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// +build windows
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package readline
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import (
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	"reflect"
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	"syscall"
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	"unsafe"
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)
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var (
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	kernel = NewKernel()
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	stdout = uintptr(syscall.Stdout)
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	stdin  = uintptr(syscall.Stdin)
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)
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type Kernel struct {
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	SetConsoleCursorPosition,
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	SetConsoleTextAttribute,
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	FillConsoleOutputCharacterW,
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	FillConsoleOutputAttribute,
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	ReadConsoleInputW,
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	GetConsoleScreenBufferInfo,
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	GetConsoleCursorInfo,
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	GetStdHandle CallFunc
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}
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type short int16
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type word uint16
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type dword uint32
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type wchar uint16
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type _COORD struct {
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	x short
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	y short
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}
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func (c *_COORD) ptr() uintptr {
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	return uintptr(*(*int32)(unsafe.Pointer(c)))
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}
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const (
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	EVENT_KEY                = 0x0001
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	EVENT_MOUSE              = 0x0002
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	EVENT_WINDOW_BUFFER_SIZE = 0x0004
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	EVENT_MENU               = 0x0008
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	EVENT_FOCUS              = 0x0010
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)
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type _KEY_EVENT_RECORD struct {
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	bKeyDown          int32
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	wRepeatCount      word
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	wVirtualKeyCode   word
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	wVirtualScanCode  word
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	unicodeChar       wchar
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	dwControlKeyState dword
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}
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// KEY_EVENT_RECORD          KeyEvent;
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// MOUSE_EVENT_RECORD        MouseEvent;
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// WINDOW_BUFFER_SIZE_RECORD WindowBufferSizeEvent;
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// MENU_EVENT_RECORD         MenuEvent;
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// FOCUS_EVENT_RECORD        FocusEvent;
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type _INPUT_RECORD struct {
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	EventType word
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	Padding   uint16
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	Event     [16]byte
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}
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type _CONSOLE_SCREEN_BUFFER_INFO struct {
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	dwSize              _COORD
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	dwCursorPosition    _COORD
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	wAttributes         word
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	srWindow            _SMALL_RECT
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	dwMaximumWindowSize _COORD
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}
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type _SMALL_RECT struct {
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	left   short
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	top    short
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	right  short
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	bottom short
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}
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type _CONSOLE_CURSOR_INFO struct {
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	dwSize   dword
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	bVisible bool
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}
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type CallFunc func(u ...uintptr) error
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func NewKernel() *Kernel {
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	k := &Kernel{}
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	kernel32 := syscall.NewLazyDLL("kernel32.dll")
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	v := reflect.ValueOf(k).Elem()
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	t := v.Type()
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	for i := 0; i < t.NumField(); i++ {
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		name := t.Field(i).Name
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		f := kernel32.NewProc(name)
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		v.Field(i).Set(reflect.ValueOf(k.Wrap(f)))
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	}
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	return k
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}
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func (k *Kernel) Wrap(p *syscall.LazyProc) CallFunc {
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	return func(args ...uintptr) error {
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		var r0 uintptr
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		var e1 syscall.Errno
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		size := uintptr(len(args))
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		if len(args) <= 3 {
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			buf := make([]uintptr, 3)
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			copy(buf, args)
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			r0, _, e1 = syscall.Syscall(p.Addr(), size,
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				buf[0], buf[1], buf[2])
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		} else {
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			buf := make([]uintptr, 6)
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			copy(buf, args)
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			r0, _, e1 = syscall.Syscall6(p.Addr(), size,
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				buf[0], buf[1], buf[2], buf[3], buf[4], buf[5],
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			)
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		}
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		if int(r0) == 0 {
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			if e1 != 0 {
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				return error(e1)
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			} else {
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				return syscall.EINVAL
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			}
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		}
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		return nil
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	}
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}
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func GetConsoleScreenBufferInfo() (*_CONSOLE_SCREEN_BUFFER_INFO, error) {
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	t := new(_CONSOLE_SCREEN_BUFFER_INFO)
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	err := kernel.GetConsoleScreenBufferInfo(
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		stdout,
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		uintptr(unsafe.Pointer(t)),
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	)
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	return t, err
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}
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func GetConsoleCursorInfo() (*_CONSOLE_CURSOR_INFO, error) {
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	t := new(_CONSOLE_CURSOR_INFO)
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	err := kernel.GetConsoleCursorInfo(stdout, uintptr(unsafe.Pointer(t)))
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	return t, err
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}
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func SetConsoleCursorPosition(c *_COORD) error {
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	return kernel.SetConsoleCursorPosition(stdout, c.ptr())
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}
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