#222
diff --git a/src/main/java/net/floodlightcontroller/bgproute/Ptree.java b/src/main/java/net/floodlightcontroller/bgproute/Ptree.java
new file mode 100644
index 0000000..d53789e
--- /dev/null
+++ b/src/main/java/net/floodlightcontroller/bgproute/Ptree.java
@@ -0,0 +1,316 @@
+package net.floodlightcontroller.bgproute;
+
+public class Ptree {
+ int maxKeyBits;
+ int maxKeyOctets;
+ int refCount;
+ PtreeNode top;
+ byte maskBits[] = { (byte)0x00, (byte)0x80, (byte)0xc0, (byte)0xe0, (byte)0xf0, (byte)0xf8, (byte)0xfc, (byte)0xfe, (byte)0xff };
+
+ // Constructor.
+ Ptree(int max_key_bits) {
+ maxKeyBits = max_key_bits;
+ maxKeyOctets = bit_to_octet(max_key_bits);
+ refCount = 0;
+ }
+
+ public PtreeNode acquire(byte [] key) {
+ return acquire(key, maxKeyBits);
+ }
+
+ public PtreeNode acquire(byte [] key, int key_bits) {
+ if (key_bits > maxKeyBits) {
+ return null;
+ }
+
+ PtreeNode node = top;
+ PtreeNode match = null;
+
+ while (node != null
+ && node.keyBits <= key_bits
+ && key_match(node.key, node.keyBits, key, key_bits) == true) {
+ if (node.keyBits == key_bits) {
+ return addReference(node);
+ }
+
+ match = node;
+
+ if (bit_check(key, node.keyBits) == true) {
+ node = node.right;
+ } else {
+ node = node.left;
+ }
+ }
+
+ PtreeNode add = null;
+
+ if (node == null) {
+ add = new PtreeNode(key, key_bits, maxKeyOctets);
+
+ if (match != null) {
+ node_link(match, add);
+ } else {
+ top = add;
+ }
+ } else {
+ add = node_common(node, key, key_bits);
+ if (add == null) {
+ return null;
+ }
+
+ if (match != null) {
+ node_link(match, add);
+ } else {
+ top = add;
+ }
+ node_link(add, node);
+
+ if (add.keyBits != key_bits) {
+ match = add;
+
+ add = new PtreeNode(key, key_bits, maxKeyOctets);
+ node_link(match, add);
+ }
+ }
+
+ return addReference(add);
+ }
+
+ public PtreeNode lookup(byte [] key, int key_bits) {
+ if (key_bits > maxKeyBits) {
+ return null;
+ }
+
+ PtreeNode node = top;
+
+ while (node != null
+ && node.keyBits <= key_bits
+ && key_match(node.key, node.keyBits, key, key_bits) == true) {
+ if (node.keyBits == key_bits) {
+ return addReference(node);
+ }
+
+ if (bit_check(key, node.keyBits) == true) {
+ node = node.right;
+ } else {
+ node = node.left;
+ }
+ }
+ return null;
+ }
+
+ public PtreeNode match(byte [] key, int key_bits) {
+ if (key_bits > maxKeyBits) {
+ return null;
+ }
+ PtreeNode node = top;
+ PtreeNode matched = null;
+
+ if(node!=null)
+
+ while (node != null
+ && node.keyBits <= key_bits
+ && key_match(node.key, node.keyBits, key, key_bits) == true) {
+ matched = node;
+
+ if (bit_check(key, node.keyBits) == true) {
+ node = node.right;
+ } else {
+ node = node.left;
+ }
+ }
+
+ if (matched != null) {
+ return addReference(matched);
+ }
+
+ return null;
+ }
+
+ public PtreeNode begin() {
+ if (top == null) {
+ return null;
+ }
+ return addReference(top);
+ }
+
+ public PtreeNode next(PtreeNode node) {
+ PtreeNode next;
+
+ if (node.left != null) {
+ next = node.left;
+ addReference(next);
+ delReference(node);
+ return next;
+ }
+ if (node.right != null) {
+ next = node.right;
