diff --git a/files.cpp b/files.cpp
index 4d4f9364..6a29ed55 100644
--- a/files.cpp
+++ b/files.cpp
@@ -27,43 +27,39 @@ void FileStore::StoreInitialize(const NameValuePairs &parameters)
 	m_stream = NULL;
 	m_file.release();
 
-	const char *fileName;
-	const wchar_t *fileNameWide;
+	const char *fileName = NULL;
+#if defined(CRYPTOPP_UNIX_AVAILABLE) || _MSC_VER >= 1400
+	const wchar_t *fileNameWide = NULL;
+	if (!parameters.GetValue(Name::InputFileNameWide(), fileNameWide))
+#endif
+		if (!parameters.GetValue(Name::InputFileName(), fileName))
+		{
+			parameters.GetValue(Name::InputStreamPointer(), m_stream);
+			return;
+		}
+
+	ios::openmode binary = parameters.GetValueWithDefault(Name::InputBinaryMode(), true) ? ios::binary : ios::openmode(0);
+	m_file.reset(new std::ifstream);
 #ifdef CRYPTOPP_UNIX_AVAILABLE
 	std::string narrowed;
+	if (fileNameWide)
+		fileName = (narrowed = StringNarrow(fileNameWide)).c_str();
 #endif
-
-	if (parameters.GetValue(Name::InputFileName(), fileName))
+#if _MSC_VER >= 1400
+	if (fileNameWide)
 	{
-#ifdef CRYPTOPP_UNIX_AVAILABLE
-narrowName:
+		m_file->open(fileNameWide, ios::in | binary);
+		if (!*m_file)
+			throw OpenErr(StringNarrow(fileNameWide, false));
+	}
 #endif
-		ios::openmode binary = parameters.GetValueWithDefault(Name::InputBinaryMode(), true) ? ios::binary : ios::openmode(0);
-		m_file.reset(new std::ifstream);
+	if (fileName)
+	{
 		m_file->open(fileName, ios::in | binary);
 		if (!*m_file)
 			throw OpenErr(fileName);
-		m_stream = m_file.get();
 	}
-#if defined(CRYPTOPP_UNIX_AVAILABLE) || _MSC_VER >= 1400
-	else if (parameters.GetValue(Name::InputFileNameWide(), fileNameWide))
-	{
-	#if _MSC_VER >= 1400
-		ios::openmode binary = parameters.GetValueWithDefault(Name::InputBinaryMode(), true) ? ios::binary : ios::openmode(0);
-		m_file.reset(new std::ifstream);
-		m_file->open(fileNameWide, ios::in | binary);
-		if (!*m_file)
-			throw OpenErr(StringNarrow(fileNameWide));
-		m_stream = m_file.get();
-	#else
-		narrowed = StringNarrow(fileNameWide);
-		fileName = narrowed.c_str();
-		goto narrowName;
-	#endif
-	}
-#endif
-	else
-		parameters.GetValue(Name::InputStreamPointer(), m_stream);
+	m_stream = m_file.get();
 }
 
 lword FileStore::MaxRetrievable() const
@@ -187,43 +183,39 @@ void FileSink::IsolatedInitialize(const NameValuePairs &parameters)
 	m_stream = NULL;
 	m_file.release();
 
-	const char *fileName;
-	const wchar_t *fileNameWide;
+	const char *fileName = NULL;
+#if defined(CRYPTOPP_UNIX_AVAILABLE) || _MSC_VER >= 1400
+	const wchar_t *fileNameWide = NULL;
+	if (!parameters.GetValue(Name::OutputFileNameWide(), fileNameWide))
+#endif
+		if (!parameters.GetValue(Name::OutputFileName(), fileName))
+		{
+			parameters.GetValue(Name::OutputStreamPointer(), m_stream);
+			return;
+		}
+
+	ios::openmode binary = parameters.GetValueWithDefault(Name::OutputBinaryMode(), true) ? ios::binary : ios::openmode(0);
+	m_file.reset(new std::ofstream);
 #ifdef CRYPTOPP_UNIX_AVAILABLE
 	std::string narrowed;
+	if (fileNameWide)
+		fileName = (narrowed = StringNarrow(fileNameWide)).c_str();
 #endif
-
-	if (parameters.GetValue(Name::OutputFileName(), fileName))
+#if _MSC_VER >= 1400
+	if (fileNameWide)
 	{
-#ifdef CRYPTOPP_UNIX_AVAILABLE
-narrowName:
+		m_file->open(fileNameWide, ios::out | ios::trunc | binary);
+		if (!*m_file)
+			throw OpenErr(StringNarrow(fileNameWide, false));
+	}
 #endif
-		ios::openmode binary = parameters.GetValueWithDefault(Name::OutputBinaryMode(), true) ? ios::binary : ios::openmode(0);
-		m_file.reset(new std::ofstream);
+	if (fileName)
+	{
 		m_file->open(fileName, ios::out | ios::trunc | binary);
 		if (!*m_file)
 			throw OpenErr(fileName);
-		m_stream = m_file.get();
 	}
-#if defined(CRYPTOPP_UNIX_AVAILABLE) || _MSC_VER >= 1400
-	else if (parameters.GetValue(Name::OutputFileNameWide(), fileNameWide))
-	{
-	#if _MSC_VER >= 1400
-		ios::openmode binary = parameters.GetValueWithDefault(Name::OutputBinaryMode(), true) ? ios::binary : ios::openmode(0);
-		m_file.reset(new std::ofstream);
-		m_file->open(fileNameWide, ios::out | ios::trunc | binary);
-		if (!*m_file)
-			throw OpenErr(StringNarrow(fileNameWide));
-		m_stream = m_file.get();
-	#else
-		narrowed = StringNarrow(fileNameWide);
-		fileName = narrowed.c_str();
-		goto narrowName;
-	#endif
-	}
-#endif
-	else
-		parameters.GetValue(Name::OutputStreamPointer(), m_stream);
+	m_stream = m_file.get();
 }
 
 bool FileSink::IsolatedFlush(bool hardFlush, bool blocking)
diff --git a/misc.h b/misc.h
index e8b80131..ac1cbda0 100644
--- a/misc.h
+++ b/misc.h
@@ -548,13 +548,20 @@ inline void SecureWipeArray(T *buf, size_t n)
 }
 
 // this function uses wcstombs(), which assumes that setlocale() has been called
-static std::string StringNarrow(const wchar_t *str)
+static std::string StringNarrow(const wchar_t *str, bool throwOnError = true)
 {
 #ifdef _MSC_VER
 #pragma warning(push)
 #pragma warning(disable: 4996)	//  'wcstombs': This function or variable may be unsafe.
 #endif
 	size_t size = wcstombs(NULL, str, 0);
+	if (size == -1)
+	{
+		if (throwOnError)
+			throw InvalidArgument("StringNarrow: wcstombs() call failed");
+		else
+			return std::string();
+	}
 	std::string result(size, 0);
 	wcstombs(&result[0], str, size);
 	return result;