How to use

readBytes

method

in

org.apache.lucene.util.ByteBlockPool

/**
 * Set the given {@link BytesRef} so that its content is equal to the
 * {@code ref.length} bytes starting at {@code offset}. Most of the time this
 * method will set pointers to internal data-structures. However, in case a
 * value crosses a boundary, a fresh copy will be returned.
 * On the contrary to {@link #setBytesRef(BytesRef, int)}, this does not
 * expect the length to be encoded with the data.
 */
public void setRawBytesRef(BytesRef ref, final long offset) {
 int bufferIndex = (int) (offset >> BYTE_BLOCK_SHIFT);
 int pos = (int) (offset & BYTE_BLOCK_MASK);
 if (pos + ref.length <= BYTE_BLOCK_SIZE) {
  ref.bytes = buffers[bufferIndex];
  ref.offset = pos;
 } else {
  ref.bytes = new byte[ref.length];
  ref.offset = 0;
  readBytes(offset, ref.bytes, 0, ref.length);
 }
}

/** Fill the provided {@link BytesRef} with the bytes at the specified offset/length slice.
 *  This will avoid copying the bytes, if the slice fits into a single block; otherwise, it uses
 *  the provided {@link BytesRefBuilder} to copy bytes over. */
void setBytesRef(BytesRefBuilder builder, BytesRef result, long offset, int length) {
 result.length = length;
 int bufferIndex = (int) (offset >> BYTE_BLOCK_SHIFT);
 byte[] buffer = buffers[bufferIndex];
 int pos = (int) (offset & BYTE_BLOCK_MASK);
 if (pos + length <= BYTE_BLOCK_SIZE) {
  // common case where the slice lives in a single block: just reference the buffer directly without copying
  result.bytes = buffer;
  result.offset = pos;
 } else {
  // uncommon case: the slice spans at least 2 blocks, so we must copy the bytes:
  builder.grow(length);
  result.bytes = builder.get().bytes;
  result.offset = 0;
  readBytes(offset, result.bytes, 0, length);
 }
}

/**
 * Returns the <i>n'th</i> element of this {@link BytesRefArray}
 * @param spare a spare {@link BytesRef} instance
 * @param index the elements index to retrieve 
 * @return the <i>n'th</i> element of this {@link BytesRefArray}
 */
public BytesRef get(BytesRefBuilder spare, int index) {
 FutureObjects.checkIndex(index, lastElement);
 int offset = offsets[index];
 int length = index == lastElement - 1 ? currentOffset - offset
   : offsets[index + 1] - offset;
 spare.grow(length);
 spare.setLength(length);
 pool.readBytes(offset, spare.bytes(), 0, spare.length());
 return spare.get();
}

/**
 * Set the given {@link BytesRef} so that its content is equal to the
 * {@code ref.length} bytes starting at {@code offset}. Most of the time this
 * method will set pointers to internal data-structures. However, in case a
 * value crosses a boundary, a fresh copy will be returned.
 * On the contrary to {@link #setBytesRef(BytesRef, int)}, this does not
 * expect the length to be encoded with the data.
 */
public void setRawBytesRef(BytesRef ref, final long offset) {
 int bufferIndex = (int) (offset >> BYTE_BLOCK_SHIFT);
 int pos = (int) (offset & BYTE_BLOCK_MASK);
 if (pos + ref.length <= BYTE_BLOCK_SIZE) {
  ref.bytes = buffers[bufferIndex];
  ref.offset = pos;
 } else {
  ref.bytes = new byte[ref.length];
  ref.offset = 0;
  readBytes(offset, ref.bytes, 0, ref.length);
 }
}

/** Fill the provided {@link BytesRef} with the bytes at the specified offset/length slice.
 *  This will avoid copying the bytes, if the slice fits into a single block; otherwise, it uses
 *  the provided {@link BytesRefBuilder} to copy bytes over. */
void setBytesRef(BytesRefBuilder builder, BytesRef result, long offset, int length) {
 result.length = length;
 int bufferIndex = (int) (offset >> BYTE_BLOCK_SHIFT);
 byte[] buffer = buffers[bufferIndex];
 int pos = (int) (offset & BYTE_BLOCK_MASK);
 if (pos + length <= BYTE_BLOCK_SIZE) {
  // common case where the slice lives in a single block: just reference the buffer directly without copying
  result.bytes = buffer;
  result.offset = pos;
 } else {
  // uncommon case: the slice spans at least 2 blocks, so we must copy the bytes:
  builder.grow(length);
  result.bytes = builder.get().bytes;
  result.offset = 0;
  readBytes(offset, result.bytes, 0, length);
 }
}

/**
 * Returns the <i>n'th</i> element of this {@link BytesRefArray}
 * @param spare a spare {@link BytesRef} instance
 * @param index the elements index to retrieve 
 * @return the <i>n'th</i> element of this {@link BytesRefArray}
 */
public BytesRef get(BytesRefBuilder spare, int index) {
 if (lastElement > index) {
  int offset = offsets[index];
  int length = index == lastElement - 1 ? currentOffset - offset
    : offsets[index + 1] - offset;
  spare.grow(length);
  spare.setLength(length);
  pool.readBytes(offset, spare.bytes(), 0, spare.length());
  return spare.get();
 }
 throw new IndexOutOfBoundsException("index " + index
   + " must be less than the size: " + lastElement);
 
}

/**
 * Returns the <i>n'th</i> element of this {@link BytesRefArray}
 * @param spare a spare {@link BytesRef} instance
 * @param index the elements index to retrieve 
 * @return the <i>n'th</i> element of this {@link BytesRefArray}
 */
public BytesRef get(BytesRefBuilder spare, int index) {
 if (lastElement > index) {
  int offset = offsets[index];
  int length = index == lastElement - 1 ? currentOffset - offset
    : offsets[index + 1] - offset;
  spare.grow(length);
  spare.setLength(length);
  pool.readBytes(offset, spare.bytes(), 0, spare.length());
  return spare.get();
 }
 throw new IndexOutOfBoundsException("index " + index
   + " must be less than the size: " + lastElement);
 
}

/**
 * Returns the <i>n'th</i> element of this {@link BytesRefArray}
 * @param spare a spare {@link BytesRef} instance
 * @param index the elements index to retrieve 
 * @return the <i>n'th</i> element of this {@link BytesRefArray}
 */
public BytesRef get(BytesRefBuilder spare, int index) {
 FutureObjects.checkIndex(index, lastElement);
 int offset = offsets[index];
 int length = index == lastElement - 1 ? currentOffset - offset
   : offsets[index + 1] - offset;
 spare.grow(length);
 spare.setLength(length);
 pool.readBytes(offset, spare.bytes(), 0, spare.length());
 return spare.get();
}