forked from ericfreese/rat
/
scanner.go
170 lines (141 loc) · 2.99 KB
/
scanner.go
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package rat
import (
"io"
"strconv"
"github.com/ericfreese/escseq"
termbox "github.com/nsf/termbox-go"
)
type TokenType uint8
const (
TokNone TokenType = iota
TokText
TokTermStyle
TokNewLine
)
type Token interface {
Type() TokenType
Val() []byte
TermStyle() TermStyle
}
type TokenReader interface {
ReadToken() (Token, error)
}
type token struct {
t TokenType
val []byte
sp TermStyle
}
func (t *token) Type() TokenType {
return t.t
}
func (t *token) Val() []byte {
return t.val
}
func (t *token) TermStyle() TermStyle {
return t.sp
}
type scanner struct {
es escseq.Scanner
fg termbox.Attribute
bg termbox.Attribute
}
func NewScanner(rd io.Reader) TokenReader {
s := &scanner{}
s.es = escseq.NewScanner(rd)
return s
}
func (s *scanner) ReadToken() (Token, error) {
t, err := s.es.ReadToken()
switch t.Type() {
case escseq.TokText:
if t.Val() == "\n" {
return &token{TokNewLine, []byte(t.Val()), nil}, err
} else {
return &token{TokText, []byte(t.Val()), nil}, err
}
case escseq.TokEsc:
s.es.UnreadToken()
if termStyle := s.scanTermStyle(); termStyle != nil {
return &token{TokTermStyle, []byte{}, termStyle}, err
} else {
return &token{TokNone, []byte{}, nil}, err
}
default:
return &token{TokNone, []byte{}, nil}, err
}
}
func (s *scanner) scanTermStyle() TermStyle {
toks := make([]escseq.Token, 0, 16)
numSgr := 0
for {
t, err := s.es.ReadToken()
if t.Type() != escseq.TokNone {
toks = append(toks, t)
}
if t.Type() == escseq.TokParamNum {
numSgr++
}
if (t.Type() == escseq.TokFe && t.Val() != "[") || t.Type() == escseq.TokFinal {
break
}
if err != nil {
break
}
}
sgr := make([]int, 0, numSgr)
for _, t := range toks {
if t.Type() == escseq.TokFe && t.Val() != "[" ||
t.Type() == escseq.TokInter ||
t.Type() == escseq.TokFinal && t.Val() != "m" {
return nil
}
if t.Type() == escseq.TokParamNum {
i, _ := strconv.Atoi(t.Val())
sgr = append(sgr, i)
}
}
return s.buildTermStyle(sgr)
}
func (s *scanner) buildTermStyle(sgr []int) TermStyle {
n := len(sgr)
if n == 0 {
s.fg = termbox.ColorDefault
s.bg = termbox.ColorDefault
return gTermStyles.Get(s.fg, s.bg)
}
for i := 0; i < n; i++ {
p := sgr[i]
switch {
case p == 0:
s.fg = termbox.ColorDefault
s.bg = termbox.ColorDefault
case p == 1:
s.fg = s.fg | termbox.AttrBold
case p == 4:
s.fg = s.fg | termbox.AttrUnderline
case p == 7:
s.fg = s.fg | termbox.AttrReverse
case p == 27:
s.fg = s.fg &^ termbox.AttrReverse
case p >= 30 && p <= 37:
s.fg = s.fg | termbox.Attribute(p-29)
case p == 38:
if n-i > 2 && sgr[i+1] == 5 {
s.fg = s.fg | termbox.Attribute(sgr[i+2]+1)
i = i + 2
}
case p == 39:
s.fg = termbox.ColorDefault
case p >= 40 && p <= 47:
s.bg = s.bg | termbox.Attribute(p-39)
case p == 48:
if n-i > 2 && sgr[i+1] == 5 {
s.bg = s.bg | termbox.Attribute(sgr[i+2]+1)
i = i + 2
}
case p == 49:
s.bg = termbox.ColorDefault
}
}
return gTermStyles.Get(s.fg, s.bg)
}