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The core module of Pcap4J.
There is a newer version: 2.0.0-alpha.6
/*_##########################################################################
  _##
  _##  Copyright (C) 2016  Pcap4J.org
  _##
  _##########################################################################
*/

package org.pcap4j.packet;

import java.math.BigInteger;
import java.nio.ByteOrder;

import org.pcap4j.packet.RadiotapPacket.RadiotapData;
import org.pcap4j.util.ByteArrays;

/**
 * Radiotap TSFT field.
 * Value in microseconds of the MAC's 64-bit 802.11 Time Synchronization Function timer
 * when the first bit of the MPDU arrived at the MAC. For received frames only.
 *
 * @see Radiotap
 * @author Kaito Yamada
 * @since pcap4j 1.6.5
 */
public final class RadiotapDataTsft implements RadiotapData {

  /**
   *
   */
  private static final long serialVersionUID = -6492811566937170319L;

  private static final int LENGTH = 8;

  private final BigInteger macTimestamp;

  /**
   * A static factory method.
   * This method validates the arguments by {@link ByteArrays#validateBounds(byte[], int, int)},
   * which may throw exceptions undocumented here.
   *
   * @param rawData rawData
   * @param offset offset
   * @param length length
   * @return a new RadiotapTsft object.
   * @throws IllegalRawDataException if parsing the raw data fails.
   */
  public static RadiotapDataTsft newInstance(
    byte[] rawData, int offset, int length
  ) throws IllegalRawDataException {
    ByteArrays.validateBounds(rawData, offset, length);
    return new RadiotapDataTsft(rawData, offset, length);
  }

  private RadiotapDataTsft(byte[] rawData, int offset, int length) throws IllegalRawDataException {
    if (length < LENGTH) {
      StringBuilder sb = new StringBuilder(200);
      sb.append("The data is too short to build a RadiotapTsft (")
        .append(LENGTH)
        .append(" bytes). data: ")
        .append(ByteArrays.toHexString(rawData, " "))
        .append(", offset: ")
        .append(offset)
        .append(", length: ")
        .append(length);
      throw new IllegalRawDataException(sb.toString());
    }

    this.macTimestamp
      = new BigInteger(
          new byte[] {
            (byte) 0,
            rawData[offset + 7],
            rawData[offset + 6],
            rawData[offset + 5],
            rawData[offset + 4],
            rawData[offset + 3],
            rawData[offset + 2],
            rawData[offset + 1],
            rawData[offset + 0],
          }
        );
  }

  private RadiotapDataTsft(Builder builder) {
    if (
         builder == null
      || builder.macTimestamp == null
    ) {
      StringBuilder sb = new StringBuilder();
      sb.append("builder: ").append(builder)
        .append(" builder.macTimestamp: ").append(builder.macTimestamp);
      throw new NullPointerException(sb.toString());
    }
    if (builder.macTimestamp.signum() == -1) {
      throw new IllegalArgumentException("macTimestamp must be positive.");
    }
    if (builder.macTimestamp.bitLength() > LENGTH * ByteArrays.BYTE_SIZE_IN_BITS) {
      throw new IllegalArgumentException("macTimestamp must be less than 18446744073709551616.");
    }

    this.macTimestamp = builder.macTimestamp;
  }

  /**
   * @return macTimestamp (unit: microseconds)
   */
  public BigInteger getMacTimestamp() { return macTimestamp; }

  @Override
  public int length() {
    return LENGTH;
  }

  @Override
  public byte[] getRawData() {
    return ByteArrays.toByteArray(macTimestamp.longValue(), ByteOrder.LITTLE_ENDIAN);
  }

  /**
   * @return a new Builder object populated with this object's fields.
   */
  public Builder getBuilder() { return new Builder(this); }

  @Override
  public String toString() {
    return toString("");
  }

  @Override
  public String toString(String indent) {
    StringBuilder sb = new StringBuilder();
    String ls = System.getProperty("line.separator");

    sb.append(indent).append("TSFT: ")
      .append(ls)
      .append(indent).append("  MAC timestamp: ")
      .append(macTimestamp)
      .append(" microseconds")
      .append(ls);

    return sb.toString();
  }

  @Override
  public int hashCode() {
    return macTimestamp.hashCode();
  }

  @Override
  public boolean equals(Object obj) {
    if (obj == this) { return true; }
    if (!this.getClass().isInstance(obj)) { return false; }
    RadiotapDataTsft other = (RadiotapDataTsft) obj;
    return macTimestamp.equals(other.macTimestamp);
  }

  /**
   * @author Kaito Yamada
   * @since pcap4j 1.6.5
   */
  public static final class Builder {

    private BigInteger macTimestamp;

    /**
     *
     */
    public Builder() {}

    private Builder(RadiotapDataTsft obj) {
      this.macTimestamp = obj.macTimestamp;
    }

    /**
     * @param macTimestamp macTimestamp
     * @return this Builder object for method chaining.
     */
    public Builder macTimestamp(BigInteger macTimestamp) {
      this.macTimestamp = macTimestamp;
      return this;
    }

    /**
     * @return a new RadiotapTsft object.
     */
    public RadiotapDataTsft build() {
      return new RadiotapDataTsft(this);
    }

  }

}