| /* |
| * 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.commons.io.input; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| import java.util.Objects; |
| |
| import org.apache.commons.io.IOUtils; |
| |
| /** |
| * |
| * An {@link InputStream} that repeats provided bytes for given target byte count. |
| * <p> |
| * Closing this input stream has no effect. The methods in this class can be called after the stream has been closed |
| * without generating an {@link IOException}. |
| * </p> |
| * |
| * @see InfiniteCircularInputStream |
| * @since 2.8.0 |
| */ |
| public class CircularInputStream extends InputStream { |
| |
| /** |
| * Throws an {@link IllegalArgumentException} if the input contains -1. |
| * |
| * @param repeatContent input to validate. |
| * @return the input. |
| */ |
| private static byte[] validate(final byte[] repeatContent) { |
| Objects.requireNonNull(repeatContent, "repeatContent"); |
| for (final byte b : repeatContent) { |
| if (b == IOUtils.EOF) { |
| throw new IllegalArgumentException("repeatContent contains the end-of-stream marker " + IOUtils.EOF); |
| } |
| } |
| return repeatContent; |
| } |
| |
| private long byteCount; |
| private int position = -1; |
| private final byte[] repeatedContent; |
| private final long targetByteCount; |
| |
| /** |
| * Creates an instance from the specified array of bytes. |
| * |
| * @param repeatContent Input buffer to be repeated this buffer is not copied. |
| * @param targetByteCount How many bytes the read. A negative number means an infinite target count. |
| */ |
| public CircularInputStream(final byte[] repeatContent, final long targetByteCount) { |
| this.repeatedContent = validate(repeatContent); |
| if (repeatContent.length == 0) { |
| throw new IllegalArgumentException("repeatContent is empty."); |
| } |
| this.targetByteCount = targetByteCount; |
| } |
| |
| @Override |
| public int read() { |
| if (targetByteCount >= 0) { |
| if (byteCount == targetByteCount) { |
| return IOUtils.EOF; |
| } |
| byteCount++; |
| } |
| position = (position + 1) % repeatedContent.length; |
| return repeatedContent[position] & 0xff; |
| } |
| |
| } |