code: /*
   * Copyright 2014 Google Inc. All rights reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.flatbuffers;
  
  import static com.google.flatbuffers.Constants.*;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.nio.charset.Charset;
  
  /// @cond FLATBUFFERS_INTERNAL
  
  /**
   * All tables in the generated code derive from this class, and add their own accessors.
   */
  public class Table {
    public final static ThreadLocal<Charset> UTF8_CHARSET = new ThreadLocal<Charset>() {
      @Override
      protected Charset initialValue() {
        return Charset.forName("UTF-8");
      }
    };
    /** Used to hold the position of the `bb` buffer. */
    protected int bb_pos;
    /** The underlying ByteBuffer to hold the data of the Table. */
    protected ByteBuffer bb;
    /** Used to hold the vtable position. */
    private int vtable_start;
    /** Used to hold the vtable size. */
    private int vtable_size;
    Utf8 utf8 = Utf8.getDefault();
  
    /**
     * Get the underlying ByteBuffer.
     *
     * @return Returns the Table's ByteBuffer.
     */
    public ByteBuffer getByteBuffer() { return bb; }
  
    /**
     * Look up a field in the vtable.
     *
     * @param vtable_offset An `int` offset to the vtable in the Table's ByteBuffer.
     * @return Returns an offset into the object, or `0` if the field is not present.
     */
    protected int __offset(int vtable_offset) {
      return vtable_offset < vtable_size ? bb.getShort(vtable_start + vtable_offset) : 0;
    }
  
    protected static int __offset(int vtable_offset, int offset, ByteBuffer bb) {
      int vtable = bb.capacity() - offset;
      return bb.getShort(vtable + vtable_offset - bb.getInt(vtable)) + vtable;
    }
  
    /**
     * Retrieve a relative offset.
     *
     * @param offset An `int` index into the Table's ByteBuffer containing the relative offset.
     * @return Returns the relative offset stored at `offset`.
     */
    protected int __indirect(int offset) {
      return offset + bb.getInt(offset);
    }
  
    protected static int __indirect(int offset, ByteBuffer bb) {
      return offset + bb.getInt(offset);
    }
  
    /**
     * Create a Java `String` from UTF-8 data stored inside the FlatBuffer.
     *
     * This allocates a new string and converts to wide chars upon each access,
     * which is not very efficient. Instead, each FlatBuffer string also comes with an
     * accessor based on __vector_as_bytebuffer below, which is much more efficient,
     * assuming your Java program can handle UTF-8 data directly.
     *
     * @param offset An `int` index into the Table's ByteBuffer.
     * @return Returns a `String` from the data stored inside the FlatBuffer at `offset`.
     */
    protected String __string(int offset) {
      offset += bb.getInt(offset);
      int length = bb.getInt(offset);
      return utf8.decodeUtf8(bb, offset + SIZEOF_INT, length);
    }
  
    /**
     * Get the length of a vector.
     *
     * @param offset An `int` index into the Table's ByteBuffer.
     * @return Returns the length of the vector whose offset is stored at `offset`.
     */
    protected int __vector_len(int offset) {
      offset += bb_pos;
      offset += bb.getInt(offset);
      return bb.getInt(offset);
    }
  
    /**
     * Get the start data of a vector.
     *
     * @param offset An `int` index into the Table's ByteBuffer.
     * @return Returns the start of the vector data whose offset is stored at `offset`.
     */
    protected int __vector(int offset) {
      offset += bb_pos;
      return offset + bb.getInt(offset) + SIZEOF_INT;  // data starts after the length
    }
  
    /**
     * Get a whole vector as a ByteBuffer.
     *
     * This is efficient, since it only allocates a new {@link ByteBuffer} object,
     * but does not actually copy the data, it still refers to the same bytes
     * as the original ByteBuffer. Also useful with nested FlatBuffers, etc.
     *
     * @param vector_offset The position of the vector in the byte buffer
     * @param elem_size The size of each element in the array
     * @return The {@link ByteBuffer} for the array
     */
    protected ByteBuffer __vector_as_bytebuffer(int vector_offset, int elem_size) {
      int o = __offset(vector_offset);
      if (o == 0) return null;
      ByteBuffer bb = this.bb.duplicate().order(ByteOrder.LITTLE_ENDIAN);
      int vectorstart = __vector(o);
      bb.position(vectorstart);
      bb.limit(vectorstart + __vector_len(o) * elem_size);
      return bb;
    }
  
    /**
     * Initialize vector as a ByteBuffer.
     *
     * This is more efficient than using duplicate, since it doesn't copy the data
     * nor allocattes a new {@link ByteBuffer}, creating no garbage to be collected.
     *
     * @param bb The {@link ByteBuffer} for the array
     * @param vector_offset The position of the vector in the byte buffer
     * @param elem_size The size of each element in the array
     * @return The {@link ByteBuffer} for the array
     */
    protected ByteBuffer __vector_in_bytebuffer(ByteBuffer bb, int vector_offset, int elem_size) {
      int o = this.__offset(vector_offset);
      if (o == 0) return null;
      int vectorstart = __vector(o);
      bb.rewind();
      bb.limit(vectorstart + __vector_len(o) * elem_size);
      bb.position(vectorstart);
      return bb;
    }
  
