- Add kad lib, from i2p.zzz.kademlia branch (without the history),

  which is a rewrite of the netdb kad
- Drop now-unused SHA1Comparator
- Efficiency tweak to NodeInfoComparator

apps/i2psnark/java/src/net/i2p/kademlia/KBucket.java

+package net.i2p.kademlia;
+/*
+ * free (adj.): unencumbered; not under the control of others
+ * Written by jrandom in 2003 and released into the public domain 
+ * with no warranty of any kind, either expressed or implied.  
+ * It probably won't make your computer catch on fire, or eat 
+ * your children, but it might.  Use at your own risk.
+ *
+ */
+
+import java.util.Set;
+
+import net.i2p.data.SimpleDataStructure;
+
+/**
+ * Group, without inherent ordering, a set of keys a certain distance away from
+ * a local key, using XOR as the distance metric
+ *
+ * Refactored from net.i2p.router.networkdb.kademlia
+ */
+public interface KBucket<T extends SimpleDataStructure> {
+
+    /** 
+     * Lowest order high bit for difference keys.
+     * The lower-bounds distance of this bucket is 2**begin.
+     * If begin == 0, this is the closest bucket.
+     */
+    public int getRangeBegin();
+
+    /**
+     * Highest high bit for the difference keys.
+     * The upper-bounds distance of this bucket is (2**(end+1)) - 1.
+     * If begin == end, the bucket cannot be split further.
+     * If end == (numbits - 1), this is the furthest bucket.
+     */
+    public int getRangeEnd();
+
+    /**
+     * Number of keys already contained in this kbucket
+     */
+    public int getKeyCount();
+
+    /**
+     * Add the peer to the bucket
+     *
+     * @return true if added
+     */
+    public boolean add(T key);
+
+    /**
+     * Remove the key from the bucket
+     * @return true if the key existed in the bucket before removing it, else false
+     */
+    public boolean remove(T key);
+    
+    /**
+     *  Update the last-changed timestamp to now.
+     */
+    public void setLastChanged();
+
+    /**
+     *  The last-changed timestamp
+     */
+    public long getLastChanged();
+
+    /**
+     * Retrieve all routing table entries stored in the bucket
+     * @return set of Hash structures
+     */
+    public Set<T> getEntries();
+
+    public void getEntries(SelectionCollector<T> collector);
+
+    public void clear();
+}

apps/i2psnark/java/src/net/i2p/kademlia/KBucketImpl.java

+package net.i2p.kademlia;
+/*
+ * free (adj.): unencumbered; not under the control of others
+ * Written by jrandom in 2003 and released into the public domain
+ * with no warranty of any kind, either expressed or implied.
+ * It probably won't make your computer catch on fire, or eat
+ * your children, but it might.  Use at your own risk.
+ *
+ */
+
+import java.util.Collections;
+import java.util.Set;
+
+import net.i2p.I2PAppContext;
+import net.i2p.data.SimpleDataStructure;
+import net.i2p.util.ConcurrentHashSet;
+
+/**
+ *  A concurrent implementation using ConcurrentHashSet.
+ *  The max size (K) may be temporarily exceeded due to concurrency,
+ *  a pending split, or the behavior of the supplied trimmer,
+ *  as explained below.
+ *  The creator is responsible for splits.
+ *
+ *  This class has no knowledge of the DHT base used for XORing,
+ *  and thus there are no validity checks in add/remove.
+ *
+ *  The begin and end values are immutable.
+ *  All entries in this bucket will have at least one bit different
+ *  from us in the range [begin, end] inclusive.
+ *  Splits must be implemented by creating two new buckets
+ *  and discarding this one.
+ *
+ *  The keys are kept in a Set and are NOT sorted by last-seen.
+ *  Per-key last-seen-time, failures, etc. must be tracked elsewhere.
+ *
+ *  If this bucket is full (i.e. begin == end && size == max)
+ *  then add() will call KBucketTrimmer.trim() do
+ *  (possibly) remove older entries, and indicate whether
+ *  to add the new entry. If the trimmer returns true without
+ *  removing entries, this KBucket will exceed the max size.
+ *
+ *  Refactored from net.i2p.router.networkdb.kademlia
+ */
+class KBucketImpl<T extends SimpleDataStructure> implements KBucket<T> {
+    /**
+     *  set of Hash objects for the peers in the kbucket
+     */
+    private final Set<T> _entries;
+    /** include if any bits equal or higher to this bit (in big endian order) */
+    private final int _begin;
+    /** include if no bits higher than this bit (inclusive) are set */
+    private final int _end;
+    private final int _max;
+    private final KBucketSet.KBucketTrimmer _trimmer;
+    /** when did we last shake things up */
+    private long _lastChanged;
+    private final I2PAppContext _context;
+    
+    /**
+     *  All entries in this bucket will have at least one bit different
+     *  from us in the range [begin, end] inclusive.
+     */
+    public KBucketImpl(I2PAppContext context, int begin, int end, int max, KBucketSet.KBucketTrimmer trimmer) {
+        if (begin > end)
+            throw new IllegalArgumentException(begin + " > " + end);
+        _context = context;
+        _entries = new ConcurrentHashSet(max + 4);
+        _begin = begin;
+        _end = end;
+        _max = max;
+        _trimmer = trimmer;
+    }
+    
+    public int getRangeBegin() { return _begin; }
+
+    public int getRangeEnd() { return _end; }
+
+    public int getKeyCount() {
+        return _entries.size();
+    }
+    
+    /**
+     *  @return an unmodifiable view; not a copy
+     */
+    public Set<T> getEntries() {
+        return Collections.unmodifiableSet(_entries);
+    }
+
+    public void getEntries(SelectionCollector<T> collector) {
+        for (T h : _entries) {
+             collector.add(h);
+        }
+    }
+    
+    public void clear() {
+        _entries.clear();
+    }
+    
+    /**
+     *  Sets last-changed if rv is true OR if the peer is already present.
+     *  Calls the trimmer if begin == end and we are full.
+     *  If begin != end then add it and caller must do bucket splitting.
+     *  @return true if added
+     */
+    public boolean add(T peer) {
+        if (_begin != _end || _entries.size() < _max ||
+            _entries.contains(peer) || _trimmer.trim(this, peer)) {
+            // do this even if already contains, to call setLastChanged()
+            boolean rv = _entries.add(peer);
+            setLastChanged();
+            return rv;
+        }
+        return false;
+    }
+    
+    /**
+     *  @return if removed. Does NOT set lastChanged.
+     */
+    public boolean remove(T peer) {
+        boolean rv = _entries.remove(peer);
+        //if (rv)
+        //    setLastChanged();
+        return rv;
+    }
+    
+    /**
+     *  Update the last-changed timestamp to now.
+     */
+    public void setLastChanged() {
+        _lastChanged = _context.clock().now();
+    }
+
+    /**
+     *  The last-changed timestamp, which actually indicates last-added or last-seen.
+     */
+    public long getLastChanged() {
+        return _lastChanged;
+    }
+    
+    @Override
+    public String toString() {
+        StringBuilder buf = new StringBuilder(1024);
+        buf.append(_entries.size());
+        buf.append(" entries in (").append(_begin).append(',').append(_end);
+        buf.append(") : ").append(_entries.toString());
+        return buf.toString();
+    }
+}

