diff --git a/rudict/rudict/utf8utf16.cpp b/rudict/rudict/utf8utf16.cpp
index 5e2ae2a..af4f3b7 100644
--- a/rudict/rudict/utf8utf16.cpp
+++ b/rudict/rudict/utf8utf16.cpp
@@ -1,15 +1,47 @@
 #include "utf8utf16.h"
 
 #include <string>
-#include <locale>
-#include <codecvt>
+
 
 std::string UTF16to8(const wchar_t * in)
 {
-	std::wstring_convert<std::codecvt_utf8<wchar_t>> conv;
-	std::string s = conv.to_bytes(in);
+	std::string out;
+    unsigned int codepoint = 0;
+    for (in;  *in != 0;  ++in)
+    {
+        if (*in >= 0xd800 && *in <= 0xdbff)
+            codepoint = ((*in - 0xd800) << 10) + 0x10000;
+        else
+        {
+            if (*in >= 0xdc00 && *in <= 0xdfff)
+                codepoint |= *in - 0xdc00;
+            else
+                codepoint = *in;
 
-	return s;
+            if (codepoint <= 0x7f)
+                out.append(1, static_cast<char>(codepoint));
+            else if (codepoint <= 0x7ff)
+            {
+                out.append(1, static_cast<char>(0xc0 | ((codepoint >> 6) & 0x1f)));
+                out.append(1, static_cast<char>(0x80 | (codepoint & 0x3f)));
+            }
+            else if (codepoint <= 0xffff)
+            {
+                out.append(1, static_cast<char>(0xe0 | ((codepoint >> 12) & 0x0f)));
+                out.append(1, static_cast<char>(0x80 | ((codepoint >> 6) & 0x3f)));
+                out.append(1, static_cast<char>(0x80 | (codepoint & 0x3f)));
+            }
+            else
+            {
+                out.append(1, static_cast<char>(0xf0 | ((codepoint >> 18) & 0x07)));
+                out.append(1, static_cast<char>(0x80 | ((codepoint >> 12) & 0x3f)));
+                out.append(1, static_cast<char>(0x80 | ((codepoint >> 6) & 0x3f)));
+                out.append(1, static_cast<char>(0x80 | (codepoint & 0x3f)));
+            }
+            codepoint = 0;
+        }
+    }
+    return out;
 }
 
 std::wstring UTF8to16(const char * in)