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/**
 * Copyright 2014 Netflix, Inc.
 *
 * Licensed 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 rx.internal.operators;

import java.util.*;
import java.util.concurrent.atomic.*;

import rx.*;
import rx.Observable;
import rx.Observable.Operator;
import rx.exceptions.MissingBackpressureException;

/**
 * This operation takes
 * values from the specified {@link Observable} source and stores them in all active chunks until the buffer
 * contains a specified number of elements. The buffer is then emitted. Chunks are created after a certain
 * amount of values have been received. When the source {@link Observable} completes or produces an error,
 * the currently active chunks are emitted, and the event is propagated to all subscribed {@link Subscriber}s.
 * 

* Note that this operation can produce non-connected, connected non-overlapping, or overlapping * chunks depending on the input parameters. *

* @param the buffered value type */ public final class OperatorBufferWithSize implements Operator, T> { final int count; final int skip; /** * @param count * the number of elements a buffer should have before being emitted * @param skip * the interval with which chunks have to be created. Note that when {@code skip == count} * the operator will produce non-overlapping chunks. If * {@code skip < count}, this buffer operation will produce overlapping chunks and if * {@code skip > count} non-overlapping chunks will be created and some values will not be pushed * into a buffer at all! */ public OperatorBufferWithSize(int count, int skip) { if (count <= 0) { throw new IllegalArgumentException("count must be greater than 0"); } if (skip <= 0) { throw new IllegalArgumentException("skip must be greater than 0"); } this.count = count; this.skip = skip; } @Override public Subscriber call(final Subscriber> child) { if (skip == count) { BufferExact parent = new BufferExact(child, count); child.add(parent); child.setProducer(parent.createProducer()); return parent; } if (skip > count) { BufferSkip parent = new BufferSkip(child, count, skip); child.add(parent); child.setProducer(parent.createProducer()); return parent; } BufferOverlap parent = new BufferOverlap(child, count, skip); child.add(parent); child.setProducer(parent.createProducer()); return parent; } static final class BufferExact extends Subscriber { final Subscriber> actual; final int count; List buffer; public BufferExact(Subscriber> actual, int count) { this.actual = actual; this.count = count; this.request(0L); } @Override public void onNext(T t) { List b = buffer; if (b == null) { b = new ArrayList(count); buffer = b; } b.add(t); if (b.size() == count) { buffer = null; actual.onNext(b); } } @Override public void onError(Throwable e) { buffer = null; actual.onError(e); } @Override public void onCompleted() { List b = buffer; if (b != null) { actual.onNext(b); } actual.onCompleted(); } Producer createProducer() { return new Producer() { @Override public void request(long n) { if (n < 0L) { throw new IllegalArgumentException("n >= required but it was " + n); } if (n != 0L) { long u = BackpressureUtils.multiplyCap(n, count); BufferExact.this.request(u); } } }; } } static final class BufferSkip extends Subscriber { final Subscriber> actual; final int count; final int skip; long index; List buffer; public BufferSkip(Subscriber> actual, int count, int skip) { this.actual = actual; this.count = count; this.skip = skip; this.request(0L); } @Override public void onNext(T t) { long i = index; List b = buffer; if (i == 0) { b = new ArrayList(count); buffer = b; } i++; if (i == skip) { index = 0; } else { index = i; } if (b != null) { b.add(t); if (b.size() == count) { buffer = null; actual.onNext(b); } } } @Override public void onError(Throwable e) { buffer = null; actual.onError(e); } @Override public void onCompleted() { List b = buffer; if (b != null) { buffer = null; actual.onNext(b); } actual.onCompleted(); } Producer createProducer() { return new BufferSkipProducer(); } final class BufferSkipProducer extends AtomicBoolean implements Producer { /** */ private static final long serialVersionUID = 3428177408082367154L; @Override public void request(long n) { if (n < 0) { throw new IllegalArgumentException("n >= 0 required but it was " + n); } if (n != 0) { BufferSkip parent = BufferSkip.this; if (!get() && compareAndSet(false, true)) { long u = BackpressureUtils.multiplyCap(n, parent.count); long v = BackpressureUtils.multiplyCap(parent.skip - parent.count, n - 1); long w = BackpressureUtils.addCap(u, v); parent.request(w); } else { long u = BackpressureUtils.multiplyCap(n, parent.skip); parent.request(u); } } } } } static final class BufferOverlap extends Subscriber { final Subscriber> actual; final int count; final int skip; long index; final ArrayDeque> queue; final AtomicLong requested; long produced; public BufferOverlap(Subscriber> actual, int count, int skip) { this.actual = actual; this.count = count; this.skip = skip; this.queue = new ArrayDeque>(); this.requested = new AtomicLong(); this.request(0L); } @Override public void onNext(T t) { long i = index; if (i == 0) { List b = new ArrayList(count); queue.offer(b); } i++; if (i == skip) { index = 0; } else { index = i; } for (List list : queue) { list.add(t); } List b = queue.peek(); if (b != null && b.size() == count) { queue.poll(); produced++; actual.onNext(b); } } @Override public void onError(Throwable e) { queue.clear(); actual.onError(e); } @Override public void onCompleted() { long p = produced; if (p != 0L) { if (p > requested.get()) { actual.onError(new MissingBackpressureException("More produced than requested? " + p)); return; } requested.addAndGet(-p); } BackpressureUtils.postCompleteDone(requested, queue, actual); } Producer createProducer() { return new BufferOverlapProducer(); } final class BufferOverlapProducer extends AtomicBoolean implements Producer { /** */ private static final long serialVersionUID = -4015894850868853147L; @Override public void request(long n) { BufferOverlap parent = BufferOverlap.this; if (BackpressureUtils.postCompleteRequest(parent.requested, n, parent.queue, parent.actual)) { if (n != 0L) { if (!get() && compareAndSet(false, true)) { long u = BackpressureUtils.multiplyCap(parent.skip, n - 1); long v = BackpressureUtils.addCap(u, parent.count); parent.request(v); } else { long u = BackpressureUtils.multiplyCap(parent.skip, n); parent.request(u); } } } } } } }




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