Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 1 | package net.onrc.onos.ofcontroller.bgproute; |
| 2 | |
| 3 | import java.util.Iterator; |
| 4 | import java.util.NoSuchElementException; |
| 5 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 6 | public class PatriciaTrie<V> implements IPatriciaTrie<V> { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 7 | private final byte maskBits[] = {(byte)0x00, (byte)0x80, (byte)0xc0, (byte)0xe0, (byte)0xf0, |
| 8 | (byte)0xf8, (byte)0xfc, (byte)0xfe, (byte)0xff}; |
| 9 | |
| 10 | private int maxPrefixLength; |
| 11 | |
| 12 | private Node top; |
| 13 | |
| 14 | public PatriciaTrie(int maxPrefixLength) { |
| 15 | this.maxPrefixLength = maxPrefixLength; |
| 16 | } |
| 17 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 18 | @Override |
| 19 | public synchronized V put(Prefix prefix, V value) { |
Naoki Shiota | 1a5ca91 | 2014-01-03 17:02:31 -0800 | [diff] [blame] | 20 | if (prefix == null || value == null) { |
| 21 | throw new NullPointerException(); |
| 22 | } |
| 23 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 24 | if (prefix.getPrefixLength() > maxPrefixLength) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 25 | throw new IllegalArgumentException(String.format( |
| 26 | "Prefix length %d is greater than max prefix length %d", |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 27 | prefix.getPrefixLength(), maxPrefixLength)); |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 28 | } |
| 29 | |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 30 | Node node = top; |
| 31 | Node match = null; |
| 32 | |
| 33 | while (node != null |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 34 | && node.prefix.getPrefixLength() <= prefix.getPrefixLength() |
| 35 | && key_match(node.prefix.getAddress(), node.prefix.getPrefixLength(), prefix.getAddress(), prefix.getPrefixLength()) == true) { |
| 36 | if (node.prefix.getPrefixLength() == prefix.getPrefixLength()) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 37 | /* |
| 38 | * Prefix is already in tree. This may be an aggregate node, in which case |
| 39 | * we are inserting a new prefix, or it could be an actual node, in which |
| 40 | * case we are inserting a new nexthop for the prefix and should return |
| 41 | * the old nexthop. |
| 42 | */ |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 43 | V oldValue = node.value; |
| 44 | node.value = value; |
| 45 | return oldValue; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 46 | } |
| 47 | |
| 48 | match = node; |
| 49 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 50 | if (bit_check(prefix.getAddress(), node.prefix.getPrefixLength()) == true) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 51 | node = node.right; |
| 52 | } else { |
| 53 | node = node.left; |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | Node add = null; |
| 58 | |
| 59 | if (node == null) { |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 60 | //add = new Node(p, r); |
| 61 | add = new Node(prefix); |
| 62 | add.value = value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 63 | |
| 64 | if (match != null) { |
| 65 | node_link(match, add); |
| 66 | } else { |
| 67 | top = add; |
| 68 | } |
| 69 | } else { |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 70 | add = node_common(node, prefix.getAddress(), prefix.getPrefixLength()); |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 71 | if (add == null) { |
| 72 | //I think this is -ENOMEM? |
| 73 | //return null; |
| 74 | } |
| 75 | |
| 76 | if (match != null) { |
| 77 | node_link(match, add); |
| 78 | } else { |
| 79 | top = add; |
| 80 | } |
| 81 | node_link(add, node); |
| 82 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 83 | if (add.prefix.getPrefixLength() != prefix.getPrefixLength()) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 84 | match = add; |
| 85 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 86 | //add = new Node(p, r); |
