/*

 * Copyright (c) 2007, 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 com.sun.media.sound;

import java.io.ByteArrayInputStream;

import java.io.DataInputStream;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.RandomAccessFile;

import java.util.Collection;

/**

 * This class is a pointer to a binary array either in memory or on disk.

 *

 * @author Karl Helgason

 */

public class ModelByteBuffer {

    private ModelByteBuffer root = this;

    private File file;

    private long fileoffset;

    private byte[] buffer;

    private long offset;

    private final long len;

    private class RandomFileInputStream extends InputStream {

        private RandomAccessFile raf;

        private long left;

        private long mark = 0;

        private long markleft = 0;

        public RandomFileInputStream() throws IOException {

            raf = new RandomAccessFile(root.file, "r");

            raf.seek(root.fileoffset + arrayOffset());

            left = capacity();

        }

        public int available() throws IOException {

            if (left > Integer.MAX_VALUE)

                return Integer.MAX_VALUE;

            return (int)left;

        }

        public synchronized void mark(int readlimit) {

            try {

                mark = raf.getFilePointer();

                markleft = left;

            } catch (IOException e) {

                //e.printStackTrace();

            }

        }

        public boolean markSupported() {

            return true;

        }

        public synchronized void reset() throws IOException {

            raf.seek(mark);

            left = markleft;

        }

        public long skip(long n) throws IOException {

            if( n < 0)

                return 0;

            if (n > left)

                n = left;

            long p = raf.getFilePointer();

            raf.seek(p + n);

            left -= n;

            return n;

        }

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

            if (len > left)

                len = (int)left;

            if (left == 0)

                return -1;

            len = raf.read(b, off, len);

            if (len == -1)

                return -1;

            left -= len;

            return len;

        }

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

            int len = b.length;

            if (len > left)

                len = (int)left;

            if (left == 0)

                return -1;

            len = raf.read(b, 0, len);

            if (len == -1)

                return -1;

            left -= len;

            return len;

        }

        public int read() throws IOException {

            if (left == 0)

                return -1;

            int b = raf.read();

            if (b == -1)

                return -1;

            left--;

            return b;

        }

        public void close() throws IOException {

            raf.close();

        }

    }

    private ModelByteBuffer(ModelByteBuffer parent,

            long beginIndex, long endIndex, boolean independent) {

        this.root = parent.root;

        this.offset = 0;

        long parent_len = parent.len;

        if (beginIndex < 0)

            beginIndex = 0;

        if (beginIndex > parent_len)

            beginIndex = parent_len;

        if (endIndex < 0)

            endIndex = 0;

        if (endIndex > parent_len)

            endIndex = parent_len;

        if (beginIndex > endIndex)

            beginIndex = endIndex;

        offset = beginIndex;

        len = endIndex - beginIndex;

        if (independent) {

            buffer = root.buffer;

            if (root.file != null) {

                file = root.file;

                fileoffset = root.fileoffset + arrayOffset();

                offset = 0;

            } else

                offset = arrayOffset();

            root = this;

        }

    }

    public ModelByteBuffer(byte[] buffer) {

        this.buffer = buffer;

        this.offset = 0;

        this.len = buffer.length;

    }

    public ModelByteBuffer(byte[] buffer, int offset, int len) {

        this.buffer = buffer;

        this.offset = offset;

        this.len = len;

    }

    public ModelByteBuffer(File file) {

        this.file = file;

        this.fileoffset = 0;

        this.len = file.length();

    }

    public ModelByteBuffer(File file, long offset, long len) {

        this.file = file;

        this.fileoffset = offset;

        this.len = len;

    }

    public void writeTo(OutputStream out) throws IOException {

        if (root.file != null && root.buffer == null) {

            InputStream is = getInputStream();

            byte[] buff = new byte[1024];

            int ret;

            while ((ret = is.read(buff)) != -1)

                out.write(buff, 0, ret);

        } else

            out.write(array(), (int) arrayOffset(), (int) capacity());

    }

    public InputStream getInputStream() {

        if (root.file != null && root.buffer == null) {

            try {

                return new RandomFileInputStream();

            } catch (IOException e) {

                //e.printStackTrace();

                return null;

            }

        }

        return new ByteArrayInputStream(array(),

                (int)arrayOffset(), (int)capacity());

    }

    public ModelByteBuffer subbuffer(long beginIndex) {

        return subbuffer(beginIndex, capacity());

    }

    public ModelByteBuffer subbuffer(long beginIndex, long endIndex) {

        return subbuffer(beginIndex, endIndex, false);

    }

    public ModelByteBuffer subbuffer(long beginIndex, long endIndex,

            boolean independent) {

        return new ModelByteBuffer(this, beginIndex, endIndex, independent);

    }

    public byte[] array() {

        return root.buffer;

    }

    public long arrayOffset() {

        if (root != this)

            return root.arrayOffset() + offset;

        return offset;

    }

    public long capacity() {

        return len;

    }

    public ModelByteBuffer getRoot() {

        return root;

    }

    public File getFile() {

        return file;

    }

    public long getFilePointer() {

        return fileoffset;

    }

    public static void loadAll(Collection<ModelByteBuffer> col)

            throws IOException {

        File selfile = null;

        RandomAccessFile raf = null;

        try {

            for (ModelByteBuffer mbuff : col) {

                mbuff = mbuff.root;

                if (mbuff.file == null)

                    continue;

                if (mbuff.buffer != null)

                    continue;

                if (selfile == null || !selfile.equals(mbuff.file)) {

                    if (raf != null) {

                        raf.close();

                        raf = null;

                    }

                    selfile = mbuff.file;

                    raf = new RandomAccessFile(mbuff.file, "r");

                }

                raf.seek(mbuff.fileoffset);

                byte[] buffer = new byte[(int) mbuff.capacity()];

                int read = 0;

                int avail = buffer.length;

                while (read != avail) {

                    if (avail - read > 65536) {

                        raf.readFully(buffer, read, 65536);

                        read += 65536;

                    } else {

                        raf.readFully(buffer, read, avail - read);

                        read = avail;

                    }

                }

                mbuff.buffer = buffer;

                mbuff.offset = 0;

            }

        } finally {

            if (raf != null)

                raf.close();

        }

    }

    public void load() throws IOException {

        if (root != this) {

            root.load();

            return;

        }

        if (buffer != null)

            return;

        if (file == null) {

            throw new IllegalStateException(

                    "No file associated with this ByteBuffer!");

        }

        DataInputStream is = new DataInputStream(getInputStream());

        buffer = new byte[(int) capacity()];

        offset = 0;

        is.readFully(buffer);

        is.close();

    }

    public void unload() {

        if (root != this) {

            root.unload();

            return;

        }

        if (file == null) {

            throw new IllegalStateException(

                    "No file associated with this ByteBuffer!");

        }

        root.buffer = null;

    }

}