Add action_tapping.[ch] for refactoring

4 files changed, 396 insertions, 369 deletions

diff --git a/common/action.c b/common/action.c
index c218808aba..07a3a64d6c 100644
--- a/common/action.c
+++ b/common/action.c
@@ -15,76 +15,19 @@ 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 "host.h"
-#include "timer.h"
-#include "keymap.h"
 #include "keycode.h"
 #include "keyboard.h"
 #include "mousekey.h"
 #include "command.h"
-#include "util.h"
 #include "debug.h"
 #include "led.h"
 #include "layer_switch.h"
+#include "action_tapping.h"
 #include "action_oneshot.h"
 #include "action_macro.h"
 #include "action.h"
 
 
-static void process_action(keyrecord_t *record);
-static void debug_event(keyevent_t event);
-static void debug_record(keyrecord_t record);
-static void debug_action(action_t action);
-
-#ifndef NO_ACTION_TAPPING
-/*
- * Tapping
- */
-/* period of tapping(ms) */
-#ifndef TAPPING_TERM
-#define TAPPING_TERM    200
-#endif
-
-/* tap count needed for toggling a feature */
-#ifndef TAPPING_TOGGLE
-#define TAPPING_TOGGLE  5
-#endif
-
-/* stores a key event of current tap. */
-static keyrecord_t tapping_key = {};
-
-#define IS_TAPPING()            !IS_NOEVENT(tapping_key.event)
-#define IS_TAPPING_PRESSED()    (IS_TAPPING() && tapping_key.event.pressed)
-#define IS_TAPPING_RELEASED()   (IS_TAPPING() && !tapping_key.event.pressed)
-#define IS_TAPPING_KEY(k)       (IS_TAPPING() && KEYEQ(tapping_key.event.key, (k)))
-#define WITHIN_TAPPING_TERM(e)  (TIMER_DIFF_16(e.time, tapping_key.event.time) < TAPPING_TERM)
-
-
-/*
- * Waiting buffer
- *
- * stores key events waiting for settling current tap.
- */
-#define WAITING_BUFFER_SIZE 8
-static keyrecord_t waiting_buffer[WAITING_BUFFER_SIZE] = {};
-/* point to empty cell to enq */
-static uint8_t waiting_buffer_head = 0;
-/* point to the oldest data cell to deq */
-static uint8_t waiting_buffer_tail = 0;
-
-
-static bool process_tapping(keyrecord_t *record);
-static bool waiting_buffer_enq(keyrecord_t record);
-static void waiting_buffer_clear(void);
-#if TAPPING_TERM >= 500
-static bool waiting_buffer_typed(keyevent_t event);
-#endif
-static void waiting_buffer_scan_tap(void);
-static void debug_tapping_key(void);
-static void debug_waiting_buffer(void);
-#endif
-
-
-
 void action_exec(keyevent_t event)
 {
     if (!IS_NOEVENT(event)) {
@@ -95,35 +38,7 @@ void action_exec(keyevent_t event)
     keyrecord_t record = { .event = event };
 
 #ifndef NO_ACTION_TAPPING
-    if (process_tapping(&record)) {
-        if (!IS_NOEVENT(record.event)) {
-            debug("processed: "); debug_record(record); debug("\n");
-        }
-    } else {
-        if (!waiting_buffer_enq(record)) {
-            // clear all in case of overflow.
-            debug("OVERFLOW: CLEAR ALL STATES\n");
-            clear_keyboard();
-            waiting_buffer_clear();
-            tapping_key = (keyrecord_t){};
-        }
-    }
-
-    // process waiting_buffer
-    if (!IS_NOEVENT(event) && waiting_buffer_head != waiting_buffer_tail) {
-        debug("---- action_exec: process waiting_buffer -----\n");
-    }
-    for (; waiting_buffer_tail != waiting_buffer_head; waiting_buffer_tail = (waiting_buffer_tail + 1) % WAITING_BUFFER_SIZE) {
-        if (process_tapping(&waiting_buffer[waiting_buffer_tail])) {
-            debug("processed: waiting_buffer["); debug_dec(waiting_buffer_tail); debug("] = ");
-            debug_record(waiting_buffer[waiting_buffer_tail]); debug("\n\n");
-        } else {
-            break;
-        }
-    }
-    if (!IS_NOEVENT(event)) {
-        debug("\n");
-    }
+    action_tapping_process(record);
 #else
     process_action(&record);
     if (!IS_NOEVENT(record.event)) {
@@ -132,7 +47,7 @@ void action_exec(keyevent_t event)
 #endif
 }
 
