Add short-cut in CFX_{Byte,Wide}String::Operator<()

core/fxcrt/fx_basic_wstring.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 <stddef.h>
 
 #include <algorithm>
 #include <cctype>
@@ skipping 176 matching lines @@
     return other.IsEmpty();
 
   if (other.IsEmpty())
     return false;
 
   return other.m_pData->m_nDataLength == m_pData->m_nDataLength &&
          wmemcmp(other.m_pData->m_String, m_pData->m_String,
                  m_pData->m_nDataLength) == 0;
 }
 
+bool CFX_WideString::operator<(const CFX_WideString& str) const {
+  if (m_pData == str.m_pData)
+    return false;
+
+  int result =
+      wmemcmp(c_str(), str.c_str(), std::min(GetLength(), str.GetLength()));
+  return result < 0 || (result == 0 && GetLength() < str.GetLength());
+}
+
 void CFX_WideString::AssignCopy(const FX_WCHAR* pSrcData, FX_STRSIZE nSrcLen) {
   AllocBeforeWrite(nSrcLen);
   m_pData->CopyContents(pSrcData, nSrcLen);
   m_pData->m_nDataLength = nSrcLen;
 }
 
 void CFX_WideString::ReallocBeforeWrite(FX_STRSIZE nNewLength) {
   if (m_pData && m_pData->CanOperateInPlace(nNewLength))
     return;
 
@@ skipping 796 matching lines @@
       FXSYS_MultiByteToWideChar(codepage, 0, bstr.c_str(), src_len, nullptr, 0);
   CFX_WideString wstr;
   if (dest_len) {
     FX_WCHAR* dest_buf = wstr.GetBuffer(dest_len);
     FXSYS_MultiByteToWideChar(codepage, 0, bstr.c_str(), src_len, dest_buf,
                               dest_len);
     wstr.ReleaseBuffer(dest_len);
   }
   return wstr;
 }