Add char_to_key_code.m

This file includes functions for getting a `CGKeyCode` from a character
reference.

Copied from Stack Overflow by Théo Winterhalter.

1 files changed, 68 insertions, 0 deletions

diff --git a/lib/char_to_key_code.m b/lib/char_to_key_code.m
new file mode 100644
index 0000000..b4fcdec
--- /dev/null
+++ b/lib/char_to_key_code.m
@@ -0,0 +1,68 @@
+// Théo Winterhalter
+// https://stackoverflow.com/users/1275975/th%c3%a9o-winterhalter
+// https://stackoverflow.com/questions/1918841/how-to-convert-ascii-character-to-cgkeycode/33584460#33584460
+
+NSString* keyCodeToString(CGKeyCode keyCode)
+{
+  TISInputSourceRef currentKeyboard = TISCopyCurrentKeyboardInputSource();
+  CFDataRef uchr =
+    (CFDataRef)TISGetInputSourceProperty(currentKeyboard,
+                                         kTISPropertyUnicodeKeyLayoutData);
+  const UCKeyboardLayout *keyboardLayout =
+    (const UCKeyboardLayout*)CFDataGetBytePtr(uchr);
+
+  if(keyboardLayout)
+  {
+    UInt32 deadKeyState = 0;
+    UniCharCount maxStringLength = 255;
+    UniCharCount actualStringLength = 0;
+    UniChar unicodeString[maxStringLength];
+
+    OSStatus status = UCKeyTranslate(keyboardLayout,
+                                     keyCode, kUCKeyActionDown, 0,
+                                     LMGetKbdType(), 0,
+                                     &deadKeyState,
+                                     maxStringLength,
+                                     &actualStringLength, unicodeString);
+
+    if (actualStringLength == 0 && deadKeyState)
+    {
+      status = UCKeyTranslate(keyboardLayout,
+                                       kVK_Space, kUCKeyActionDown, 0,
+                                       LMGetKbdType(), 0,
+                                       &deadKeyState,
+                                       maxStringLength,
+                                       &actualStringLength, unicodeString);
+    }
+    if(actualStringLength > 0 && status == noErr)
+      return [[NSString stringWithCharacters:unicodeString
+                        length:(NSUInteger)actualStringLength] lowercaseString];
+  }
+
+  return nil;
+}
+
+NSNumber* charToKeyCode(const char c)
+{
+  static NSMutableDictionary* dict = nil;
+
+  if (dict == nil)
+  {
+    dict = [NSMutableDictionary dictionary];
+
+    // For every keyCode
+    size_t i;
+    for (i = 0; i < 128; ++i)
+    {
+      NSString* str = keyCodeToString((CGKeyCode)i);
+      if(str != nil && ![str isEqualToString:@""])
+      {
+        [dict setObject:[NSNumber numberWithInt:i] forKey:str];
+      }
+    }
+  }
+
+  NSString * keyChar = [NSString stringWithFormat:@"%c" , c];
+
+  return [dict objectForKey:keyChar];
+}