Encoded8To3ButtonConfig.h

/*
MIT License
 
Copyright (c) 2020 Brian T. Park
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
 
#ifndef ACE_BUTTON_ENCODED_8TO3_BUTTON_CONFIG_H
#define ACE_BUTTON_ENCODED_8TO3_BUTTON_CONFIG_H
 
#include "ButtonConfig.h"
 
namespace ace_button {
 
class Encoded8To3ButtonConfig : public ButtonConfig {
  public:
 
    Encoded8To3ButtonConfig(uint8_t pin0, uint8_t pin1, uint8_t pin2,
        uint8_t defaultReleasedState = HIGH):
      mPin0(pin0),
      mPin1(pin1),
      mPin2(pin2),
      mPressedState(defaultReleasedState ^ 0x1) {}
 
    int readButton(uint8_t pin) override {
      int s0 = digitalRead(mPin0);
      int s1 = digitalRead(mPin1);
      int s2 = digitalRead(mPin2);
 
      // Convert the actual pins states into a binary number which becomes
      // the encoded virtual pin numbers of the buttons.
      uint8_t virtualPin = (s0 == mPressedState)
        | ((s1 == mPressedState) << 1)
        | ((s2 == mPressedState) << 2);
      return (virtualPin == pin) ? mPressedState : (mPressedState ^ 0x1);
    }
 
  private:
    const uint8_t mPin0;
    const uint8_t mPin1;
    const uint8_t mPin2;
    const uint8_t mPressedState;
};
 
}
 
#endif