _IOERR;
  24         return EOF;
  25     }
  26
  27     /* Is this was a read buffer */
  28     if (stream->_flag & _IOREAD)
  29     {
  30         /* Must be at the end of the file */
  31         if (!(stream->_flag & _IOEOF))
  32         {
  33             stream->_flag |= _IOERR;
  34             stream->_cnt = 0;
  35             return EOF;
  36         }
  37
  38         /* Reset buffer */
  39         stream->_ptr = stream->_base;
  40     }
  41
  42     /* Fixup flags */
  43     stream->_flag &= ~(_IOREAD|_IOEOF);
  44     stream->_flag |= _IOWRT;
  45
  46     /* If we have no buffer, try to allocate one */
  47     if (!stream->_base && stream != stdout && stream != stderr)
  48     {
  49         alloc_buffer(stream);
  50     }
  51
  52     /* Check if we have a buffer now */
  53     if (stream->_base)
  54     {
  55         /* We have one, check if there is something to write */
  56         count = stream->_ptr - stream->_base;
  57         if (count > 0)
  58             written = _write(stream->_file, stream->_base, count);
  59         else
  60             written = 0;
  61
  62         /* Reset buffer and put the char into it */
  63         stream->_ptr = stream->_base + sizeof(TCHAR);
  64         stream->_cnt = stream->_bufsiz - sizeof(TCHAR);
  65         *(TCHAR*)stream->_base = ch;
  66     }
  67     else
  68     {
  69         /* There is no buffer, write the char directly */
  70         count = sizeof(TCHAR);
  71         written = _write(stream->_file, &ch, sizeof(TCHAR));
  72     }
  73
  74     /* Check for failure */
  75     if (written != count)
  76     {
  77         stream->_flag |= _IOERR;
  78         return EOF;
  79     }
  80
  81     return (TCHAR)ch;
  82 }