package org.apache.lucene.index;

import java.util.Arrays;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

final class IntBlockPool {

  public int[][] buffers = new int[10][];

  int bufferUpto = -1;                        // Which buffer we are upto
  public int intUpto = DocumentsWriterPerThread.INT_BLOCK_SIZE;             // Where we are in head buffer

  public int[] buffer;                              // Current head buffer
  public int intOffset = -DocumentsWriterPerThread.INT_BLOCK_SIZE;          // Current head offset

  final private DocumentsWriterPerThread docWriter;

  public IntBlockPool(DocumentsWriterPerThread docWriter) {
    this.docWriter = docWriter;
  }

  public void reset() {
    if (bufferUpto != -1) {
      // Reuse first buffer
      if (bufferUpto > 0) {
        docWriter.recycleIntBlocks(buffers, 1, bufferUpto-1);
        Arrays.fill(buffers, 1, bufferUpto, null);
      }
      bufferUpto = 0;
      intUpto = 0;
      intOffset = 0;
      buffer = buffers[0];
    }
  }

  public void nextBuffer() {
    if (1+bufferUpto == buffers.length) {
      int[][] newBuffers = new int[(int) (buffers.length*1.5)][];
      System.arraycopy(buffers, 0, newBuffers, 0, buffers.length);
      buffers = newBuffers;
    }
    buffer = buffers[1+bufferUpto] = docWriter.getIntBlock();
    bufferUpto++;

    intUpto = 0;
    intOffset += DocumentsWriterPerThread.INT_BLOCK_SIZE;
  }
}