| 87 | add = new Node(prefix); |
| 88 | add.value = value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 89 | node_link(match, add); |
| 90 | } |
| 91 | else { |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 92 | add.value = value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 93 | } |
| 94 | } |
| 95 | |
| 96 | //If we added a new Node, there was no previous mapping |
| 97 | return null; |
| 98 | //return addReference(add); |
| 99 | } |
| 100 | |
| 101 | /*exact match*/ |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 102 | @Override |
| 103 | public synchronized V lookup(Prefix prefix) { |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 104 | if (prefix.getPrefixLength() > maxPrefixLength) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 105 | return null; |
| 106 | } |
| 107 | |
| 108 | /* |
| 109 | Node node = top; |
| 110 | |
| 111 | while (node != null |
| 112 | && node.prefix.getPrefixLength() <= p.getPrefixLength() |
| 113 | && key_match(node.prefix.getAddress(), node.prefix.getPrefixLength(), p.getAddress(), p.getPrefixLength()) == true) { |
| 114 | if (node.prefix.getPrefixLength() == p.getPrefixLength()) { |
| 115 | //return addReference(node); |
| 116 | return node.rib; |
| 117 | } |
| 118 | |
| 119 | if (bit_check(p.getAddress(), node.prefix.getPrefixLength()) == true) { |
| 120 | node = node.right; |
| 121 | } else { |
| 122 | node = node.left; |
| 123 | } |
| 124 | } |
| 125 | */ |
| 126 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 127 | Node node = findNode(prefix); |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 128 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 129 | return node == null ? null : node.value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 130 | } |
| 131 | |
| 132 | /*closest containing prefix*/ |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 133 | @Override |
| 134 | public synchronized V match(Prefix prefix) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 135 | //TODO |
Jonathan Hart | abf1022 | 2013-08-13 10:19:34 +1200 | [diff] [blame] | 136 | if (prefix.getPrefixLength() > maxPrefixLength) { |
| 137 | return null; |
| 138 | } |
| 139 | |
| 140 | Node closestNode = findClosestNode(prefix); |
| 141 | |
| 142 | return closestNode == null ? null : closestNode.value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 143 | } |
| 144 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 145 | @Override |
| 146 | public synchronized boolean remove(Prefix prefix, V value) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 147 | Node child; |
| 148 | Node parent; |
| 149 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 150 | if (prefix == null || value == null) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 151 | return false; |
| 152 | } |
| 153 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 154 | Node node = findNode(prefix); |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 155 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 156 | if (node == null || node.isAggregate() || !node.value.equals(value)) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 157 | //Given <prefix, nexthop> mapping is not in the tree |
| 158 | return false; |
| 159 | } |
| 160 | |
| 161 | if (node.left != null && node.right != null) { |
Jonathan Hart | b39a67d | 2013-08-10 23:59:50 +1200 | [diff] [blame] | 162 | //Remove the RibEntry entry and leave this node as an aggregate node |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 163 | //In the future, maybe we should re-evaluate what the aggregate prefix should be? |
| 164 | //It shouldn't necessarily stay the same. |
| 165 | //More complicated if the above prefix is also aggregate. |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 166 | node.value = null; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 167 | return true; |
| 168 | } |
| 169 | |
| 170 | if (node.left != null) { |
| 171 | child = node.left; |
| 172 | } else { |
| 173 | child = node.right; |
