libc/stdio/fread.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2009  Tomas 'ZeXx86' Jedrzejek (zexx86@zexos.org)
   4  *
   5  *  This program is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19
  20 #include <errno.h>
  21 #include <stdio.h>
  22 #include <fcntl.h>
  23 #include <stdlib.h>
  24
  25 size_t fread (void *ptr, size_t size, size_t nmemb, FILE *stream)
  26 {
  27         if (!stream)
  28                 goto err;
  29
  30         if (stream->mode & O_WRONLY)
  31                 goto err;
  32
  33         unsigned s = size * nmemb;
  34         int fd = stream->fd;
  35
  36         int len = read (fd, ptr, s);
  37
  38         if (!len)
  39                 goto err;
  40
  41         stream->off += len;
  42
  43         return 1;
  44 err:
  45         errno_update ();
  46
  47         return 0;
  48 }