libjava/java/util/zip/InflaterInputStream.java

// InflaterInputStream.java - Input stream filter for decompressing.

/* Copyright (C) 1999  Cygnus Solutions

   This file is part of libgcj.

This software is copyrighted work licensed under the terms of the
Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
details.  */

package java.util.zip;

import java.io.FilterInputStream;
import java.io.InputStream;
import java.io.IOException;

/**
 * @author Tom Tromey
 * @date May 17, 1999
 */

/* Written using on-line Java Platform 1.2 API Specification
 * and JCL book.
 * Believed complete and correct.
 */

public class InflaterInputStream extends FilterInputStream
{
  protected void fill () throws IOException
  {
    len = in.read(buf, 0, buf.length);
    if (len != -1)
      inf.setInput(buf, 0, len);
  }

  public InflaterInputStream (InputStream in)
  {
    this (in, new Inflater (), 512);
  }

  public InflaterInputStream (InputStream in, Inflater infl)
  {
    this (in, infl, 512);
  }

  public InflaterInputStream (InputStream in, Inflater infl, int bufsize)
  {
    super (in);
    this.inf = infl;
    this.buf = new byte[bufsize];
  }

  public int read () throws IOException
  {
    byte[] buf = new byte[1];
    int r = read (buf, 0, 1);
    if (r != -1)
      r = buf[0] & 0xff;
    return r;
  }

  public int read (byte[] buf, int off, int len) throws IOException
  {
    if (inf.finished())
      return -1;
    if (inf.needsInput())
      fill ();
    if (inf.needsDictionary())
      return -1;
    try
      {
	return inf.inflate(buf, off, len);
      }
    catch (DataFormatException dfe)
      {
	throw new ZipException (dfe.getMessage());
      }
  }

  public long skip (long n) throws IOException
  {
    if (n == 0)
      return 0;

    int min = (int) Math.min(n, 1024);
    byte[] buf = new byte[min];

    long s = 0;
    while (n > 0)
      {
	int r = read (buf, 0, min);
	if (r == -1)
	  break;
	n -= r;
	s += r;
      }

    return s;
  }

  // Buffer for delivering uncompressed data to inflater.
  protected byte[] buf;

  // Inflater used to decompress data.
  protected Inflater inf;

  // Number of read bytes in buf.
  protected int len;
}