Add deleteWord.

bug: 6669677

Change-Id: I1a5b90ee05e5cffd74a5c140384a3e37c79e7e70

java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java

@@ -201,4 +201,26 @@ public class BinaryDictIOUtils {
         }
         return FormatSpec.NOT_VALID_WORD;
     }
+
+    /**
+     * Delete the word from the binary file.
+     *
+     * @param buffer the buffer to write.
+     * @param word the word we delete
+     * @throws IOException
+     * @throws UnsupportedFormatException
+     */
+    public static void deleteWord(final FusionDictionaryBufferInterface buffer,
+            final String word) throws IOException, UnsupportedFormatException {
+        buffer.position(0);
+        final FileHeader header = BinaryDictInputOutput.readHeader(buffer);
+        final int wordPosition = getTerminalPosition(buffer, word);
+        if (wordPosition == FormatSpec.NOT_VALID_WORD) return;
+
+        buffer.position(wordPosition);
+        final int flags = buffer.readUnsignedByte();
+        final int newFlags = flags ^ FormatSpec.FLAG_IS_TERMINAL;
+        buffer.position(wordPosition);
+        buffer.put((byte)newFlags);
+    }
 }

java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java

@@ -392,7 +392,7 @@ public class BinaryDictInputOutput {
     /**
      * Helper method to check whether the CharGroup has a parent address.
      */
-    private static boolean hasParentAddress(final FormatOptions options) {
+    public static boolean hasParentAddress(final FormatOptions options) {
         return options.mVersion >= FormatSpec.FIRST_VERSION_WITH_PARENT_ADDRESS
                 && options.mHasParentAddress;
     }

tests/src/com/android/inputmethod/latin/makedict/BinaryDictIOTests.java

@@ -25,6 +25,7 @@ import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
 import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
 
 import android.test.AndroidTestCase;
+import android.test.MoreAsserts;
 import android.util.Log;
 import android.util.SparseArray;
 
@@ -517,7 +518,7 @@ public class BinaryDictIOTests extends AndroidTestCase {
     public void testGetTerminalPosition() {
         File file = null;
         try {
-            file = File.createTempFile("runReadUnigrams", ".dict");
+            file = File.createTempFile("testGetTerminalPosition", ".dict");
         } catch (IOException e) {
             // do nothing
         }
@@ -564,4 +565,38 @@ public class BinaryDictIOTests extends AndroidTestCase {
             runGetTerminalPosition(buffer, word, i, false);
         }
     }
+
+    public void testDeleteWord() {
+        File file = null;
+        try {
+            file = File.createTempFile("testGetTerminalPosition", ".dict");
+        } catch (IOException e) {
+            // do nothing
+        }
+        assertNotNull(file);
+
+        final FusionDictionary dict = new FusionDictionary(new Node(),
+                new FusionDictionary.DictionaryOptions(
+                        new HashMap<String, String>(), false, false));
+        addUnigrams(sWords.size(), dict, sWords, null /* shortcutMap */);
+        timeWritingDictToFile(file, dict, VERSION3_WITH_LINKEDLIST_NODE);
+
+        final FusionDictionaryBufferInterface buffer = getBuffer(file, USE_BYTE_ARRAY);
+
+        try {
+            MoreAsserts.assertNotEqual(FormatSpec.NOT_VALID_WORD,
+                    BinaryDictIOUtils.getTerminalPosition(buffer, sWords.get(0)));
+            BinaryDictIOUtils.deleteWord(buffer, sWords.get(0));
+            assertEquals(FormatSpec.NOT_VALID_WORD,
+                    BinaryDictIOUtils.getTerminalPosition(buffer, sWords.get(0)));
+
+            MoreAsserts.assertNotEqual(FormatSpec.NOT_VALID_WORD,
+                    BinaryDictIOUtils.getTerminalPosition(buffer, sWords.get(5)));
+            BinaryDictIOUtils.deleteWord(buffer, sWords.get(5));
+            assertEquals(FormatSpec.NOT_VALID_WORD,
+                    BinaryDictIOUtils.getTerminalPosition(buffer, sWords.get(5)));
+        } catch (IOException e) {
+        } catch (UnsupportedFormatException e) {
+        }
+    }
 }