func (s *cScreen) writeString(x, y int, style Style, ch []uint16) {
// we assume the caller has hidden the cursor
if len(ch) == 0 {
return
}
nw := uint32(len(ch))
procSetConsoleTextAttribute.Call(
uintptr(s.out),
uintptr(mapStyle(style)))
s.setCursorPos(x, y)
syscall.WriteConsole(s.out, &ch[0], nw, &nw, nil)
}
// writeConsole writes len(b) bytes to the console File.
// It returns the number of bytes written and an error, if any.
func (f *File) writeConsole(b []byte) (n int, err error) {
n = len(b)
runes := make([]rune, 0, 256)
if len(f.lastbits) > 0 {
b = append(f.lastbits, b...)
f.lastbits = nil
}
for len(b) >= utf8.UTFMax || utf8.FullRune(b) {
r, l := utf8.DecodeRune(b)
runes = append(runes, r)
b = b[l:]
}
if len(b) > 0 {
f.lastbits = make([]byte, len(b))
copy(f.lastbits, b)
}
// syscall.WriteConsole seems to fail, if given large buffer.
// So limit the buffer to 16000 characters. This number was
// discovered by experimenting with syscall.WriteConsole.
const maxWrite = 16000
for len(runes) > 0 {
m := len(runes)
if m > maxWrite {
m = maxWrite
}
chunk := runes[:m]
runes = runes[m:]
uint16s := utf16.Encode(chunk)
for len(uint16s) > 0 {
var written uint32
err = syscall.WriteConsole(f.fd, &uint16s[0], uint32(len(uint16s)), &written, nil)
if err != nil {
return 0, nil
}
uint16s = uint16s[written:]
}
}
return n, nil
}