Fix an out-of-boundary issue for wide string

fpdfsdk/src/fpdfdoc.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../include/fsdk_define.h"
 #include "../include/fpdfdoc.h"
 
 static int this_module = 0;
@@ skipping 18 matching lines @@
 }
 
 DLLEXPORT FPDF_BOOKMARK STDCALL FPDFBookmark_Find(FPDF_DOCUMENT document, FPDF_WIDESTRING title)
 {
         if (document == NULL) return NULL;
         if (title == NULL || title[0] == 0) return NULL;
 
         CPDF_Document* pDoc = (CPDF_Document*)document;
         CPDF_BookmarkTree tree(pDoc);
 
-        CFX_WideString wstr = CFX_WideString::FromUTF16LE(title);
+        FX_STRSIZE len = CFX_WideString::WStringLength(title);
+        CFX_WideString wstr = CFX_WideString::FromUTF16LE(title, len);
         return FindBookmark(tree, NULL, wstr);
 }
 
 DLLEXPORT FPDF_DEST STDCALL FPDFBookmark_GetDest(FPDF_DOCUMENT document, FPDF_BOOKMARK bookmark)
 {
         if (document == NULL) return NULL;
         if (bookmark == NULL) return NULL;
 
         CPDF_Bookmark Bookmark = (CPDF_Dictionary*)bookmark;
         CPDF_Document* pDoc = (CPDF_Document*)document;
@@ skipping 200 matching lines @@
         CFX_ByteString bstr = text.UTF16LE_Encode();
         unsigned long len = bstr.GetLength();
         if (buffer != NULL && buflen >= len+2) {
                 FXSYS_memcpy(buffer, (FX_LPCSTR)bstr, len);
                 // use double zero as trailer
                 ((FX_BYTE*)buffer)[len] = ((FX_BYTE*)buffer)[len+1] = 0;
         }
         return len+2;
 }