1 files changed, 58 insertions, 0 deletions
diff --git a/prev/common_windows.go b/prev/common_windows.go
new file mode 100644
index 0000000..7a12a8a
--- /dev/null
+++ b/prev/common_windows.go
@@ -0,0 +1,58 @@
+// 12 july 2014
+
+package ui
+
+import (
+	"fmt"
+	"reflect"
+	"syscall"
+	"unsafe"
+)
+
+// #include "winapi_windows.h"
+import "C"
+
+//export xpanic
+func xpanic(msg *C.char, lasterr C.DWORD) {
+	panic(fmt.Errorf("%s: %s", C.GoString(msg), syscall.Errno(lasterr)))
+}
+
+//export xpanichresult
+func xpanichresult(msg *C.char, hresult C.HRESULT) {
+	panic(fmt.Errorf("%s; HRESULT: 0x%X", C.GoString(msg), hresult))
+}
+
+//export xpaniccomdlg
+func xpaniccomdlg(msg *C.char, err C.DWORD) {
+	panic(fmt.Errorf("%s; comdlg32.dll extended error: 0x%X", C.GoString(msg), err))
+}
+
+//export xmissedmsg
+func xmissedmsg(purpose *C.char, f *C.char, uMsg C.UINT) {
+	panic(fmt.Errorf("%s window procedure message %d does not return a value (bug in %s)", C.GoString(purpose), uMsg, C.GoString(f)))
+}
+
+func toUTF16(s string) C.LPWSTR {
+	return C.LPWSTR(unsafe.Pointer(syscall.StringToUTF16Ptr(s)))
+}
+
+func getWindowText(hwnd C.HWND) string {
+	// WM_GETTEXTLENGTH and WM_GETTEXT return the count /without/ the terminating null character
+	// but WM_GETTEXT expects the buffer size handed to it to /include/ the terminating null character
+	n := C.getWindowTextLen(hwnd)
+	buf := make([]uint16, int(n+1))
+	C.getWindowText(hwnd, C.WPARAM(n),
+		C.LPWSTR(unsafe.Pointer(&buf[0])))
+	return syscall.UTF16ToString(buf)
+}
+
+func wstrToString(wstr *C.WCHAR) string {
+	n := C.wcslen((*C.wchar_t)(unsafe.Pointer(wstr)))
+	xbuf := &reflect.SliceHeader{
+		Data: uintptr(unsafe.Pointer(wstr)),
+		Len:  int(n + 1),
+		Cap:  int(n + 1),
+	}
+	buf := (*[]uint16)(unsafe.Pointer(xbuf))
+	return syscall.UTF16ToString(*buf)
+}