summaryrefslogtreecommitdiff
path: root/quantum/process_keycode/process_key_lock.c
blob: d7978f91c7a2784cb9eddc1010eb9413012f8201 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/* Copyright 2017 Fredric Silberberg
 *
 * 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/>.
 */

#include "inttypes.h"
#include "stdint.h"
#include "process_key_lock.h"

#define BV_64(shift) (((uint64_t)1) << (shift))
#define GET_KEY_ARRAY(code) (((code) < 0x40) ? key_state[0] : \
                             ((code) < 0x80) ? key_state[1] : \
                             ((code) < 0xC0) ? key_state[2] : key_state[3])
#define GET_CODE_INDEX(code) (((code) < 0x40) ? (code) : \
                              ((code) < 0x80) ? (code) - 0x40 : \
                              ((code) < 0xC0) ? (code) - 0x80 : (code) - 0xC0)
#define KEY_STATE(code)  (GET_KEY_ARRAY(code) & BV_64(GET_CODE_INDEX(code))) == BV_64(GET_CODE_INDEX(code))
#define SET_KEY_ARRAY_STATE(code, val) do { \
    switch (code) { \
        case 0x00 ... 0x3F: \
            key_state[0] = (val); \
            break; \
        case 0x40 ... 0x7F: \
            key_state[1] = (val); \
            break; \
        case 0x80 ... 0xBF: \
            key_state[2] = (val); \
            break; \
        case 0xC0 ... 0xFF: \
            key_state[3] = (val); \
            break; \
    } \
} while(0)
#define SET_KEY_STATE(code) SET_KEY_ARRAY_STATE(code, (GET_KEY_ARRAY(code) | BV_64(GET_CODE_INDEX(code))))
#define UNSET_KEY_STATE(code) SET_KEY_ARRAY_STATE(code, (GET_KEY_ARRAY(code)) & ~(BV_64(GET_CODE_INDEX(code))))
#define IS_STANDARD_KEYCODE(code) ((code) <= 0xFF)

// Locked key state. This is an array of 256 bits, one for each of the standard keys supported qmk.
uint64_t key_state[4] = { 0x0, 0x0, 0x0, 0x0 };
bool watching = false;

// Translate any OSM keycodes back to their unmasked versions.
uint16_t inline translate_keycode(uint16_t keycode) {
    if (keycode > QK_ONE_SHOT_MOD && keycode <= QK_ONE_SHOT_MOD_MAX) {
        return keycode ^ QK_ONE_SHOT_MOD;
    } else {
        return keycode;
    }
}

bool process_key_lock(uint16_t *keycode, keyrecord_t *record) {
    // We start by categorizing the keypress event. In the event of a down
    // event, there are several possibilities:
    // 1. The key is not being locked, and we are not watching for new keys.
    //    In this case, we bail immediately. This is the common case for down events.
    // 2. The key was locked, and we need to unlock it. In this case, we will
    //    reset the state in our map and return false. When the user releases the
    //    key, the up event will no longer be masked and the OS will observe the
    //    released key.
    // 3. KC_LOCK was just pressed. In this case, we set up the state machine
    //    to watch for the next key down event, and finish processing
    // 4. The keycode is below 0xFF, and we are watching for new keys. In this case,
    //    we will send the key down event to the os, and set the key_state for that
    //    key to mask the up event.
    // 5. The keycode is above 0xFF, and we're wathing for new keys. In this case,
    //    the user pressed a key that we cannot "lock", as it's a series of keys,
    //    or a macro invocation, or a layer transition, or a custom-defined key, or
    //    or some other arbitrary code. In this case, we bail immediately, reset
    //    our watch state, and return true.
    //
    // In the event of an up event, there are these possibilities:
    // 1. The key is not being locked. In this case, we return true and bail
    //    immediately. This is the common case.
    // 2. The key is being locked. In this case, we will mask the up event
    //    by returning false, so the OS never sees that the key was released
    //    until the user pressed the key again.

    // We translate any OSM keycodes back to their original keycodes, so that if the key being
    // one-shot modded is a standard keycode, we can handle it. This is the only set of special
    // keys that we handle
    uint16_t translated_keycode = translate_keycode(*keycode);

    if (record->event.pressed) {
        // Non-standard keycode, reset and return
        if (!(IS_STANDARD_KEYCODE(translated_keycode) || translated_keycode == KC_LOCK)) {
            watching = false;
            return true;
        }

        // If we're already watching, turn off the watch.
        if (translated_keycode == KC_LOCK) {
            watching = !watching;
            return false;
        }

        if (IS_STANDARD_KEYCODE(translated_keycode)) {
            // We check watching first. This is so that in the following scenario, we continue to
            // hold the key: KC_LOCK, KC_F, KC_LOCK, KC_F
            // If we checked in reverse order, we'd end up holding the key pressed after the second
            // KC_F press is registered, when the user likely meant to hold F
            if (watching) {
                watching = false;
                SET_KEY_STATE(translated_keycode);
                // We need to set the keycode passed in to be the translated keycode, in case we
                // translated a OSM back to the original keycode.
                *keycode = translated_keycode;
                // Let the standard keymap send the keycode down event. The up event will be masked.
                return true;
            }

            if (KEY_STATE(translated_keycode)) {
                UNSET_KEY_STATE(translated_keycode);
                // The key is already held, stop this process. The up event will be sent when the user
                // releases the key.
                return false;
            }
        }

        // Either the key isn't a standard key, or we need to send the down event. Continue standard
        // processing
        return true;
    } else {
        // Stop processing if it's a standard key and we're masking up.
        return !(IS_STANDARD_KEYCODE(translated_keycode) && KEY_STATE(translated_keycode));
    }
}