1 /*
2  * This file is part of libsidplayfp, a SID player engine.
3  *
4  * Copyright 2012-2014 Leandro Nini <drfiemost@users.sourceforge.net>
5  * Copyright 2010 Antti Lankila
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
20  */
21 
22 #ifndef NULLSID_H
23 #define NULLSID_H
24 
25 #include "c64/c64sid.h"
26 
27 #include "sidcxx11.h"
28 
29 namespace libsidplayfp
30 {
31 
32 /**
33  * SID chip placeholder which does nothing and returns 0xff on reading.
34  */
35 class NullSid final : public c64sid
36 {
37 private:
NullSid()38     NullSid() {}
~NullSid()39     virtual ~NullSid() {}
40 
41 public:
42     /**
43      * Returns singleton instance.
44      */
getInstance()45     static NullSid *getInstance()
46     {
47         static NullSid nullsid;
48         return &nullsid;
49     }
50 
reset(uint8_t)51     void reset(uint8_t) override {}
52 
write(uint_least8_t,uint8_t)53     void write(uint_least8_t, uint8_t) override {}
read(uint_least8_t)54     uint8_t read(uint_least8_t) override { return 0xff; }
55 };
56 
57 }
58 
59 #endif // NULLSID_H
60