len is not
* zero, the method will block until some input can be decompressed; otherwise,
* no bytes are read and 0 is returned.
* @param b the buffer into which the data is read
* @param off the start offset in the destination array b
* @param len the maximum number of bytes read
* @return the actual number of bytes read, or -1 if the end of the
* compressed input is reached or a preset dictionary is needed
* @exception NullPointerException If b is null.
* @exception IndexOutOfBoundsException If off is negative,
* len is negative, or len is greater than
* b.length - off
* @exception ZipException if a ZIP format error has occurred
* @exception IOException if an I/O error has occurred
*/
public int read(byte[] b, int off, int len) throws IOException {
ensureOpen();
if (b == null) {
throw new NullPointerException();
} else if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
} else if (len == 0) {
return 0;
}
try {
int n;
while ((n = inf.inflate(b, off, len)) == 0) {
if (inf.finished() || inf.needsDictionary()) {
reachEOF = true;
return -1;
}
if (inf.needsInput()) {
fill();
}
}
return n;
} catch (DataFormatException e) {
String s = e.getMessage();
throw new ZipException(s != null ? s : "Invalid ZLIB data format");
}
}
/**
* 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 1 before EOF and 0 after EOF.
* @exception IOException if an I/O error occurs.
*
*/
public int available() throws IOException {
ensureOpen();
if (reachEOF) {
return 0;
} else {
return 1;
}
}
private byte[] b = new byte[512];
/**
* Skips specified number of bytes of uncompressed data.
* @param n the number of bytes to skip
* @return the actual number of bytes skipped.
* @exception IOException if an I/O error has occurred
* @exception IllegalArgumentException if n < 0
*/
public long skip(long n) throws IOException {
if (n < 0) {
throw new IllegalArgumentException("negative skip length");
}
ensureOpen();
int max = (int)Math.min(n, Integer.MAX_VALUE);
int total = 0;
while (total < max) {
int len = max - total;
if (len > b.length) {
len = b.length;
}
len = read(b, 0, len);
if (len == -1) {
reachEOF = true;
break;
}
total += len;
}
return total;
}
/**
* Closes this input stream and releases any system resources associated
* with the stream.
* @exception IOException if an I/O error has occurred
*/
public void close() throws IOException {
if (!closed) {
if (usesDefaultInflater)
inf.end();
in.close();
closed = true;
}
}
/**
* Fills input buffer with more data to decompress.
* @exception IOException if an I/O error has occurred
*/
protected void fill() throws IOException {
ensureOpen();
len = in.read(buf, 0, buf.length);
if (len == -1) {
throw new EOFException("Unexpected end of ZLIB input stream");
}
inf.setInput(buf, 0, len);
}
/**
* Tests if this input stream supports the mark and
* reset methods. The markSupported
* method of InflaterInputStream returns
* false.
*
* @return a boolean indicating if this stream type supports
* the mark and reset methods.
* @see java.io.InputStream#mark(int)
* @see java.io.InputStream#reset()
*/
public boolean markSupported() {
return false;
}
/**
* Marks the current position in this input stream.
*
*
The mark method of InflaterInputStream
* does nothing.
*
* @param readlimit the maximum limit of bytes that can be read before
* the mark position becomes invalid.
* @see java.io.InputStream#reset()
*/
public synchronized void mark(int readlimit) {
}
/**
* Repositions this stream to the position at the time the
* mark method was last called on this input stream.
*
*
The method reset for class
* InflaterInputStream does nothing except throw an
* IOException.
*
* @exception IOException if this method is invoked.
* @see java.io.InputStream#mark(int)
* @see java.io.IOException
*/
public synchronized void reset() throws IOException {
throw new IOException("mark/reset not supported");
}
}