/*

 * Copyright (c) 1996, 2009, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.security.ssl;

import java.io.*;

/**

 * InputStream for application data as returned by SSLSocket.getInputStream().

 * It uses an InputRecord as internal buffer that is refilled on demand

 * whenever it runs out of data.

 *

 * @author David Brownell

 */

class AppInputStream extends InputStream {

    // static dummy array we use to implement skip()

    private final static byte[] SKIP_ARRAY = new byte[1024];

    private SSLSocketImpl c;

    InputRecord r;

    // One element array used to implement the single byte read() method

    private final byte[] oneByte = new byte[1];

    AppInputStream(SSLSocketImpl conn) {

        r = new InputRecord();

        c = conn;

    }

    /**

     * Return the minimum number of bytes that can be read without blocking.

     * Currently not synchronized.

     */

    public int available() throws IOException {

        if (c.checkEOF() || (r.isAppDataValid() == false)) {

            return 0;

        }

        return r.available();

    }

    /**

     * Read a single byte, returning -1 on non-fault EOF status.

     */

    public synchronized int read() throws IOException {

        int n = read(oneByte, 0, 1);

        if (n <= 0) { // EOF

            return -1;

        }

        return oneByte[0] & 0xff;

    }

    /**

     * Read up to "len" bytes into this buffer, starting at "off".

     * If the layer above needs more data, it asks for more, so we

     * are responsible only for blocking to fill at most one buffer,

     * and returning "-1" on non-fault EOF status.

     */

    public synchronized int read(byte b[], int off, int len)

            throws IOException {

        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;

        }

        if (c.checkEOF()) {

            return -1;

        }

        try {

            /*

             * Read data if needed ... notice that the connection guarantees

             * that handshake, alert, and change cipher spec data streams are

             * handled as they arrive, so we never see them here.

             */

            while (r.available() == 0) {

                c.readDataRecord(r);

                if (c.checkEOF()) {

                    return -1;

                }

            }

            int howmany = Math.min(len, r.available());

            howmany = r.read(b, off, howmany);

            return howmany;

        } catch (Exception e) {

            // shutdown and rethrow (wrapped) exception as appropriate

            c.handleException(e);

            // dummy for compiler

            return -1;

        }

    }

    /**

     * Skip n bytes. This implementation is somewhat less efficient

     * than possible, but not badly so (redundant copy). We reuse

     * the read() code to keep things simpler. Note that SKIP_ARRAY

     * is static and may garbled by concurrent use, but we are not interested

     * in the data anyway.

     */

    public synchronized long skip(long n) throws IOException {

        long skipped = 0;

        while (n > 0) {

            int len = (int)Math.min(n, SKIP_ARRAY.length);

            int r = read(SKIP_ARRAY, 0, len);

            if (r <= 0) {

                break;

            }

            n -= r;

            skipped += r;

        }

        return skipped;

    }

    /*

     * Socket close is already synchronized, no need to block here.

     */

    public void close() throws IOException {

        c.close();

    }

    // inherit default mark/reset behavior (throw Exceptions) from InputStream

}