Added iterator() method.

tzaeschke · Jul 28, 2014 · 42a1a5a · 42a1a5a
1 parent 49a0ccb
commit 42a1a5a
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diff --git a/CritBit/src/org/zoodb/index/critbit/CritBit.java b/CritBit/src/org/zoodb/index/critbit/CritBit.java
@@ -49,6 +49,10 @@
  * T.Zaeschke, C.Zimmerli, M.C.Norrie:  The PH-Tree - A Space-Efficient Storage Structure and 
  * Multi-Dimensional Index (SIGMOD 2014)
  * 
+ * 
+ * Version: 1.2  
+ *   --  Added iterator() to iterate over all entries
+ * 
  * Version: 1.1  
  *   --  Slight performance improvements in mergeLong() and  readAndSplit()
  * 
@@ -695,6 +699,145 @@ private void updateParentAfterRemove(Node<V> parent, long[] newPost, V newVal,
 		size--;
 	}
 
+	/**
+	 * Create an iterator over all values, keys or entries.
+	 * @return the iterator
+	 */
+	public FullIterator<V> iterator() {
+		checkDim0(); 
+		return new FullIterator<V>(this, DEPTH);
+	}
+
+	public static class FullIterator<V> implements Iterator<V> {
+		private final long[] valIntTemplate;
+		private long[] nextKey = null; 
+		private V nextValue = null;
+		private final Node<V>[] stack;
+		 //0==read_lower; 1==read_upper; 2==go_to_parent
+		private static final byte READ_LOWER = 0;
+		private static final byte READ_UPPER = 1;
+		private static final byte RETURN_TO_PARENT = 2;
+		private final byte[] readHigherNext;
+		private int stackTop = -1;
+
+		@SuppressWarnings("unchecked")
+		public FullIterator(CritBit<V> cb, int DEPTH) {
+			this.stack = new Node[DEPTH];
+			this.readHigherNext = new byte[DEPTH];  // default = false
+			int intArrayLen = (DEPTH+63) >>> 6;
+			this.valIntTemplate = new long[intArrayLen];
+
+			if (cb.rootKey != null) {
+				readNextVal(cb.rootKey, cb.rootVal);
+				return;
+			}
+			if (cb.root == null) {
+				//Tree is empty
+				return;
+			}
+			Node<V> n = cb.root;
+			CritBit.readInfix(n, valIntTemplate);
+			stack[++stackTop] = cb.root;
+			findNext();
+		}
+
+		private void findNext() {
+			while (stackTop >= 0) {
+				Node<V> n = stack[stackTop];
+				//check lower
+				if (readHigherNext[stackTop] == READ_LOWER) {
+					readHigherNext[stackTop] = READ_UPPER;
+					//TODO use bit directly to check validity
+					BitTools.setBit(valIntTemplate, n.posDiff, false);
+					if (n.loPost != null) {
+						CritBit.readPostFix(n.loPost, valIntTemplate);
+						readNextVal(valIntTemplate, n.loVal);
+						return;
+						//proceed to check upper
+					} else {
+						CritBit.readInfix(n.lo, valIntTemplate);
+						stack[++stackTop] = n.lo;
+						readHigherNext[stackTop] = READ_LOWER;
+						continue;
+					}
+				}
+				//check upper
+				if (readHigherNext[stackTop] == READ_UPPER) {
+					readHigherNext[stackTop] = RETURN_TO_PARENT;
+					BitTools.setBit(valIntTemplate, n.posDiff, true);
+					if (n.hiPost != null) {
+						CritBit.readPostFix(n.hiPost, valIntTemplate);
+						readNextVal(valIntTemplate, n.hiVal);
+						--stackTop;
+						return;
+						//proceed to move up a level
+					} else {
+						CritBit.readInfix(n.hi, valIntTemplate);
+						stack[++stackTop] = n.hi;
+						readHigherNext[stackTop] = READ_LOWER;
+						continue;
+					}
+				}
+				//proceed to move up a level
+				--stackTop;
+			}
+			//Finished
+			nextValue = null;
+			nextKey = null;
+		}
+
+
+		/**
+		 * Full comparison on the parameter. Assigns the parameter to 'nextVal' if comparison
+		 * fits.
+		 * @param keyTemplate
+		 * @return Whether we have a match or not
+		 */
+		private void readNextVal(long[] keyTemplate, V value) {
+			nextValue = value;
+			nextKey = CritBit.clone(keyTemplate);
+		}
+
+		@Override
+		public boolean hasNext() {
+			return nextValue != null;
+		}
+
+		@Override
+		public V next() {
+			if (!hasNext()) {
+				throw new NoSuchElementException();
+			}
+			V ret = nextValue;
+			findNext();
+			return ret;
+		}
+
+		public long[] nextKey() {
+			if (!hasNext()) {
+				throw new NoSuchElementException();
+			}
+			long[] ret = nextKey;
+			findNext();
+			return ret;
+		}
+
+		public Entry<V> nextEntry() {
+			if (!hasNext()) {
+				throw new NoSuchElementException();
+			}
+			Entry<V> ret = new Entry<V>(nextKey, nextValue);
+			findNext();
+			return ret;
+		}
+
+		@Override
+		public void remove() {
+			throw new UnsupportedOperationException();
+		}
+
+	}
+
 	public QueryIterator<V> query(long[] min, long[] max) {
 		checkDim0(); 
 		return new QueryIterator<V>(this, min, max, DEPTH);

diff --git a/CritBit/src/org/zoodb/index/critbit/CritBit1D.java b/CritBit/src/org/zoodb/index/critbit/CritBit1D.java
@@ -20,6 +20,7 @@
  */
 package org.zoodb.index.critbit;
 
+import org.zoodb.index.critbit.CritBit.FullIterator;
 import org.zoodb.index.critbit.CritBit.QueryIterator;
 
 /**
@@ -49,4 +50,6 @@ public interface CritBit1D<V> {
 	/** @see CritBit#get(long[]) */
 	V get(long[] key);
 
+	/** @see CritBit#iterator() */
+	FullIterator<V> iterator();
 }
diff --git a/CritBit/src/org/zoodb/index/critbit/TestCritBit.java b/CritBit/src/org/zoodb/index/critbit/TestCritBit.java
@@ -33,6 +33,7 @@
 
 import org.junit.Test;
 import org.zoodb.index.critbit.CritBit.Entry;
+import org.zoodb.index.critbit.CritBit.FullIterator;
 import org.zoodb.index.critbit.CritBit.QueryIterator;
 
 /**
@@ -840,6 +841,34 @@ public void test64_True1D_queries_Single() {
 		assertFalse(it.hasNext());
 	}
 
+	@Test
+	public void testIterator() {
+		int N = 10000;
+		int k = 5;
+		Random R = new Random(0);
+
+		CritBit1D<Integer> cb = newCritBit(k*64);
+		long[][] data = new long[N][];
+		for (int i = 0; i < N; i++) {
+			long[] l = new long[k];
+			for (int d = 0; d < k; d++) {
+				l[d] = R.nextInt(12345); 
+			}
+			data[i] = l;
+			cb.put(l, i);
+		}
+
+		//test
+		FullIterator<Integer> it = cb.iterator();
+		int n = 0;
+		while (it.hasNext()) {
+			Entry<Integer> e = it.nextEntry();
+			assertTrue(isEqual(data[e.value()], e.key()));
+			n++;
+		}
+		assertEquals(N, n);
+	}
+
 	private boolean isEqual(long[] a, long[] r) {
 		for (int k = 0; k < a.length; k++) {
 			if (a[k] != r[k]) {