1 /* 2 * RangeDecoderFromStream 3 * 4 * Authors: Lasse Collin <lasse.collin (at) tukaani.org> 5 * Igor Pavlov <http://7-zip.org/> 6 * 7 * This file has been put into the public domain. 8 * You can do whatever you want with this file. 9 */ 10 11 package org.tukaani.xz.rangecoder; 12 13 import java.io.InputStream; 14 import java.io.DataInputStream; 15 import java.io.IOException; 16 import org.tukaani.xz.CorruptedInputException; 17 18 public final class RangeDecoderFromStream extends RangeDecoder { 19 private final DataInputStream inData; 20 21 public RangeDecoderFromStream(InputStream in) throws IOException { 22 inData = new DataInputStream(in); 23 24 if (inData.readUnsignedByte() != 0x00) 25 throw new CorruptedInputException(); 26 27 code = inData.readInt(); 28 range = 0xFFFFFFFF; 29 } 30 31 public boolean isFinished() { 32 return code == 0; 33 } 34 35 public void normalize() throws IOException { 36 if ((range & TOP_MASK) == 0) { 37 code = (code << SHIFT_BITS) | inData.readUnsignedByte(); 38 range <<= SHIFT_BITS; 39 } 40 } 41 } 42