| 174 | } |
| 175 | |
| 176 | parent = node.parent; |
| 177 | |
| 178 | if (child != null) { |
| 179 | child.parent = parent; |
| 180 | } |
| 181 | |
| 182 | if (parent != null) { |
| 183 | if (parent.left == node) { |
| 184 | parent.left = child; |
| 185 | } else { |
| 186 | parent.right = child; |
| 187 | } |
| 188 | } else { |
| 189 | top = child; |
| 190 | } |
| 191 | |
| 192 | /* |
| 193 | * TODO not sure what to do here. I think this is lazily deleting aggregate nodes, |
| 194 | * notice that it used to do nothing if it detected both children were not null earlier. |
| 195 | * But here, what we really should do is reevaluate the aggregate prefix of the parent |
| 196 | * node (if it is indeed an aggregate). Because at the moment, no aggregate node will ever |
| 197 | * be removed. BUT, I don't actually think this presents a correctness problem, at |
| 198 | * least from an external point of view. |
| 199 | */ |
| 200 | //if (parent != null && parent.refCount == 0) { |
| 201 | //node_remove(parent); |
| 202 | //} |
| 203 | |
| 204 | return true; |
| 205 | } |
| 206 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 207 | @Override |
| 208 | public Iterator<Entry<V>> iterator() { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 209 | return new PatriciaTrieIterator(top); |
| 210 | } |
| 211 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 212 | private Node findNode(Prefix prefix) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 213 | Node node = top; |
| 214 | |
| 215 | while (node != null |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 216 | && node.prefix.getPrefixLength() <= prefix.getPrefixLength() |
| 217 | && key_match(node.prefix.getAddress(), node.prefix.getPrefixLength(), prefix.getAddress(), prefix.getPrefixLength()) == true) { |
| 218 | if (node.prefix.getPrefixLength() == prefix.getPrefixLength()) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 219 | //return addReference(node); |
| 220 | return node; |
| 221 | } |
| 222 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 223 | if (bit_check(prefix.getAddress(), node.prefix.getPrefixLength()) == true) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 224 | node = node.right; |
| 225 | } else { |
| 226 | node = node.left; |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | return null; |
| 231 | } |
| 232 | |
Jonathan Hart | abf1022 | 2013-08-13 10:19:34 +1200 | [diff] [blame] | 233 | private Node findClosestNode(Prefix prefix) { |
| 234 | Node node = top; |
| 235 | Node match = null; |
| 236 | |
| 237 | while (node != null |
| 238 | && node.prefix.getPrefixLength() <= prefix.getPrefixLength() |
| 239 | && key_match(node.prefix.getAddress(), node.prefix.getPrefixLength(), prefix.getAddress(), prefix.getPrefixLength()) == true) { |
| 240 | if (!node.isAggregate()) { |
| 241 | match = node; |
| 242 | } |
| 243 | |
| 244 | if (bit_check(prefix.getAddress(), node.prefix.getPrefixLength()) == true) { |
| 245 | node = node.right; |
| 246 | } else { |
| 247 | node = node.left; |
| 248 | } |
| 249 | } |
| 250 | |
| 251 | return match; |
| 252 | } |
| 253 | |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 254 | /* |
| 255 | * Receives a 1-based bit index |
| 256 | * Returns a 1-based byte index |
| 257 | * eg. (0 => 1), 1 => 1, 8 => 1, 9 => 2, 17 => 3 |
| 258 | */ |
| 259 | private int getByteContainingBit(int bitNumber) { |
| 260 | return Math.max((bitNumber + 7) / 8, 1); |
| 261 | } |
| 262 | |
| 263 | private boolean key_match(byte [] key1, int key1_len, byte [] key2, int key2_len) { |
| 264 | //int offset; |
| 265 | //int shift; |
| 266 | |
| 267 | if (key1_len > key2_len) { |
| 268 | return false; |
| 269 | } |
| 270 | |
| 271 | int offset = (Math.min(key1_len, key2_len)) / 8; |
| 272 | int shift = (Math.min(key1_len, key2_len)) % 8; |
| 273 | |
| 274 | if (shift != 0) { |
| 275 | if ((maskBits[shift] & (key1[offset] ^ key2[offset])) != 0) { |
| 276 | return false; |
| 277 | } |
| 278 | } |
| 279 | |
