LogUtils.java

package com.sleepycat.je.log;
import java.nio.ByteBuffer;
import java.sql.Timestamp;
import javax.transaction.xa.Xid;
import de.ovgu.cide.jakutil.*;
/** 
 * This class holds convenience methods for marshalling internal JE data to and
 * from the log.
 */
public class LogUtils {
  public static final int SHORT_BYTES=2;
  public static final int INT_BYTES=4;
  public static final int LONG_BYTES=8;
  public static final int UNSIGNED_INT_BYTES=4;
  private static final boolean DEBUG=false;
  public static final byte[] ZERO_LENGTH_BYTE_ARRAY=new byte[0];
  /** 
 * Marshall a long into the next 4 bytes in this buffer. Necessary when the
 * long is used to hold an unsigned int.
 */
  public static void writeUnsignedInt(  ByteBuffer buf,  long value){
    buf.put((byte)(value >>> 0));
    buf.put((byte)(value >>> 8));
    buf.put((byte)(value >>> 16));
    buf.put((byte)(value >>> 24));
  }
  /** 
 * Unmarshall the next four bytes which hold an unsigned int into a long.
 */
  public static long getUnsignedInt(  ByteBuffer buf){
    long ret=(buf.get() & 0xFFL) << 0;
    ret+=(buf.get() & 0xFFL) << 8;
    ret+=(buf.get() & 0xFFL) << 16;
    ret+=(buf.get() & 0xFFL) << 24;
    return ret;
  }
  /** 
 * Write a short into the log.
 */
  public static void writeShort(  ByteBuffer logBuf,  short i){
    byte b=(byte)((i >> 0) & 0xff);
    logBuf.put(b);
    b=(byte)((i >> 8) & 0xff);
    logBuf.put(b);
  }
  /** 
 * Read a short from the log.
 */
  public static short readShort(  ByteBuffer logBuf){
    return (short)(((logBuf.get() & 0xFF) << 0) + ((logBuf.get() & 0xFF) << 8));
  }
  /** 
 * Write an int into the log.
 */
  public static void writeInt(  ByteBuffer logBuf,  int i){
    byte b=(byte)((i >> 0) & 0xff);
    logBuf.put(b);
    b=(byte)((i >> 8) & 0xff);
    logBuf.put(b);
    b=(byte)((i >> 16) & 0xff);
    logBuf.put(b);
    b=(byte)((i >> 24) & 0xff);
    logBuf.put(b);
  }
  /** 
 * Read a int from the log.
 */
  public static int readInt(  ByteBuffer logBuf){
    int ret=(logBuf.get() & 0xFF) << 0;
    ret+=(logBuf.get() & 0xFF) << 8;
    ret+=(logBuf.get() & 0xFF) << 16;
    ret+=(logBuf.get() & 0xFF) << 24;
    return ret;
  }
  /** 
 * @return log storage size for a byteArray.
 */
  public static int getIntLogSize(){
    return INT_BYTES;
  }
  /** 
 * Write an int into the log in MSB order.  Used for ordered keys.
 */
  public static void writeIntMSB(  ByteBuffer logBuf,  int i){
    byte b=(byte)((i >> 24) & 0xff);
    logBuf.put(b);
    b=(byte)((i >> 16) & 0xff);
    logBuf.put(b);
    b=(byte)((i >> 8) & 0xff);
    logBuf.put(b);
    b=(byte)((i >> 0) & 0xff);
    logBuf.put(b);
  }
  /** 
 * Read a int from the log in MSB order.  Used for ordered keys.
 */
  public static int readIntMSB(  ByteBuffer logBuf){
    int ret=(logBuf.get() & 0xFF) << 24;
    ret+=(logBuf.get() & 0xFF) << 16;
    ret+=(logBuf.get() & 0xFF) << 8;
    ret+=(logBuf.get() & 0xFF) << 0;
    return ret;
  }
  /** 
 * Write a long into the log.
