Repository: commons-io Updated Branches: refs/heads/master e95134229 -> fcc636194
IO-493: Add infinite circular input stream (closes #8) Project: http://git-wip-us.apache.org/repos/asf/commons-io/repo Commit: http://git-wip-us.apache.org/repos/asf/commons-io/commit/699d6f0e Tree: http://git-wip-us.apache.org/repos/asf/commons-io/tree/699d6f0e Diff: http://git-wip-us.apache.org/repos/asf/commons-io/diff/699d6f0e Branch: refs/heads/master Commit: 699d6f0eca65837501d7ab7a92ae2c614f8e6cbf Parents: e951342 Author: Piotr Turski <piotr.tur...@gmail.com> Authored: Wed Dec 2 00:22:59 2015 +0100 Committer: pascalschumacher <pascalschumac...@gmx.net> Committed: Thu Dec 1 22:40:50 2016 +0100 ---------------------------------------------------------------------- .../io/input/InfiniteCircularInputStream.java | 52 +++++++++++++++++ .../input/InfiniteCircularInputStreamTest.java | 61 ++++++++++++++++++++ 2 files changed, 113 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/commons-io/blob/699d6f0e/src/main/java/org/apache/commons/io/input/InfiniteCircularInputStream.java ---------------------------------------------------------------------- diff --git a/src/main/java/org/apache/commons/io/input/InfiniteCircularInputStream.java b/src/main/java/org/apache/commons/io/input/InfiniteCircularInputStream.java new file mode 100644 index 0000000..2b2841c --- /dev/null +++ b/src/main/java/org/apache/commons/io/input/InfiniteCircularInputStream.java @@ -0,0 +1,52 @@ +/* + * 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.InputStream; + +/** + * + * An {@link InputStream} that infinitely repeats provided bytes. + * <p> + * Closing a <tt>InfiniteCircularInputStream</tt> has no effect. The methods in + * this class can be called after the stream has been closed without generating + * an <tt>IOException</tt>. + * + */ +public class InfiniteCircularInputStream extends InputStream { + + final private byte[] repeatedContent; + private int position = -1; + + /** + * Creates a InfiniteCircularStream from the specified array of chars. + * + * @param repeatedContent + * Input buffer to be repeated (not copied) + */ + public InfiniteCircularInputStream(byte[] repeatedContent) { + this.repeatedContent = repeatedContent; + } + + @Override + public int read() { + position = (position + 1) % repeatedContent.length; + return repeatedContent[position] & 0xff; // copied from + // java.io.ByteArrayInputStream.read() + } + +} http://git-wip-us.apache.org/repos/asf/commons-io/blob/699d6f0e/src/test/java/org/apache/commons/io/input/InfiniteCircularInputStreamTest.java ---------------------------------------------------------------------- diff --git a/src/test/java/org/apache/commons/io/input/InfiniteCircularInputStreamTest.java b/src/test/java/org/apache/commons/io/input/InfiniteCircularInputStreamTest.java new file mode 100644 index 0000000..711a3f0 --- /dev/null +++ b/src/test/java/org/apache/commons/io/input/InfiniteCircularInputStreamTest.java @@ -0,0 +1,61 @@ +/* + * 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.Arrays; + +import org.junit.Assert; +import org.junit.Test; + +public class InfiniteCircularInputStreamTest { + + @Test + public void should_cycle_bytes() throws IOException { + byte[] input = new byte[] { 1, 2 }; + byte[] expected = new byte[] { 1, 2, 1, 2, 1 }; + + assertStreamOutput(input, expected); + } + + @Test + public void should_handle_whole_range_of_bytes() throws IOException { + int size = Byte.MAX_VALUE - Byte.MIN_VALUE + 1; + byte[] contentToCycle = new byte[size]; + byte value = Byte.MIN_VALUE; + for (int i = 0; i < contentToCycle.length; i++) { + contentToCycle[i] = value++; + } + + byte[] expectedOutput = Arrays.copyOf(contentToCycle, size); + + assertStreamOutput(contentToCycle, expectedOutput); + } + + private void assertStreamOutput(byte[] toCycle, byte[] expected) throws IOException { + byte[] actual = new byte[expected.length]; + + try (InputStream infStream = new InfiniteCircularInputStream(toCycle)) { + int actualReadBytes = infStream.read(actual); + + Assert.assertArrayEquals(expected, actual); + Assert.assertEquals(expected.length, actualReadBytes); + } + } + +}
