reactos/lib/msvcrt/io/read.c

   1 /*
   2  * COPYRIGHT:   See COPYING in the top level directory
   3  * PROJECT:     ReactOS system libraries
   4  * FILE:        lib/msvcrt/io/read.c
   5  * PURPOSE:     Reads a file
   6  * PROGRAMER:   Boudewijn Dekker
   7  * UPDATE HISTORY:
   8  *              28/12/1998: Created
   9  *              03/05/2002: made _read() non-greedy - it now returns as soon as
  10  *                          any amount of data has been read. It's the expected
  11  *                          behavior for line-buffered streams (KJK::Hyperion)
  12  */
  13 #include <windows.h>
  14 #include <msvcrt/io.h>
  15 #include <msvcrt/internal/file.h>
  16
  17 #define NDEBUG
  18 #include <msvcrt/msvcrtdbg.h>
  19
  20 size_t _read(int _fd, void *_buf, size_t _nbyte)
  21 {
  22    DWORD _rbyte = 0, nbyte = _nbyte;
  23    char *bufp = (char*)_buf;
  24    HANDLE hfile;
  25    int istext;
  26
  27    DPRINT("_read(fd %d, buf %x, nbyte %d)\n", _fd, _buf, _nbyte);
  28
  29    /* null read */
  30    if(_nbyte == 0)
  31       return 0;
  32
  33    hfile = _get_osfhandle(_fd);
  34    istext = __fileno_getmode(_fd) & O_TEXT;
  35
  36    /* read data */
  37    if (!ReadFile(hfile, bufp, nbyte, &_rbyte, NULL))
  38    {
  39       /* failure */
  40       return -1;
  41    }
  42
  43    /* text mode */
  44    if (_rbyte && istext)
  45    {
  46       int cr = 0;
  47       DWORD count = _rbyte;
  48
  49       /* repeat for all bytes in the buffer */
  50       for(; count; bufp++, count--)
  51       {
  52          /* carriage return */
  53          if (*bufp == '\r')
  54             cr++;
  55          /* shift characters back, to ignore carriage returns */
  56          else if (cr != 0)
  57             *(bufp - cr) = *bufp;
  58
  59       }
  60
  61       /* ignore the carriage returns */
  62       _rbyte -= cr;
  63    }
  64
  65    DPRINT("%d\n", _rbyte);
  66    return _rbyte;
  67 }