src/main/common/tristate.h

   1 /*
   2  * This file is part of INAV.
   3  *
   4  * INAV is free software. You can redistribute this software
   5  * and/or modify this software under the terms of the
   6  * GNU General Public License as published by the Free Software
   7  * Foundation, either version 3 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * INAV is distributed in the hope that they will be
  11  * useful, but WITHOUT ANY WARRANTY; without even the implied
  12  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  * See the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this software.
  17  *
  18  * If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #pragma once
  22
  23 #include <stdbool.h>
  24
  25 // tristate_e represents something that can take a default AUTO
  26 // value and two explicit ON and OFF values. To ease the transition
  27 // from boolean settings (0 = OFF, 1 = ON), the 1 value has
  28 // been picked as ON while OFF is represented by 2. AUTO is represented
  29 // by 0.
  30 typedef enum {
  31     TRISTATE_AUTO = 0,
  32     TRISTATE_ON = 1,
  33     TRISTATE_OFF = 2,
  34 } tristate_e;
  35
  36 // tristateWithDefaultOnIsActive returns false is tristate is TRISTATE_OFF
  37 // and true otherwise.
  38 static inline bool tristateWithDefaultOnIsActive(tristate_e tristate)
  39 {
  40     return tristate != TRISTATE_OFF;
  41 }
  42
  43 // tristateWithDefaultOffIsActive returns true is tristate is TRISTATE_ON
  44 // and false otherwise.
  45 static inline bool tristateWithDefaultOffIsActive(tristate_e tristate)
  46 {
  47     return tristate == TRISTATE_ON;
  48 }
  49
  50 // tristateWithDefaultIsActive() calls tristateWithDefaultOnIsActive() when
  51 // def is true, and tristateWithDefaultOffIsActive() otherwise.
  52 // See tristateWithDefaultOnIsActive() and tristateWithDefaultOffIsActive()
  53 static inline bool tristateWithDefaultIsActive(tristate_e tristate, bool def)
  54 {
  55     return def ? tristateWithDefaultOnIsActive(tristate) : tristateWithDefaultOffIsActive(tristate);
  56 }