use dep

vendor/github.com/jesseduffield/gocui/escape.go

@@ -0,0 +1,229 @@
+// Copyright 2014 The gocui Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gocui
+
+import (
+	"errors"
+	"strconv"
+)
+
+type escapeInterpreter struct {
+	state                  escapeState
+	curch                  rune
+	csiParam               []string
+	curFgColor, curBgColor Attribute
+	mode                   OutputMode
+}
+
+type escapeState int
+
+const (
+	stateNone escapeState = iota
+	stateEscape
+	stateCSI
+	stateParams
+)
+
+var (
+	errNotCSI        = errors.New("Not a CSI escape sequence")
+	errCSIParseError = errors.New("CSI escape sequence parsing error")
+	errCSITooLong    = errors.New("CSI escape sequence is too long")
+)
+
+// runes in case of error will output the non-parsed runes as a string.
+func (ei *escapeInterpreter) runes() []rune {
+	switch ei.state {
+	case stateNone:
+		return []rune{0x1b}
+	case stateEscape:
+		return []rune{0x1b, ei.curch}
+	case stateCSI:
+		return []rune{0x1b, '[', ei.curch}
+	case stateParams:
+		ret := []rune{0x1b, '['}
+		for _, s := range ei.csiParam {
+			ret = append(ret, []rune(s)...)
+			ret = append(ret, ';')
+		}
+		return append(ret, ei.curch)
+	}
+	return nil
+}
+
+// newEscapeInterpreter returns an escapeInterpreter that will be able to parse
+// terminal escape sequences.
+func newEscapeInterpreter(mode OutputMode) *escapeInterpreter {
+	ei := &escapeInterpreter{
+		state:      stateNone,
+		curFgColor: ColorDefault,
+		curBgColor: ColorDefault,
+		mode:       mode,
+	}
+	return ei
+}
+
+// reset sets the escapeInterpreter in initial state.
+func (ei *escapeInterpreter) reset() {
+	ei.state = stateNone
+	ei.curFgColor = ColorDefault
+	ei.curBgColor = ColorDefault
+	ei.csiParam = nil
+}
+
+// parseOne parses a rune. If isEscape is true, it means that the rune is part
+// of an escape sequence, and as such should not be printed verbatim. Otherwise,
+// it's not an escape sequence.
+func (ei *escapeInterpreter) parseOne(ch rune) (isEscape bool, err error) {
+	// Sanity checks
+	if len(ei.csiParam) > 20 {
+		return false, errCSITooLong
+	}
+	if len(ei.csiParam) > 0 && len(ei.csiParam[len(ei.csiParam)-1]) > 255 {
+		return false, errCSITooLong
+	}
+
+	ei.curch = ch
+
+	switch ei.state {
+	case stateNone:
+		if ch == 0x1b {
+			ei.state = stateEscape
+			return true, nil
+		}
+		return false, nil
+	case stateEscape:
+		if ch == '[' {
+			ei.state = stateCSI
+			return true, nil
+		}
+		return false, errNotCSI
+	case stateCSI:
+		switch {
+		case ch >= '0' && ch <= '9':
+			ei.csiParam = append(ei.csiParam, "")
+		case ch == 'm':
+			ei.csiParam = append(ei.csiParam, "0")
+		default:
+			return false, errCSIParseError
+		}
+		ei.state = stateParams
+		fallthrough
+	case stateParams:
+		switch {
+		case ch >= '0' && ch <= '9':
+			ei.csiParam[len(ei.csiParam)-1] += string(ch)
+			return true, nil
+		case ch == ';':
+			ei.csiParam = append(ei.csiParam, "")
+			return true, nil
+		case ch == 'm':
+			var err error
+			switch ei.mode {
+			case OutputNormal:
+				err = ei.outputNormal()
+			case Output256:
+				err = ei.output256()
+			}
+			if err != nil {
+				return false, errCSIParseError
+			}
+
+			ei.state = stateNone
+			ei.csiParam = nil
+			return true, nil
+		default:
+			return false, errCSIParseError
+		}
+	}
+	return false, nil
+}
+
+// outputNormal provides 8 different colors:
+//   black, red, green, yellow, blue, magenta, cyan, white
+func (ei *escapeInterpreter) outputNormal() error {
+	for _, param := range ei.csiParam {
+		p, err := strconv.Atoi(param)
+		if err != nil {
+			return errCSIParseError
+		}
+
+		switch {
+		case p >= 30 && p <= 37:
+			ei.curFgColor = Attribute(p - 30 + 1)
+		case p == 39:
+			ei.curFgColor = ColorDefault
+		case p >= 40 && p <= 47:
+			ei.curBgColor = Attribute(p - 40 + 1)
+		case p == 49:
+			ei.curBgColor = ColorDefault
+		case p == 1:
+			ei.curFgColor |= AttrBold
+		case p == 4:
+			ei.curFgColor |= AttrUnderline
+		case p == 7:
+			ei.curFgColor |= AttrReverse
+		case p == 0:
+			ei.curFgColor = ColorDefault
+			ei.curBgColor = ColorDefault
+		}
+	}
+
+	return nil
+}
+
+// output256 allows you to leverage the 256-colors terminal mode:
+//   0x01 - 0x08: the 8 colors as in OutputNormal
+//   0x09 - 0x10: Color* | AttrBold
+//   0x11 - 0xe8: 216 different colors
+//   0xe9 - 0x1ff: 24 different shades of grey
+func (ei *escapeInterpreter) output256() error {
+	if len(ei.csiParam) < 3 {
+		return ei.outputNormal()
+	}
+
+	mode, err := strconv.Atoi(ei.csiParam[1])
+	if err != nil {
+		return errCSIParseError
+	}
+	if mode != 5 {
+		return ei.outputNormal()
+	}
+
+	fgbg, err := strconv.Atoi(ei.csiParam[0])
+	if err != nil {
+		return errCSIParseError
+	}
+	color, err := strconv.Atoi(ei.csiParam[2])
+	if err != nil {
+		return errCSIParseError
+	}
+
+	switch fgbg {
+	case 38:
+		ei.curFgColor = Attribute(color + 1)
+
+		for _, param := range ei.csiParam[3:] {
+			p, err := strconv.Atoi(param)
+			if err != nil {
+				return errCSIParseError
+			}
+
+			switch {
+			case p == 1:
+				ei.curFgColor |= AttrBold
+			case p == 4:
+				ei.curFgColor |= AttrUnderline
+			case p == 7:
+				ei.curFgColor |= AttrReverse
+			}
+		}
+	case 48:
+		ei.curBgColor = Attribute(color + 1)
+	default:
+		return errCSIParseError
+	}
+
+	return nil
+}