[WDF] Add Windows Driver Framework files

Takern from Microsoft GitHub repo:
d9c6040fe9

Licensed under MIT

sdk/lib/drivers/wdf/shared/inc/private/common/fxstring.hpp

@@ -0,0 +1,152 @@
+/*++
+
+Copyright (c) Microsoft Corporation
+
+Module Name:
+
+    FxString.hpp
+
+Abstract:
+
+    This module implements a simple string class to operate on
+    unicode strings.
+
+Author:
+
+
+
+
+Environment:
+
+    Both kernel and user mode
+
+Revision History:
+
+
+--*/
+#ifndef _FXSTRING_H_
+#define _FXSTRING_H_
+
+class FxString : public FxObject {
+public:
+    //
+    // Length describes the length of the string in bytes (not WCHARs)
+    // MaximumLength describes the size of the buffer in bytes
+    //
+    UNICODE_STRING m_UnicodeString;
+
+public:
+    FxString(
+        __in PFX_DRIVER_GLOBALS FxDriverGlobals
+        );
+
+    ~FxString();
+
+    VOID
+    __inline
+    ReleaseString(
+        __out PUNICODE_STRING ReleaseTo
+        )
+    {
+        RtlCopyMemory(ReleaseTo, &m_UnicodeString, sizeof(UNICODE_STRING));
+        RtlZeroMemory(&m_UnicodeString, sizeof(m_UnicodeString));
+    }
+
+    __inline
+    operator PUNICODE_STRING(
+        )
+    {
+        return &m_UnicodeString;
+    }
+
+    PUNICODE_STRING
+    __inline
+    GetUnicodeString(
+        VOID
+        )
+    {
+        return &m_UnicodeString;
+    }
+
+    _Must_inspect_result_
+    NTSTATUS
+    Assign(
+        __in PCWSTR SourceString
+        );
+
+    _Must_inspect_result_
+    NTSTATUS
+    Assign(
+        __in const UNICODE_STRING* UnicodeString
+        );
+
+    __inline
+    USHORT
+    Length(
+        VOID
+        )
+    {
+        return m_UnicodeString.Length;
+    }
+
+    __inline
+    USHORT
+    ByteLength(
+        __in BOOLEAN IncludeNull
+        )
+    {
+        if (IncludeNull) {
+            return m_UnicodeString.Length + sizeof(UNICODE_NULL);
+        }
+        else {
+            return m_UnicodeString.Length;
+        }
+    }
+
+    __inline
+    USHORT
+    CharacterLength(
+        VOID
+        )
+    {
+        return m_UnicodeString.Length / sizeof(WCHAR);
+    }
+
+    __inline
+    USHORT
+    MaximumLength(
+        VOID
+        )
+    {
+        return m_UnicodeString.MaximumLength;
+    }
+
+    __inline
+    USHORT
+    MaximumByteLength(
+        VOID
+        )
+    {
+        return m_UnicodeString.MaximumLength;
+    }
+
+    __inline
+    USHORT
+    MaximumCharacterLength(
+        VOID
+        )
+    {
+        return m_UnicodeString.MaximumLength / sizeof(WCHAR);
+    }
+
+    __inline
+    PWCHAR
+    Buffer(
+        VOID
+        )
+    {
+        return m_UnicodeString.Buffer;
+    }
+};
+
+#endif // _FXSTRING_H_