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vendor/github.com/andybalholm/brotli/matchfinder/emitter.go

@@ -0,0 +1,45 @@
+package matchfinder
+
+// An absoluteMatch is like a Match, but it stores indexes into the byte
+// stream instead of lengths.
+type absoluteMatch struct {
+	// Start is the index of the first byte.
+	Start int
+
+	// End is the index of the byte after the last byte
+	// (so that End - Start = Length).
+	End int
+
+	// Match is the index of the previous data that matches
+	// (Start - Match = Distance).
+	Match int
+}
+
+// A matchEmitter manages the output of matches for a MatchFinder.
+type matchEmitter struct {
+	// Dst is the destination slice that Matches are added to.
+	Dst []Match
+
+	// NextEmit is the index of the next byte to emit.
+	NextEmit int
+}
+
+func (e *matchEmitter) emit(m absoluteMatch) {
+	e.Dst = append(e.Dst, Match{
+		Unmatched: m.Start - e.NextEmit,
+		Length:    m.End - m.Start,
+		Distance:  m.Start - m.Match,
+	})
+	e.NextEmit = m.End
+}
+
+// trim shortens m if it extends past maxEnd. Then if the length is at least
+// minLength, the match is emitted.
+func (e *matchEmitter) trim(m absoluteMatch, maxEnd int, minLength int) {
+	if m.End > maxEnd {
+		m.End = maxEnd
+	}
+	if m.End-m.Start >= minLength {
+		e.emit(m)
+	}
+}