--- /dev/null
+package org.apache.lucene.util.packed;
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import org.apache.lucene.store.DataInput;
+import org.apache.lucene.util.RamUsageEstimator;
+
+import java.io.IOException;
+import java.util.Arrays;
+
+/**
+ * Direct wrapping of 16 bit values to a backing array of shorts.
+ * @lucene.internal
+ */
+
+class Direct16 extends PackedInts.ReaderImpl
+ implements PackedInts.Mutable {
+ private short[] values;
+ private static final int BITS_PER_VALUE = 16;
+
+ public Direct16(int valueCount) {
+ super(valueCount, BITS_PER_VALUE);
+ values = new short[valueCount];
+ }
+
+ public Direct16(DataInput in, int valueCount) throws IOException {
+ super(valueCount, BITS_PER_VALUE);
+ short[] values = new short[valueCount];
+ for(int i=0;i<valueCount;i++) {
+ values[i] = in.readShort();
+ }
+ final int mod = valueCount % 4;
+ if (mod != 0) {
+ final int pad = 4-mod;
+ // round out long
+ for(int i=0;i<pad;i++) {
+ in.readShort();
+ }
+ }
+
+ this.values = values;
+ }
+
+ /**
+ * Creates an array backed by the given values.
+ * </p><p>
+ * Note: The values are used directly, so changes to the values will
+ * affect the structure.
+ * @param values used as the internal backing array.
+ */
+ public Direct16(short[] values) {
+ super(values.length, BITS_PER_VALUE);
+ this.values = values;
+ }
+
+ public long get(final int index) {
+ return 0xFFFFL & values[index];
+ }
+
+ public void set(final int index, final long value) {
+ values[index] = (short)(value & 0xFFFF);
+ }
+
+ public long ramBytesUsed() {
+ return RamUsageEstimator.NUM_BYTES_ARRAY_HEADER +
+ values.length * RamUsageEstimator.NUM_BYTES_SHORT;
+ }
+
+ public void clear() {
+ Arrays.fill(values, (short)0);
+ }
+
+ @Override
+ public Object getArray() {
+ return values;
+ }
+
+ @Override
+ public boolean hasArray() {
+ return true;
+ }
+}