Move some compression only initialization to the compressor.

klauspost · Apr 2, 2018 · 5fb1f31 · 5fb1f31
1 parent 30b4e9b
commit 5fb1f31
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Showing 2 changed files with 7 additions and 8 deletions.
diff --git a/huff0/compress.go b/huff0/compress.go
@@ -35,6 +35,7 @@ func compress(in []byte, s *Scratch, compressor func(src []byte) ([]byte, error)
 	if s.Reuse == ReusePolicyNone {
 		s.prevTable = s.prevTable[:0]
 	}
+
 	// Create histogram, if none was provided.
 	maxCount := s.maxCount
 	var canReuse = false
@@ -338,6 +339,10 @@ type cTableEntry struct {
 const huffNodesMask = huffNodesLen - 1
 
 func (s *Scratch) buildCTable() error {
+	if cap(s.cTable) < maxSymbolValue+1 {
+		s.cTable = make([]cTableEntry, 0, maxSymbolValue+1)
+	}
+
 	s.huffSort()
 	s.cTable = s.cTable[:s.symbolLen]
 

diff --git a/huff0/huff0.go b/huff0/huff0.go
@@ -122,22 +122,16 @@ func (s *Scratch) prepare(in []byte) (*Scratch, error) {
 		s.Out = make([]byte, 0, len(in))
 	}
 	s.Out = s.Out[:0]
-	if cap(s.cTable) < maxSymbolValue+1 {
-		s.cTable = make([]cTableEntry, 0, maxSymbolValue+1)
-	}
-	s.cTable = s.cTable[:0]
-	if cap(s.prevTable) < maxSymbolValue+1 {
-		s.prevTable = make([]cTableEntry, 0, maxSymbolValue+1)
-	}
+
 	s.OutTable = nil
 	s.OutData = nil
 	if cap(s.nodes) < huffNodesLen+1 {
 		s.nodes = make([]nodeElt, 0, huffNodesLen+1)
 	}
+	s.nodes = s.nodes[:0]
 	if s.fse == nil {
 		s.fse = &fse.Scratch{}
 	}
-	s.nodes = s.nodes[:0]
 	s.br.init(in)
 
 	return s, nil