/*
    * 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.compress.compressors.lz4;
  
  import static org.hamcrest.CoreMatchers.containsString;
  import static org.hamcrest.MatcherAssert.assertThat;
  import static org.junit.jupiter.api.Assertions.assertArrayEquals;
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  import java.io.BufferedInputStream;
  import java.io.ByteArrayInputStream;
  import java.io.File;
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.file.Files;
  import java.util.Arrays;
  
  import org.apache.commons.compress.AbstractTest;
  import org.apache.commons.compress.compressors.CompressorStreamFactory;
  import org.apache.commons.io.IOUtils;
  import org.junit.jupiter.api.Test;
  
  public final class FramedLZ4CompressorInputStreamTest extends AbstractTest {
  
      interface StreamWrapper {
          InputStream wrap(InputStream in) throws Exception;
      }
  
      private static byte[] duplicate(final byte[] from) {
          final byte[] to = Arrays.copyOf(from, 2 * from.length);
          System.arraycopy(from, 0, to, from.length, from.length);
          return to;
      }
  
      private void expectIOException(final String fileName) {
          assertThrows(IOException.class, () -> {
              try (InputStream is = Files.newInputStream(getFile(fileName).toPath());
                      FramedLZ4CompressorInputStream in = new FramedLZ4CompressorInputStream(is)) {
                  IOUtils.toByteArray(in);
              }
          });
      }
  
      private void readDoubledBlaLz4(final StreamWrapper wrapper, final boolean expectDuplicateOutput) throws Exception {
          byte[] singleInput;
          try (InputStream i = newInputStream("bla.tar.lz4")) {
              singleInput = IOUtils.toByteArray(i);
          }
          final byte[] input = duplicate(singleInput);
          try (InputStream a = wrapper.wrap(new ByteArrayInputStream(input));
                  InputStream e = newInputStream("bla.tar")) {
              final byte[] expected = IOUtils.toByteArray(e);
              final byte[] actual = IOUtils.toByteArray(a);
              assertArrayEquals(expectDuplicateOutput ? duplicate(expected) : expected, actual);
          }
      }
  
      @Test
      public void testBackreferenceAtStartCausesIOException() {
          expectIOException("COMPRESS-490/ArrayIndexOutOfBoundsException1.lz4");
      }
  
      @Test
      public void testBackreferenceOfSize0CausesIOException() {
          expectIOException("COMPRESS-490/ArithmeticException.lz4");
      }
  
      @Test
      public void testBackreferenceWithOffsetTooBigCausesIOException() {
          expectIOException("COMPRESS-490/ArrayIndexOutOfBoundsException2.lz4");
      }
  
      @Test
      public void testMatches() throws IOException {
          assertFalse(FramedLZ4CompressorInputStream.matches(new byte[10], 4));
          final byte[] expected = readAllBytes("bla.tar.lz4");
          assertFalse(FramedLZ4CompressorInputStream.matches(expected, 3));
          assertTrue(FramedLZ4CompressorInputStream.matches(expected, 4));
          assertTrue(FramedLZ4CompressorInputStream.matches(expected, 5));
     }
 
     @Test
     public void testMultiByteReadConsistentlyReturnsMinusOneAtEof() throws IOException {
         final File input = getFile("bla.tar.lz4");
         final byte[] buf = new byte[2];
         try (InputStream is = Files.newInputStream(input.toPath());
                 FramedLZ4CompressorInputStream in = new FramedLZ4CompressorInputStream(is)) {
             IOUtils.toByteArray(in);
             assertEquals(-1, in.read(buf));
             assertEquals(-1, in.read(buf));
         }
     }
 
     @Test
     public void testReadBlaDumpLz4() throws IOException {
         try (InputStream a = new FramedLZ4CompressorInputStream(newInputStream("bla.dump.lz4"));
                 InputStream e = newInputStream("bla.dump")) {
             final byte[] expected = IOUtils.toByteArray(e);
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(expected, actual);
         }
     }
 
     @Test
     public void testReadBlaLz4() throws IOException {
         try (InputStream a = new FramedLZ4CompressorInputStream(newInputStream("bla.tar.lz4"));
                 InputStream e = newInputStream("bla.tar")) {
             final byte[] expected = IOUtils.toByteArray(e);
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(expected, actual);
         }
     }
 
     @Test
     public void testReadBlaLz4ViaFactory() throws Exception {
         try (InputStream a = new CompressorStreamFactory().createCompressorInputStream(CompressorStreamFactory.getLZ4Framed(), newInputStream("bla.tar.lz4"));
                 InputStream e = newInputStream("bla.tar")) {
             final byte[] expected = IOUtils.toByteArray(e);
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(expected, actual);
         }
     }
 