-static void process_action(keyrecord_t *record)
+void process_action(keyrecord_t *record)
 {
     keyevent_t event = record->event;
     uint8_t tap_count = record->tap.count;
@@ -224,7 +139,7 @@ static void process_action(keyrecord_t *record)
                     default:
                         if (event.pressed) {
                             if (tap_count > 0) {
-                                if (waiting_buffer_has_anykey_pressed()) {
+                                if (record->tap.interrupted) {
                                     debug("MODS_TAP: Tap: Cancel: add_mods\n");
                                     // ad hoc: set 0 to cancel tap
                                     record->tap.count = 0;
@@ -774,20 +689,23 @@ bool is_tap_key(key_t key)
 /*
  * debug print
  */
-static void debug_event(keyevent_t event)
+void debug_event(keyevent_t event)
 {
     debug_hex16((event.key.row<<8) | event.key.col);
     if (event.pressed) debug("d("); else debug("u(");
     debug_dec(event.time); debug(")");
 }
 
-static void debug_record(keyrecord_t record)
+void debug_record(keyrecord_t record)
 {
-    debug_event(record.event); debug(":"); debug_dec(record.tap.count);
+    debug_event(record.event);
+#ifndef NO_ACTION_TAPPING
+    debug(":"); debug_dec(record.tap.count);
     if (record.tap.interrupted) debug("-");
+#endif
 }
 