apps/i2psnark/java/src/net/i2p/kademlia/SelectionCollector.java

+package net.i2p.kademlia;
+
+import net.i2p.data.SimpleDataStructure;
+
+/**
+ * Visit kbuckets, gathering matches
+ */
+public interface SelectionCollector<T extends SimpleDataStructure> {
+    public void add(T entry);
+}

apps/i2psnark/java/src/org/klomp/snark/dht/SHA1Comparator.java → apps/i2psnark/java/src/net/i2p/kademlia/XORComparator.java

-package org.klomp.snark.dht;
-/*
- *  From zzzot, modded and relicensed to GPLv2
- */
+package net.i2p.kademlia;
 
 import java.util.Comparator;
 
-import net.i2p.crypto.SHA1Hash;
 import net.i2p.data.DataHelper;
+import net.i2p.data.SimpleDataStructure;
 
 /**
- *  Closest to a InfoHash or NID key.
- *  Use for InfoHashes and NIDs.
+ * Help sort Hashes in relation to a base key using the XOR metric
  *
- * @since 0.8.4
- * @author zzz
  */
-class SHA1Comparator implements Comparator<SHA1Hash> {
+class XORComparator<T extends SimpleDataStructure> implements Comparator<T> {
     private final byte[] _base;
 
-    public SHA1Comparator(SHA1Hash h) {
-        _base = h.getData();
+    /**
+     * @param target key to compare distances with
+     */
+    public XORComparator(T target) {
+        _base = target.getData();
     }
 
-    public int compare(SHA1Hash lhs, SHA1Hash rhs) {
+    public int compare(T lhs, T rhs) {
         byte lhsDelta[] = DataHelper.xor(lhs.getData(), _base);
         byte rhsDelta[] = DataHelper.xor(rhs.getData(), _base);
         return DataHelper.compareTo(lhsDelta, rhsDelta);
     }
-
 }

apps/i2psnark/java/src/org/klomp/snark/dht/NodeInfoComparator.java

@@ -16,15 +16,15 @@ import net.i2p.data.DataHelper;
  * @author zzz
  */
 class NodeInfoComparator implements Comparator<NodeInfo> {
-    private final SHA1Hash _base;
+    private final byte[] _base;
 
     public NodeInfoComparator(SHA1Hash h) {
-        _base = h;
+        _base = h.getData();
     }
 
     public int compare(NodeInfo lhs, NodeInfo rhs) {
-        byte lhsDelta[] = DataHelper.xor(lhs.getNID().getData(), _base.getData());
-        byte rhsDelta[] = DataHelper.xor(rhs.getNID().getData(), _base.getData());
+        byte lhsDelta[] = DataHelper.xor(lhs.getNID().getData(), _base);
+        byte rhsDelta[] = DataHelper.xor(rhs.getNID().getData(), _base);
         return DataHelper.compareTo(lhsDelta, rhsDelta);
     }