code: /*
   * 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.rxjava3.internal.operators.maybe;
  
  import java.util.Arrays;
  import java.util.Objects;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.Exceptions;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.disposables.EmptyDisposable;
  import io.reactivex.rxjava3.internal.operators.maybe.MaybeZipArray.ZipCoordinator;
  
  public final class MaybeZipIterable<T, R> extends Maybe<R> {
  
      final Iterable<? extends MaybeSource<? extends T>> sources;
  
      final Function<? super Object[], ? extends R> zipper;
  
      public MaybeZipIterable(Iterable<? extends MaybeSource<? extends T>> sources, Function<? super Object[], ? extends R> zipper) {
          this.sources = sources;
          this.zipper = zipper;
      }
  
      @Override
      protected void subscribeActual(MaybeObserver<? super R> observer) {
          @SuppressWarnings("unchecked")
          MaybeSource<? extends T>[] a = new MaybeSource[8];
          int n = 0;
  
          try {
              for (MaybeSource<? extends T> source : sources) {
                  if (source == null) {
                      EmptyDisposable.error(new NullPointerException("One of the sources is null"), observer);
                      return;
                  }
                  if (n == a.length) {
                      a = Arrays.copyOf(a, n + (n >> 2));
                  }
                  a[n++] = source;
              }
          } catch (Throwable ex) {
              Exceptions.throwIfFatal(ex);
              EmptyDisposable.error(ex, observer);
              return;
          }
  
          if (n == 0) {
              EmptyDisposable.complete(observer);
              return;
          }
  
          if (n == 1) {
              a[0].subscribe(new MaybeMap.MapMaybeObserver<>(observer, new SingletonArrayFunc()));
              return;
          }
  
          ZipCoordinator<T, R> parent = new ZipCoordinator<>(observer, n, zipper);
  
          observer.onSubscribe(parent);
  
          for (int i = 0; i < n; i++) {
              if (parent.isDisposed()) {
                  return;
              }
  
              a[i].subscribe(parent.observers[i]);
          }
      }
  
      final class SingletonArrayFunc implements Function<T, R> {
          @Override
          public R apply(T t) throws Throwable {
              return Objects.requireNonNull(zipper.apply(new Object[] { t }), "The zipper returned a null value");
          }
      }
  }
  