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/***

 * ASM: a very small and fast Java bytecode manipulation framework

 * Copyright (c) 2000-2005 INRIA, France Telecom

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the copyright holders nor the names of its

 *    contributors may be used to endorse or promote products derived from

 *    this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF

 * THE POSSIBILITY OF SUCH DAMAGE.

 */

package org.objectweb.asm;

/**

 * A dynamically extensible vector of bytes. This class is roughly equivalent to

 * a DataOutputStream on top of a ByteArrayOutputStream, but is more efficient.

 *

 * @author Eric Bruneton

 */

public class ByteVector {

    /**

     * The content of this vector.

     */

    byte[] data;

    /**

     * Actual number of bytes in this vector.

     */

    int length;

    /**

     * Constructs a new {@link ByteVector ByteVector} with a default initial

     * size.

     */

    public ByteVector() {

        data = new byte[64];

    }

    /**

     * Constructs a new {@link ByteVector ByteVector} with the given initial

     * size.

     *

     * @param initialSize the initial size of the byte vector to be constructed.

     */

    public ByteVector(final int initialSize) {

        data = new byte[initialSize];

    }

    /**

     * Puts a byte into this byte vector. The byte vector is automatically

     * enlarged if necessary.

     *

     * @param b a byte.

     * @return this byte vector.

     */

    public ByteVector putByte(final int b) {

        int length = this.length;

        if (length + 1 > data.length) {

            enlarge(1);

        }

        data[length++] = (byte) b;

        this.length = length;

        return this;

    }

    /**

     * Puts two bytes into this byte vector. The byte vector is automatically

     * enlarged if necessary.

     *

     * @param b1 a byte.

     * @param b2 another byte.

     * @return this byte vector.

     */

    ByteVector put11(final int b1, final int b2) {

        int length = this.length;

        if (length + 2 > data.length) {

            enlarge(2);

        }

        byte[] data = this.data;

        data[length++] = (byte) b1;

        data[length++] = (byte) b2;

        this.length = length;

        return this;

    }

    /**

     * Puts a short into this byte vector. The byte vector is automatically

     * enlarged if necessary.

     *

     * @param s a short.

     * @return this byte vector.

     */

    public ByteVector putShort(final int s) {

        int length = this.length;

        if (length + 2 > data.length) {

            enlarge(2);

        }

        byte[] data = this.data;

        data[length++] = (byte) (s >>> 8);

        data[length++] = (byte) s;

        this.length = length;

        return this;

    }

    /**

     * Puts a byte and a short into this byte vector. The byte vector is

     * automatically enlarged if necessary.

     *

     * @param b a byte.

     * @param s a short.

     * @return this byte vector.

     */

    ByteVector put12(final int b, final int s) {

        int length = this.length;

        if (length + 3 > data.length) {

            enlarge(3);

        }

        byte[] data = this.data;

        data[length++] = (byte) b;

        data[length++] = (byte) (s >>> 8);

        data[length++] = (byte) s;

        this.length = length;

        return this;

    }

    /**

     * Puts an int into this byte vector. The byte vector is automatically

     * enlarged if necessary.

     *

     * @param i an int.

     * @return this byte vector.

     */

    public ByteVector putInt(final int i) {

        int length = this.length;

        if (length + 4 > data.length) {

            enlarge(4);

        }

        byte[] data = this.data;

        data[length++] = (byte) (i >>> 24);

        data[length++] = (byte) (i >>> 16);

        data[length++] = (byte) (i >>> 8);

        data[length++] = (byte) i;

        this.length = length;

        return this;

    }

    /**

     * Puts a long into this byte vector. The byte vector is automatically

     * enlarged if necessary.

     *

     * @param l a long.

     * @return this byte vector.

     */

    public ByteVector putLong(final long l) {

        int length = this.length;

        if (length + 8 > data.length) {

            enlarge(8);

        }

        byte[] data = this.data;

        int i = (int) (l >>> 32);

        data[length++] = (byte) (i >>> 24);

        data[length++] = (byte) (i >>> 16);

        data[length++] = (byte) (i >>> 8);

        data[length++] = (byte) i;

        i = (int) l;

        data[length++] = (byte) (i >>> 24);

        data[length++] = (byte) (i >>> 16);

        data[length++] = (byte) (i >>> 8);

        data[length++] = (byte) i;

        this.length = length;

        return this;

    }

    /**

     * Puts an UTF8 string into this byte vector. The byte vector is

     * automatically enlarged if necessary.

     *

     * @param s a String.

     * @return this byte vector.

     */

    public ByteVector putUTF8(final String s) {

        int charLength = s.length();

        if (length + 2 + charLength > data.length) {

            enlarge(2 + charLength);

        }

        int len = length;

        byte[] data = this.data;

        // optimistic algorithm: instead of computing the byte length and then

        // serializing the string (which requires two loops), we assume the byte

        // length is equal to char length (which is the most frequent case), and

        // we start serializing the string right away. During the serialization,

        // if we find that this assumption is wrong, we continue with the

        // general method.

        data[len++] = (byte) (charLength >>> 8);

        data[len++] = (byte) (charLength);

        for (int i = 0; i < charLength; ++i) {

            char c = s.charAt(i);

            if (c >= '\001' && c <= '\177') {

                data[len++] = (byte) c;

            } else {

                int byteLength = i;

                for (int j = i; j < charLength; ++j) {

                    c = s.charAt(j);

                    if (c >= '\001' && c <= '\177') {

                        byteLength++;

                    } else if (c > '\u07FF') {

                        byteLength += 3;

                    } else {

                        byteLength += 2;

                    }

                }

                data[length] = (byte) (byteLength >>> 8);

                data[length + 1] = (byte) (byteLength);

                if (length + 2 + byteLength > data.length) {

                    length = len;

                    enlarge(2 + byteLength);

                    data = this.data;

                }

                for (int j = i; j < charLength; ++j) {

                    c = s.charAt(j);

                    if (c >= '\001' && c <= '\177') {

                        data[len++] = (byte) c;

                    } else if (c > '\u07FF') {

                        data[len++] = (byte) (0xE0 | c >> 12 & 0xF);

                        data[len++] = (byte) (0x80 | c >> 6 & 0x3F);

                        data[len++] = (byte) (0x80 | c & 0x3F);

                    } else {

                        data[len++] = (byte) (0xC0 | c >> 6 & 0x1F);

                        data[len++] = (byte) (0x80 | c & 0x3F);

                    }

                }

                break;

            }

        }

        length = len;

        return this;

    }

    /**

     * Puts an array of bytes into this byte vector. The byte vector is

     * automatically enlarged if necessary.

     *

     * @param b an array of bytes. May be <tt>null</tt> to put <tt>len</tt>

     *        null bytes into this byte vector.

     * @param off index of the fist byte of b that must be copied.

     * @param len number of bytes of b that must be copied.

     * @return this byte vector.

     */

    public ByteVector putByteArray(final byte[] b, final int off, final int len)

    {

        if (length + len > data.length) {

            enlarge(len);

        }

        if (b != null) {

            System.arraycopy(b, off, data, length, len);

        }

        length += len;

        return this;

    }

    /**

     * Enlarge this byte vector so that it can receive n more bytes.

     *

     * @param size number of additional bytes that this byte vector should be

     *        able to receive.

     */

    private void enlarge(final int size) {

        int length1 = 2 * data.length;

        int length2 = length + size;

        byte[] newData = new byte[length1 > length2 ? length1 : length2];

        System.arraycopy(data, 0, newData, 0, length);

        data = newData;

    }

}