     @Test
     public void testReadBlaLz4ViaFactoryAutoDetection() throws Exception {
         try (InputStream a = new CompressorStreamFactory().createCompressorInputStream(new BufferedInputStream(newInputStream("bla.tar.lz4")));
                 InputStream e = newInputStream("bla.tar")) {
             final byte[] expected = IOUtils.toByteArray(e);
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(expected, actual);
         }
     }
 
     @Test
     public void testReadBlaLz4ViaFactoryWithDecompressConcatenated() throws Exception {
         try (InputStream a = new CompressorStreamFactory().createCompressorInputStream(CompressorStreamFactory.getLZ4Framed(), newInputStream("bla.tar.lz4"),
                 true);
                 InputStream e = newInputStream("bla.tar")) {
             final byte[] expected = IOUtils.toByteArray(e);
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(expected, actual);
         }
     }
 
     @Test
     public void testReadBlaLz4WithDecompressConcatenated() throws IOException {
         try (InputStream a = new FramedLZ4CompressorInputStream(newInputStream("bla.tar.lz4"), true);
                 InputStream e = newInputStream("bla.tar")) {
             final byte[] expected = IOUtils.toByteArray(e);
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(expected, actual);
         }
     }
 
     @Test
     public void testReadDoubledBlaLz4ViaFactoryWithDecompressConcatenatedFalse() throws Exception {
         readDoubledBlaLz4(in -> new CompressorStreamFactory().createCompressorInputStream(CompressorStreamFactory.getLZ4Framed(), in, false), false);
     }
 
     @Test
     public void testReadDoubledBlaLz4ViaFactoryWithDecompressConcatenatedTrue() throws Exception {
         readDoubledBlaLz4(in -> new CompressorStreamFactory().createCompressorInputStream(CompressorStreamFactory.getLZ4Framed(), in, true), true);
     }
 
     @Test
     public void testReadDoubledBlaLz4ViaFactoryWithoutExplicitDecompressConcatenated() throws Exception {
         readDoubledBlaLz4(in -> new CompressorStreamFactory().createCompressorInputStream(CompressorStreamFactory.getLZ4Framed(), in), false);
     }
 
     @Test
     public void testReadDoubledBlaLz4WithDecompressConcatenatedFalse() throws Exception {
         readDoubledBlaLz4(in -> new FramedLZ4CompressorInputStream(in, false), false);
     }
 
     @Test
     public void testReadDoubledBlaLz4WithDecompressConcatenatedTrue() throws Exception {
         readDoubledBlaLz4(in -> new FramedLZ4CompressorInputStream(in, true), true);
     }
 
     @Test
     public void testReadDoubledBlaLz4WithoutExplicitDecompressConcatenated() throws Exception {
         readDoubledBlaLz4(FramedLZ4CompressorInputStream::new, false);
     }
 
     @Test
     public void testReadsUncompressedBlocks() throws IOException {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
         };
         try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(new byte[] { 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!' }, actual);
         }
     }
 
     @Test
     public void testReadsUncompressedBlocksUsingSingleByteRead() throws IOException {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
         };
         try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
             final int h = a.read();
             assertEquals('H', h);
         }
     }
 
     @Test
     public void testRejectsBlocksWithoutChecksum() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x70, // flag - Version 01, block independent, with block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 114, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("block checksum"));
     }
 
     @Test
     public void testRejectsFileWithBadHeaderChecksum() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x64, // flag - Version 01, block independent, no block checksum, no content size, with content checksum
                 0x70, // block size 4MB
                 0, };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("header checksum mismatch"));
     }
 
     @Test
     public void testRejectsFileWithInsufficientContentSize() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x6C, // flag - Version 01, block independent, no block checksum, with content size, with content checksum
                 0x70, // block size 4MB
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("content size"));
     }
 
     @Test
     public void testRejectsFileWithoutBlockSizeByte() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x64, // flag - Version 01, block independent, no block checksum, no content size, with content checksum
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("BD byte"));
     }
 
     @Test
     public void testRejectsFileWithoutFrameDescriptor() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18 // signature
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("frame flags"));
     }
 
     @Test
     public void testRejectsFileWithoutHeaderChecksum() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x64, // flag - Version 01, block independent, no block checksum, no content size, with content checksum
                 0x70, // block size 4MB
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("header checksum"));
     }
 
     @Test
     public void testRejectsFileWithWrongVersion() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x24, // flag - Version 00, block independent, no block checksum, no content size, with content checksum
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("version"));
     }
 
     @Test
     public void testRejectsNonLZ4Stream() {
         assertThrows(IOException.class, () -> new FramedLZ4CompressorInputStream(newInputStream("bla.tar")));
     }
 
