/*
 * Copyright (c) 1999, 2012, 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
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 */

package com.sun.tools.javac.util;

import java.io.*;

A byte buffer is a flexible array which grows when elements are
 appended. There are also methods to append names to byte buffers
 and to convert byte buffers to names.
 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/** A byte buffer is a flexible array which grows when elements are
 *  appended. There are also methods to append names to byte buffers
 *  and to convert byte buffers to names.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 */
public class ByteBuffer {

    
An array holding the bytes in this buffer; can be grown.
/** An array holding the bytes in this buffer; can be grown.
     */
    public byte[] elems;

    
The current number of defined bytes in this buffer.
/** The current number of defined bytes in this buffer.
     */
    public int length;

    
Create a new byte buffer.
/** Create a new byte buffer.
     */
    public ByteBuffer() {
        this(64);
    }

    
Create a new byte buffer with an initial elements array
 of given size.
/** Create a new byte buffer with an initial elements array
     *  of given size.
     */
    public ByteBuffer(int initialSize) {
        elems = new byte[initialSize];
        length = 0;
    }

    
Append byte to this buffer.
/** Append byte to this buffer.
     */
    public void appendByte(int b) {
        elems = ArrayUtils.ensureCapacity(elems, length);
        elems[length++] = (byte)b;
    }

    
Append `len' bytes from byte array,
 starting at given `start' offset.
/** Append `len' bytes from byte array,
     *  starting at given `start' offset.
     */
    public void appendBytes(byte[] bs, int start, int len) {
        elems = ArrayUtils.ensureCapacity(elems, length + len);
        System.arraycopy(bs, start, elems, length, len);
        length += len;
    }

    
Append all bytes from given byte array.
/** Append all bytes from given byte array.
     */
    public void appendBytes(byte[] bs) {
        appendBytes(bs, 0, bs.length);
    }

    
Append a character as a two byte number.
/** Append a character as a two byte number.
     */
    public void appendChar(int x) {
        elems = ArrayUtils.ensureCapacity(elems, length + 1);
        elems[length  ] = (byte)((x >>  8) & 0xFF);
        elems[length+1] = (byte)((x      ) & 0xFF);
        length = length + 2;
    }

    
Append an integer as a four byte number.
/** Append an integer as a four byte number.
     */
    public void appendInt(int x) {
        elems = ArrayUtils.ensureCapacity(elems, length + 3);
        elems[length  ] = (byte)((x >> 24) & 0xFF);
        elems[length+1] = (byte)((x >> 16) & 0xFF);
        elems[length+2] = (byte)((x >>  8) & 0xFF);
        elems[length+3] = (byte)((x      ) & 0xFF);
        length = length + 4;
    }

    
Append a long as an eight byte number.
/** Append a long as an eight byte number.
     */
    public void appendLong(long x) {
        ByteArrayOutputStream buffer = new ByteArrayOutputStream(8);
        DataOutputStream bufout = new DataOutputStream(buffer);
        try {
            bufout.writeLong(x);
            appendBytes(buffer.toByteArray(), 0, 8);
        } catch (IOException e) {
            throw new AssertionError("write");
        }
    }

    
Append a float as a four byte number.
/** Append a float as a four byte number.
     */
    public void appendFloat(float x) {
        ByteArrayOutputStream buffer = new ByteArrayOutputStream(4);
        DataOutputStream bufout = new DataOutputStream(buffer);
        try {
            bufout.writeFloat(x);
            appendBytes(buffer.toByteArray(), 0, 4);
        } catch (IOException e) {
            throw new AssertionError("write");
        }
    }

    
Append a double as a eight byte number.
/** Append a double as a eight byte number.
     */
    public void appendDouble(double x) {
        ByteArrayOutputStream buffer = new ByteArrayOutputStream(8);
        DataOutputStream bufout = new DataOutputStream(buffer);
        try {
            bufout.writeDouble(x);
            appendBytes(buffer.toByteArray(), 0, 8);
        } catch (IOException e) {
            throw new AssertionError("write");
        }
    }

    
Append a name.
/** Append a name.
     */
    public void appendName(Name name) {
        appendBytes(name.getByteArray(), name.getByteOffset(), name.getByteLength());
    }

     
Append the content of a given input stream.
/** Append the content of a given input stream.
     */
    public void appendStream(InputStream is) throws IOException {
        try {
            int start = length;
            int initialSize = is.available();
            elems = ArrayUtils.ensureCapacity(elems, length + initialSize);
            int r = is.read(elems, start, initialSize);
            int bp = start;
            while (r != -1) {
                bp += r;
                elems = ArrayUtils.ensureCapacity(elems, bp);
                r = is.read(elems, bp, elems.length - bp);
            }
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                /* Ignore any errors, as this stream may have already
                 * thrown a related exception which is the one that
                 * should be reported.
                 */
            }
        }
    }

    
Extract an integer at position bp from elems.
/** Extract an integer at position bp from elems.
     */
    public int getInt(int bp) {
        return
            ((elems[bp] & 0xFF) << 24) +
            ((elems[bp+1] & 0xFF) << 16) +
            ((elems[bp+2] & 0xFF) << 8) +
            (elems[bp+3] & 0xFF);
    }


    
Extract a long integer at position bp from elems.
/** Extract a long integer at position bp from elems.
     */
    public long getLong(int bp) {
        DataInputStream elemsin =
            new DataInputStream(new ByteArrayInputStream(elems, bp, 8));
        try {
            return elemsin.readLong();
        } catch (IOException e) {
            throw new AssertionError(e);
        }
    }

    
Extract a float at position bp from elems.
/** Extract a float at position bp from elems.
     */
    public float getFloat(int bp) {
        DataInputStream elemsin =
            new DataInputStream(new ByteArrayInputStream(elems, bp, 4));
        try {
            return elemsin.readFloat();
        } catch (IOException e) {
            throw new AssertionError(e);
        }
    }

    
Extract a double at position bp from elems.
/** Extract a double at position bp from elems.
     */
    public double getDouble(int bp) {
        DataInputStream elemsin =
            new DataInputStream(new ByteArrayInputStream(elems, bp, 8));
        try {
            return elemsin.readDouble();
        } catch (IOException e) {
            throw new AssertionError(e);
        }
    }

    
Extract a character at position bp from elems.
/** Extract a character at position bp from elems.
     */
    public char getChar(int bp) {
        return
            (char)(((elems[bp] & 0xFF) << 8) + (elems[bp+1] & 0xFF));
    }

    public byte getByte(int bp) {
        return elems[bp];
    }

    
Reset to zero length.
/** Reset to zero length.
     */
    public void reset() {
        length = 0;
    }

    
Convert contents to name.
/** Convert contents to name.
     */
    public Name toName(Names names) {
        return names.fromUtf(elems, 0, length);
    }
}