File	Doc	Category	Size	Date	Package
DeflaterInputStream.java	API Doc	Java SE 6 API	8418	Tue Jun 10 00:26:00 BST 2008	java.util.zip

DeflaterInputStream

• java.lang.Object
  • java.io.InputStream
    • java.io.FilterInputStream

Fields Summary
protected final Deflater	def Compressor for this stream.
protected final byte[]	buf Input buffer for reading compressed data.
private byte[]	rbuf Temporary read buffer.
private boolean	usesDefaultDeflater Default compressor is used.
private boolean	reachEOF End of the underlying input stream has been reached.

Constructors Summary
public DeflaterInputStream(InputStream in) Creates a new input stream with a default compressor and buffer size. param in input stream to read the uncompressed data to throws NullPointerException if {@code in} is null this(in, new Deflater()); usesDefaultDeflater = true;
public DeflaterInputStream(InputStream in, Deflater defl) Creates a new input stream with the specified compressor and a default buffer size. param in input stream to read the uncompressed data to param defl compressor ("deflater") for this stream throws NullPointerException if {@code in} or {@code defl} is null this(in, defl, 512);
public DeflaterInputStream(InputStream in, Deflater defl, int bufLen) Creates a new input stream with the specified compressor and buffer size. param in input stream to read the uncompressed data to param defl compressor ("deflater") for this stream param bufLen compression buffer size throws IllegalArgumentException if {@code bufLen} is <= 0 throws NullPointerException if {@code in} or {@code defl} is null super(in); // Sanity checks if (in == null) throw new NullPointerException("Null input"); if (defl == null) throw new NullPointerException("Null deflater"); if (bufLen < 1) throw new IllegalArgumentException("Buffer size < 1"); // Initialize def = defl; buf = new byte[bufLen];

Methods Summary
public int	available() Returns 0 after EOF has been reached, otherwise always return 1. Programs should not count on this method to return the actual number of bytes that could be read without blocking return zero after the end of the underlying input stream has been reached, otherwise always returns 1 throws IOException if an I/O error occurs or if this stream is already closed ensureOpen(); if (reachEOF) { return 0; } return 1;
public void	close() Closes this input stream and its underlying input stream, discarding any pending uncompressed data. throws IOException if an I/O error occurs if (in != null) { try { // Clean up if (usesDefaultDeflater) { def.end(); } in.close(); } finally { in = null; } }
private void	ensureOpen() Check to make sure that this stream has not been closed. if (in == null) { throw new IOException("Stream closed"); }
public void	mark(int limit) This operation is not supported. param limit maximum bytes that can be read before invalidating the position marker // Operation not supported
public boolean	markSupported() Always returns {@code false} because this input stream does not support the {@link #mark mark()} and {@link #reset reset()} methods. return false, always return false;
public int	read() Reads a single byte of compressed data from the input stream. This method will block until some input can be read and compressed. return a single byte of compressed data, or -1 if the end of the uncompressed input stream is reached throws IOException if an I/O error occurs or if this stream is already closed // Read a single byte of compressed data int len = read(rbuf, 0, 1); if (len <= 0) return -1; return (rbuf[0] & 0xFF);
public int	read(byte[] b, int off, int len) Reads compressed data into a byte array. This method will block until some input can be read and compressed. param b buffer into which the data is read param off starting offset of the data within {@code b} param len maximum number of compressed bytes to read into {@code b} return the actual number of bytes read, or -1 if the end of the uncompressed input stream is reached throws IndexOutOfBoundsException if {@code len} > {@code b.length - off} throws IOException if an I/O error occurs or if this input stream is already closed // Sanity checks ensureOpen(); if (b == null) { throw new NullPointerException("Null buffer for read"); } else if (off < 0 || len < 0 || len > b.length - off) { throw new IndexOutOfBoundsException(); } else if (len == 0) { return 0; } // Read and compress (deflate) input data bytes int cnt = 0; while (len > 0 && !def.finished()) { int n; // Read data from the input stream if (def.needsInput()) { n = in.read(buf, 0, buf.length); if (n < 0) { // End of the input stream reached def.finish(); } else if (n > 0) { def.setInput(buf, 0, n); } } // Compress the input data, filling the read buffer n = def.deflate(b, off, len); cnt += n; off += n; len -= n; } if (cnt == 0 && def.finished()) { reachEOF = true; cnt = -1; } return cnt;
public void	reset() This operation is not supported. throws IOException always thrown throw new IOException("mark/reset not supported");
public long	skip(long n) Skips over and discards data from the input stream. This method may block until the specified number of bytes are read and skipped. Note: While {@code n} is given as a {@code long}, the maximum number of bytes which can be skipped is {@code Integer.MAX_VALUE}. param n number of bytes to be skipped return the actual number of bytes skipped throws IOException if an I/O error occurs or if this stream is already closed if (n < 0) { throw new IllegalArgumentException("negative skip length"); } ensureOpen(); // Skip bytes by repeatedly decompressing small blocks if (rbuf.length < 512) rbuf = new byte[512]; int total = (int)Math.min(n, Integer.MAX_VALUE); long cnt = 0; while (total > 0) { // Read a small block of uncompressed bytes int len = read(rbuf, 0, (total <= rbuf.length ? total : rbuf.length)); if (len < 0) { break; } cnt += len; total -= len; } return cnt;