46 lines
1.1 KiB
Go
46 lines
1.1 KiB
Go
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package matchfinder
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// An absoluteMatch is like a Match, but it stores indexes into the byte
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// stream instead of lengths.
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type absoluteMatch struct {
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// Start is the index of the first byte.
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Start int
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// End is the index of the byte after the last byte
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// (so that End - Start = Length).
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End int
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// Match is the index of the previous data that matches
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// (Start - Match = Distance).
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Match int
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}
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// A matchEmitter manages the output of matches for a MatchFinder.
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type matchEmitter struct {
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// Dst is the destination slice that Matches are added to.
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Dst []Match
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// NextEmit is the index of the next byte to emit.
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NextEmit int
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}
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func (e *matchEmitter) emit(m absoluteMatch) {
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e.Dst = append(e.Dst, Match{
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Unmatched: m.Start - e.NextEmit,
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Length: m.End - m.Start,
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Distance: m.Start - m.Match,
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})
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e.NextEmit = m.End
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}
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// trim shortens m if it extends past maxEnd. Then if the length is at least
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// minLength, the match is emitted.
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func (e *matchEmitter) trim(m absoluteMatch, maxEnd int, minLength int) {
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if m.End > maxEnd {
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m.End = maxEnd
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}
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if m.End-m.Start >= minLength {
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e.emit(m)
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}
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}
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