forgejo/vendor/github.com/yuin/goldmark/text/segment.go
2020-02-28 13:06:10 +00:00

210 lines
4.7 KiB
Go
Vendored

package text
import (
"bytes"
"github.com/yuin/goldmark/util"
)
var space = []byte(" ")
// A Segment struct holds information about source positions.
type Segment struct {
// Start is a start position of the segment.
Start int
// Stop is a stop position of the segment.
// This value should be excluded.
Stop int
// Padding is a padding length of the segment.
Padding int
}
// NewSegment return a new Segment.
func NewSegment(start, stop int) Segment {
return Segment{
Start: start,
Stop: stop,
Padding: 0,
}
}
// NewSegmentPadding returns a new Segment with the given padding.
func NewSegmentPadding(start, stop, n int) Segment {
return Segment{
Start: start,
Stop: stop,
Padding: n,
}
}
// Value returns a value of the segment.
func (t *Segment) Value(buffer []byte) []byte {
if t.Padding == 0 {
return buffer[t.Start:t.Stop]
}
result := make([]byte, 0, t.Padding+t.Stop-t.Start+1)
result = append(result, bytes.Repeat(space, t.Padding)...)
return append(result, buffer[t.Start:t.Stop]...)
}
// Len returns a length of the segment.
func (t *Segment) Len() int {
return t.Stop - t.Start + t.Padding
}
// Between returns a segment between this segment and the given segment.
func (t *Segment) Between(other Segment) Segment {
if t.Stop != other.Stop {
panic("invalid state")
}
return NewSegmentPadding(
t.Start,
other.Start,
t.Padding-other.Padding,
)
}
// IsEmpty returns true if this segment is empty, otherwise false.
func (t *Segment) IsEmpty() bool {
return t.Start >= t.Stop && t.Padding == 0
}
// TrimRightSpace returns a new segment by slicing off all trailing
// space characters.
func (t *Segment) TrimRightSpace(buffer []byte) Segment {
v := buffer[t.Start:t.Stop]
l := util.TrimRightSpaceLength(v)
if l == len(v) {
return NewSegment(t.Start, t.Start)
}
return NewSegmentPadding(t.Start, t.Stop-l, t.Padding)
}
// TrimLeftSpace returns a new segment by slicing off all leading
// space characters including padding.
func (t *Segment) TrimLeftSpace(buffer []byte) Segment {
v := buffer[t.Start:t.Stop]
l := util.TrimLeftSpaceLength(v)
return NewSegment(t.Start+l, t.Stop)
}
// TrimLeftSpaceWidth returns a new segment by slicing off leading space
// characters until the given width.
func (t *Segment) TrimLeftSpaceWidth(width int, buffer []byte) Segment {
padding := t.Padding
for ; width > 0; width-- {
if padding == 0 {
break
}
padding--
}
if width == 0 {
return NewSegmentPadding(t.Start, t.Stop, padding)
}
text := buffer[t.Start:t.Stop]
start := t.Start
for _, c := range text {
if start >= t.Stop-1 || width <= 0 {
break
}
if c == ' ' {
width--
} else if c == '\t' {
width -= 4
} else {
break
}
start++
}
if width < 0 {
padding = width * -1
}
return NewSegmentPadding(start, t.Stop, padding)
}
// WithStart returns a new Segment with same value except Start.
func (t *Segment) WithStart(v int) Segment {
return NewSegmentPadding(v, t.Stop, t.Padding)
}
// WithStop returns a new Segment with same value except Stop.
func (t *Segment) WithStop(v int) Segment {
return NewSegmentPadding(t.Start, v, t.Padding)
}
// ConcatPadding concats the padding to the given slice.
func (t *Segment) ConcatPadding(v []byte) []byte {
if t.Padding > 0 {
return append(v, bytes.Repeat(space, t.Padding)...)
}
return v
}
// Segments is a collection of the Segment.
type Segments struct {
values []Segment
}
// NewSegments return a new Segments.
func NewSegments() *Segments {
return &Segments{
values: nil,
}
}
// Append appends the given segment after the tail of the collection.
func (s *Segments) Append(t Segment) {
if s.values == nil {
s.values = make([]Segment, 0, 20)
}
s.values = append(s.values, t)
}
// AppendAll appends all elements of given segments after the tail of the collection.
func (s *Segments) AppendAll(t []Segment) {
if s.values == nil {
s.values = make([]Segment, 0, 20)
}
s.values = append(s.values, t...)
}
// Len returns the length of the collection.
func (s *Segments) Len() int {
if s.values == nil {
return 0
}
return len(s.values)
}
// At returns a segment at the given index.
func (s *Segments) At(i int) Segment {
return s.values[i]
}
// Set sets the given Segment.
func (s *Segments) Set(i int, v Segment) {
s.values[i] = v
}
// SetSliced replace the collection with a subsliced value.
func (s *Segments) SetSliced(lo, hi int) {
s.values = s.values[lo:hi]
}
// Sliced returns a subslice of the collection.
func (s *Segments) Sliced(lo, hi int) []Segment {
return s.values[lo:hi]
}
// Clear delete all element of the collection.
func (s *Segments) Clear() {
s.values = nil
}
// Unshift insert the given Segment to head of the collection.
func (s *Segments) Unshift(v Segment) {
s.values = append(s.values[0:1], s.values[0:]...)
s.values[0] = v
}