10 func runeToByteIndex(n int, txt []byte) int {
18 _, size := utf8.DecodeRune(txt)
31 // A LineArray simply stores and array of lines and makes it easy to insert
33 type LineArray struct {
37 // NewLineArray returns a new line array from an array of bytes
38 func NewLineArray(reader io.Reader) *LineArray {
40 br := bufio.NewReader(reader)
44 data, err := br.ReadBytes('\n')
47 la.lines = append(la.lines, data[:len(data)])
52 la.lines = append(la.lines, data[:len(data)-1])
60 // Returns the String representation of the LineArray
61 func (la *LineArray) String() string {
62 return string(bytes.Join(la.lines, []byte("\n")))
65 // NewlineBelow adds a newline below the given line number
66 func (la *LineArray) NewlineBelow(y int) {
67 la.lines = append(la.lines, []byte(" "))
68 copy(la.lines[y+2:], la.lines[y+1:])
69 la.lines[y+1] = []byte("")
72 // inserts a byte array at a given location
73 func (la *LineArray) insert(pos Loc, value []byte) {
74 x, y := runeToByteIndex(pos.X, la.lines[pos.Y]), pos.Y
75 // x, y := pos.x, pos.y
76 for i := 0; i < len(value); i++ {
83 la.insertByte(Loc{x, y}, value[i])
88 // inserts a byte at a given location
89 func (la *LineArray) insertByte(pos Loc, value byte) {
90 la.lines[pos.Y] = append(la.lines[pos.Y], 0)
91 copy(la.lines[pos.Y][pos.X+1:], la.lines[pos.Y][pos.X:])
92 la.lines[pos.Y][pos.X] = value
95 // JoinLines joins the two lines a and b
96 func (la *LineArray) JoinLines(a, b int) {
97 la.insert(Loc{len(la.lines[a]), a}, la.lines[b])
101 // Split splits a line at a given position
102 func (la *LineArray) Split(pos Loc) {
103 la.NewlineBelow(pos.Y)
104 la.insert(Loc{0, pos.Y + 1}, la.lines[pos.Y][pos.X:])
105 la.DeleteToEnd(Loc{pos.X, pos.Y})
108 // removes from start to end
109 func (la *LineArray) remove(start, end Loc) string {
110 sub := la.Substr(start, end)
111 startX := runeToByteIndex(start.X, la.lines[start.Y])
112 endX := runeToByteIndex(end.X, la.lines[end.Y])
113 if start.Y == end.Y {
114 la.lines[start.Y] = append(la.lines[start.Y][:startX], la.lines[start.Y][endX:]...)
116 for i := start.Y + 1; i <= end.Y-1; i++ {
117 la.DeleteLine(start.Y + 1)
119 la.DeleteToEnd(Loc{startX, start.Y})
120 la.DeleteFromStart(Loc{endX - 1, start.Y + 1})
121 la.JoinLines(start.Y, start.Y+1)
126 // DeleteToEnd deletes from the end of a line to the position
127 func (la *LineArray) DeleteToEnd(pos Loc) {
128 la.lines[pos.Y] = la.lines[pos.Y][:pos.X]
131 // DeleteFromStart deletes from the start of a line to the position
132 func (la *LineArray) DeleteFromStart(pos Loc) {
133 la.lines[pos.Y] = la.lines[pos.Y][pos.X+1:]
136 // DeleteLine deletes the line number
137 func (la *LineArray) DeleteLine(y int) {
138 la.lines = la.lines[:y+copy(la.lines[y:], la.lines[y+1:])]
141 // DeleteByte deletes the byte at a position
142 func (la *LineArray) DeleteByte(pos Loc) {
143 la.lines[pos.Y] = la.lines[pos.Y][:pos.X+copy(la.lines[pos.Y][pos.X:], la.lines[pos.Y][pos.X+1:])]
146 // Substr returns the string representation between two locations
147 func (la *LineArray) Substr(start, end Loc) string {
148 startX := runeToByteIndex(start.X, la.lines[start.Y])
149 endX := runeToByteIndex(end.X, la.lines[end.Y])
150 if start.Y == end.Y {
151 return string(la.lines[start.Y][startX:endX])
154 str += string(la.lines[start.Y][startX:]) + "\n"
155 for i := start.Y + 1; i <= end.Y-1; i++ {
156 str += string(la.lines[i]) + "\n"
158 str += string(la.lines[end.Y][:endX])