forked from toolshed/abra
77 lines
1.4 KiB
Go
77 lines
1.4 KiB
Go
package ansi
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import (
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"bytes"
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"io"
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"unicode/utf8"
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)
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type Writer struct {
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Forward io.Writer
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ansi bool
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ansiseq bytes.Buffer
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lastseq bytes.Buffer
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seqchanged bool
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runeBuf []byte
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}
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// Write is used to write content to the ANSI buffer.
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func (w *Writer) Write(b []byte) (int, error) {
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for _, c := range string(b) {
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if c == Marker {
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// ANSI escape sequence
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w.ansi = true
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w.seqchanged = true
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_, _ = w.ansiseq.WriteRune(c)
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} else if w.ansi {
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_, _ = w.ansiseq.WriteRune(c)
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if IsTerminator(c) {
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// ANSI sequence terminated
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w.ansi = false
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if bytes.HasSuffix(w.ansiseq.Bytes(), []byte("[0m")) {
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// reset sequence
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w.lastseq.Reset()
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w.seqchanged = false
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} else if c == 'm' {
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// color code
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_, _ = w.lastseq.Write(w.ansiseq.Bytes())
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}
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_, _ = w.ansiseq.WriteTo(w.Forward)
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}
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} else {
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_, err := w.writeRune(c)
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if err != nil {
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return 0, err
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}
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}
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}
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return len(b), nil
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}
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func (w *Writer) writeRune(r rune) (int, error) {
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if w.runeBuf == nil {
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w.runeBuf = make([]byte, utf8.UTFMax)
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}
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n := utf8.EncodeRune(w.runeBuf, r)
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return w.Forward.Write(w.runeBuf[:n])
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}
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func (w *Writer) LastSequence() string {
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return w.lastseq.String()
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}
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func (w *Writer) ResetAnsi() {
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if !w.seqchanged {
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return
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}
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_, _ = w.Forward.Write([]byte("\x1b[0m"))
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}
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func (w *Writer) RestoreAnsi() {
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_, _ = w.Forward.Write(w.lastseq.Bytes())
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}
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