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Diffstat (limited to 'core/src/main/scala/org/apache/spark/util/collection/PrimitiveVector.scala')
-rw-r--r-- | core/src/main/scala/org/apache/spark/util/collection/PrimitiveVector.scala | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/core/src/main/scala/org/apache/spark/util/collection/PrimitiveVector.scala b/core/src/main/scala/org/apache/spark/util/collection/PrimitiveVector.scala new file mode 100644 index 0000000000..b84eb65c62 --- /dev/null +++ b/core/src/main/scala/org/apache/spark/util/collection/PrimitiveVector.scala @@ -0,0 +1,69 @@ +/* + * 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. + */ + +package org.apache.spark.util.collection + +import scala.reflect.ClassTag + +/** + * An append-only, non-threadsafe, array-backed vector that is optimized for primitive types. + */ +private[spark] +class PrimitiveVector[@specialized(Long, Int, Double) V: ClassTag](initialSize: Int = 64) { + private var _numElements = 0 + private var _array: Array[V] = _ + + // NB: This must be separate from the declaration, otherwise the specialized parent class + // will get its own array with the same initial size. + _array = new Array[V](initialSize) + + def apply(index: Int): V = { + require(index < _numElements) + _array(index) + } + + def +=(value: V) { + if (_numElements == _array.length) { + resize(_array.length * 2) + } + _array(_numElements) = value + _numElements += 1 + } + + def capacity: Int = _array.length + + def length: Int = _numElements + + def size: Int = _numElements + + /** Gets the underlying array backing this vector. */ + def array: Array[V] = _array + + /** Trims this vector so that the capacity is equal to the size. */ + def trim(): PrimitiveVector[V] = resize(size) + + /** Resizes the array, dropping elements if the total length decreases. */ + def resize(newLength: Int): PrimitiveVector[V] = { + val newArray = new Array[V](newLength) + _array.copyToArray(newArray) + _array = newArray + if (newLength < _numElements) { + _numElements = newLength + } + this + } +} |