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");
- }
-}