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/* read-uart.c. Implementation of the _read syscall for newlib with UART.

   Copyright (C) 2004, Jacob Bower

   Copyright (C) 2010, Embecosm Limited <info@embecosm.com>

   Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>

   This file is part of Newlib.

   The original work by Jacob Bower is provided as-is without any kind of

   warranty. Use it at your own risk!

   All subsequent work is bound by version 3 of the GPL as follows.

   This program is free software; you can redistribute it and/or modify it

   under the terms of the GNU General Public License as published by the Free

   Software Foundation; either version 3 of the License, or (at your option)

   any later version.

   This program is distributed in the hope that it will be useful, but WITHOUT

   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

   more details.

   You should have received a copy of the GNU General Public License along

   with this program.  If not, see <http:#www.gnu.org/licenses/>.             */

/* -------------------------------------------------------------------------- */

/* This program is commented throughout in a fashion suitable for processing

   with Doxygen.                                                              */

/* -------------------------------------------------------------------------- */

#include <errno.h>

#include <unistd.h>

extern int  errno;

/* -------------------------------------------------------------------------- */

/*!Read from a file with a UART.

   We only support reading from stdin.

   Remember that this function is *not* reentrant, so no static state should

   be held.

   @param[in] file  The fileno to read.

   @param[in] buf   Buffer into which to read.

   @param[in] len   Number of bytes to read.

   @return  number of bytes read if the file is stdin, otherwise -1 to

            indicate failure, with an error code in the global variable

            errno.                                                            */

/* -------------------------------------------------------------------------- */

int

_read (int   file,

       char *buf,

       int   len)

{

  if (STDIN_FILENO == file)

    {

      int  i;

      for (i = 0; i < len; i++)

        {

          buf[i] = _uart_getc ();

#ifdef UART_AUTO_ECHO

          _uart_putc (buf[i]);

#endif

          /* Return partial buffer if we get EOL */

          if ('\n' == buf[i])

            {

              return  i;

            }

        }

      return  i;                        /* Filled the buffer */

    }

  else

    {

      errno = EBADF;

      return  -1;

    }

}       /* _read () */