am 065aad95: Add DictDecoder.

* commit '065aad9501ae446aee5d73450c01dc21b8f3242a':
  Add DictDecoder.

1 files changed, 127 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/makedict/DictDecoder.java b/java/src/com/android/inputmethod/latin/makedict/DictDecoder.java
new file mode 100644
index 000000000..a63d9d5ba
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/makedict/DictDecoder.java
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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 com.android.inputmethod.latin.makedict;
+
+import com.android.inputmethod.annotations.UsedForTesting;
+import com.android.inputmethod.latin.makedict.BinaryDictDecoderUtils.DictBuffer;
+import com.android.inputmethod.latin.makedict.FormatSpec.FileHeader;
+import com.android.inputmethod.latin.utils.ByteArrayDictBuffer;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+
+/**
+ * An interface of binary dictionary decoder.
+ */
+public interface DictDecoder {
+    public FileHeader readHeader() throws IOException, UnsupportedFormatException;
+
+    public interface DictionaryBufferFactory {
+        public DictBuffer getDictionaryBuffer(final File file)
+                throws FileNotFoundException, IOException;
+    }
+
+    /**
+     * Creates DictionaryBuffer using a ByteBuffer
+     *
+     * This class uses less memory than DictionaryBufferFromByteArrayFactory,
+     * but doesn't perform as fast.
+     * When operating on a big dictionary, this class is preferred.
+     */
+    public static final class DictionaryBufferFromReadOnlyByteBufferFactory
+            implements DictionaryBufferFactory {
+        @Override
+        public DictBuffer getDictionaryBuffer(final File file)
+                throws FileNotFoundException, IOException {
+            FileInputStream inStream = null;
+            ByteBuffer buffer = null;
+            try {
+                inStream = new FileInputStream(file);
+                buffer = inStream.getChannel().map(FileChannel.MapMode.READ_ONLY,
+                        0, file.length());
+            } finally {
+                if (inStream != null) {
+                    inStream.close();
+                }
+            }
+            if (buffer != null) {
+                return new BinaryDictDecoderUtils.ByteBufferDictBuffer(buffer);
+            }
+            return null;
+        }
+    }
+
+    /**
+     * Creates DictionaryBuffer using a byte array
+     *
+     * This class performs faster than other classes, but consumes more memory.
+     * When operating on a small dictionary, this class is preferred.
+     */
+    public static final class DictionaryBufferFromByteArrayFactory
+            implements DictionaryBufferFactory {
+        @Override
+        public DictBuffer getDictionaryBuffer(final File file)
+                throws FileNotFoundException, IOException {
+            FileInputStream inStream = null;
+            try {
+                inStream = new FileInputStream(file);
+                final byte[] array = new byte[(int) file.length()];
+                inStream.read(array);
+                return new ByteArrayDictBuffer(array);
+            } finally {
+                if (inStream != null) {
+                    inStream.close();
+                }
+            }
+        }
+    }
+
+    /**
+     * Creates DictionaryBuffer using a writable ByteBuffer and a RandomAccessFile.
+     *
+     * This class doesn't perform as fast as other classes,
+     * but this class is the only option available for destructive operations (insert or delete)
+     * on a dictionary.
+     */
+    @UsedForTesting
+    public static final class DictionaryBufferFromWritableByteBufferFactory
+            implements DictionaryBufferFactory {
+        @Override
+        public DictBuffer getDictionaryBuffer(final File file)
+                throws FileNotFoundException, IOException {
+            RandomAccessFile raFile = null;
+            ByteBuffer buffer = null;
+            try {
+                raFile = new RandomAccessFile(file, "rw");
+                buffer = raFile.getChannel().map(FileChannel.MapMode.READ_WRITE, 0, file.length());
+            } finally {
+                if (raFile != null) {
+                    raFile.close();
+                }
+            }
+            if (buffer != null) {
+                return new BinaryDictDecoderUtils.ByteBufferDictBuffer(buffer);
+            }
+            return null;
+        }
+    }
+}