reactos/lib/msvcrt/stdio/fwrite.c

   1 #include <msvcrti.h>
   2
   3 #define NDEBUG
   4 #include <msvcrtdbg.h>
   5
   6
   7 size_t fwrite(const void *vptr, size_t size, size_t count, FILE *iop)
   8 {
   9   size_t to_write, n_written;
  10   unsigned char *ptr = (unsigned char *)vptr;
  11   int copy;
  12
  13   DPRINT("fwrite(%x, %d, %d, %x)\n", vptr, size, count, iop);
  14
  15   to_write = size*count;
  16   if (!OPEN4WRITING(iop))
  17     {
  18       __set_errno (EINVAL);
  19       return 0;
  20     }
  21
  22   if (iop == NULL)
  23     {
  24       __set_errno (EINVAL);
  25       return 0;
  26     }
  27
  28   if (ferror (iop))
  29     return 0;
  30   if (vptr == NULL || to_write == 0)
  31     return 0;
  32
  33   if (iop->_base == NULL && !(iop->_flag&_IONBF))
  34   {
  35      if (EOF == _flsbuf(*ptr++, iop))
  36         return 0;
  37      if (--to_write == 0)
  38         return 1;
  39   }
  40
  41   if (iop->_flag & _IOLBF)
  42   {
  43      while (to_write > 0)
  44      {
  45         if (EOF == putc(*ptr++, iop))
  46         {
  47            iop->_flag |= _IOERR;
  48            break;
  49         }
  50         to_write--;
  51      }
  52   }
  53   else
  54   {
  55      if (iop->_cnt > 0 && to_write > 0)
  56      {
  57         copy = min(iop->_cnt, to_write);
  58         memcpy(iop->_ptr, ptr, copy);
  59         ptr += copy;
  60         iop->_ptr += copy;
  61         iop->_cnt -= copy;
  62         to_write -= copy;
  63         iop->_flag |= _IODIRTY;
  64      }
  65
  66      if (to_write > 0)
  67      {
  68         // if the buffer is dirty it will have to be written now
  69         // otherwise the file pointer won't match anymore.
  70         fflush(iop);
  71         if (to_write >= iop->_bufsiz)
  72         {
  73            while (to_write > 0)
  74            {
  75               n_written = _write(_fileno(iop), ptr, to_write);
  76               if (n_written <= 0)
  77               {
  78                  iop->_flag |= _IOERR;
  79                  break;
  80               }
  81               to_write -= n_written;
  82               ptr += n_written;
  83            }
  84
  85            // check to see if this will work with in combination with ungetc
  86
  87            // the file buffer is empty and there is no read ahead information anymore.
  88            iop->_flag &= ~_IOAHEAD;
  89         }
  90         else
  91         {
  92            if (EOF != _flsbuf(*ptr++, iop))
  93            {
  94               if (--to_write > 0)
  95               {
  96                  memcpy(iop->_ptr, ptr, to_write);
  97                  iop->_ptr += to_write;
  98                  iop->_cnt -= to_write;
  99                  iop->_flag |= _IODIRTY;
 100                  return count;
 101               }
 102            }
 103         }
 104      }
 105   }
 106
 107   return count - (to_write/size);
 108 }