    /**
     * Initialize any Table-derived type to point to the union at the given `offset`.
     *
     * @param t A `Table`-derived type that should point to the union at `offset`.
     * @param offset An `int` index into the Table's ByteBuffer.
     * @return Returns the Table that points to the union at `offset`.
     */
    protected Table __union(Table t, int offset) {
      offset += bb_pos;
      t.bb_pos = offset + bb.getInt(offset);
      t.bb = bb;
      t.vtable_start = t.bb_pos - bb.getInt(t.bb_pos);
      t.vtable_size = bb.getShort(t.vtable_start);
      return t;
    }
  
    /**
     * Check if a {@link ByteBuffer} contains a file identifier.
     *
     * @param bb A {@code ByteBuffer} to check if it contains the identifier
     * `ident`.
     * @param ident A `String` identifier of the FlatBuffer file.
     * @return True if the buffer contains the file identifier
     */
    protected static boolean __has_identifier(ByteBuffer bb, String ident) {
      if (ident.length() != FILE_IDENTIFIER_LENGTH)
          throw new AssertionError("FlatBuffers: file identifier must be length " +
                                   FILE_IDENTIFIER_LENGTH);
      for (int i = 0; i < FILE_IDENTIFIER_LENGTH; i++) {
        if (ident.charAt(i) != (char)bb.get(bb.position() + SIZEOF_INT + i)) return false;
      }
      return true;
    }
  
    /**
     * Sort tables by the key.
     *
     * @param offsets An 'int' indexes of the tables into the bb.
     * @param bb A {@code ByteBuffer} to get the tables.
     */
    protected void sortTables(int[] offsets, final ByteBuffer bb) {
      Integer[] off = new Integer[offsets.length];
      for (int i = 0; i < offsets.length; i++) off[i] = offsets[i];
      java.util.Arrays.sort(off, new java.util.Comparator<Integer>() {
        public int compare(Integer o1, Integer o2) {
          return keysCompare(o1, o2, bb);
        }
      });
      for (int i = 0; i < offsets.length; i++) offsets[i] = off[i];
    }
  
    /**
     * Compare two tables by the key.
     *
     * @param o1 An 'Integer' index of the first key into the bb.
     * @param o2 An 'Integer' index of the second key into the bb.
     * @param bb A {@code ByteBuffer} to get the keys.
     */
    protected int keysCompare(Integer o1, Integer o2, ByteBuffer bb) { return 0; }
  
    /**
     * Compare two strings in the buffer.
     *
     * @param offset_1 An 'int' index of the first string into the bb.
     * @param offset_2 An 'int' index of the second string into the bb.
     * @param bb A {@code ByteBuffer} to get the strings.
     */
    protected static int compareStrings(int offset_1, int offset_2, ByteBuffer bb) {
      offset_1 += bb.getInt(offset_1);
      offset_2 += bb.getInt(offset_2);
      int len_1 = bb.getInt(offset_1);
      int len_2 = bb.getInt(offset_2);
      int startPos_1 = offset_1 + SIZEOF_INT;
      int startPos_2 = offset_2 + SIZEOF_INT;
      int len = Math.min(len_1, len_2);
      for(int i = 0; i < len; i++) {
        if (bb.get(i + startPos_1) != bb.get(i + startPos_2))
          return bb.get(i + startPos_1) - bb.get(i + startPos_2);
      }
      return len_1 - len_2;
    }
  
    /**
     * Compare string from the buffer with the 'String' object.
     *
     * @param offset_1 An 'int' index of the first string into the bb.
     * @param key Second string as a byte array.
     * @param bb A {@code ByteBuffer} to get the first string.
     */
    protected static int compareStrings(int offset_1, byte[] key, ByteBuffer bb) {
      offset_1 += bb.getInt(offset_1);
      int len_1 = bb.getInt(offset_1);
      int len_2 = key.length;
      int startPos_1 = offset_1 + Constants.SIZEOF_INT;
      int len = Math.min(len_1, len_2);
      for (int i = 0; i < len; i++) {
        if (bb.get(i + startPos_1) != key[i])
          return bb.get(i + startPos_1) - key[i];
      }
      return len_1 - len_2;
    }
  
    /**
     * Re-init the internal state with an external buffer {@code ByteBuffer} and an offset within.
     *
     * This method exists primarily to allow recycling Table instances without risking memory leaks
     * due to {@code ByteBuffer} references.
     */
    protected void __reset(int _i, ByteBuffer _bb) { 
      bb = _bb;
      if (bb != null) {
        bb_pos = _i;
        vtable_start = bb_pos - bb.getInt(bb_pos);
        vtable_size = bb.getShort(vtable_start);
      } else {
        bb_pos = 0;
        vtable_start = 0;
        vtable_size = 0;
      }
    }
  
    /**
     * Resets the internal state with a null {@code ByteBuffer} and a zero position.
     *
     * This method exists primarily to allow recycling Table instances without risking memory leaks
     * due to {@code ByteBuffer} references. The instance will be unusable until it is assigned
     * again to a {@code ByteBuffer}.
     */
    public void __reset() {
      __reset(0, null);
    }
  }
  
  /// @endcond
  