/*

 * 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 com.sun.media.sound;

import java.io.EOFException;

import java.io.IOException;

import java.io.InputStream;

/**

 * Resource Interchange File Format (RIFF) stream decoder.

 *

 * @author Karl Helgason

 */

public final class RIFFReader extends InputStream {

    private final RIFFReader root;

    private long filepointer = 0;

    private final String fourcc;

    private String riff_type = null;

    private final long ckSize;

    private long avail = 0xffffffffL; // MAX_UNSIGNED_INT

    private RIFFReader lastiterator = null;

    public RIFFReader(final InputStream stream) throws IOException {

        if (stream instanceof RIFFReader) {

            root = ((RIFFReader) stream).root;

        } else {

            root = this;

        }

        this.stream = stream;

        // Check for RIFF null paddings,

        int b;

        while (true) {

            b = read();

            if (b == -1) {

                fourcc = ""; // don't put null value into fourcc,

                // because it is expected to

                // always contain a string value

                riff_type = null;

                ckSize = 0;

                avail = 0;

                return;

            }

            if (b != 0) {

                break;

            }

        }

        byte[] fourcc = new byte[4];

        fourcc[0] = (byte) b;

        readFully(fourcc, 1, 3);

        this.fourcc = new String(fourcc, "ascii");

        ckSize = readUnsignedInt();

        avail = ckSize;

        if (getFormat().equals("RIFF") || getFormat().equals("LIST")) {

            byte[] format = new byte[4];

            readFully(format);

            this.riff_type = new String(format, "ascii");

        }

    }

    public long getFilePointer() throws IOException {

        return root.filepointer;

    }

    public boolean hasNextChunk() throws IOException {

        if (lastiterator != null)

            lastiterator.finish();

        return avail != 0;

    }

    public RIFFReader nextChunk() throws IOException {

        if (lastiterator != null)

            lastiterator.finish();

        if (avail == 0)

            return null;

        lastiterator = new RIFFReader(this);

        return lastiterator;

    }

    public String getFormat() {

        return fourcc;

    }

    public String getType() {

        return riff_type;

    }

    public long getSize() {

        return ckSize;

    }

    @Override

    public int read() throws IOException {

        if (avail == 0) {

            return -1;

        }

        int b = stream.read();

        if (b == -1) {

            avail = 0;

            return -1;

        }

        avail--;

        filepointer++;

        return b;

    }

    @Override

    public int read(byte[] b, int offset, int len) throws IOException {

        if (avail == 0) {

            return -1;

        }

        if (len > avail) {

            int rlen = stream.read(b, offset, (int)avail);

            if (rlen != -1)

                filepointer += rlen;

            avail = 0;

            return rlen;

        } else {

            int ret = stream.read(b, offset, len);

            if (ret == -1) {

                avail = 0;

                return -1;

            }

            avail -= ret;

            filepointer += ret;

            return ret;

        }

    }

    public void readFully(byte b[]) throws IOException {

        readFully(b, 0, b.length);

    }

    public void readFully(byte b[], int off, int len) throws IOException {

        if (len < 0)

            throw new IndexOutOfBoundsException();

        while (len > 0) {

            int s = read(b, off, len);

            if (s < 0)

                throw new EOFException();

            if (s == 0)

                Thread.yield();

            off += s;

            len -= s;

        }

    }

    @Override

    public long skip(final long n) throws IOException {

        if (n <= 0 || avail == 0) {

            return 0;

        }

        // will not skip more than

        long remaining = Math.min(n, avail);

        while (remaining > 0) {

            // Some input streams like FileInputStream can return more bytes,

            // when EOF is reached.

            long ret = Math.min(stream.skip(remaining), remaining);

            if (ret == 0) {

                // EOF or not? we need to check.

                Thread.yield();

                if (stream.read() == -1) {

                    avail = 0;

                    break;

                }

                ret = 1;

            } else if (ret < 0) {

                // the skip should not return negative value, but check it also

                avail = 0;

                break;

            }

            remaining -= ret;

            avail -= ret;

            filepointer += ret;

        }

        return n - remaining;

    }

    @Override

    public int available() {

        return avail > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) avail;

    }

    public void finish() throws IOException {

        if (avail != 0) {

            skip(avail);

        }

    }

    // Read ASCII chars from stream

    public String readString(final int len) throws IOException {

        final byte[] buff;

        try {

            buff = new byte[len];

        } catch (final OutOfMemoryError oom) {

            throw new IOException("Length too big", oom);

        }

        readFully(buff);

        for (int i = 0; i < buff.length; i++) {

            if (buff[i] == 0) {

                return new String(buff, 0, i, "ascii");

            }

        }

        return new String(buff, "ascii");

    }

    // Read 8 bit signed integer from stream

    public byte readByte() throws IOException {

        int ch = read();

        if (ch < 0)

            throw new EOFException();

        return (byte) ch;

    }

    // Read 16 bit signed integer from stream

    public short readShort() throws IOException {

        int ch1 = read();

        int ch2 = read();

        if (ch1 < 0)

            throw new EOFException();

        if (ch2 < 0)

            throw new EOFException();

        return (short)(ch1 | (ch2 << 8));

    }

    // Read 32 bit signed integer from stream

    public int readInt() throws IOException {

        int ch1 = read();

        int ch2 = read();

        int ch3 = read();

        int ch4 = read();

        if (ch1 < 0)

            throw new EOFException();

        if (ch2 < 0)

            throw new EOFException();

        if (ch3 < 0)

            throw new EOFException();

        if (ch4 < 0)

            throw new EOFException();

        return ch1 + (ch2 << 8) | (ch3 << 16) | (ch4 << 24);

    }

    // Read 64 bit signed integer from stream

    public long readLong() throws IOException {

        long ch1 = read();

        long ch2 = read();

        long ch3 = read();

        long ch4 = read();

        long ch5 = read();

        long ch6 = read();

        long ch7 = read();

        long ch8 = read();

        if (ch1 < 0)

            throw new EOFException();

        if (ch2 < 0)

            throw new EOFException();

        if (ch3 < 0)

            throw new EOFException();

        if (ch4 < 0)

            throw new EOFException();

        if (ch5 < 0)

            throw new EOFException();

        if (ch6 < 0)

            throw new EOFException();

        if (ch7 < 0)

            throw new EOFException();

        if (ch8 < 0)

            throw new EOFException();

        return ch1 | (ch2 << 8) | (ch3 << 16) | (ch4 << 24)

                | (ch5 << 32) | (ch6 << 40) | (ch7 << 48) | (ch8 << 56);

    }

    // Read 8 bit unsigned integer from stream

    public int readUnsignedByte() throws IOException {

        int ch = read();

        if (ch < 0)

            throw new EOFException();

        return ch;

    }

    // Read 16 bit unsigned integer from stream

    public int readUnsignedShort() throws IOException {

        int ch1 = read();

        int ch2 = read();

        if (ch1 < 0)

            throw new EOFException();

        if (ch2 < 0)

            throw new EOFException();

        return ch1 | (ch2 << 8);

    }

    // Read 32 bit unsigned integer from stream

    public long readUnsignedInt() throws IOException {

        long ch1 = read();

        long ch2 = read();

        long ch3 = read();

        long ch4 = read();

        if (ch1 < 0)

            throw new EOFException();

        if (ch2 < 0)

            throw new EOFException();

        if (ch3 < 0)

            throw new EOFException();

        if (ch4 < 0)

            throw new EOFException();

        return ch1 + (ch2 << 8) | (ch3 << 16) | (ch4 << 24);

    }

    @Override

    public void close() throws IOException {

        finish();

    }

}