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/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * 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 io.reactivex.internal.util;

import org.reactivestreams.Subscriber;

import io.reactivex.Observer;
import io.reactivex.functions.*;

/**
 * A linked-array-list implementation that only supports appending and consumption.
 *
 * @param  the value type
 */
public class AppendOnlyLinkedArrayList {
    final int capacity;
    final Object[] head;
    Object[] tail;
    int offset;

    /**
     * Constructs an empty list with a per-link capacity.
     * @param capacity the capacity of each link
     */
    public AppendOnlyLinkedArrayList(int capacity) {
        this.capacity = capacity;
        this.head = new Object[capacity + 1];
        this.tail = head;
    }

    /**
     * Append a non-null value to the list.
     * 

Don't add null to the list! * @param value the value to append */ public void add(T value) { final int c = capacity; int o = offset; if (o == c) { Object[] next = new Object[c + 1]; tail[c] = next; tail = next; o = 0; } tail[o] = value; offset = o + 1; } /** * Set a value as the first element of the list. * @param value the value to set */ public void setFirst(T value) { head[0] = value; } /** * Predicate interface suppressing the exception. * * @param the value type */ public interface NonThrowingPredicate extends Predicate { @Override boolean test(T t); } /** * Loops over all elements of the array until a null element is encountered or * the given predicate returns true. * @param consumer the consumer of values that returns true if the forEach should terminate */ @SuppressWarnings("unchecked") public void forEachWhile(NonThrowingPredicate consumer) { Object[] a = head; final int c = capacity; while (a != null) { for (int i = 0; i < c; i++) { Object o = a[i]; if (o == null) { break; } if (consumer.test((T)o)) { return; } } a = (Object[])a[c]; } } /** * Interprets the contents as NotificationLite objects and calls * the appropriate Subscriber method. * * @param the target type * @param subscriber the subscriber to emit the events to * @return true if a terminal event has been reached */ public boolean accept(Subscriber subscriber) { Object[] a = head; final int c = capacity; while (a != null) { for (int i = 0; i < c; i++) { Object o = a[i]; if (o == null) { break; } if (NotificationLite.acceptFull(o, subscriber)) { return true; } } a = (Object[])a[c]; } return false; } /** * Interprets the contents as NotificationLite objects and calls * the appropriate Observer method. * * @param the target type * @param observer the observer to emit the events to * @return true if a terminal event has been reached */ public boolean accept(Observer observer) { Object[] a = head; final int c = capacity; while (a != null) { for (int i = 0; i < c; i++) { Object o = a[i]; if (o == null) { break; } if (NotificationLite.acceptFull(o, observer)) { return true; } } a = (Object[])a[c]; } return false; } /** * Loops over all elements of the array until a null element is encountered or * the given predicate returns true. * @param the extra state type * @param state the extra state passed into the consumer * @param consumer the consumer of values that returns true if the forEach should terminate * @throws Exception if the predicate throws */ @SuppressWarnings("unchecked") public void forEachWhile(S state, BiPredicate consumer) throws Exception { Object[] a = head; final int c = capacity; for (;;) { for (int i = 0; i < c; i++) { Object o = a[i]; if (o == null) { return; } if (consumer.test(state, (T)o)) { return; } } a = (Object[])a[c]; } } }