better grow method

previously removed the wrong (effizient) branch

buffer.go

@@ -23,8 +23,9 @@ type buffer struct {
 }
 
 func newBuffer(rd io.Reader) *buffer {
+ var b [defaultBufSize]byte
  return &buffer{
- buf: make([]byte, defaultBufSize),
+ buf: b[:],
  rd: rd,
  }
 }
@@ -38,14 +39,9 @@ func (b *buffer) fill(need int) (err error) {
 
  // grow buffer if necessary
  if need > len(b.buf) {
- for {
- b.buf = append(b.buf, 0)
- b.buf = b.buf[:cap(b.buf)]
-
- if cap(b.buf) >= need {
- break
- }
- }
+ newBuf := make([]byte, need)
+ copy(newBuf, b.buf)
+ b.buf = newBuf
  }
 
  b.idx = 0