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Fix overflows in WPM calculations (#13128)

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* Fix overflow in WPM calculations.

First, the "fresh" WPM calculation could end up being up to 12000 (with
default `WPM_ESTIMATED_WORD_SIZE`) if keys were pressed more or less
simultaneously. This value has now been clamped down to 255, in effect
clamping WPM to its max value of 255.

Second, with `WPM_ALLOW_COUNT_REGRESSION` enabled, it was possible to
regress the WPM below 0 (i.e. to 255) by just repeatedly pressing
backspace.

* Fix WPM being limited to 235 due to float/int logic.
This commit is contained in:
Joakim Tufvegren 2021-08-03 23:40:08 +02:00 • committed by GitHub
parent f2fc23d1b1
commit 2b097d670a
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GPG key ID: 4AEE18F83AFDEB23
1 changed files with 12 additions and 2 deletions
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14
quantum/wpm.c
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@ -17,6 +17,8 @@
#include "wpm.h"
#include <math.h>
// WPM Stuff
static uint8_t current_wpm = 0;
static uint16_t wpm_timer = 0;
@ -69,14 +71,22 @@ __attribute__((weak)) uint8_t wpm_regress_count(uint16_t keycode) {
void update_wpm(uint16_t keycode) {
if (wpm_keycode(keycode)) {
if (wpm_timer > 0) {
current_wpm += ((60000 / timer_elapsed(wpm_timer) / WPM_ESTIMATED_WORD_SIZE) - current_wpm) * wpm_smoothing;
uint16_t latest_wpm = 60000 / timer_elapsed(wpm_timer) / WPM_ESTIMATED_WORD_SIZE;
if (latest_wpm > UINT8_MAX) {
latest_wpm = UINT8_MAX;
}
current_wpm += ceilf((latest_wpm - current_wpm) * wpm_smoothing);
}
wpm_timer = timer_read();
}
#ifdef WPM_ALLOW_COUNT_REGRESSION
uint8_t regress = wpm_regress_count(keycode);
if (regress) {
current_wpm -= regress;
if (current_wpm < regress) {
current_wpm = 0;
} else {
current_wpm -= regress;
}
wpm_timer = timer_read();
}
#endif