func (dd *dictDecoder) histSize() int {
	if dd.full {
		return len(dd.hist)
	}
	return dd.wrPos
}

// availRead reports the number of bytes that can be flushed by readFlush.
func (dd *dictDecoder) availRead() int {
	return dd.wrPos - dd.rdPos
}

// availWrite reports the available amount of output buffer space.
func (dd *dictDecoder) availWrite() int {

		f.toRead = f.dict.readFlush()
		f.step = (*decompressor).copyData
		return
	}
	f.finishBlock()
}

func (f *decompressor) finishBlock() {
	if f.final {
		if f.dict.availRead() > 0 {
			f.toRead = f.dict.readFlush()
		}
		f.err = io.EOF
	}
	f.step = (*decompressor).nextBlock
}

// noEOF returns err, unless err == io.EOF, in which case it returns io.ErrUnexpectedEOF.