[AD2] Add a helper method to read an arbitrary dict header
Bug: 7702011
Change-Id: Ib88f6dc222892831ae6932635b65fd2595b16b43
diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
index ee0e9cd..fa5451b 100644
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
+++ b/java/src/com/android/inputmethod/latin/makedict/BinaryDictIOUtils.java
@@ -25,8 +25,12 @@
import com.android.inputmethod.latin.makedict.FusionDictionary.CharGroup;
import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
+import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
@@ -977,4 +981,27 @@
}
return null;
}
+
+ /**
+ * Convenience method to read the header of a binary file.
+ *
+ * This is quite resource intensive - don't call when performance is critical.
+ *
+ * @param file The file to read.
+ */
+ private static final int HEADER_READING_BUFFER_SIZE = 16384;
+ public static FileHeader getDictionaryFileHeader(final File file)
+ throws FileNotFoundException, IOException, UnsupportedFormatException {
+ final byte[] buffer = new byte[HEADER_READING_BUFFER_SIZE];
+ final FileInputStream inStream = new FileInputStream(file);
+ try {
+ inStream.read(buffer);
+ final BinaryDictInputOutput.ByteBufferWrapper wrapper =
+ new BinaryDictInputOutput.ByteBufferWrapper(inStream.getChannel().map(
+ FileChannel.MapMode.READ_ONLY, 0, file.length()));
+ return BinaryDictInputOutput.readHeader(wrapper);
+ } finally {
+ inStream.close();
+ }
+ }
}