refactoring and started to reimplement histogram diff

src/main/java/difflib/algorithm/DifferentiationFailedException.java

@@ -17,16 +17,14 @@ See the License for the specific language governing permissions and
 limitations under the License.
  * #L%
  */
-package difflib.algorithm.myers;
+package difflib.algorithm;
 
 import difflib.algorithm.DiffException;
 
 /**
  * Thrown whenever the differencing engine cannot produce the differences between two revisions of
  * ta text.
- *
- *
- * @author <a href="mailto:juanco@suigeneris.org">Juanco Anez</a>
+
  * @see MyersDiff
  * @see difflib.DiffAlgorithm
  */

src/main/java/difflib/algorithm/myers/MyersDiff.java

@@ -19,6 +19,7 @@ limitations under the License.
  */
 package difflib.algorithm.myers;
 
+import difflib.algorithm.DifferentiationFailedException;
 import difflib.algorithm.DiffAlgorithm;
 import difflib.algorithm.DiffException;
 import difflib.patch.ChangeDelta;

src/main/java/difflib/algorithm/xdiff/XDFEnv.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2017 java-diff-utils.
+ *
+ * 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 difflib.algorithm.xdiff;
+
+/**
+ *
+ * @author tw
+ */
+public class XDFEnv<T> {
+    public final XDFile<T> xdf1 = new XDFile<>();
+    public final XDFile<T> xdf2 = new XDFile<>();
+}

src/main/java/difflib/algorithm/xdiff/XDFile.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2017 java-diff-utils.
+ *
+ * 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 difflib.algorithm.xdiff;
+
+import java.util.List;
+
+/**
+ *
+ * @author tw
+ */
+public class XDFile<T> {
+
+    int dend;
+
+    int dstart;
+    public int ha[];
+    public List<T> data;
+}

src/main/java/difflib/algorithm/xdiff/XDLClassifier.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2017 java-diff-utils.
+ *
+ * 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 difflib.algorithm.xdiff;
+
+/**
+ *
+ * @author tw
+ */
+public class XDLClassifier {
+    
+}

src/main/java/difflib/algorithm/xdiff/XHistogram.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2017 java-diff-utils.
+ *
+ * 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 difflib.algorithm.xdiff;
+
+import difflib.algorithm.DiffAlgorithm;
+import difflib.algorithm.DiffException;
+import difflib.patch.Patch;
+import java.util.List;
+
+/**
+ * Histogram diff implementation.
+ * @author tw
+ */
+public class XHistogram<T> implements DiffAlgorithm<T> {
+
+    XPParam xpp;
+    final XDFEnv env = new XDFEnv();
+    
+    @Override
+    public Patch<T> diff(List<T> original, List<T> revised) throws DiffException {
+        XPrepare.prepareEnvironment(original, revised, xpp, env);
+        
+        histogramDiff(xpp, env, 
+                env.xdf1.dstart + 1, env.xdf1.dend - env.xdf1.dstart + 1,
+                env.xdf2.dstart + 1, env.xdf2.dend - env.xdf2.dstart + 1);
+        return null;
+    }
+
+    private void histogramDiff(XPParam xpp, XDFEnv env, int line1, int count1, int line2, int count2) {
+        throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
+    }
+}

src/main/java/difflib/algorithm/xdiff/XPParam.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2017 java-diff-utils.
+ *
+ * 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 difflib.algorithm.xdiff;
+
+/**
+ *
+ * @author tw
+ */
+public class XPParam {
+    public DiffAlgorithmType type;
+    public long flags;
+    
+    public static enum DiffAlgorithmType {
+        HISTOGRAM_DIFF
+    }
+}

