1 files changed, 48 insertions, 6 deletions
diff --git a/generic/tclLink.c b/generic/tclLink.c
index cd2c731..1973067 100644
--- a/generic/tclLink.c
+++ b/generic/tclLink.c
@@ -526,14 +526,56 @@ GetUWide(
     Tcl_Obj *objPtr,
     Tcl_WideUInt *uwidePtr)
 {
-    if (Tcl_GetWideUIntFromObj(NULL, objPtr, uwidePtr) != TCL_OK) {
-	int intValue;
-
-	if (GetInvalidIntFromObj(objPtr, &intValue) != TCL_OK) {
-	    return 1;
+    Tcl_WideInt *widePtr = (Tcl_WideInt *) uwidePtr;
+    void *clientData;
+    int type, intValue;
+
+    if (Tcl_GetNumberFromObj(NULL, objPtr, &clientData, &type) == TCL_OK) {
+	if (type == TCL_NUMBER_INT) {
+	    *widePtr = *((const Tcl_WideInt *) clientData);
+	    return (*widePtr < 0);
+	} else if (type == TCL_NUMBER_BIG) {
+	    mp_int *numPtr = (mp_int *)clientData;
+	    Tcl_WideUInt value = 0;
+	    union {
+		Tcl_WideUInt value;
+		unsigned char bytes[sizeof(Tcl_WideUInt)];
+	    } scratch;
+	    size_t numBytes;
+	    unsigned char *bytes = scratch.bytes;
+
+	    if (numPtr->sign || (MP_OKAY != mp_to_ubin(numPtr,
+		    bytes, sizeof(Tcl_WideUInt), &numBytes))) {
+		/*
+		 * If the sign bit is set (a negative value) or if the value
+		 * can't possibly fit in the bits of an unsigned wide, there's
+		 * no point in doing further conversion.
+		 */
+		return 1;
+	    }
+#ifndef WORDS_BIGENDIAN
+	    while (numBytes-- > 0) {
+		value = (value << CHAR_BIT) | *bytes++;
+	    }
+#else /* WORDS_BIGENDIAN */
+	    /*
+	     * Big-endian can read the value directly.
+	     */
+	    value = scratch.value;
+#endif /* WORDS_BIGENDIAN */
+	    *uwidePtr = value;
+	    return 0;
 	}
-	*uwidePtr = intValue;
     }
+
+    /*
+     * Evil edge case fallback.
+     */
+
+    if (GetInvalidIntFromObj(objPtr, &intValue) != TCL_OK) {
+	return 1;
+    }
+    *uwidePtr = intValue;
     return 0;
 }