 */
  public static void writeLong(  ByteBuffer logBuf,  long l){
    byte b=(byte)(l >>> 0);
    logBuf.put(b);
    b=(byte)(l >>> 8);
    logBuf.put(b);
    b=(byte)(l >>> 16);
    logBuf.put(b);
    b=(byte)(l >>> 24);
    logBuf.put(b);
    b=(byte)(l >>> 32);
    logBuf.put(b);
    b=(byte)(l >>> 40);
    logBuf.put(b);
    b=(byte)(l >>> 48);
    logBuf.put(b);
    b=(byte)(l >>> 56);
    logBuf.put(b);
  }
  /** 
 * Read a long from the log.
 */
  public static long readLong(  ByteBuffer logBuf){
    long ret=(logBuf.get() & 0xFFL) << 0;
    ret+=(logBuf.get() & 0xFFL) << 8;
    ret+=(logBuf.get() & 0xFFL) << 16;
    ret+=(logBuf.get() & 0xFFL) << 24;
    ret+=(logBuf.get() & 0xFFL) << 32;
    ret+=(logBuf.get() & 0xFFL) << 40;
    ret+=(logBuf.get() & 0xFFL) << 48;
    ret+=(logBuf.get() & 0xFFL) << 56;
    return ret;
  }
  /** 
 * @return log storage size for a byteArray.
 */
  public static int getLongLogSize(){
    return LONG_BYTES;
  }
  /** 
 * Write a byte array into the log. The size is stored first as an integer.
 */
  public static void writeByteArray(  ByteBuffer logBuf,  byte[] b){
    writeInt(logBuf,b.length);
    logBuf.put(b);
  }
  /** 
 * Read a byte array from the log. The size is stored first as an integer.
 */
  public static byte[] readByteArray(  ByteBuffer logBuf){
    int size=readInt(logBuf);
    if (DEBUG) {
      System.out.println("pos = " + logBuf.position() + " byteArray is "+ size+ " on read");
    }
    if (size == 0) {
      return ZERO_LENGTH_BYTE_ARRAY;
    }
    byte[] b=new byte[size];
    logBuf.get(b);
    return b;
  }
  /** 
 * @return log storage size for a byteArray
 */
  public static int getByteArrayLogSize(  byte[] b){
    return INT_BYTES + b.length;
  }
  /** 
 * Write a string into the log. The size is stored first as an integer.
 */
  public static void writeString(  ByteBuffer logBuf,  String stringVal){
    writeByteArray(logBuf,stringVal.getBytes());
  }
  /** 
 * Read a string from the log. The size is stored first as an integer.
 */
  public static String readString(  ByteBuffer logBuf){
    return new String(readByteArray(logBuf));
  }
  /** 
 * @return log storage size for a string
 */
  public static int getStringLogSize(  String s){
    return INT_BYTES + s.length();
  }
  /** 
 * Write a timestamp into the log.
 */
  public static void writeTimestamp(  ByteBuffer logBuf,  Timestamp time){
    writeLong(logBuf,time.getTime());
  }
  /** 
 * Read a timestamp from the log.
 */
  public static Timestamp readTimestamp(  ByteBuffer logBuf){
    long millis=readLong(logBuf);
    return new Timestamp(millis);
  }
  /** 
 * @return log storage size for a timestamp
 */
  public static int getTimestampLogSize(){
    return LONG_BYTES;
  }
  /** 
 * Write a boolean into the log.
 */
  public static void writeBoolean(  ByteBuffer logBuf,  boolean bool){
    byte val=bool ? (byte)1 : (byte)0;
    logBuf.put(val);
  }
  /** 
 * Read a boolean from the log.
 */
  public static boolean readBoolean(  ByteBuffer logBuf){
    byte val=logBuf.get();
    return (val == (byte)1) ? true : false;
  }
  /** 
 * @return log storage size for a boolean.