| 280 | while (offset != 0) { |
| 281 | offset--; |
| 282 | if (key1[offset] != key2[offset]) { |
| 283 | return false; |
| 284 | } |
| 285 | } |
| 286 | return true; |
| 287 | } |
| 288 | |
| 289 | private boolean bit_check(byte [] key, int key_bits) { |
| 290 | int offset = key_bits / 8; |
| 291 | int shift = 7 - (key_bits % 8); |
| 292 | int bit = key[offset] & 0xff; |
| 293 | |
| 294 | bit >>= shift; |
| 295 | |
| 296 | if ((bit & 1) == 1) { |
| 297 | return true; |
| 298 | } else { |
| 299 | return false; |
| 300 | } |
| 301 | } |
| 302 | |
| 303 | private void node_link(Node node, Node add) { |
| 304 | boolean bit = bit_check(add.prefix.getAddress(), node.prefix.getPrefixLength()); |
| 305 | |
| 306 | if (bit == true) { |
| 307 | node.right = add; |
| 308 | } else { |
| 309 | node.left = add; |
| 310 | } |
| 311 | add.parent = node; |
| 312 | } |
| 313 | |
| 314 | private Node node_common(Node node, byte [] key, int key_bits) { |
| 315 | int i; |
| 316 | int limit = Math.min(node.prefix.getPrefixLength(), key_bits) / 8; |
| 317 | |
| 318 | for (i = 0; i < limit; i++) { |
| 319 | if (node.prefix.getAddress()[i] != key[i]) { |
| 320 | break; |
| 321 | } |
| 322 | } |
| 323 | |
| 324 | int common_len = i * 8; |
| 325 | int boundary = 0; |
| 326 | |
| 327 | if (common_len != key_bits) { |
| 328 | byte diff = (byte)(node.prefix.getAddress()[i] ^ key[i]); |
| 329 | byte mask = (byte)0x80; |
| 330 | int shift_mask = 0; |
| 331 | |
| 332 | while (common_len < key_bits && ((mask & diff) == 0)) { |
| 333 | boundary = 1; |
| 334 | |
| 335 | shift_mask = (mask & 0xff); |
| 336 | shift_mask >>= 1; |
| 337 | mask = (byte)shift_mask; |
| 338 | |
| 339 | common_len++; |
| 340 | } |
| 341 | } |
| 342 | |
| 343 | //Node add = new Node(null, common_len, maxKeyOctets); |
| 344 | //if (add == null) |
| 345 | //Another -ENOMEM; |
| 346 | //return null; |
| 347 | |
| 348 | //Creating a new Prefix with a prefix length of common_len |
| 349 | //Bits are copied from node's up until the common_len'th bit |
Jonathan Hart | b39a67d | 2013-08-10 23:59:50 +1200 | [diff] [blame] | 350 | //RibEntry is null, because this is an aggregate prefix - it's not |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 351 | //actually been added to the trie. |
| 352 | |
| 353 | byte[] newPrefix = new byte[getByteContainingBit(maxPrefixLength)]; |
| 354 | |
| 355 | int j; |
| 356 | for (j = 0; j < i; j++) |
| 357 | newPrefix[j] = node.prefix.getAddress()[j]; |
| 358 | |
| 359 | if (boundary != 0) |
| 360 | newPrefix[j] = (byte)(node.prefix.getAddress()[j] & maskBits[common_len % 8]); |
| 361 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 362 | //return new Node(new Prefix(newPrefix, common_len), null); |
| 363 | return new Node(new Prefix(newPrefix, common_len)); |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 364 | //return add; |
| 365 | } |
| 366 | |
| 367 | private class Node { |
| 368 | public Node parent = null; |
| 369 | public Node left = null; |
| 370 | public Node right = null; |
| 371 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 372 | public final Prefix prefix; |
| 373 | public V value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 374 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 375 | //public Node(Prefix p, RibEntry r) { |
| 376 | // this.prefix = p; |
| 377 | // this.rib = r; |
| 378 | //} |
| 379 | public Node(Prefix p) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 380 | this.prefix = p; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 381 | } |
| 382 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 383 | public boolean isAggregate() { |
| 384 | return value == null; |
| 385 | } |
| 386 | |
| 387 | public Entry<V> getEntry() { |
| 388 | return new PatriciaTrieEntry(prefix, value); |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 389 | } |
| 390 | } |
