ChillDataHeader.java

package edu.colostate.vchill.chill;

import edu.colostate.vchill.ChillDefines;
import edu.colostate.vchill.ScaleManager;
import edu.colostate.vchill.socket.SocketUtil;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.ArrayList;

/**
 * Data header
 *
 * @author Jochen Deyke
 * @author jpont
 * @version 2009-06-01
 */
public class ChillDataHeader extends ChillHeader {
    private static final ScaleManager sm = ScaleManager.getInstance();

    /**
     * size (in bytes) of this header (including ChillHeaderHeader, but not including extraData)
     */
    public static final int BYTE_SIZE = ChillHeaderHeader.BYTE_SIZE +
            2 * ChillDefines.LONG_BYTE_SIZE + 9 * ChillDefines.INT_BYTE_SIZE;

    /**
     * Bit map of data types requested by client (ppi).
     * See moment.h  e.g. ZDR_MOM for definitions
     */
    public long requestedData;

    /**
     * bit map as above for what fields are available from processor
     */
    public long availableData;

    /**
     * Ant position at start of integration cycle.
     * All angles scaled as indicated by angleScale in ChillHSKHeader.java
     */
    public int startAz, startEl;

    /**
     * Ant position at end of integration cycle.
     * All angles scaled as indicated by angleScale in ChillHSKHeader.java
     */
    public int endAz, endEl;

    /**
     * number of gates in this ray
     */
    public int numGates;

    /**
     * the range to the first data gate in millimeters
     */
    public int startRange;

    /**
     * unix time word for (first txmit pulse in) this ray (seconds)
     */
    public long dataTime;

    /**
     * aditional nanoseconds to first txmit pulse
     */
    public int fractionalSecs;

    /**
     * ray number within this volume, starts at 1
     */
    public int rayNumber;

    public ChillDataHeader() {
        super(new ChillHeaderHeader(ChillDefines.GEN_MOM_DATA, BYTE_SIZE));
        super.extraData = new byte[0];
    }

    public ChillDataHeader(final ChillDataHeader other) {
        super(new ChillHeaderHeader(other.header));
        assert header.recordType == ChillDefines.GEN_MOM_DATA;
        assert header.headerLength - ChillDataHeader.BYTE_SIZE >= 0;
        this.requestedData = other.requestedData;
        this.availableData = other.availableData;
        this.startAz = other.startAz;
        this.startEl = other.startEl;
        this.endAz = other.endAz;
        this.endEl = other.endEl;
        this.numGates = other.numGates;
        this.startRange = other.startRange;
        this.dataTime = other.dataTime;
        this.fractionalSecs = other.fractionalSecs;
        this.rayNumber = other.rayNumber;
        this.extraData = new byte[other.extraData.length];
        for (int i = 0; i < this.extraData.length; ++i)
            this.extraData[i] = other.extraData[i];
    }

    /**
     * Constructs a header by reading initial values from a DataInput.
     *
     * @param in the DataInput to read initialization values from
     */
    public ChillDataHeader(final DataInput in, final ChillHeaderHeader header) throws IOException {
        super(header);
        assert header.recordType == ChillDefines.GEN_MOM_DATA;
        assert header.headerLength - ChillDataHeader.BYTE_SIZE >= 0;
        this.requestedData = in.readLong();
        this.availableData = in.readLong();
        this.startAz = in.readInt();
        this.startEl = in.readInt();
        this.endAz = in.readInt();
        this.endEl = in.readInt();
        this.numGates = in.readInt();
        this.startRange = in.readInt();
        this.dataTime = SocketUtil.readUnsignedInt(in);
        this.fractionalSecs = in.readInt();
        this.rayNumber = in.readInt();
        in.readFully(super.extraData = new byte[header.headerLength - ChillDataHeader.BYTE_SIZE]);
    }

    /**
     * Writes this header to a DataOut
     *
     * @param out the DataOutput to write values to
     */
    public void write(final DataOutput out) throws IOException {
        assert header.recordType == ChillDefines.GEN_MOM_DATA;
        assert header.headerLength == ChillDataHeader.BYTE_SIZE + extraData.length;
        super.header.write(out);
        out.writeLong(this.requestedData);
        out.writeLong(this.availableData);
        out.writeInt(this.startAz);
        out.writeInt(this.startEl);
        out.writeInt(this.endAz);
        out.writeInt(this.endEl);
        out.writeInt(this.numGates);
        out.writeInt(this.startRange);
        SocketUtil.writeUnsignedInt(this.dataTime, out);
        out.writeInt(this.fractionalSecs);
        out.writeInt(this.rayNumber);
        out.write(this.extraData);
    }

    public ArrayList<String> calculateTypes() {
        long available = this.requestedData & this.availableData;
        int numAvailableFields = Long.bitCount(available);
        ArrayList<String> types = new ArrayList<String>(numAvailableFields);
        for (int i = 0; i < numAvailableFields; i++) {
            /* Get the bit position of the first available field. */
            int fieldNumber = Long.numberOfTrailingZeros(available);
			/* Add the field to the list if the field header exists. */
            ChillMomentFieldScale scale = sm.getScale(fieldNumber);
            if (scale != null) {
                types.add(scale.fieldName);
            } else {
				/*
				 * Just because we don't know about the field, VCHILL
				 * still needs to know how many fields to read in so
				 * add null to increase the size.
				 */
                types.add(null);
            }
			/* Remove this field bit from the mask. */
            available ^= (1l << fieldNumber);
        }

        return types;
    }
}