huff0: Remove byteReader (#886)

The only method that was used was remain, but that just returns the
input length as long as no other methods are called.

Author: greatroar

huff0/bytereader.go

@@ -416,7 +416,7 @@ func (s *Scratch) validateTable(c cTable) bool {
 
 // minTableLog provides the minimum logSize to safely represent a distribution.
 func (s *Scratch) minTableLog() uint8 {
-	minBitsSrc := highBit32(uint32(s.br.remain())) + 1
+	minBitsSrc := highBit32(uint32(s.srcLen)) + 1
 	minBitsSymbols := highBit32(uint32(s.symbolLen-1)) + 2
 	if minBitsSrc < minBitsSymbols {
 		return uint8(minBitsSrc)
@@ -428,7 +428,7 @@ func (s *Scratch) minTableLog() uint8 {
 func (s *Scratch) optimalTableLog() {
 	tableLog := s.TableLog
 	minBits := s.minTableLog()
-	maxBitsSrc := uint8(highBit32(uint32(s.br.remain()-1))) - 1
+	maxBitsSrc := uint8(highBit32(uint32(s.srcLen-1))) - 1
 	if maxBitsSrc < tableLog {
 		// Accuracy can be reduced
 		tableLog = maxBitsSrc

huff0/compress.go

@@ -88,7 +88,7 @@ type Scratch struct {
 	// Decoders will return ErrMaxDecodedSizeExceeded is this limit is exceeded.
 	MaxDecodedSize int
 
-	br byteReader
+	srcLen int
 
 	// MaxSymbolValue will override the maximum symbol value of the next block.
 	MaxSymbolValue uint8
@@ -170,7 +170,7 @@ func (s *Scratch) prepare(in []byte) (*Scratch, error) {
 	if s.fse == nil {
 		s.fse = &fse.Scratch{}
 	}
-	s.br.init(in)
+	s.srcLen = len(in)
 
 	return s, nil
 }