Fix Utf16ToUtfProc() (from TIP #548): If last code-point is higher surrogate, make sure that actual conversion is delayed until the next round, assuring proper merging of two surrogates into a single UTF-8 character.

1 files changed, 9 insertions, 3 deletions

diff --git a/generic/tclEncoding.c b/generic/tclEncoding.c
index 9896f85..0ec0649 100644
--- a/generic/tclEncoding.c
+++ b/generic/tclEncoding.c
@@ -2485,10 +2485,16 @@ Utf16ToUtfProc(
 	charLimit = *dstCharsPtr;
     }
     result = TCL_OK;
-    if ((srcLen % sizeof(unsigned short)) != 0) {
+
+    /* check alignment with utf-16 (2 == sizeof(UTF-16)) */
+    if ((srcLen % 2) != 0) {
+	result = TCL_CONVERT_MULTIBYTE;
+	srcLen--;
+    }
+    /* If last code point is a high surrogate, we cannot handle that yet */
+    if ((srcLen >= 2) && ((src[srcLen - (clientData?1:2)] & 0xFC) == 0xD8)) {
 	result = TCL_CONVERT_MULTIBYTE;
-	srcLen /= sizeof(unsigned short);
-	srcLen *= sizeof(unsigned short);
+	srcLen-= 2;
     }
 
     srcStart = src;