/**
 * 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.
 */

namespace Lucene.Net.Index
{
    sealed class CharBlockPool
    {
        public char[][] buffers = new char[10][];

        int bufferUpto = -1;                        // Which buffer we are upto
        public int charUpto = DocumentsWriter.CHAR_BLOCK_SIZE;             // Where we are in head buffer

        public char[] buffer;                              // Current head buffer
        public int charOffset = -DocumentsWriter.CHAR_BLOCK_SIZE;          // Current head offset
        private readonly DocumentsWriter docWriter;

        public CharBlockPool(DocumentsWriter docWriter)
        {
            this.docWriter = docWriter;
        }

        public void reset()
        {
            docWriter.RecycleCharBlocks(buffers, 1 + bufferUpto);
            bufferUpto = -1;
            charUpto = DocumentsWriter.CHAR_BLOCK_SIZE;
            charOffset = -DocumentsWriter.CHAR_BLOCK_SIZE;
        }

        public void nextBuffer()
        {
            if (1 + bufferUpto == buffers.Length)
            {
                char[][] newBuffers = new char[(int)(buffers.Length * 1.5)][];
                System.Array.Copy(buffers, 0, newBuffers, 0, buffers.Length);
                buffers = newBuffers;
            }
            buffer = buffers[1 + bufferUpto] = docWriter.GetCharBlock();
            bufferUpto++;

            charUpto = 0;
            charOffset += DocumentsWriter.CHAR_BLOCK_SIZE;
        }
    }
}