2 files changed, 120 insertions, 2 deletions

diff --git a/quantum/process_keycode/process_unicode.c b/quantum/process_keycode/process_unicode.c
index 55e47f179..8a6509300 100644
--- a/quantum/process_keycode/process_unicode.c
+++ b/quantum/process_keycode/process_unicode.c
@@ -68,4 +68,95 @@ bool process_unicode(uint16_t keycode, keyrecord_t *record) {
     unicode_input_finish();
   }
   return true;
-}
\ No newline at end of file
+}
+
+#ifdef UCIS_ENABLE
+void qk_ucis_start(void) {
+  qk_ucis_state.count = 0;
+  qk_ucis_state.in_progress = true;
+
+  unicode_input_start();
+  register_hex(0x2328);
+  unicode_input_finish();
+}
+
+static bool is_uni_seq(char *seq) {
+  uint8_t i;
+
+  for (i = 0; seq[i]; i++) {
+    uint16_t code;
+    if (('1' <= seq[i]) && (seq[i] <= '0'))
+      code = seq[i] - '1' + KC_1;
+    else
+      code = seq[i] - 'a' + KC_A;
+
+    if (i > qk_ucis_state.count || qk_ucis_state.codes[i] != code)
+      return false;
+  }
+
+  return (qk_ucis_state.codes[i] == KC_ENT ||
+          qk_ucis_state.codes[i] == KC_SPC);
+}
+
+__attribute__((weak))
+void qk_ucis_symbol_fallback (void) {
+  for (uint8_t i = 0; i < qk_ucis_state.count - 1; i++) {
+    uint8_t code = qk_ucis_state.codes[i];
+    register_code(code);
+    unregister_code(code);
+  }
+}
+
+bool process_record_ucis (uint16_t keycode, keyrecord_t *record) {
+  uint8_t i;
+
+  if (!qk_ucis_state.in_progress || !record->event.pressed)
+    return true;
+
+  qk_ucis_state.codes[qk_ucis_state.count] = keycode;
+  qk_ucis_state.count++;
+
+  if (keycode == KC_BSPC) {
+    if (qk_ucis_state.count >= 2) {
+      qk_ucis_state.count -= 2;
+      return true;
+    } else {
+      qk_ucis_state.count--;
+      return false;
+    }
+  }
+
+  if (keycode == KC_ENT || keycode == KC_SPC || keycode == KC_ESC) {
+    bool symbol_found = false;
+
+    for (i = qk_ucis_state.count; i > 0; i--) {
+      register_code (KC_BSPC);
+      unregister_code (KC_BSPC);
+    }
+
+    if (keycode == KC_ESC) {
+      qk_ucis_state.in_progress = false;
+      return false;
+    }
+
+    unicode_input_start();
+    for (i = 0; ucis_symbol_table[i].symbol; i++) {
+      if (is_uni_seq (ucis_symbol_table[i].symbol)) {
+        symbol_found = true;
+        for (uint8_t j = 0; ucis_symbol_table[i].codes[j]; j++) {
+          register_hex(ucis_symbol_table[i].codes[j]);
+        }
+        break;
+      }
+    }
+    if (!symbol_found) {
+      qk_ucis_symbol_fallback();
+    }
+    unicode_input_finish();
+
+    qk_ucis_state.in_progress = false;
+    return false;
+  }
+  return true;
+}
+#endif
diff --git a/quantum/process_keycode/process_unicode.h b/quantum/process_keycode/process_unicode.h
index f719a1226..372ea2f0d 100644
--- a/quantum/process_keycode/process_unicode.h
+++ b/quantum/process_keycode/process_unicode.h
@@ -15,6 +15,33 @@ void register_hex(uint16_t hex);
 
 bool process_unicode(uint16_t keycode, keyrecord_t *record);
 
+#ifdef UCIS_ENABLE
+#ifndef UCIS_MAX_SYMBOL_LENGTH
+#define UCIS_MAX_SYMBOL_LENGTH 32
+#endif
+
+typedef struct {
+  char *symbol;
+  uint16_t codes[4];
+} qk_ucis_symbol_t;
+
+struct {
+  uint8_t count;
+  uint16_t codes[UCIS_MAX_SYMBOL_LENGTH];
+  bool in_progress:1;
+} qk_ucis_state;
+
+#define UCIS_TABLE(...) {__VA_ARGS__, {NULL, {}}}
+#define UCIS_SYM(name, ...) {name, {__VA_ARGS__, 0}}
+
+extern const qk_ucis_symbol_t ucis_symbol_table[];
+
+void qk_ucis_start(void);
+void qk_ucis_symbol_fallback (void);
+bool process_record_ucis (uint16_t keycode, keyrecord_t *record);
+
+#endif
+
 #define UC_BSPC	UC(0x0008)
 
 #define UC_SPC	UC(0x0020)
@@ -122,4 +149,4 @@ bool process_unicode(uint16_t keycode, keyrecord_t *record);
 #define UC_TILD	UC(0x007E)
 #define UC_DEL	UC(0x007F)
 
-#endif
\ No newline at end of file
+#endif