-static void debug_action(action_t action)
+void debug_action(action_t action)
 {
     switch (action.kind.id) {
         case ACT_LMODS:             debug("ACT_LMODS");             break;
@@ -809,267 +727,3 @@ static void debug_action(action_t action)
     debug_hex8(action.kind.param & 0xff);
     debug("]");
 }
-
-
-
-#ifndef NO_ACTION_TAPPING
-/* Tapping
- *
- * Rule: Tap key is typed(pressed and released) within TAPPING_TERM.
- *       (without interfering by typing other key)
- */
-/* return true when key event is processed or consumed. */
-static bool process_tapping(keyrecord_t *keyp)
-{
-    keyevent_t event = keyp->event;
-
-    // if tapping
-    if (IS_TAPPING_PRESSED()) {
-        if (WITHIN_TAPPING_TERM(event)) {
-            if (tapping_key.tap.count == 0) {
-                if (IS_TAPPING_KEY(event.key) && !event.pressed) {
-                    // first tap!
-                    debug("Tapping: First tap(0->1).\n");
-                    tapping_key.tap.count = 1;
-                    tapping_key.tap.interrupted  = (waiting_buffer_has_anykey_pressed() ? true : false);
-                    debug_tapping_key();
-                    process_action(&tapping_key);
-
-                    // enqueue
-                    keyp->tap = tapping_key.tap;
-                    return false;
-                }
-#if TAPPING_TERM >= 500
-                /* This can prevent from typing some tap keys in a row at a time. */
-                else if (!event.pressed && waiting_buffer_typed(event)) {
-                    // other key typed. not tap.
-                    debug("Tapping: End. No tap. Interfered by typing key\n");
-                    process_action(&tapping_key);
-                    tapping_key = (keyrecord_t){};
-                    debug_tapping_key();
-
-                    // enqueue
-                    return false;
-                }
-#endif
-                else {
-                    // other key events shall be enq'd till tapping state settles.
-                    return false;
-                }
-            }
-            // tap_count > 0
-            else {
-                if (IS_TAPPING_KEY(event.key) && !event.pressed) {
-                    debug("Tapping: Tap release("); debug_dec(tapping_key.tap.count); debug(")\n");
-                    keyp->tap = tapping_key.tap;
-                    process_action(keyp);
-                    tapping_key = *keyp;
-                    debug_tapping_key();
-                    return true;
-                }
-                else if (is_tap_key(keyp->event.key) && event.pressed) {
-                    if (tapping_key.tap.count > 1) {
-                        debug("Tapping: Start new tap with releasing last tap(>1).\n");
-                        // unregister key
-                        process_action(&(keyrecord_t){
-                                .tap = tapping_key.tap,
-                                .event.key = tapping_key.event.key,
-                                .event.time = event.time,
-                                .event.pressed = false
-                        });
-                    } else {
-                        debug("Tapping: Start while last tap(1).\n");
-                    }
-                    tapping_key = *keyp;
-                    waiting_buffer_scan_tap();
-                    debug_tapping_key();
-                    return true;
-                }
-                else {
-                    if (!IS_NOEVENT(keyp->event)) {
-                        debug("Tapping: key event while last tap(>0).\n");
-                    }
-                    process_action(keyp);
-                    return true;
-                }
-            }
-        }
-        // after TAPPING_TERM
-        else {
-            if (tapping_key.tap.count == 0) {
-                debug("Tapping: End. Timeout. Not tap(0): ");
-                debug_event(event); debug("\n");
-                process_action(&tapping_key);
-                tapping_key = (keyrecord_t){};
-                debug_tapping_key();
-                return false;
-            }  else {
-                if (IS_TAPPING_KEY(event.key) && !event.pressed) {
-                    debug("Tapping: End. last timeout tap release(>0).");
-                    keyp->tap = tapping_key.tap;
-                    process_action(keyp);
-                    tapping_key = (keyrecord_t){};
-                    return true;
-                }
-                else if (is_tap_key(keyp->event.key) && event.pressed) {
-                    if (tapping_key.tap.count > 1) {
-                        debug("Tapping: Start new tap with releasing last timeout tap(>1).\n");
-                        // unregister key
-                        process_action(&(keyrecord_t){
-                                .tap = tapping_key.tap,
-                                .event.key = tapping_key.event.key,
-                                .event.time = event.time,
-                                .event.pressed = false
-                        });
-                    } else {
-                        debug("Tapping: Start while last timeout tap(1).\n");
