content: /***
   * ASM: a very small and fast Java bytecode manipulation framework
   * Copyright (c) 2000-2007 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 com.alibaba.fastjson.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 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();
          int len = length;
          if (len + 2 + charLength > data.length) {
              enlarge(2 + charLength);
          }
          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 {
                  throw new UnsupportedOperationException();
              }
          }
          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;
      }
  }
  