From d257de6d2ca3b8c1b8494276d2bdfd5ef137e7ba Mon Sep 17 00:00:00 2001
From: "jan.nijtmans" <nijtmans@users.sourceforge.net>
Date: Tue, 30 Aug 2016 10:24:09 +0000
Subject: Enhance TkpGetString() to handle Unicode characters, even when
 TCL_UTF_MAX==3.

---
 win/tkWinFont.c |  2 +-
 win/tkWinKey.c  | 16 ++++++++++++----
 win/tkWinX.c    | 10 ++++++++--
 3 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/win/tkWinFont.c b/win/tkWinFont.c
index 9172b00..940bc10 100644
--- a/win/tkWinFont.c
+++ b/win/tkWinFont.c
@@ -2188,7 +2188,7 @@ FontMapLoadPage(
 {
     FontFamily *familyPtr;
     Tcl_Encoding encoding;
-    char src[TCL_UTF_MAX], buf[16];
+    char src[XMaxTransChars], buf[16];
     USHORT *startCount, *endCount;
     int i, j, bitOffset, end, segCount;
 
diff --git a/win/tkWinKey.c b/win/tkWinKey.c
index ed546f7..a49898f 100644
--- a/win/tkWinKey.c
+++ b/win/tkWinKey.c
@@ -102,7 +102,7 @@ TkpGetString(
 	 */
 
 	int unichar;
-	char buf[TCL_UTF_MAX];
+	char buf[XMaxTransChars];
 	int len;
 
 	unichar = keyEv->trans_chars[1] & 0xff;
@@ -115,10 +115,18 @@ TkpGetString(
     } else if (keyEv->send_event == -3) {
 	/*
 	 * Special case for WM_UNICHAR. xkey.trans_chars[] already contains a
-	 * UTF-8 char.
+	 * UTF-8 char, except when nbytes == 0 (then it didn't fit there).
 	 */
 
-	Tcl_DStringAppend(dsPtr, keyEv->trans_chars, keyEv->nbytes);
+	if (keyEv->nbytes) {
+	    Tcl_DStringAppend(dsPtr, keyEv->trans_chars, keyEv->nbytes);
+	} else if (keyEv->keycode > 0xffff) {
+	    char buf[XMaxTransChars];
+	    Tcl_UniCharToUtf(((keyEv->keycode - 0x10000) >> 10) | 0xd800, buf);
+	    Tcl_DStringAppend(dsPtr, buf, 3);
+	    Tcl_UniCharToUtf(((keyEv->keycode - 0x10000) & 0x3ff) | 0xdc00, buf);
+	    Tcl_DStringAppend(dsPtr, buf, 3);
+	}
     } else {
 	/*
 	 * This is an event generated from generic code. It has no nchars or
@@ -129,7 +137,7 @@ TkpGetString(
 
 	if (((keysym != NoSymbol) && (keysym > 0) && (keysym < 256))
 		|| (keysym == XK_Return) || (keysym == XK_Tab)) {
-	    char buf[TCL_UTF_MAX];
+	    char buf[XMaxTransChars];
 	    int len;
 
 	    len = Tcl_UniCharToUtf((Tcl_UniChar) (keysym & 255), buf);
diff --git a/win/tkWinX.c b/win/tkWinX.c
index 2180f52..6b8bdff 100644
--- a/win/tkWinX.c
+++ b/win/tkWinX.c
@@ -1252,8 +1252,14 @@ GenerateXEvent(
 	    event.xany.send_event = -3;
 	    event.xkey.keycode = wParam;
 	    event.xkey.nbytes = Tcl_UniCharToUtf((int)wParam, buffer);
-	    for (i=0; i<event.xkey.nbytes && i<XMaxTransChars; ++i) {
-		event.xkey.trans_chars[i] = buffer[i];
+	    if(((int)wParam > 0xffff) && (event.xkey.nbytes < 4)) {
+		/* trans_chars buffer is not big enough to hold 2 surrogate
+		   characters, so don't store anything */
+		event.xkey.nbytes = 0;
+	    } else {
+		for (i=0; i<event.xkey.nbytes && i<XMaxTransChars; ++i) {
+		    event.xkey.trans_chars[i] = buffer[i];
+		}
 	    }
 	    Tk_QueueWindowEvent(&event, TCL_QUEUE_TAIL);
 	    event.type = KeyRelease;
-- 
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