UniSet
1.4.0
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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 // --------------------------------------------------------------------------