| /* |
| * 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. |
| */ |
| |
| |
| /* Class that Posting and PostingVector use to write byte |
| * streams into shared fixed-size byte[] arrays. The idea |
| * is to allocate slices of increasing lengths For |
| * example, the first slice is 5 bytes, the next slice is |
| * 14, etc. We start by writing our bytes into the first |
| * 5 bytes. When we hit the end of the slice, we allocate |
| * the next slice and then write the address of the new |
| * slice into the last 4 bytes of the previous slice (the |
| * "forwarding address"). |
| * |
| * Each slice is filled with 0's initially, and we mark |
| * the end with a non-zero byte. This way the methods |
| * that are writing into the slice don't need to record |
| * its length and instead allocate a new slice once they |
| * hit a non-zero byte. */ |
| |
| using System; |
| using System.Collections.Generic; |
| using Lucene.Net.Support; |
| |
| namespace Lucene.Net.Index |
| { |
| |
| sealed public class ByteBlockPool |
| { |
| private void InitBlock() |
| { |
| byteUpto = DocumentsWriter.BYTE_BLOCK_SIZE; |
| } |
| |
| public /*internal*/ abstract class Allocator |
| { |
| public /*internal*/ abstract void RecycleByteBlocks(byte[][] blocks, int start, int end); |
| public /*internal*/ abstract void RecycleByteBlocks(IList<byte[]> blocks); |
| public /*internal*/ abstract byte[] GetByteBlock(bool trackAllocations); |
| } |
| |
| public byte[][] buffers = new byte[10][]; |
| |
| internal int bufferUpto = - 1; // Which buffer we are upto |
| public int byteUpto; // Where we are in head buffer |
| |
| public byte[] buffer; // Current head buffer |
| public int byteOffset = - DocumentsWriter.BYTE_BLOCK_SIZE; // Current head offset |
| |
| private readonly bool trackAllocations; |
| private readonly Allocator allocator; |
| |
| public ByteBlockPool(Allocator allocator, bool trackAllocations) |
| { |
| InitBlock(); |
| this.allocator = allocator; |
| this.trackAllocations = trackAllocations; |
| } |
| |
| public void Reset() |
| { |
| if (bufferUpto != - 1) |
| { |
| // We allocated at least one buffer |
| |
| for (int i = 0; i < bufferUpto; i++) |
| // Fully zero fill buffers that we fully used |
| System.Array.Clear(buffers[i], 0, buffers[i].Length); |
| |
| // Partial zero fill the final buffer |
| System.Array.Clear(buffers[bufferUpto], 0, byteUpto); |
| |
| if (bufferUpto > 0) |
| // Recycle all but the first buffer |
| allocator.RecycleByteBlocks(buffers, 1, 1 + bufferUpto); |
| |
| // Re-use the first buffer |
| bufferUpto = 0; |
| byteUpto = 0; |
| byteOffset = 0; |
| buffer = buffers[0]; |
| } |
| } |
| |
| public void NextBuffer() |
| { |
| if (1 + bufferUpto == buffers.Length) |
| { |
| var newBuffers = new byte[(int) (buffers.Length * 1.5)][]; |
| Array.Copy(buffers, 0, newBuffers, 0, buffers.Length); |
| buffers = newBuffers; |
| } |
| buffer = buffers[1 + bufferUpto] = allocator.GetByteBlock(trackAllocations); |
| bufferUpto++; |
| |
| byteUpto = 0; |
| byteOffset += DocumentsWriter.BYTE_BLOCK_SIZE; |
| } |
| |
| public int NewSlice(int size) |
| { |
| if (byteUpto > DocumentsWriter.BYTE_BLOCK_SIZE - size) |
| NextBuffer(); |
| int upto = byteUpto; |
| byteUpto += size; |
| buffer[byteUpto - 1] = 16; |
| return upto; |
| } |
| |
| // Size of each slice. These arrays should be at most 16 |
| // elements (index is encoded with 4 bits). First array |
| // is just a compact way to encode X+1 with a max. Second |
| // array is the length of each slice, ie first slice is 5 |
| // bytes, next slice is 14 bytes, etc. |
| internal static readonly int[] nextLevelArray = new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 9}; |
| internal static readonly int[] levelSizeArray = new int[]{5, 14, 20, 30, 40, 40, 80, 80, 120, 200}; |
| internal static readonly int FIRST_LEVEL_SIZE = levelSizeArray[0]; |
| public readonly static int FIRST_LEVEL_SIZE_For_NUnit_Test = levelSizeArray[0]; |
| |
| public int AllocSlice(byte[] slice, int upto) |
| { |
| |
| int level = slice[upto] & 15; |
| int newLevel = nextLevelArray[level]; |
| int newSize = levelSizeArray[newLevel]; |
| |
| // Maybe allocate another block |
| if (byteUpto > DocumentsWriter.BYTE_BLOCK_SIZE - newSize) |
| NextBuffer(); |
| |
| int newUpto = byteUpto; |
| int offset = newUpto + byteOffset; |
| byteUpto += newSize; |
| |
| // Copy forward the past 3 bytes (which we are about |
| // to overwrite with the forwarding address): |
| buffer[newUpto] = slice[upto - 3]; |
| buffer[newUpto + 1] = slice[upto - 2]; |
| buffer[newUpto + 2] = slice[upto - 1]; |
| |
| // Write forwarding address at end of last slice: |
| slice[upto - 3] = (byte) (Number.URShift(offset, 24)); |
| slice[upto - 2] = (byte) (Number.URShift(offset, 16)); |
| slice[upto - 1] = (byte) (Number.URShift(offset, 8)); |
| slice[upto] = (byte) offset; |
| |
| // Write new level: |
| buffer[byteUpto - 1] = (byte) (16 | newLevel); |
| |
| return newUpto + 3; |
| } |
| |
| public static int FIRST_LEVEL_SIZE_ForNUnit |
| { |
| get { return FIRST_LEVEL_SIZE; } |
| } |
| } |
| } |