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// +build linux darwin openbsd freebsd netbsd
package liner
import (
"fmt"
"os"
"strings"
"syscall"
"unsafe"
)
func (s *State) cursorPos(x int) {
if s.useCHA {
// 'G' is "Cursor Character Absolute (CHA)"
fmt.Printf("\x1b[%dG", x+1)
} else {
// 'C' is "Cursor Forward (CUF)"
fmt.Print("\r")
if x > 0 {
fmt.Printf("\x1b[%dC", x)
}
}
}
func (s *State) eraseLine() {
fmt.Print("\x1b[0K")
}
func (s *State) eraseScreen() {
fmt.Print("\x1b[H\x1b[2J")
}
func (s *State) moveUp(lines int) {
fmt.Printf("\x1b[%dA", lines)
}
func (s *State) moveDown(lines int) {
fmt.Printf("\x1b[%dB", lines)
}
func (s *State) emitNewLine() {
fmt.Print("\n")
}
type winSize struct {
row, col uint16
xpixel, ypixel uint16
}
func (s *State) getColumns() bool {
var ws winSize
ok, _, _ := syscall.Syscall(syscall.SYS_IOCTL, uintptr(syscall.Stdout),
syscall.TIOCGWINSZ, uintptr(unsafe.Pointer(&ws)))
if int(ok) < 0 {
return false
}
s.columns = int(ws.col)
if cursorColumn && s.columns > 1 {
s.columns--
}
return true
}
func (s *State) checkOutput() {
// xterm is known to support CHA
if strings.Contains(strings.ToLower(os.Getenv("TERM")), "xterm") {
s.useCHA = true
return
}
// The test for functional ANSI CHA is unreliable (eg the Windows
// telnet command does not support reading the cursor position with
// an ANSI DSR request, despite setting TERM=ansi)
// Assume CHA isn't supported (which should be safe, although it
// does result in occasional visible cursor jitter)
s.useCHA = false
}
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