UniSet  1.4.0
Trigger.h
См. документацию.
00001 /* This file is part of the UniSet project
00002  * Copyright (c) 2002 Free Software Foundation, Inc.
00003  * Copyright (c) 2002 Pavel Vainerman
00004  *
00005  * This program is free software; you can redistribute it and/or modify
00006  * it under the terms of the GNU General Public License as published by
00007  * the Free Software Foundation; either version 2 of the License, or
00008  * (at your option) any later version.
00009  *
00010  * This program is distributed in the hope that it will be useful,
00011  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013  * GNU General Public License for more details.
00014  *
00015  * You should have received a copy of the GNU General Public License
00016  * along with this program; if not, write to the Free Software
00017  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
00018  */
00019 // --------------------------------------------------------------------------
00024 //--------------------------------------------------------------------------
00025 #ifndef UNITRIGGER_H_
00026 #define UNITRIGGER_H_
00027 //--------------------------------------------------------------------------
00029 class Trigger
00030 {
00031     public:
00032         Trigger(bool initial = false)
00033         {
00034             oldstate = initial;
00035         }
00036 
00038         bool hi(bool state)
00039         {
00040             if (oldstate != state) {
00041                 oldstate = state;
00042                 if (state)
00043                     return true;
00044             }
00045             return false;
00046         }
00048         bool low(bool state)
00049         {
00050             if (oldstate != state) {
00051                 oldstate = state;
00052                 if (!state)
00053                     return true;
00054             }
00055             return false;
00056         }
00058         bool change(bool state)
00059         {
00060             if (oldstate != state) {
00061                 oldstate = state;
00062                 return true;
00063             }
00064             return false;
00065         }
00066     private:
00067         bool oldstate; 
00068 };
00069 // --------------------------------------------------------------------------
00070 #endif
00071 // --------------------------------------------------------------------------