Fix test-case registry-6.20, which started failing starting with the TIP #389 commit.

1 files changed, 16 insertions, 2 deletions

diff --git a/win/tclWin32Dll.c b/win/tclWin32Dll.c
index 74787c5..26da566 100644
--- a/win/tclWin32Dll.c
+++ b/win/tclWin32Dll.c
@@ -471,14 +471,28 @@ Tcl_WinUtfToTChar(
     Tcl_DString *dsPtr)		/* Uninitialized or free DString in which the
 				 * converted string is stored. */
 {
-    TCHAR *wp;
+    TCHAR *wp, *p;
     int size = MultiByteToWideChar(CP_UTF8, 0, string, len, 0, 0);
 
     Tcl_DStringInit(dsPtr);
     Tcl_DStringSetLength(dsPtr, 2*size+2);
-    wp = (TCHAR *)Tcl_DStringValue(dsPtr);
+    p = wp = (TCHAR *)Tcl_DStringValue(dsPtr);
     MultiByteToWideChar(CP_UTF8, 0, string, len, wp, size+1);
     if (len == -1) --size; /* account for 0-byte at string end */
+
+    /* It turns out that MultiByteToWideChar() cannot handle the 'modified'
+     * UTF-8 as used by Tcl. Every sequence of 0xC0 followed by 0x80 will
+     * be translated to two 0xfffd characters. This results in a test-failure
+     * of the registry-6.20 test-case. The simplest solution is to search for
+     * those two 0xfffd characters and replace them by a \u0000 character. */
+    while (p < wp + size - 1) {
+	if (p[0] == 0xfffd && p[1] == 0xfffd) {
+	    memmove(p+1, p+2, sizeof(TCHAR) * (p - wp + size - 2));
+	    p[0] = 0;
+	    ++p; --size;
+	}
+	++p;
+    }
     Tcl_DStringSetLength(dsPtr, 2*size);
     wp[size] = 0;
     return wp;