reactos/lib/crtdll/stdio/fread.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
   7
   8 // carriage return line feed conversion is done in filbuf and  flsbuf
   9 #if 0
  10 size_t
  11 fread(void *p, size_t size, size_t count, FILE *iop)
  12 {
  13   char *ptr = (char *)p;
  14   int to_read;
  15
  16   to_read = size * count;
  17
  18
  19
  20   while ( to_read > 0 ) {
  21         *ptr = getc(iop) ;
  22         if ( *ptr == EOF )
  23                 break;
  24         to_read--;
  25         ptr++;
  26   }
  27
  28
  29
  30   return count- (to_read/size);
  31 }
  32
  33
  34 #else
  35 size_t fread(void *vptr, size_t size, size_t count, FILE *iop)
  36 {
  37         char *ptr = (char *)vptr;
  38         size_t  to_read ,n_read;
  39
  40         to_read = size * count;
  41
  42         if (!OPEN4READING(iop))
  43         {
  44                 __set_errno (EINVAL);
  45                 return 0;
  46         }
  47
  48         if (!__validfp (iop) )
  49         {
  50                 __set_errno (EINVAL);
  51                 return 0;
  52         }
  53         if (feof (iop) || ferror (iop))
  54                 return 0;
  55
  56         if (vptr == NULL || to_read == 0)
  57                 return 0;
  58
  59
  60         while(iop->_cnt > 0 && to_read > 0 ) {
  61                 to_read--;
  62                 *ptr++ = getc(iop);
  63         }
  64
  65         // if the buffer is dirty it will have to be written now
  66         // otherwise the file pointer won't match anymore.
  67
  68         fflush(iop);
  69
  70          // check to see if this will work with in combination with ungetc
  71
  72         n_read =  _read(fileno(iop), ptr, to_read);
  73         if ( n_read != -1 )
  74                 to_read -= n_read;
  75
  76         // the file buffer is empty and there is no read ahead information anymore.
  77
  78         iop->_flag &= ~_IOAHEAD;
  79
  80         return count- (to_read/size);
  81 }
  82 #endif
  83