reactos/lib/msvcrt/stdio/fwrite.c

   1 #include <msvcrt/stdio.h>
   2 #include <msvcrt/stdlib.h>
   3 #include <msvcrt/string.h>
   4 #include <msvcrt/errno.h>
   5 #include <msvcrt/internal/file.h>
   6 #define NDEBUG
   7 #include <msvcrt/msvcrtdbg.h>
   8
   9
  10 size_t fwrite(const void *vptr, size_t size, size_t count, FILE *iop)
  11 {
  12   size_t to_write, n_written;
  13   unsigned char *ptr = (unsigned char *)vptr;
  14   int copy;
  15
  16   DPRINT("fwrite(%x, %d, %d, %x)\n", vptr, size, count, iop);
  17
  18   to_write = size*count;
  19   if (!OPEN4WRITING(iop))
  20     {
  21       __set_errno (EINVAL);
  22       return 0;
  23     }
  24
  25   if (iop == NULL)
  26     {
  27       __set_errno (EINVAL);
  28       return 0;
  29     }
  30
  31   if (ferror (iop))
  32     return 0;
  33   if (vptr == NULL || to_write == 0)
  34     return 0;
  35
  36   if (iop->_base == NULL && !(iop->_flag&_IONBF))
  37   {
  38      if (EOF == _flsbuf(*ptr++, iop))
  39         return 0;
  40      if (--to_write == 0)
  41         return 1;
  42   }
  43
  44   if (iop->_flag & _IOLBF)
  45   {
  46      while (to_write > 0)
  47      {
  48         if (EOF == putc(*ptr++, iop))
  49         {
  50            iop->_flag |= _IOERR;
  51            break;
  52         }
  53         to_write--;
  54      }
  55   }
  56   else
  57   {
  58      if (iop->_cnt > 0 && to_write > 0)
  59      {
  60         copy = min(iop->_cnt, to_write);
  61         memcpy(iop->_ptr, ptr, copy);
  62         ptr += copy;
  63         iop->_ptr += copy;
  64         iop->_cnt -= copy;
  65         to_write -= copy;
  66         iop->_flag |= _IODIRTY;
  67      }
  68
  69      if (to_write > 0)
  70      {
  71         // if the buffer is dirty it will have to be written now
  72         // otherwise the file pointer won't match anymore.
  73         fflush(iop);
  74         if (to_write >= iop->_bufsiz)
  75         {
  76            while (to_write > 0)
  77            {
  78               n_written = _write(fileno(iop), ptr, to_write);
  79               if (n_written <= 0)
  80               {
  81                  iop->_flag |= _IOERR;
  82                  break;
  83               }
  84               to_write -= n_written;
  85               ptr += n_written;
  86            }
  87
  88            // check to see if this will work with in combination with ungetc
  89
  90            // the file buffer is empty and there is no read ahead information anymore.
  91            iop->_flag &= ~_IOAHEAD;
  92         }
  93         else
  94         {
  95            if (EOF != _flsbuf(*ptr++, iop))
  96            {
  97               if (--to_write > 0)
  98               {
  99                  memcpy(iop->_ptr, ptr, to_write);
 100                  iop->_ptr += to_write;
 101                  iop->_cnt -= to_write;
 102                  iop->_flag |= _IODIRTY;
 103                  return count;
 104               }
 105            }
 106         }
 107      }
 108   }
 109
 110   return count - (to_write/size);
 111 }