Add Len() to Ranger (#24)

* Add Len() to Ranger

brute.go

@@ -108,6 +108,11 @@ func (b *bruteRanger) CoveredNetworks(network net.IPNet) ([]RangerEntry, error)
 	return results, nil
 }
 
+// Len returns number of networks in ranger.
+func (b *bruteRanger) Len() int {
+	return len(b.ipV4Entries) + len(b.ipV6Entries)
+}
+
 func (b *bruteRanger) getEntriesByVersion(ip net.IP) (map[string]RangerEntry, error) {
 	if ip.To4() != nil {
 		return b.ipV4Entries, nil

cidranger.go

@@ -72,6 +72,7 @@ type Ranger interface {
 	Contains(ip net.IP) (bool, error)
 	ContainingNetworks(ip net.IP) ([]RangerEntry, error)
 	CoveredNetworks(network net.IPNet) ([]RangerEntry, error)
+	Len() int
 }
 
 // NewPCTrieRanger returns a versionedRanger that supports both IPv4 and IPv6

trie.go

@@ -42,6 +42,8 @@ type prefixTrie struct {
 
 	network rnet.Network
 	entry   RangerEntry
+
+	size int // This is only maintained in the root trie.
 }
 
 // newPrefixTree creates a new prefixTrie.
@@ -79,12 +81,20 @@ func newEntryTrie(network rnet.Network, entry RangerEntry) *prefixTrie {
 // Insert inserts a RangerEntry into prefix trie.
 func (p *prefixTrie) Insert(entry RangerEntry) error {
 	network := entry.Network()
-	return p.insert(rnet.NewNetwork(network), entry)
+	sizeIncreased, err := p.insert(rnet.NewNetwork(network), entry)
+	if sizeIncreased {
+		p.size++
+	}
+	return err
 }
 
 // Remove removes RangerEntry identified by given network from trie.
 func (p *prefixTrie) Remove(network net.IPNet) (RangerEntry, error) {
-	return p.remove(rnet.NewNetwork(network))
+	entry, err := p.remove(rnet.NewNetwork(network))
+	if entry != nil {
+		p.size--
+	}
+	return entry, err
 }
 
 // Contains returns boolean indicating whether given ip is contained in any
@@ -115,6 +125,11 @@ func (p *prefixTrie) CoveredNetworks(network net.IPNet) ([]RangerEntry, error) {
 	return p.coveredNetworks(net)
 }
 
+// Len returns number of networks in ranger.
+func (p *prefixTrie) Len() int {
+	return p.size
+}
+
 // String returns string representation of trie, mainly for visualization and
 // debugging.
 func (p *prefixTrie) String() string {
@@ -203,22 +218,23 @@ func (p *prefixTrie) coveredNetworks(network rnet.Network) ([]RangerEntry, error
 	return results, nil
 }
 
-func (p *prefixTrie) insert(network rnet.Network, entry RangerEntry) error {
+func (p *prefixTrie) insert(network rnet.Network, entry RangerEntry) (bool, error) {
 	if p.network.Equal(network) {
+		sizeIncreased := p.entry == nil
 		p.entry = entry
-		return nil
+		return sizeIncreased, nil
 	}
 
 	bit, err := p.targetBitFromIP(network.Number)
 	if err != nil {
-		return err
+		return false, err
 	}
 	existingChild := p.children[bit]
 
 	// No existing child, insert new leaf trie.
 	if existingChild == nil {
 		p.appendTrie(bit, newEntryTrie(network, entry))
-		return nil
+		return true, nil
 	}
 
 	// Check whether it is necessary to insert additional path prefix between current trie and existing child,
@@ -229,7 +245,7 @@ func (p *prefixTrie) insert(network rnet.Network, entry RangerEntry) error {
 		pathPrefix := newPathprefixTrie(network, p.totalNumberOfBits()-lcb)
 		err := p.insertPrefix(bit, pathPrefix, existingChild)
 		if err != nil {
-			return err
+			return false, err
 		}
 		// Update new child
 		existingChild = pathPrefix

trie_test.go

@@ -71,6 +71,9 @@ func TestPrefixTrieInsert(t *testing.T) {
 				err := trie.Insert(NewBasicRangerEntry(*network))
 				assert.NoError(t, err)
 			}
+
+			assert.Equal(t, len(tc.expectedNetworksInDepthOrder), trie.Len(), "trie size should match")
+
 			walk := trie.walkDepth()
 			for _, network := range tc.expectedNetworksInDepthOrder {
 				_, ipnet, _ := net.ParseCIDR(network)
@@ -198,6 +201,9 @@ func TestPrefixTrieRemove(t *testing.T) {
 					assert.Nil(t, removed)
 				}
 			}
+
+			assert.Equal(t, len(tc.expectedNetworksInDepthOrder), trie.Len(), "trie size should match after revmoval")
+
 			walk := trie.walkDepth()
 			for _, network := range tc.expectedNetworksInDepthOrder {
 				_, ipnet, _ := net.ParseCIDR(network)
@@ -476,11 +482,15 @@ func TestTrieMemUsage(t *testing.T) {
 
 	var baseLineHeap, totalHeapAllocOverRuns uint64
 	for i := 0; i < runs; i++ {
+		t.Logf("Executing Run %d of %d", i+1, runs)
 
 		// Insert networks.
 		for n := 0; n < numIPs; n++ {
 			trie.Insert(NewBasicRangerEntry(GenLeafIPNet(GenIPV4())))
 		}
+		t.Logf("Inserted All (%d networks)", trie.Len())
+		assert.Less(t, 0, trie.Len(), "Len should > 0")
+		assert.LessOrEqualf(t, trie.Len(), numIPs, "Len should <= %d", numIPs)
 
 		// Remove networks.
 		_, all, _ := net.ParseCIDR("0.0.0.0/0")
@@ -488,6 +498,8 @@ func TestTrieMemUsage(t *testing.T) {
 		for i := 0; i < len(ll); i++ {
 			trie.Remove(ll[i].Network())
 		}
+		t.Logf("Removed All (%d networks)", len(ll))
+		assert.Equal(t, 0, trie.Len(), "Len after removal should == 0")
 
 		// Perform GC
 		runtime.GC()
@@ -495,7 +507,7 @@ func TestTrieMemUsage(t *testing.T) {
 		// Get HeapAlloc stats.
 		heapAlloc := GetHeapAllocation()
 		totalHeapAllocOverRuns += heapAlloc
-		if i ==0 {
+		if i == 0 {
 			baseLineHeap = heapAlloc
 		}
 	}

version.go

@@ -61,6 +61,11 @@ func (v *versionedRanger) CoveredNetworks(network net.IPNet) ([]RangerEntry, err
 	return ranger.CoveredNetworks(network)
 }
 
+// Len returns number of networks in ranger.
+func (v *versionedRanger) Len() int {
+	return v.ipV4Ranger.Len() + v.ipV6Ranger.Len()
+}
+
 func (v *versionedRanger) getRangerForIP(ip net.IP) (Ranger, error) {
 	if ip.To4() != nil {
 		return v.ipV4Ranger, nil