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- /*
- Copyright 2021 Chad Austin <chad@chadaustin.me>
- This program is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation, either version 2 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
- /*
- Symmetric per-row debounce algorithm. Changes only apply when
- DEBOUNCE milliseconds have elapsed since the last change.
- */
-
- #include "matrix.h"
- #include "timer.h"
- #include "quantum.h"
- #include <stdlib.h>
-
- #ifndef DEBOUNCE
- # define DEBOUNCE 5
- #endif
-
- static uint16_t last_time;
- // [row] milliseconds until key's state is considered debounced.
- static uint8_t* countdowns;
- // [row]
- static matrix_row_t* last_raw;
-
- void debounce_init(uint8_t num_rows) {
- countdowns = (uint8_t*)calloc(num_rows, sizeof(uint8_t));
- last_raw = (matrix_row_t*)calloc(num_rows, sizeof(matrix_row_t));
-
- last_time = timer_read();
- }
-
- void debounce_free(void) {
- free(countdowns);
- countdowns = NULL;
- free(last_raw);
- last_raw = NULL;
- }
-
- void debounce(matrix_row_t raw[], matrix_row_t cooked[], uint8_t num_rows, bool changed) {
- uint16_t now = timer_read();
- uint16_t elapsed16 = TIMER_DIFF_16(now, last_time);
- last_time = now;
- uint8_t elapsed = (elapsed16 > 255) ? 255 : elapsed16;
-
- uint8_t* countdown = countdowns;
-
- for (uint8_t row = 0; row < num_rows; ++row, ++countdown) {
- matrix_row_t raw_row = raw[row];
-
- if (raw_row != last_raw[row]) {
- *countdown = DEBOUNCE;
- last_raw[row] = raw_row;
- } else if (*countdown > elapsed) {
- *countdown -= elapsed;
- } else if (*countdown) {
- cooked[row] = raw_row;
- *countdown = 0;
- }
- }
- }
-
- bool debounce_active(void) {
- return true;
- }
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