1 files changed, 107 insertions, 0 deletions
diff --git a/common_windows.go b/common_windows.go
new file mode 100644
index 0000000..2b3c5c8
--- /dev/null
+++ b/common_windows.go
@@ -0,0 +1,107 @@
+// 7 february 2014
+
+package ui
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+var (
+	user32   = syscall.NewLazyDLL("user32.dll")
+	kernel32 = syscall.NewLazyDLL("kernel32.dll")
+	gdi32    = syscall.NewLazyDLL("gdi32.dll")
+	comctl32 *syscall.LazyDLL // comctl32 not defined here; see comctl_windows.go
+	msimg32  = syscall.NewLazyDLL("msimg32.dll")
+)
+
+type _HANDLE uintptr
+type _HWND _HANDLE
+type _HBRUSH _HANDLE
+type _HMENU _HANDLE
+
+// In MSDN, _LPARAM and _LRESULT are listed as signed pointers, however their interpretation is message-specific. Ergo, just cast them yourself; it'll be the same. (Thanks to Tv` in #go-nuts for helping me realize this.)
+type _WPARAM uintptr
+type _LPARAM uintptr
+type _LRESULT uintptr
+
+func (w _WPARAM) LOWORD() uint16 {
+	// according to windef.h
+	return uint16(w & 0xFFFF)
+}
+
+func (w _WPARAM) HIWORD() uint16 {
+	// according to windef.h
+	return uint16((w >> 16) & 0xFFFF)
+}
+
+func (l _LPARAM) X() int32 {
+	// according to windowsx.h
+	loword := uint16(l & 0xFFFF)
+	short := int16(loword) // convert to signed...
+	return int32(short)    // ...and sign extend
+}
+
+func (l _LPARAM) Y() int32 {
+	// according to windowsx.h
+	hiword := uint16((l & 0xFFFF0000) >> 16)
+	short := int16(hiword) // convert to signed...
+	return int32(short)    // ...and sign extend
+}
+
+type _POINT struct {
+	x int32
+	y int32
+}
+
+type _RECT struct {
+	left   int32
+	top    int32
+	right  int32
+	bottom int32
+}
+
+// Go doesn't allow negative constants to be forced into unsigned types at compile-time; this will do it at runtime.
+// This is safe; see http://stackoverflow.com/questions/24022225/what-are-the-sign-extension-rules-for-calling-windows-api-functions-stdcall-t
+func negConst(c int) uintptr {
+	return uintptr(c)
+}
+
+// the next two are convenience wrappers
+// the intention is not to say utf16ToArg(toUTF16(s)) - even though it appears to work fine, that's just because the garbage collector scheduling makes it run long after we're finished; if we store these uintptrs globally instead, then things will break
+// instead, call them separately - s := toUTF16(str); winapifunc.Call(utf16ToArg(s))
+
+func toUTF16(s string) *uint16 {
+	return syscall.StringToUTF16Ptr(s)
+}
+
+func utf16ToArg(s *uint16) uintptr {
+	return uintptr(unsafe.Pointer(s))
+}
+
+func utf16ToLPARAM(s *uint16) uintptr {
+	return uintptr(_LPARAM(unsafe.Pointer(s)))
+}
+
+var (
+	_adjustWindowRectEx = user32.NewProc("AdjustWindowRectEx")
+	_createWindowEx     = user32.NewProc("CreateWindowExW")
+	_getClientRect      = user32.NewProc("GetClientRect")
+	_moveWindow         = user32.NewProc("MoveWindow")
+	_setWindowPos       = user32.NewProc("SetWindowPos")
+	_setWindowText      = user32.NewProc("SetWindowTextW")
+	_showWindow         = user32.NewProc("ShowWindow")
+	_getWindowRect      = user32.NewProc("GetWindowRect")
+)
+
+type _MINMAXINFO struct {
+	ptReserved     _POINT
+	ptMaxSize      _POINT
+	ptMaxPosition  _POINT
+	ptMinTrackSize _POINT
+	ptMaxTrackSize _POINT
+}
+
+func (l _LPARAM) MINMAXINFO() *_MINMAXINFO {
+	return (*_MINMAXINFO)(unsafe.Pointer(l))
+}