+ addReference(next);
+ delReference(node);
+ return next;
+ }
+
+ PtreeNode start = node;
+ while (node.parent != null) {
+ if (node.parent.left == node && node.parent.right != null) {
+ next = node.parent.right;
+ addReference(next);
+ delReference(start);
+ return next;
+ }
+ node = node.parent;
+ }
+
+ delReference(start);
+
+ return null;
+ }
+
+ static public int bit_to_octet(int key_bits) {
+ return Math.max((key_bits + 7) / 8, 1);
+ }
+
+ private PtreeNode addReference(PtreeNode node) {
+ node.refCount++;
+ return node;
+ }
+
+ public void delReference(PtreeNode node) {
+ if (node.refCount > 0) {
+ node.refCount--;
+ }
+ if (node.refCount == 0) {
+ node_remove(node);
+ }
+ }
+
+ private boolean key_match(byte [] key1, int key1_len, byte [] key2, int key2_len) {
+ int offset;
+ int shift;
+
+ if (key1_len > key2_len) {
+ return false;
+ }
+
+ offset = (Math.min(key1_len, key2_len)) / 8;
+ shift = (Math.min(key1_len, key2_len)) % 8;
+
+ if (shift != 0) {
+ if ((maskBits[shift] & (key1[offset] ^ key2[offset])) != 0) {
+ return false;
+ }
+ }
+
+ while (offset != 0) {
+ offset--;
+ if (key1[offset] != key2[offset]) {
+ return false;
+ }
+ }
+ return true;
+ }
+
+ private boolean bit_check(byte [] key, int key_bits) {
+ int offset = key_bits / 8;
+ int shift = 7 - (key_bits % 8);
+ int bit = key[offset] & 0xff;
+
+ bit >>= shift;
+
+ if ((bit & 1) == 1) {
+ return true;
+ } else {
+ return false;
+ }
+ }
+
+ private void node_link(PtreeNode node, PtreeNode add) {
+ boolean bit = bit_check(add.key, node.keyBits);
+
+ if (bit == true) {
+ node.right = add;
+ } else {
+ node.left = add;
+ }
+ add.parent = node;
+ }
+
+ @SuppressWarnings("unused")
+ private PtreeNode node_common(PtreeNode node, byte [] key, int key_bits) {
+ int i;
+ int limit = Math.min(node.keyBits, key_bits) / 8;
+
+ for (i = 0; i < limit; i++) {
+ if (node.key[i] != key[i]) {
+ break;
+ }
+ }
+
+ int common_len = i * 8;
+ int boundary = 0;
+
+ if (common_len != key_bits) {
+ byte diff = (byte)(node.key[i] ^ key[i]);
+ byte mask = (byte)0x80;
+ int shift_mask = 0;
+
+ while (common_len < key_bits && ((mask & diff) == 0)) {
+ boundary = 1;
+
+ shift_mask = (mask & 0xff);
+ shift_mask >>= 1;
+ mask = (byte)shift_mask;
+
+ common_len++;
+ }
+ }
+
+ PtreeNode add = new PtreeNode(null, common_len, maxKeyOctets);
+ if (add == null)
+ return null;
+
+ int j;
+ for (j = 0; j < i; j++)
+ add.key[j] = node.key[j];
+
+ if (boundary != 0)
+ add.key[j] = (byte)(node.key[j] & maskBits[add.keyBits % 8]);
+
+ return add;
+ }
+
+ private void node_remove(PtreeNode node) {
+ PtreeNode child;
+ PtreeNode parent;
+
+ if (node.left != null && node.right != null) {
+ return;
+ }
+
+ if (node.left != null) {
+ child = node.left;
+ } else {
+ child = node.right;
+ }
+
+ parent = node.parent;
+
+ if (child != null) {
+ child.parent = parent;
+ }
+
+ if (parent != null) {
+ if (parent.left == node) {
+ parent.left = child;
+ } else {
+ parent.right = child;
+ }
+ } else {
+ top = child;
+ }
+
+ if (parent != null && parent.refCount == 0) {
+ node_remove(parent);
+ }
+ }
+}