// WndProcThunk.h
// Interfaces to the CWndProcThunk class responsible for WNDPROC class-thunking
// For details, see http://www.hackcraft.net/cpp/windowsThunk/thiscall/
// Also available is a CDlgProcThunk class doing the same work for DIALOGPROC
// MD: Made NX-compat by allocating the code structure using VirtualAlloc(..., PAGE_EXECUTE_READWRITE)
// fwd:
template <class W> class CWndProcThunk;
#ifndef WNDPROCTHUNK_H_INCLUDED
#define WNDPROCTHUNK_H_INCLUDED
template<typename To, typename From> inline To union_cast(From fr) throw()
{
union
{
From f;
To t;
} uc;
uc.f = fr;
return uc.t;
}
#pragma warning(push)
#pragma warning(disable : 4355)
#if defined(_M_IX86)
#pragma pack(push,1)
template <class W> class CWndProcThunk
{
typedef ::LRESULT (W::* WndProc)(::HWND, ::UINT, ::WPARAM, ::LPARAM);
typedef CWndProcThunk ThisClass;
struct SCode
{
BYTE m_mov; // mov ECX, m_this
W * m_this; //
BYTE m_jmp; // jmp m_relproc
ptrdiff_t m_relproc; // relative jmp
};
SCode * Code;
public:
ThisClass(WndProc proc, W * obj)
{
Code = (SCode *)VirtualAlloc(NULL, sizeof(SCode), MEM_COMMIT, PAGE_EXECUTE_READWRITE);
Code->m_mov = 0xB9,
Code->m_this = obj,
Code->m_jmp = 0xE9,
Code->m_relproc = union_cast<char *>(proc) - reinterpret_cast<char *>(Code) - sizeof(*Code);
::FlushInstructionCache(::GetCurrentProcess(), Code, sizeof(*Code));
}
virtual ~CWndProcThunk()
{
VirtualFree(Code, sizeof(*Code), MEM_RELEASE);
Code = NULL;
}
operator ::WNDPROC() const {return reinterpret_cast<::WNDPROC>(Code); }
operator ::LONG_PTR() const {return reinterpret_cast<::LONG_PTR>(Code); }
} ;
template <class W> class CDlgProcThunk
{
typedef ::BOOL (W::* DlgProc)(::HWND, ::UINT, ::WPARAM, ::LPARAM);
typedef CDlgProcThunk ThisClass;
struct SCode
{
BYTE m_mov; // mov ECX, m_this
W * m_this; //
BYTE m_jmp; // jmp m_relproc
ptrdiff_t m_relproc; // relative jmp
};
SCode * Code;
public:
CDlgProcThunk(DlgProc proc, W * obj)
{
Code = (SCode *)VirtualAlloc(NULL, sizeof(SCode), MEM_COMMIT, PAGE_EXECUTE_READWRITE);
Code->m_mov = 0xB9,
Code->m_this = obj,
Code->m_jmp = 0xE9,
Code->m_relproc = union_cast<char *>(proc) - reinterpret_cast<char *>(Code) - sizeof(*Code);
::FlushInstructionCache(::GetCurrentProcess(), Code, sizeof(*Code));
}
virtual ~CDlgProcThunk()
{
VirtualFree(Code, sizeof(*Code), MEM_RELEASE);
Code = NULL;
}
operator ::DLGPROC() const {return reinterpret_cast<::DLGPROC>(Code); }
operator ::LONG_PTR() const {return reinterpret_cast<::LONG_PTR>(Code); }
} ;
#pragma pack(pop)
#else // _M_IX86
#error Only X86 supported
#endif
#endif // WNDPROCTHUNK_H_INCLUDED