     @Test
     public void testRejectsSkippableFrameFollowedByJunk() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x50, 0x2a, 0x4d, 0x18, // skippable frame signature
                 2, 0, 0, 0, // skippable frame has length 2
                 1, 2, // content of skippable frame
                 1, 0x22, 0x4d, 0x18, // bad signature
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("garbage"));
     }
 
     @Test
     public void testRejectsSkippableFrameFollowedByTooFewBytes() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x52, 0x2a, 0x4d, 0x18, // skippable frame signature
                 2, 0, 0, 0, // skippable frame has length 2
                 1, 2, // content of skippable frame
                 4, // too short for signature
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("garbage"));
     }
 
     @Test
     public void testRejectsSkippableFrameWithBadSignaturePrefix() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x60, 0x2a, 0x4d, 0x18, // broken skippable frame signature
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
                 IOUtils.toByteArray(a);
                 fail();
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("garbage"));
     }
 
     @Test
     public void testRejectsSkippableFrameWithBadSignatureTrailer() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x51, 0x2a, 0x4d, 0x17, // broken skippable frame signature
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("garbage"));
     }
 
     @Test
     public void testRejectsSkippableFrameWithPrematureEnd() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x50, 0x2a, 0x4d, 0x18, // skippable frame signature
                 2, 0, 0, 0, // skippable frame has length 2
                 1, // content of skippable frame (should be two bytes)
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("Premature end of stream while skipping frame"));
     }
 
     @Test
     public void testRejectsSkippableFrameWithPrematureEndInLengthBytes() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x55, 0x2a, 0x4d, 0x18, // skippable frame signature
                 2, 0, 0, // should be four byte length
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("Premature end of data"));
     }
 
     @Test
     public void testRejectsStreamsWithBadContentChecksum() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x64, // flag - Version 01, block independent, no block checksum, no content size, with content checksum
                 0x70, // block size 4MB
                 (byte) 185, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 1, 2, 3, 4, };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("content checksum mismatch"));
     }
 
     @Test
     public void testRejectsStreamsWithoutContentChecksum() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x64, // flag - Version 01, block independent, no block checksum, no content size, with content checksum
                 0x70, // block size 4MB
                 (byte) 185, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input))) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("content checksum"));
     }
 
     @Test
     public void testRejectsTrailingBytesAfterValidFrame() {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x56, 0x2a, 0x4d, // too short for any signature
         };
         final IOException ex = assertThrows(IOException.class, () -> {
             try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
                 IOUtils.toByteArray(a);
             }
         }, "expected exception");
         assertThat(ex.getMessage(), containsString("garbage"));
     }
 
     @Test
     public void testSingleByteReadConsistentlyReturnsMinusOneAtEof() throws IOException {
         final File input = getFile("bla.tar.lz4");
         try (InputStream is = Files.newInputStream(input.toPath());
                 FramedLZ4CompressorInputStream in = new FramedLZ4CompressorInputStream(is);) {
             IOUtils.toByteArray(in);
             assertEquals(-1, in.read());
             assertEquals(-1, in.read());
         }
     }
 
     @Test
     public void testSkipsOverSkippableFrames() throws IOException {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x5f, 0x2a, 0x4d, 0x18, // skippable frame signature
                 2, 0, 0, 0, // skippable frame has length 2
                 1, 2, // content of skippable frame
                 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 1, 0, 0, (byte) 0x80, // 1 bytes length and uncompressed bit set
                 '!', // content
                 0, 0, 0, 0, // empty block marker
         };
         try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(new byte[] { 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', '!' }, actual);
         }
     }
 
     @Test
     public void testSkipsOverTrailingSkippableFrames() throws IOException {
         final byte[] input = { 4, 0x22, 0x4d, 0x18, // signature
                 0x60, // flag - Version 01, block independent, no block checksum, no content size, no content checksum
                 0x70, // block size 4MB
                 115, // checksum
                 13, 0, 0, (byte) 0x80, // 13 bytes length and uncompressed bit set
                 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!', // content
                 0, 0, 0, 0, // empty block marker
                 0x51, 0x2a, 0x4d, 0x18, // skippable frame signature
                 2, 0, 0, 0, // skippable frame has length 2
                 1, 2, // content of skippable frame
         };
         try (InputStream a = new FramedLZ4CompressorInputStream(new ByteArrayInputStream(input), true)) {
             final byte[] actual = IOUtils.toByteArray(a);
             assertArrayEquals(new byte[] { 'H', 'e', 'l', 'l', 'o', ',', ' ', 'w', 'o', 'r', 'l', 'd', '!' }, actual);
         }
     }
 
 }