content: /*
   * 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.
   */
  package org.apache.cassandra.io.compress;
  
  import io.netty.util.concurrent.FastThreadLocal;
  import org.apache.cassandra.schema.CompressionParams;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.Collections;
  import java.util.Map;
  import java.util.Set;
  import java.util.zip.DataFormatException;
  import java.util.zip.Deflater;
  import java.util.zip.Inflater;
  
  import com.google.common.collect.ImmutableSet;
  
  public class DeflateCompressor implements ICompressor
  {
      public static final DeflateCompressor instance = new DeflateCompressor();
  
      private static final FastThreadLocal<byte[]> threadLocalScratchBuffer = new FastThreadLocal<byte[]>()
      {
          @Override
          protected byte[] initialValue()
          {
              return new byte[CompressionParams.DEFAULT_CHUNK_LENGTH];
          }
      };
  
      public static byte[] getThreadLocalScratchBuffer()
      {
          return threadLocalScratchBuffer.get();
      }
  
      private final FastThreadLocal<Deflater> deflater;
      private final FastThreadLocal<Inflater> inflater;
      private final Set<Uses> recommendedUses;
  
      public static DeflateCompressor create(Map<String, String> compressionOptions)
      {
          // no specific options supported so far
          return instance;
      }
  
      private DeflateCompressor()
      {
          deflater = new FastThreadLocal<Deflater>()
          {
              @Override
              protected Deflater initialValue()
              {
                  return new Deflater();
              }
          };
          inflater = new FastThreadLocal<Inflater>()
          {
              @Override
              protected Inflater initialValue()
              {
                  return new Inflater();
              }
          };
          recommendedUses = ImmutableSet.of(Uses.GENERAL);
      }
  
      public Set<String> supportedOptions()
      {
          return Collections.emptySet();
      }
  
      public int initialCompressedBufferLength(int sourceLen)
      {
          // Taken from zlib deflateBound(). See http://www.zlib.net/zlib_tech.html.
          return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + (sourceLen >> 25) + 13;
      }
  
      public void compress(ByteBuffer input, ByteBuffer output)
      {
          if (input.hasArray() && output.hasArray())
          {
              int length = compressArray(input.array(), input.arrayOffset() + input.position(), input.remaining(),
                                         output.array(), output.arrayOffset() + output.position(), output.remaining());
              input.position(input.limit());
              output.position(output.position() + length);
          }
          else
              compressBuffer(input, output);
      }
  
      public int compressArray(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset, int maxOutputLength)
      {
          Deflater def = deflater.get();
          def.reset();
          def.setInput(input, inputOffset, inputLength);
          def.finish();
          if (def.needsInput())
              return 0;
  
          int len = def.deflate(output, outputOffset, maxOutputLength);
          assert def.finished();
          return len;
      }
  
      public void compressBuffer(ByteBuffer input, ByteBuffer output)
      {
          Deflater def = deflater.get();
          def.reset();
  
          byte[] buffer = getThreadLocalScratchBuffer();
          // Use half the buffer for input, half for output.
          int chunkLen = buffer.length / 2;
          while (input.remaining() > chunkLen)
          {
              input.get(buffer, 0, chunkLen);
              def.setInput(buffer, 0, chunkLen);
              while (!def.needsInput())
              {
                  int len = def.deflate(buffer, chunkLen, chunkLen);
                  output.put(buffer, chunkLen, len);
              }
          }
          int inputLength = input.remaining();
          input.get(buffer, 0, inputLength);
          def.setInput(buffer, 0, inputLength);
          def.finish();
          while (!def.finished())
          {
              int len = def.deflate(buffer, chunkLen, chunkLen);
              output.put(buffer, chunkLen, len);
          }
      }
  
  
      public void uncompress(ByteBuffer input, ByteBuffer output) throws IOException
      {
          if (input.hasArray() && output.hasArray())
          {
              int length = uncompress(input.array(), input.arrayOffset() + input.position(), input.remaining(),
                                      output.array(), output.arrayOffset() + output.position(), output.remaining());
              input.position(input.limit());
              output.position(output.position() + length);
          }
          else
              uncompressBuffer(input, output);
      }
  
      public void uncompressBuffer(ByteBuffer input, ByteBuffer output) throws IOException
      {
          try
          {
              Inflater inf = inflater.get();
              inf.reset();
  
              byte[] buffer = getThreadLocalScratchBuffer();
              // Use half the buffer for input, half for output.
              int chunkLen = buffer.length / 2;
              while (input.remaining() > chunkLen)
              {
                  input.get(buffer, 0, chunkLen);
                  inf.setInput(buffer, 0, chunkLen);
                  while (!inf.needsInput())
                  {
                      int len = inf.inflate(buffer, chunkLen, chunkLen);
                      output.put(buffer, chunkLen, len);
                  }
              }
              int inputLength = input.remaining();
              input.get(buffer, 0, inputLength);
              inf.setInput(buffer, 0, inputLength);
              while (!inf.needsInput())
              {
                  int len = inf.inflate(buffer, chunkLen, chunkLen);
                  output.put(buffer, chunkLen, len);
              }
          }
          catch (DataFormatException e)
          {
              throw new IOException(e);
          }
      }
  
      public int uncompress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset) throws IOException
      {
          return uncompress(input, inputOffset, inputLength, output, outputOffset, output.length - outputOffset);
      }
  
      public int uncompress(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset, int maxOutputLength) throws IOException
      {
          Inflater inf = inflater.get();
          inf.reset();
          inf.setInput(input, inputOffset, inputLength);
          if (inf.needsInput())
              return 0;
  
          // We assume output is big enough
          try
          {
              return inf.inflate(output, outputOffset, maxOutputLength);
          }
          catch (DataFormatException e)
          {
              throw new IOException(e);
          }
      }
  
      public boolean supports(BufferType bufferType)
      {
          return true;
      }
  
      public BufferType preferredBufferType()
      {
          // Prefer array-backed buffers.
          return BufferType.ON_HEAP;
      }
  
      @Override
      public Set<Uses> recommendedUses()
      {
          return recommendedUses;
      }
  }
  