46 lines
909 B
Go
46 lines
909 B
Go
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package segments
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import (
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"sort"
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)
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func NewIndex(segments LengthIter) (ret Index) {
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var start Length
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for l, ok := segments(); ok; l, ok = segments() {
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ret.segments = append(ret.segments, Extent{start, l})
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start += l
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}
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return
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}
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type Index struct {
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segments []Extent
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}
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func (me Index) iterSegments() func() (Length, bool) {
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return func() (Length, bool) {
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if len(me.segments) == 0 {
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return 0, false
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} else {
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l := me.segments[0].Length
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me.segments = me.segments[1:]
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return l, true
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}
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}
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}
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func (me Index) Locate(e Extent, output Callback) bool {
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first := sort.Search(len(me.segments), func(i int) bool {
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_e := me.segments[i]
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return _e.End() > e.Start
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})
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if first == len(me.segments) {
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return false
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}
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e.Start -= me.segments[first].Start
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me.segments = me.segments[first:]
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return Scan(me.iterSegments(), e, func(i int, e Extent) bool {
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return output(i+first, e)
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})
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}
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