-                    }
-                    tapping_key = *keyp;
-                    waiting_buffer_scan_tap();
-                    debug_tapping_key();
-                    return true;
-                }
-                else {
-                    if (!IS_NOEVENT(keyp->event)) {
-                        debug("Tapping: key event while last timeout tap(>0).\n");
-                    }
-                    process_action(keyp);
-                    return true;
-                }
-            }
-        }
-    } else if (IS_TAPPING_RELEASED()) {
-        if (WITHIN_TAPPING_TERM(event)) {
-            if (tapping_key.tap.count > 0 && IS_TAPPING_KEY(event.key) && event.pressed) {
-                // sequential tap.
-                keyp->tap = tapping_key.tap;
-                keyp->tap.count += 1;
-                debug("Tapping: Tap press("); debug_dec(keyp->tap.count); debug(")\n");
-                process_action(keyp);
-                tapping_key = *keyp;
-                debug_tapping_key();
-                return true;
-            } else if (event.pressed && is_tap_key(event.key)) {
-                // Sequential tap can be interfered with other tap key.
-                debug("Tapping: Start with interfering other tap.\n");
-                tapping_key = *keyp;
-                waiting_buffer_scan_tap();
-                debug_tapping_key();
-                return true;
-            } else {
-                if (!IS_NOEVENT(keyp->event)) debug("Tapping: other key just after tap.\n");
-                process_action(keyp);
-                return true;
-            }
-        } else {
-            // timeout. no sequential tap.
-            debug("Tapping: End(Timeout after releasing last tap): ");
-            debug_event(event); debug("\n");
-            tapping_key = (keyrecord_t){};
-            debug_tapping_key();
-            return false;
-        }
-    }
-    // not tapping satate
-    else {
-        if (event.pressed && is_tap_key(event.key)) {
-            debug("Tapping: Start(Press tap key).\n");
-            tapping_key = *keyp;
-            waiting_buffer_scan_tap();
-            debug_tapping_key();
-            return true;
-        } else {
-            process_action(keyp);
-            return true;
-        }
-    }
-}
-
-
-/*
- * Waiting buffer
- */
-static bool waiting_buffer_enq(keyrecord_t record)
-{
-    if (IS_NOEVENT(record.event)) {
-        return true;
-    }
-
-    if ((waiting_buffer_head + 1) % WAITING_BUFFER_SIZE == waiting_buffer_tail) {
-        debug("waiting_buffer_enq: Over flow.\n");
-        return false;
-    }
-
-    waiting_buffer[waiting_buffer_head] = record;
-    waiting_buffer_head = (waiting_buffer_head + 1) % WAITING_BUFFER_SIZE;
-
-    debug("waiting_buffer_enq: "); debug_waiting_buffer();
-    return true;
-}
-
-static void waiting_buffer_clear(void)
-{
-    waiting_buffer_head = 0;
-    waiting_buffer_tail = 0;
-}
-
-#if TAPPING_TERM >= 500
-static bool waiting_buffer_typed(keyevent_t event)
-{
-    for (uint8_t i = waiting_buffer_tail; i != waiting_buffer_head; i = (i + 1) % WAITING_BUFFER_SIZE) {
-        if (KEYEQ(event.key, waiting_buffer[i].event.key) && event.pressed !=  waiting_buffer[i].event.pressed) {
-            return true;
-        }
-    }
-    return false;
-}
-#endif
-
-bool waiting_buffer_has_anykey_pressed(void)
-{
-    for (uint8_t i = waiting_buffer_tail; i != waiting_buffer_head; i = (i + 1) % WAITING_BUFFER_SIZE) {
-        if (waiting_buffer[i].event.pressed) return true;
-    }
-    return false;
-}
-/* scan buffer for tapping */
-static void waiting_buffer_scan_tap(void)
-{
-    // tapping already is settled
-    if (tapping_key.tap.count > 0) return;
-    // invalid state: tapping_key released && tap.count == 0
-    if (!tapping_key.event.pressed) return;
-
-    for (uint8_t i = waiting_buffer_tail; i != waiting_buffer_head; i = (i + 1) % WAITING_BUFFER_SIZE) {
-        if (IS_TAPPING_KEY(waiting_buffer[i].event.key) &&
-                !waiting_buffer[i].event.pressed &&
-                WITHIN_TAPPING_TERM(waiting_buffer[i].event)) {
-            tapping_key.tap.count = 1;
-            waiting_buffer[i].tap.count = 1;
-            process_action(&tapping_key);
-
-            debug("waiting_buffer_scan_tap: found at ["); debug_dec(i); debug("]\n");
-            debug_waiting_buffer();
-            return;
-        }
-    }
-}
-
-
-/*
- * debug print
- */
-static void debug_tapping_key(void)
-{
-    debug("TAPPING_KEY="); debug_record(tapping_key); debug("\n");
-}
-
-static void debug_waiting_buffer(void)
-{
-    debug("{ ");
-    for (uint8_t i = waiting_buffer_tail; i != waiting_buffer_head; i = (i + 1) % WAITING_BUFFER_SIZE) {
-        debug("["); debug_dec(i); debug("]="); debug_record(waiting_buffer[i]); debug(" ");
-    }
-    debug("}\n");
-}
-#endif
diff --git a/common/action.h b/common/action.h
index ead917983c..a6cb453840 100644
--- a/common/action.h
+++ b/common/action.h
@@ -17,25 +17,25 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #ifndef ACTION_H
 #define ACTION_H
 