| 391 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 392 | private class PatriciaTrieEntry implements Entry<V> { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 393 | private Prefix prefix; |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 394 | private V value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 395 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 396 | public PatriciaTrieEntry(Prefix prefix, V value) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 397 | this.prefix = prefix; |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 398 | this.value = value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 399 | } |
| 400 | |
| 401 | @Override |
| 402 | public Prefix getPrefix() { |
| 403 | return prefix; |
| 404 | } |
| 405 | |
| 406 | @Override |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 407 | public V getValue() { |
| 408 | return value; |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 409 | } |
| 410 | } |
| 411 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 412 | private class PatriciaTrieIterator implements Iterator<Entry<V>> { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 413 | |
| 414 | private Node current; |
| 415 | private boolean started = false; |
| 416 | |
| 417 | public PatriciaTrieIterator(Node start) { |
| 418 | current = start; |
| 419 | |
| 420 | //If the start is an aggregate node fast forward to find the next valid node |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 421 | if (current != null && current.isAggregate()) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 422 | current = findNext(current); |
| 423 | } |
| 424 | } |
| 425 | |
| 426 | @Override |
| 427 | public boolean hasNext() { |
| 428 | if (current == null) { |
| 429 | return false; |
| 430 | } |
| 431 | |
| 432 | if (!started) { |
| 433 | return true; |
| 434 | } |
| 435 | |
| 436 | return findNext(current) != null; |
| 437 | } |
| 438 | |
| 439 | @Override |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 440 | public Entry<V> next() { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 441 | if (current == null) { |
| 442 | throw new NoSuchElementException(); |
| 443 | } |
| 444 | |
| 445 | if (!started) { |
| 446 | started = true; |
| 447 | return current.getEntry(); |
| 448 | } |
| 449 | |
| 450 | current = findNext(current); |
| 451 | if (current == null) { |
| 452 | throw new NoSuchElementException(); |
| 453 | } |
| 454 | |
| 455 | return current.getEntry(); |
| 456 | } |
| 457 | |
| 458 | @Override |
| 459 | public void remove() { |
| 460 | // TODO This could be implemented, if it were needed |
| 461 | throw new NoSuchElementException(); |
| 462 | } |
| 463 | |
| 464 | private Node findNext(Node node) { |
| 465 | Node next = null; |
| 466 | |
| 467 | if (node.left != null) { |
| 468 | next = node.left; |
| 469 | //addReference(next); |
| 470 | //delReference(node); |
| 471 | //return next; |
| 472 | } |
| 473 | else if (node.right != null) { |
| 474 | next = node.right; |
| 475 | //addReference(next); |
| 476 | //delReference(node); |
| 477 | //return next; |
| 478 | } |
| 479 | else { |
| 480 | //Node start = node; |
| 481 | while (node.parent != null) { |
| 482 | if (node.parent.left == node && node.parent.right != null) { |
| 483 | next = node.parent.right; |
| 484 | //addReference(next); |
| 485 | //delReference(start); |
| 486 | //return next; |
| 487 | break; |
| 488 | } |
| 489 | node = node.parent; |
| 490 | } |
| 491 | } |
| 492 | |
| 493 | if (next == null) { |
| 494 | return null; |
| 495 | } |
| 496 | |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 497 | //If the node doesn't have a value, it's not an actual node, it's an artifically |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 498 | //inserted aggregate node. We don't want to return these to the user. |
Jonathan Hart | 29b972d | 2013-08-12 23:43:51 +1200 | [diff] [blame] | 499 | if (next.isAggregate()) { |
Jonathan Hart | 8f5f468 | 2013-08-07 22:13:39 +1200 | [diff] [blame] | 500 | return findNext(next); |
| 501 | } |
| 502 | |
| 503 | return next; |
| 504 | } |
| 505 | } |
| 506 | } |