diff --git a/core/include/fpdfapi/fpdf_resource.h b/core/include/fpdfapi/fpdf_resource.h
index 3050985..02edd55 100644
--- a/core/include/fpdfapi/fpdf_resource.h
+++ b/core/include/fpdfapi/fpdf_resource.h
@@ -525,8 +525,8 @@
         return !m_bType1;
     }
 
-    virtual FX_DWORD        GetNextChar(const FX_LPCSTR pString, int nStrLen, int& offset) const override;
-    virtual int             CountChar(const FX_LPCSTR pString, int size) const;
+    virtual FX_DWORD        GetNextChar(FX_LPCSTR pString, int nStrLen, int& offset) const override;
+    virtual int             CountChar(FX_LPCSTR pString, int size) const;
     virtual int             AppendChar(FX_LPSTR str, FX_DWORD charcode) const;
     virtual int             GetCharSize(FX_DWORD charcode) const;