new: parsing BLE flags and company identifiers from advertisements

vendor/github.com/chzyer/readline/utils_unix.go

@@ -0,0 +1,90 @@
+// +build darwin dragonfly freebsd linux,!appengine netbsd openbsd
+
+package readline
+
+import (
+	"io"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"unsafe"
+)
+
+type winsize struct {
+	Row    uint16
+	Col    uint16
+	Xpixel uint16
+	Ypixel uint16
+}
+
+// SuspendMe use to send suspend signal to myself, when we in the raw mode.
+// For OSX it need to send to parent's pid
+// For Linux it need to send to myself
+func SuspendMe() {
+	p, _ := os.FindProcess(os.Getppid())
+	p.Signal(syscall.SIGTSTP)
+	p, _ = os.FindProcess(os.Getpid())
+	p.Signal(syscall.SIGTSTP)
+}
+
+// get width of the terminal
+func getWidth(stdoutFd int) int {
+	ws := &winsize{}
+	retCode, _, errno := syscall.Syscall(syscall.SYS_IOCTL,
+		uintptr(stdoutFd),
+		uintptr(syscall.TIOCGWINSZ),
+		uintptr(unsafe.Pointer(ws)))
+
+	if int(retCode) == -1 {
+		_ = errno
+		return -1
+	}
+	return int(ws.Col)
+}
+
+func GetScreenWidth() int {
+	w := getWidth(syscall.Stdout)
+	if w < 0 {
+		w = getWidth(syscall.Stderr)
+	}
+	return w
+}
+
+// ClearScreen clears the console screen
+func ClearScreen(w io.Writer) (int, error) {
+	return w.Write([]byte("\033[H"))
+}
+
+func DefaultIsTerminal() bool {
+	return IsTerminal(syscall.Stdin) && (IsTerminal(syscall.Stdout) || IsTerminal(syscall.Stderr))
+}
+
+func GetStdin() int {
+	return syscall.Stdin
+}
+
+// -----------------------------------------------------------------------------
+
+var (
+	widthChange         sync.Once
+	widthChangeCallback func()
+)
+
+func DefaultOnWidthChanged(f func()) {
+	widthChangeCallback = f
+	widthChange.Do(func() {
+		ch := make(chan os.Signal, 1)
+		signal.Notify(ch, syscall.SIGWINCH)
+
+		go func() {
+			for {
+				_, ok := <-ch
+				if !ok {
+					break
+				}
+				widthChangeCallback()
+			}
+		}()
+	})
+}