 */
  public static int getBooleanLogSize(){
    return 1;
  }
  public static boolean dumpBoolean(  ByteBuffer itemBuffer,  StringBuffer sb,  String tag){
    sb.append("<");
    sb.append(tag);
    sb.append(" exists = \"");
    boolean exists=readBoolean(itemBuffer);
    sb.append(exists);
    if (exists) {
      sb.append("\">");
    }
 else {
      sb.append("\"/>");
    }
    return exists;
  }
  /** 
 * The byte[]'s in Xid's are known to be 255 or less in length.  So instead
 * of using read/writeByteArray(), we can save 6 bytes per record by making
 * the byte[] length be 1 byte instead of 4.
 */
  public static int getXidSize(  Xid xid){
    byte[] gid=xid.getGlobalTransactionId();
    byte[] bqual=xid.getBranchQualifier();
    return INT_BYTES + 1 + 1+ (gid == null ? 0 : gid.length)+ (bqual == null ? 0 : bqual.length);
  }
  public static void writeXid(  ByteBuffer logBuf,  Xid xid){
    byte[] gid=xid.getGlobalTransactionId();
    byte[] bqual=xid.getBranchQualifier();
    writeInt(logBuf,xid.getFormatId());
    if (gid == null) {
      logBuf.put((byte)-1);
    }
 else {
      logBuf.put((byte)(gid.length));
      logBuf.put(gid);
    }
    if (bqual == null) {
      logBuf.put((byte)-1);
    }
 else {
      logBuf.put((byte)(bqual.length));
      logBuf.put(bqual);
    }
  }
  public static Xid readXid(  ByteBuffer logBuf){
    int formatId=readInt(logBuf);
    int gidLen=logBuf.get();
    byte[] gid=null;
    if (gidLen >= 0) {
      gid=new byte[gidLen];
      logBuf.get(gid);
    }
    int bqualLen=logBuf.get();
    byte[] bqual=null;
    if (bqualLen >= 0) {
      bqual=new byte[bqualLen];
      logBuf.get(bqual);
    }
    return new XidImpl(formatId,gid,bqual);
  }
public static class XidImpl implements Xid {
    private int formatId;
    private byte[] gid;
    private byte[] bqual;
    public XidImpl(    int formatId,    byte[] gid,    byte[] bqual){
      this.formatId=formatId;
      this.gid=gid;
      this.bqual=bqual;
    }
    public int getFormatId(){
      return formatId;
    }
    public byte[] getGlobalTransactionId(){
      return gid;
    }
    public byte[] getBranchQualifier(){
      return bqual;
    }
    public boolean equals(    Object o){
      if (!(o instanceof XidImpl)) {
        return false;
      }
      XidImpl xid=(XidImpl)o;
      if (xid.getFormatId() != formatId) {
        return false;
      }
      if (compareByteArrays(xid.getGlobalTransactionId(),gid) && compareByteArrays(xid.getBranchQualifier(),bqual)) {
        return true;
      }
      return false;
    }
    public int hashCode(){
      int code=formatId;
      if (gid != null) {
        for (int i=0; i < gid.length; i++) {
          code+=gid[i];
        }
      }
      if (bqual != null) {
        for (int i=0; i < bqual.length; i++) {
          code+=bqual[i];
        }
      }
      return code;
    }
    private boolean compareByteArrays(    byte[] b1,    byte[] b2){
      if (b1 == null || b2 == null) {
        return b1 == b2;
      }
      if (b1.length != b2.length) {
        return false;
      }
      for (int i=0; i < b1.length; i++) {
        if (b1[i] != b2[i]) {
          return false;
        }
      }
      return true;
    }
    public String toString(){
      StringBuffer sb=new StringBuffer();
      sb.append("<Xid formatId=\"").append(formatId);
      sb.append("\" gTxnId=\"");
      if (gid == null) {
        sb.append("null");
      }
 else {
        sb.append(new String(gid));
      }
      sb.append("\" bqual=\"");
      if (bqual == null) {
        sb.append("null");
      }
 else {
        sb.append(new String(bqual));
      }
      sb.append("\"/>");
      return sb.toString();
    }
  }
}