kernel/lib/stdio/read.c

   1 /*
   2  *  ZeX/OS
   3  *  Copyright (C) 2007  Tomas 'ZeXx86' Jedrzejek (zexx86@gmail.com)
   4  *  Copyright (C) 2008  Tomas 'ZeXx86' Jedrzejek (zexx86@gmail.com)
   5  *  Copyright (C) 2009  Tomas 'ZeXx86' Jedrzejek (zexx86@gmail.com)
   6  *  Copyright (C) 2009  Martin 'povik' Poviser (martin.povik@gmail.com)
   7  *
   8  *  This program is free software: you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation, either version 3 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22
  23 #include <system.h>
  24 #include <string.h>
  25 #include <file.h>
  26 #include <dev.h>
  27 #include <fd.h>
  28 #include <pipe.h>
  29
  30 int read (unsigned fd, void *buf, unsigned len)
  31 {
  32         fd_t *d = fd_get (fd);
  33
  34         if (!d)
  35                 return 0;
  36
  37         if (d->flags & FD_PIPE) {
  38                 pipe_t *p = pipe_get (fd);
  39                 if (p) {
  40                         return pipe_read (p, buf, len);
  41                 } else
  42                         return 0;
  43         }
  44
  45         if (len > d->e)
  46                 len = d->e;
  47
  48         memcpy ((char *) buf, d->s+d->p, len);
  49 //      memset ((char *) buf+len, 0, 1);
  50
  51         d->e -= len;
  52         d->p += len;
  53
  54         /* HACK: this should call UPDATE handler */
  55         if (d->dev)
  56                 d->dev->handler (DEV_ACT_UPDATE);
  57
  58         return len;
  59 }
  60
  61