+#include <stdint.h>
+#include <stdbool.h>
 #include "keyboard.h"
 #include "keycode.h"
 #include "action_macro.h"
 
 
-/* Struct to record event and tap count  */
-typedef union {
+typedef struct {
+    keyevent_t  event;
+#ifndef NO_ACTION_TAPPING
+    /* tapping count and state */
     struct {
         bool    interrupted :1;
         bool    reserved2   :1;
         bool    reserved1   :1;
         bool    reserved0   :1;
         uint8_t count       :4;
-    };
-} tap_t;
-
-typedef struct {
-    keyevent_t  event;
-    tap_t tap;
+    } tap;
+#endif
 } keyrecord_t;
 
 /* Action struct.
@@ -99,9 +99,8 @@ const prog_macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t op
 /* user defined special function */
 void action_function(keyrecord_t *record, uint8_t id, uint8_t opt);
 
-/*
- * Utilities for actions.
- */
+/* Utilities for actions.  */
+void process_action(keyrecord_t *record);
 void register_code(uint8_t code);
 void unregister_code(uint8_t code);
 void add_mods(uint8_t mods);
@@ -112,7 +111,11 @@ void clear_keyboard_but_mods(void);
 bool sending_anykey(void);
 void layer_switch(uint8_t new_layer);
 bool is_tap_key(key_t key);
-bool waiting_buffer_has_anykey_pressed(void);
+
+/* debug */
+void debug_event(keyevent_t event);
+void debug_record(keyrecord_t record);
+void debug_action(action_t action);
 
