1 files changed, 67 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/compress/archivers/sevenz/DeltaDecoder.java b/src/main/java/org/apache/commons/compress/archivers/sevenz/DeltaDecoder.java
new file mode 100644
index 000000000..bc58c636d
--- /dev/null
+++ b/src/main/java/org/apache/commons/compress/archivers/sevenz/DeltaDecoder.java
@@ -0,0 +1,67 @@
+/*
+ *  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.archivers.sevenz;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import org.tukaani.xz.DeltaOptions;
+import org.tukaani.xz.FinishableWrapperOutputStream;
+import org.tukaani.xz.UnsupportedOptionsException;
+
+class DeltaDecoder extends CoderBase {
+    DeltaDecoder() {
+        super(Number.class);
+    }
+
+    @Override
+    InputStream decode(final String archiveName, final InputStream in, final long uncompressedLength,
+            final Coder coder, final byte[] password) throws IOException {
+        return new DeltaOptions(getOptionsFromCoder(coder)).getInputStream(in);
+    }
+
+    @SuppressWarnings("resource")
+    @Override
+    OutputStream encode(final OutputStream out, final Object options) throws IOException {
+        final int distance = numberOptionOrDefault(options, 1);
+        try {
+            return new DeltaOptions(distance).getOutputStream(new FinishableWrapperOutputStream(out));
+        } catch (final UnsupportedOptionsException ex) {
+            throw new IOException(ex.getMessage());
+        }
+    }
+
+    @Override
+    byte[] getOptionsAsProperties(final Object options) {
+        return new byte[] {
+            (byte) (numberOptionOrDefault(options, 1) - 1)
+        };
+    }
+
+    @Override
+    Object getOptionsFromCoder(final Coder coder, final InputStream in) {
+        return getOptionsFromCoder(coder);
+    }
+
+    private int getOptionsFromCoder(final Coder coder) {
+        if (coder.properties == null || coder.properties.length == 0) {
+            return 1;
+        }
+        return (0xff & coder.properties[0]) + 1;
+    }
+}