Class ZstdCodec

java/core/src/java/org/apache/orc/impl/ZstdCodec.java:29–280

import java.nio.ByteBuffer;

public class ZstdCodec implements CompressionCodec, DirectDecompressionCodec {
  private ZstdOptions zstdOptions = null;
  private ZstdCompressCtx zstdCompressCtx = null;

  public ZstdCodec(int level, int windowLog, int strategy) {
    this.zstdOptions = new ZstdOptions(level, windowLog, strategy);
  }

  public ZstdCodec() {
    this(3, 0, 0);
  }

  public ZstdOptions getZstdOptions() {
    return zstdOptions;
  }

  // Thread local buffer
  private static final ThreadLocal<byte[]> threadBuffer =
          ThreadLocal.withInitial(() -> null);

  protected static byte[] getBuffer(int size) {
    byte[] result = threadBuffer.get();
    if (result == null || result.length < size || result.length > size * 2) {
      result = new byte[size];
      threadBuffer.set(result);
    }
    return result;
  }

  static class ZstdOptions implements Options {
    private int level;
    private int windowLog;
    private int strategy;

    ZstdOptions(int level, int windowLog, int strategy) {
      this.level = level;
      this.windowLog = windowLog;
      this.strategy = strategy;
    }

    @Override
    public ZstdOptions copy() {
      return new ZstdOptions(level, windowLog, strategy);
    }

    @Override
    public Options setSpeed(SpeedModifier newValue) {
      return this;
    }

    /**
     * Sets the Zstandard long mode maximum back-reference distance, expressed
     * as a power of 2.
     * <p>
     * The value must be between ZSTD_WINDOWLOG_MIN (10) and ZSTD_WINDOWLOG_MAX
     * (30 and 31 on 32/64-bit architectures, respectively).
     * <p>
     * A value of 0 is a special value indicating to use the default