 
 
diff --git a/common/action_tapping.c b/common/action_tapping.c
new file mode 100644
index 0000000000..abb0bf5182
--- /dev/null
+++ b/common/action_tapping.c
@@ -0,0 +1,330 @@
+#include <stdint.h>
+#include <stdbool.h>
+#include "action.h"
+#include "action_tapping.h"
+#include "timer.h"
+#include "debug.h"
+
+
+#ifndef NO_ACTION_TAPPING
+
+#define IS_TAPPING()            !IS_NOEVENT(tapping_key.event)
+#define IS_TAPPING_PRESSED()    (IS_TAPPING() && tapping_key.event.pressed)
+#define IS_TAPPING_RELEASED()   (IS_TAPPING() && !tapping_key.event.pressed)
+#define IS_TAPPING_KEY(k)       (IS_TAPPING() && KEYEQ(tapping_key.event.key, (k)))
+#define WITHIN_TAPPING_TERM(e)  (TIMER_DIFF_16(e.time, tapping_key.event.time) < TAPPING_TERM)
+
+
+static keyrecord_t tapping_key = {};
+static keyrecord_t waiting_buffer[WAITING_BUFFER_SIZE] = {};
+static uint8_t waiting_buffer_head = 0;
+static uint8_t waiting_buffer_tail = 0;
+
+static bool process_tapping(keyrecord_t *record);
+static bool waiting_buffer_enq(keyrecord_t record);
+static void waiting_buffer_clear(void);
+#if TAPPING_TERM >= 500
+static bool waiting_buffer_typed(keyevent_t event);
+#endif
+static bool waiting_buffer_has_anykey_pressed(void);
+static void waiting_buffer_scan_tap(void);
+static void debug_tapping_key(void);
+static void debug_waiting_buffer(void);
+
+
+void action_tapping_process(keyrecord_t record)
+{
+    if (process_tapping(&record)) {
+        if (!IS_NOEVENT(record.event)) {
+            debug("processed: "); debug_record(record); debug("\n");
+        }
+    } else {
+        if (!waiting_buffer_enq(record)) {
+            // clear all in case of overflow.
+            debug("OVERFLOW: CLEAR ALL STATES\n");
+            clear_keyboard();
+            waiting_buffer_clear();
+            tapping_key = (keyrecord_t){};
+        }
+    }
+
+    // process waiting_buffer
+    if (!IS_NOEVENT(record.event) && waiting_buffer_head != waiting_buffer_tail) {
+        debug("---- action_exec: process waiting_buffer -----\n");
+    }
+    for (; waiting_buffer_tail != waiting_buffer_head; waiting_buffer_tail = (waiting_buffer_tail + 1) % WAITING_BUFFER_SIZE) {
+        if (process_tapping(&waiting_buffer[waiting_buffer_tail])) {
+            debug("processed: waiting_buffer["); debug_dec(waiting_buffer_tail); debug("] = ");
+            debug_record(waiting_buffer[waiting_buffer_tail]); debug("\n\n");
+        } else {
+            break;
+        }
+    }
+    if (!IS_NOEVENT(record.event)) {
+        debug("\n");
+    }
+}
+
+
+/* Tapping
+ *
+ * Rule: Tap key is typed(pressed and released) within TAPPING_TERM.
+ *       (without interfering by typing other key)
+ */
+/* return true when key event is processed or consumed. */
+bool process_tapping(keyrecord_t *keyp)
+{
+    keyevent_t event = keyp->event;
+
+    // if tapping
+    if (IS_TAPPING_PRESSED()) {
+        if (WITHIN_TAPPING_TERM(event)) {
+            if (tapping_key.tap.count == 0) {
+                if (IS_TAPPING_KEY(event.key) && !event.pressed) {
+                    // first tap!
+                    debug("Tapping: First tap(0->1).\n");
+                    tapping_key.tap.count = 1;
+                    tapping_key.tap.interrupted  = (waiting_buffer_has_anykey_pressed() ? true : false);
+                    debug_tapping_key();
+                    process_action(&tapping_key);
+
+                    // enqueue
+                    keyp->tap = tapping_key.tap;
+                    return false;
+                }
+#if TAPPING_TERM >= 500
+                /* This can prevent from typing some tap keys in a row at a time. */
+                else if (!event.pressed && waiting_buffer_typed(event)) {
+                    // other key typed. not tap.
+                    debug("Tapping: End. No tap. Interfered by typing key\n");
+                    process_action(&tapping_key);
+                    tapping_key = (keyrecord_t){};
+                    debug_tapping_key();
+
+                    // enqueue
+                    return false;
+                }
+#endif
+                else {
+                    // other key events shall be enq'd till tapping state settles.
+                    return false;
+                }
+            }
+            // tap_count > 0
+            else {
+                if (IS_TAPPING_KEY(event.key) && !event.pressed) {
+                    debug("Tapping: Tap release("); debug_dec(tapping_key.tap.count); debug(")\n");
+                    keyp->tap = tapping_key.tap;
+                    process_action(keyp);
+                    tapping_key = *keyp;
+                    debug_tapping_key();
+                    return true;
+                }
+                else if (is_tap_key(keyp->event.key) && event.pressed) {
+                    if (tapping_key.tap.count > 1) {
+                        debug("Tapping: Start new tap with releasing last tap(>1).\n");
+                        // unregister key
+                        process_action(&(keyrecord_t){
+                                .tap = tapping_key.tap,
+                                .event.key = tapping_key.event.key,
+                                .event.time = event.time,
+                                .event.pressed = false
+                        });
+                    } else {
+                        debug("Tapping: Start while last tap(1).\n");
+                    }
+                    tapping_key = *keyp;
+                    waiting_buffer_scan_tap();
+                    debug_tapping_key();
+                    return true;
+                }
+                else {
+                    if (!IS_NOEVENT(keyp->event)) {
+                        debug("Tapping: key event while last tap(>0).\n");
+                    }
+                    process_action(keyp);
+                    return true;
+                }
+            }
+        }
+        // after TAPPING_TERM
+        else {
+            if (tapping_key.tap.count == 0) {
+                debug("Tapping: End. Timeout. Not tap(0): ");
+                debug_event(event); debug("\n");
+                process_action(&tapping_key);
+                tapping_key = (keyrecord_t){};
+                debug_tapping_key();
+                return false;
+            }  else {
+                if (IS_TAPPING_KEY(event.key) && !event.pressed) {
+                    debug("Tapping: End. last timeout tap release(>0).");
