support getWinsize on windows

Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>

go.mod

@@ -0,0 +1,5 @@
+module github.com/buger/goterm
+
+go 1.16
+
+require golang.org/x/sys v0.0.0-20210331175145-43e1dd70ce54

go.sum

@@ -0,0 +1,2 @@
+golang.org/x/sys v0.0.0-20210331175145-43e1dd70ce54 h1:rF3Ohx8DRyl8h2zw9qojyLHLhrJpEMgyPOImREEryf0=
+golang.org/x/sys v0.0.0-20210331175145-43e1dd70ce54/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

terminal_nosysioctl.go

@@ -1,4 +1,4 @@
-// +build windows plan9 solaris
+// +build !windows plan9 solaris
 
 package goterm
 

terminal_windows.go

@@ -0,0 +1,22 @@
+// +build windows
+
+package goterm
+
+import (
+	"golang.org/x/sys/windows"
+	"os"
+)
+
+func getWinsize() (*winsize, error) {
+	ws := new(winsize)
+	fd := os.Stdout.Fd()
+	var info windows.ConsoleScreenBufferInfo
+	if err := windows.GetConsoleScreenBufferInfo(windows.Handle(fd), &info); err != nil {
+		return nil, err
+	}
+
+	ws.Col = uint16(info.Window.Right - info.Window.Left + 1)
+	ws.Row = uint16(info.Window.Bottom - info.Window.Top + 1)
+
+	return ws, nil
+}