src/main/java/difflib/algorithm/xdiff/XPrepare.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2017 java-diff-utils.
+ *
+ * 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 difflib.algorithm.xdiff;
+
+import java.util.List;
+
+/**
+ *
+ * @author tw
+ */
+public final class XPrepare {
+
+    private static <T> void prepareContext(List<T> data, XPParam xpp, XDLClassifier cf, XDFile xdf) {      
+        xdf.data = data;
+        xdf.ha = new int[data.size()];
+        for (int i=0;i<data.size();i++) {
+            xdf.ha[i] = data.get(i).hashCode();
+        }
+        xdf.dstart = 0;
+        xdf.dend = data.size()-1;
+    }
+    
+    
+    public static <T> void prepareEnvironment(List<T> original, List<T> revised, XPParam xpp, XDFEnv env) {
+        //sample calculation not needed, due to already List
+        long enl1 = original.size() + 1;
+        long enl2 = revised.size() + 1;
+        XDLClassifier cf = new XDLClassifier();
+        
+        prepareContext(original, xpp, cf, env.xdf1);
+        prepareContext(revised, xpp, cf, env.xdf2);
+    }
+}

src/test/java/difflib/algorithm/xdiff/XHistogramTest.java

@@ -0,0 +1,83 @@
+/*
+ * Copyright 2017 java-diff-utils.
+ *
+ * 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 difflib.algorithm.xdiff;
+
+import difflib.DiffUtils;
+import static difflib.DiffUtilsTest.readStringListFromInputStream;
+import difflib.TestConstants;
+import difflib.algorithm.DiffException;
+import difflib.algorithm.myers.MyersDiff;
+import difflib.patch.Patch;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.zip.ZipFile;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import static org.junit.Assert.*;
+import org.junit.Ignore;
+
+/**
+ *
+ * @author tw
+ */
+public class XHistogramTest {
+    
+    public XHistogramTest() {
+    }
+    
+    @BeforeClass
+    public static void setUpClass() {
+    }
+    
+    @AfterClass
+    public static void tearDownClass() {
+    }
+    
+    @Before
+    public void setUp() {
+    }
+    
+    @After
+    public void tearDown() {
+    }
+
+    /**
+     * Test of diff method, of class XHistogram.
+     */
+    @Test
+    public void testDiff() throws Exception {
+        final Patch<String> patch = new XHistogram<String>().diff(
+                Arrays.asList("A","B","C","A","B","B","A"), 
+                Arrays.asList("C","B","A","B","A","C"));
+        assertNotNull(patch);
+        assertEquals(4, patch.getDeltas().size());
+        assertEquals("Patch{deltas=[[DeleteDelta, position: 0, lines: [A, B]], [InsertDelta, position: 3, lines: [B]], [DeleteDelta, position: 5, lines: [B]], [InsertDelta, position: 7, lines: [C]]]}", patch.toString());
+    }
+    
+    @Test
+    public void testPossibleDiffHangOnLargeDatasetDnaumenkoIssue26() throws IOException, DiffException {
+        ZipFile zip = new ZipFile(TestConstants.MOCK_FOLDER + "/large_dataset1.zip");
+        
+        Patch<String> patch = new XHistogram<String>().diff(
+                readStringListFromInputStream(zip.getInputStream(zip.getEntry("ta"))), 
+                readStringListFromInputStream(zip.getInputStream(zip.getEntry("tb"))));
+        
+        System.out.println("done");
+    }
+}

src/test/java/difflib/algorithm/xdiff/XPrepareTest.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2017 java-diff-utils.
+ *
+ * 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 difflib.algorithm.xdiff;
+
+import java.util.Arrays;
+import org.junit.After;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+/**
+ *
+ * @author tw
+ */
+public class XPrepareTest {
+    
+    public XPrepareTest() {
+    }
+    
+    @BeforeClass
+    public static void setUpClass() {
+    }
+    
+    @AfterClass
+    public static void tearDownClass() {
+    }
+    
+    @Before
+    public void setUp() {
+    }
+    
+    @After
+    public void tearDown() {
+    }
+
+    /**
+     * Test of prepareEnvironment method, of class XPrepare.
+     */
+    @Test
+    public void testPrepareEnvironment() {
+        XDFEnv<String> env = new XDFEnv<>();
+        XPrepare.prepareEnvironment(
+                Arrays.asList("A","B","C","A","B","B","A"), 
+                Arrays.asList("C","B","A","B","A","C"),
+                new XPParam(),
+                env);
+        System.out.println(Arrays.toString(env.xdf1.ha));
+        System.out.println(Arrays.toString(env.xdf2.ha));
+    }
+    
+}