X-Git-Url: http://plrg.eecs.uci.edu/git/?p=iotcloud.git;a=blobdiff_plain;f=src%2Fjava%2Fiotcloud%2FSlot.java;h=9de69db52d06dd09f786f15a2fc0e9cfce917c52;hp=8d12fc27cfa3d4c2c24397d9b61b0c810f695d4a;hb=57f0a878de30fb3afc7e84fc085ce149eeb6af41;hpb=021c91a082ea8c5f22b368ddca3926d97101279c

diff --git a/src/java/iotcloud/Slot.java b/src/java/iotcloud/Slot.java
index 8d12fc2..9de69db 100644
--- a/src/java/iotcloud/Slot.java
+++ b/src/java/iotcloud/Slot.java
@@ -4,30 +4,65 @@ import java.nio.ByteBuffer;
 import javax.crypto.Mac;
 import java.util.Arrays;
 
-class Slot {
-	public static final int SLOT_SIZE=2048;
-	public static final int HMAC_SIZE=32;
+class Slot implements Liveness {
+	static final int SLOT_SIZE=2048;
+	static final int RESERVED_SPACE=64;
+	static final int HMAC_SIZE=32;
 
-	long seqnum;
-	byte[] prevhmac;
-	byte[] hmac;
-	long machineid;
-	Vector<Entry> entries;
+	private long seqnum;
+	private byte[] prevhmac;
+	private byte[] hmac;
+	private long machineid;
+	private Vector<Entry> entries;
+	private int livecount;
+	private boolean seqnumlive;
+	private int freespace;
 
-	Slot(Vector _entries) {
-		entries=_entries;
-	}
-
-	Slot(long _seqnum, long _machineid, byte[] _prevhmac, byte[] _hmac, Vector<Entry> _entries) {
+	Slot(long _seqnum, long _machineid, byte[] _prevhmac, byte[] _hmac) {
 		seqnum=_seqnum;
 		machineid=_machineid;
 		prevhmac=_prevhmac;
 		hmac=_hmac;
-		entries=_entries;
+		entries=new Vector<Entry>();
+		livecount=1;
+		seqnumlive=true;
+		freespace = SLOT_SIZE - getBaseSize();
 	}
-	
-	Slot(long _seqnum, byte[] _bytes) {
-		seqnum=_seqnum;
+
+	Slot(long _seqnum, long _machineid, byte[] _prevhmac) {
+		this(_seqnum, _machineid, _prevhmac, null);
+	}
+
+	Slot(long _seqnum, long _machineid) {
+		this(_seqnum, _machineid, new byte[HMAC_SIZE], null);
+	}
+
+	byte[] getHMAC() {
+		return hmac;
+	}
+
+	byte[] getPrevHMAC() {
+		return prevhmac;
+	}
+
+	void addEntry(Entry e) {
+		entries.add(e);
+		livecount++;
+		freespace -= e.getSize();
+	}
+
+	boolean hasSpace(Entry e) {
+		int newfreespace = freespace - e.getSize();
+		return newfreespace > RESERVED_SPACE;
+	}
+
+	boolean canFit(Entry e) {
+		int newfreespace = freespace - e.getSize();
+		return newfreespace >= 0;
+	}
+
+	Vector<Entry> getEntries() {
+		return entries;
 	}
 
 	static Slot decode(byte[] array, Mac mac) {
@@ -40,23 +75,24 @@ class Slot {
 		bb.get(hmac);
 		bb.get(prevhmac);
 		if (!Arrays.equals(realmac, hmac))
-			throw new Error("Invalid HMAC!  Potential Attack!");
+			throw new Error("Server Error: Invalid HMAC!  Potential Attack!");
 
 		long seqnum=bb.getLong();
 		long machineid=bb.getLong();
 		int numentries=bb.getInt();
-		Vector<Entry> entries=new Vector();
-		for(int i=0;i<numentries;i++) {
-			entries.add(Entry.decode(bb));
+		Slot slot=new Slot(seqnum, machineid, prevhmac, hmac);
+
+		for(int i=0; i<numentries; i++) {
+			slot.addEntry(Entry.decode(slot, bb));
 		}
-		
-		return new Slot(seqnum, machineid, prevhmac, hmac, entries);
+
+		return slot;
 	}
 
 	byte[] encode(Mac mac) {
 		byte[] array=new byte[SLOT_SIZE];
 		ByteBuffer bb=ByteBuffer.wrap(array);
-		bb.position(HMAC_SIZE); //Leave space for the HMACs
+		bb.position(HMAC_SIZE);																																																																																																																															//Leave space for the HMACs
 		bb.put(prevhmac);
 		bb.putLong(seqnum);
 		bb.putLong(machineid);
@@ -67,20 +103,50 @@ class Slot {
 		//Compute our HMAC
 		mac.update(array, HMAC_SIZE, array.length-HMAC_SIZE);
 		byte[] realmac=mac.doFinal();
+		hmac = realmac;
 		bb.position(0);
 		bb.put(realmac);
 		return array;
 	}
-	
+
+	int getBaseSize() {
+		return 2*HMAC_SIZE+2*Long.BYTES+Integer.BYTES;
+	}
+
+	Vector<Entry> getLiveEntries() {
+		Vector<Entry> liveEntries=new Vector<Entry>();
+		for(Entry entry: entries)
+			if (entry.isLive())
+				liveEntries.add(entry);
+
+		if (seqnumlive)
+			liveEntries.add(new LastMessage(this, machineid, seqnum));
+
+		return liveEntries;
+	}
+
 	long getSequenceNumber() {
 		return seqnum;
 	}
 
-	byte[] getBytes() {
-		return null;
+	long getMachineID() {
+		return machineid;
+	}
+
+	void setDead() {
+		decrementLiveCount();
+		seqnumlive=false;
+	}
+
+	void decrementLiveCount() {
+		livecount--;
+	}
+
+	boolean isLive() {
+		return livecount > 0;
 	}
-	
+
 	public String toString() {
-		return "<"+getSequenceNumber()+", "+new String(getBytes())+">";
+		return "<"+getSequenceNumber()+">";
 	}
 }