+                    keyp->tap = tapping_key.tap;
+                    process_action(keyp);
+                    tapping_key = (keyrecord_t){};
+                    return true;
+                }
+                else if (is_tap_key(keyp->event.key) && event.pressed) {
+                    if (tapping_key.tap.count > 1) {
+                        debug("Tapping: Start new tap with releasing last timeout tap(>1).\n");
+                        // unregister key
+                        process_action(&(keyrecord_t){
+                                .tap = tapping_key.tap,
+                                .event.key = tapping_key.event.key,
+                                .event.time = event.time,
+                                .event.pressed = false
+                        });
+                    } else {
+                        debug("Tapping: Start while last timeout tap(1).\n");
+                    }
+                    tapping_key = *keyp;
+                    waiting_buffer_scan_tap();
+                    debug_tapping_key();
+                    return true;
+                }
+                else {
+                    if (!IS_NOEVENT(keyp->event)) {
+                        debug("Tapping: key event while last timeout tap(>0).\n");
+                    }
+                    process_action(keyp);
+                    return true;
+                }
+            }
+        }
+    } else if (IS_TAPPING_RELEASED()) {
+        if (WITHIN_TAPPING_TERM(event)) {
+            if (tapping_key.tap.count > 0 && IS_TAPPING_KEY(event.key) && event.pressed) {
+                // sequential tap.
+                keyp->tap = tapping_key.tap;
+                keyp->tap.count += 1;
+                debug("Tapping: Tap press("); debug_dec(keyp->tap.count); debug(")\n");
+                process_action(keyp);
+                tapping_key = *keyp;
+                debug_tapping_key();
+                return true;
+            } else if (event.pressed && is_tap_key(event.key)) {
+                // Sequential tap can be interfered with other tap key.
+                debug("Tapping: Start with interfering other tap.\n");
+                tapping_key = *keyp;
+                waiting_buffer_scan_tap();
+                debug_tapping_key();
+                return true;
+            } else {
+                if (!IS_NOEVENT(keyp->event)) debug("Tapping: other key just after tap.\n");
+                process_action(keyp);
+                return true;
+            }
+        } else {
+            // timeout. no sequential tap.
+            debug("Tapping: End(Timeout after releasing last tap): ");
+            debug_event(event); debug("\n");
+            tapping_key = (keyrecord_t){};
+            debug_tapping_key();
+            return false;
+        }
+    }
+    // not tapping satate
+    else {
+        if (event.pressed && is_tap_key(event.key)) {
+            debug("Tapping: Start(Press tap key).\n");
+            tapping_key = *keyp;
+            waiting_buffer_scan_tap();
+            debug_tapping_key();
+            return true;
+        } else {
+            process_action(keyp);
+            return true;
+        }
+    }
+}
+
+
+/*
+ * Waiting buffer
+ */
+bool waiting_buffer_enq(keyrecord_t record)
+{
+    if (IS_NOEVENT(record.event)) {
+        return true;
+    }
+
+    if ((waiting_buffer_head + 1) % WAITING_BUFFER_SIZE == waiting_buffer_tail) {
+        debug("waiting_buffer_enq: Over flow.\n");
+        return false;
+    }
+
+    waiting_buffer[waiting_buffer_head] = record;
+    waiting_buffer_head = (waiting_buffer_head + 1) % WAITING_BUFFER_SIZE;
+
+    debug("waiting_buffer_enq: "); debug_waiting_buffer();
+    return true;
+}
+
+void waiting_buffer_clear(void)
+{
+    waiting_buffer_head = 0;
+    waiting_buffer_tail = 0;
+}
+
+#if TAPPING_TERM >= 500
+bool waiting_buffer_typed(keyevent_t event)
+{
+    for (uint8_t i = waiting_buffer_tail; i != waiting_buffer_head; i = (i + 1) % WAITING_BUFFER_SIZE) {
+        if (KEYEQ(event.key, waiting_buffer[i].event.key) && event.pressed !=  waiting_buffer[i].event.pressed) {
+            return true;
+        }
+    }
+    return false;
+}
+#endif
+
+bool waiting_buffer_has_anykey_pressed(void)
+{
+    for (uint8_t i = waiting_buffer_tail; i != waiting_buffer_head; i = (i + 1) % WAITING_BUFFER_SIZE) {
+        if (waiting_buffer[i].event.pressed) return true;
+    }
+    return false;
+}
+
+/* scan buffer for tapping */
+void waiting_buffer_scan_tap(void)
+{
+    // tapping already is settled
+    if (tapping_key.tap.count > 0) return;
+    // invalid state: tapping_key released && tap.count == 0
+    if (!tapping_key.event.pressed) return;
+
+    for (uint8_t i = waiting_buffer_tail; i != waiting_buffer_head; i = (i + 1) % WAITING_BUFFER_SIZE) {
+        if (IS_TAPPING_KEY(waiting_buffer[i].event.key) &&
+                !waiting_buffer[i].event.pressed &&
+                WITHIN_TAPPING_TERM(waiting_buffer[i].event)) {
+            tapping_key.tap.count = 1;
+            waiting_buffer[i].tap.count = 1;
+            process_action(&tapping_key);
+
+            debug("waiting_buffer_scan_tap: found at ["); debug_dec(i); debug("]\n");
+            debug_waiting_buffer();
+            return;
+        }
+    }
+}
+
+
+/*
+ * debug print
+ */
+static void debug_tapping_key(void)
+{
+    debug("TAPPING_KEY="); debug_record(tapping_key); debug("\n");
+}
+
+static void debug_waiting_buffer(void)
+{
+    debug("{ ");
+    for (uint8_t i = waiting_buffer_tail; i != waiting_buffer_head; i = (i + 1) % WAITING_BUFFER_SIZE) {
+        debug("["); debug_dec(i); debug("]="); debug_record(waiting_buffer[i]); debug(" ");
+    }
+    debug("}\n");
+}
+
+#endif
diff --git a/common/action_tapping.h b/common/action_tapping.h
new file mode 100644
index 0000000000..c9f09f576d
--- /dev/null
+++ b/common/action_tapping.h
@@ -0,0 +1,40 @@
+/*
+Copyright 2013 Jun Wako <wakojun@gmail.com>
+
+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/>.
+*/
+#ifndef ACTION_TAPPING_H
+#define ACTION_TAPPING_H
+
+
+#ifndef NO_ACTION_TAPPING
+
+/* period of tapping(ms) */
+#ifndef TAPPING_TERM
+#define TAPPING_TERM    200
+#endif
+
+/* tap count needed for toggling a feature */
+#ifndef TAPPING_TOGGLE
+#define TAPPING_TOGGLE  5
+#endif
+
+#define WAITING_BUFFER_SIZE 8
+
+
+void action_tapping_process(keyrecord_t record);
+
+#endif
+
+#endif