Revert 14083 && 14144 (#14150)

* Revert "Short term bodge for firmware size bloat (#14144)"

This reverts commit a8d65473461c337fb1e168d907bfb8c3ac8fdbd0.

* Revert "Tidy up quantum.c now some of tmk_core has been merged (#14083)"

This reverts commit c4dbf4bf0118dd785802861beb247433b5b7411d.

1 files changed, 90 insertions, 0 deletions

diff --git a/quantum/quantum.c b/quantum/quantum.c
index 00426c3973..e60378afe4 100644
--- a/quantum/quantum.c
+++ b/quantum/quantum.c
@@ -51,6 +51,63 @@ float default_layer_songs[][16][2] = DEFAULT_LAYER_SONGS;
 #    endif
 #endif
 
+#ifdef AUTO_SHIFT_ENABLE
+#    include "process_auto_shift.h"
+#endif
+
+uint8_t extract_mod_bits(uint16_t code) {
+    switch (code) {
+        case QK_MODS ... QK_MODS_MAX:
+            break;
+        default:
+            return 0;
+    }
+
+    uint8_t mods_to_send = 0;
+
+    if (code & QK_RMODS_MIN) {  // Right mod flag is set
+        if (code & QK_LCTL) mods_to_send |= MOD_BIT(KC_RCTL);
+        if (code & QK_LSFT) mods_to_send |= MOD_BIT(KC_RSFT);
+        if (code & QK_LALT) mods_to_send |= MOD_BIT(KC_RALT);
+        if (code & QK_LGUI) mods_to_send |= MOD_BIT(KC_RGUI);
+    } else {
+        if (code & QK_LCTL) mods_to_send |= MOD_BIT(KC_LCTL);
+        if (code & QK_LSFT) mods_to_send |= MOD_BIT(KC_LSFT);
+        if (code & QK_LALT) mods_to_send |= MOD_BIT(KC_LALT);
+        if (code & QK_LGUI) mods_to_send |= MOD_BIT(KC_LGUI);
+    }
+
+    return mods_to_send;
+}
+
+static void do_code16(uint16_t code, void (*f)(uint8_t)) { f(extract_mod_bits(code)); }
+
+void register_code16(uint16_t code) {
+    if (IS_MOD(code) || code == KC_NO) {
+        do_code16(code, register_mods);
+    } else {
+        do_code16(code, register_weak_mods);
+    }
+    register_code(code);
+}
+
+void unregister_code16(uint16_t code) {
+    unregister_code(code);
+    if (IS_MOD(code) || code == KC_NO) {
+        do_code16(code, unregister_mods);
+    } else {
+        do_code16(code, unregister_weak_mods);
+    }
+}
+
+void tap_code16(uint16_t code) {
+    register_code16(code);
+#if TAP_CODE_DELAY > 0
+    wait_ms(TAP_CODE_DELAY);
+#endif
+    unregister_code16(code);
+}
+
 __attribute__((weak)) bool process_action_kb(keyrecord_t *record) { return true; }
 
 __attribute__((weak)) bool process_record_kb(uint16_t keycode, keyrecord_t *record) { return process_record_user(keycode, record); }
@@ -85,6 +142,39 @@ void reset_keyboard(void) {
     bootloader_jump();
 }
 
+/* Convert record into usable keycode via the contained event. */
+uint16_t get_record_keycode(keyrecord_t *record, bool update_layer_cache) {
+#ifdef COMBO_ENABLE
+    if (record->keycode) { return record->keycode; }
+#endif
+    return get_event_keycode(record->event, update_layer_cache);
+}
+
+
+/* Convert event into usable keycode. Checks the layer cache to ensure that it
+ * retains the correct keycode after a layer change, if the key is still pressed.
+ * "update_layer_cache" is to ensure that it only updates the layer cache when
+ * appropriate, otherwise, it will update it and cause layer tap (and other keys)
+ * from triggering properly.
+ */
+uint16_t get_event_keycode(keyevent_t event, bool update_layer_cache) {
+#if !defined(NO_ACTION_LAYER) && !defined(STRICT_LAYER_RELEASE)
+    /* TODO: Use store_or_get_action() or a similar function. */
+    if (!disable_action_cache) {
+        uint8_t layer;
+
+        if (event.pressed && update_layer_cache) {
+            layer = layer_switch_get_layer(event.key);
+            update_source_layers_cache(event.key, layer);
+        } else {
+            layer = read_source_layers_cache(event.key);
+        }
+        return keymap_key_to_keycode(layer, event.key);
+    } else
+#endif
+        return keymap_key_to_keycode(layer_switch_get_layer(event.key), event.key);
+}
+
 /* Get keycode, and then process pre tapping functionality */
 bool pre_process_record_quantum(keyrecord_t *record) {
     if (!(