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// fake_serial.cc
// nono - programme du robot 2004. {{{
//
// Copyright (C) 2004 Nicolas Schodet
//
// Robot APB Team/Efrei 2004.
//        Web: http://assos.efrei.fr/robot/
//      Email: robot AT efrei DOT fr
//
// 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 2 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, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// }}}
#include "fake_serial.h"
#include "utils/rand.h"

/// Constructeur.
FakeSerial::FakeSerial (bool blocking/*false*/)
    : blocking_ (blocking), lostP_ (1000), errorP_ (1000)
{
}

/// Lit un bloc, retourne le nombre d'octets lus ou <= 0 en cas d'erreur
/// ou si aucun caract�re n'est disponible. Pour le robot, pr�ferer en
/// g�n�ral getchar() pour du non-bloquant.
ssize_t
FakeSerial::read (void *buf, size_t size)
{
    char p[size];
    int ret;
    do
      {
	ret = ::read (0, p, size);
	if (ret > 0)
	  {
	    char *po = reinterpret_cast<char *> (buf);
	    int n = 0;
	    for (int i = 0; i < ret; ++i)
	      {
		if (!(rand () % lostP_))
		  {
		    // Saute le caract�re.
		  }
		else
		  {
		    po[n++] = doError (p[i]);
		  }
	      }
	    ret = n;
	  }
	else
	    return ret;
      } while (ret <= 0 && blocking_);
    return ret;
}

/// Lit un caract�re, ou -1 en cas d'erreur ou si aucun caract�re n'est
/// disponible.
int
FakeSerial::getchar (void)
{
    char c;
    return read (&c, 1) > 0 ? c : -1;
}

/// Ecrit un bloc.
void
FakeSerial::write (const void *buf, size_t size)
{
    const unsigned char *p = reinterpret_cast<const unsigned char *> (buf);
    size_t i;
    char c;
    for (i = 0; i < size; ++i)
      {
	if (!(rand () % lostP_))
	    continue;
	c = doError (p[i]);
	::write (1, &c, 1);
      }
}

/// Ecrit un caract�re.
void
FakeSerial::putchar (int c)
{
    write (&c, 1);
}

/// Inverse peut-�tre un bit al�atoirement.
char
FakeSerial::doError (char c)
{
    if (!(rand () % errorP_))
	return c ^ (1 << (rand () % 8));
    else
	return c;
}