// readOneUTF16FromConsole reads single character from console,
// converts it into utf16 and return it to the caller.
func (f *File) readOneUTF16FromConsole() (uint16, error) {
var buf [1]byte
mbytes := make([]byte, 0, 4)
cp := getCP()
for {
var nmb uint32
err := readFile(f.fd, buf[:], &nmb, nil)
if err != nil {
return 0, err
}
if nmb == 0 {
continue
}
mbytes = append(mbytes, buf[0])
// Convert from 8-bit console encoding to UTF16.
// MultiByteToWideChar defaults to Unicode NFC form, which is the expected one.
nwc, err := windows.MultiByteToWideChar(cp, windows.MB_ERR_INVALID_CHARS, &mbytes[0], int32(len(mbytes)), nil, 0)
if err != nil {
if err == windows.ERROR_NO_UNICODE_TRANSLATION {
continue
}
return 0, err
}
if nwc != 1 {
return 0, errors.New("MultiByteToWideChar returns " + itoa(int(nwc)) + " characters, but only 1 expected")
}
var wchars [1]uint16
nwc, err = windows.MultiByteToWideChar(cp, windows.MB_ERR_INVALID_CHARS, &mbytes[0], int32(len(mbytes)), &wchars[0], nwc)
if err != nil {
return 0, err
}
return wchars[0], nil
}
}
// readConsole reads utf16 characters from console File,
// encodes them into utf8 and stores them in buffer b.
// It returns the number of utf8 bytes read and an error, if any.
func (f *File) readConsole(b []byte) (n int, err error) {
if len(b) == 0 {
return 0, nil
}
if len(f.readbuf) == 0 {
numBytes := len(b)
// Windows can't read bytes over max of int16.
if numBytes > 32767 {
numBytes = 32767
}
mbytes := make([]byte, numBytes)
var nmb uint32
err := syscall.ReadFile(f.fd, mbytes, &nmb, nil)
if err != nil {
return 0, err
}
if nmb > 0 {
var pmb *byte
if len(b) > 0 {
pmb = &mbytes[0]
}
acp, err := windows.GetACP()
if err != nil {
return 0, err
}
nwc, err := windows.MultiByteToWideChar(acp, 2, pmb, int32(nmb), nil, 0)
if err != nil {
return 0, err
}
wchars := make([]uint16, nwc)
pwc := &wchars[0]
nwc, err = windows.MultiByteToWideChar(acp, 2, pmb, int32(nmb), pwc, int32(nwc))
if err != nil {
return 0, err
}
f.readbuf = utf16.Decode(wchars[:nwc])
}
}
for i, r := range f.readbuf {
if utf8.RuneLen(r) > len(b) {
f.readbuf = f.readbuf[i:]
return n, nil
}
nr := utf8.EncodeRune(b, r)
b = b[nr:]
n += nr
}
f.readbuf = nil
return n, nil
}