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