[Refactor] Divide BinaryDictInputOutput into BinaryDictEncoder and BinaryDictDecoder.

Change-Id: I7c3269d77e3e3b567e459dcaa1bc029903941744

1 files changed, 0 insertions, 1783 deletions

diff --git a/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java b/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java
deleted file mode 100644
index a33cddb49..000000000
--- a/java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java
+++ /dev/null
@@ -1,1783 +0,0 @@
-/*
- * Copyright (C) 2011 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.FormatSpec.FileHeader;
-import com.android.inputmethod.latin.makedict.FormatSpec.FormatOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.CharGroup;
-import com.android.inputmethod.latin.makedict.FusionDictionary.DictionaryOptions;
-import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
-import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
-import com.android.inputmethod.latin.utils.JniUtils;
-
-import java.io.ByteArrayOutputStream;
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileNotFoundException;
-import java.io.IOException;
-import java.io.OutputStream;
-import java.nio.ByteBuffer;
-import java.nio.channels.FileChannel;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.Map;
-import java.util.TreeMap;
-
-/**
- * Reads and writes XML files for a FusionDictionary.
- *
- * All the methods in this class are static.
- */
-public final class BinaryDictInputOutput {
-
-    private static final boolean DBG = MakedictLog.DBG;
-
-    static {
-        JniUtils.loadNativeLibrary();
-    }
-
-    // TODO: implement something sensical instead of just a phony method
-    private static native int doNothing();
-
-    // Arbitrary limit to how much passes we consider address size compression should
-    // terminate in. At the time of this writing, our largest dictionary completes
-    // compression in five passes.
-    // If the number of passes exceeds this number, makedict bails with an exception on
-    // suspicion that a bug might be causing an infinite loop.
-    private static final int MAX_PASSES = 24;
-    private static final int MAX_JUMPS = 12;
-
-    @UsedForTesting
-    public interface FusionDictionaryBufferInterface {
-        public int readUnsignedByte();
-        public int readUnsignedShort();
-        public int readUnsignedInt24();
-        public int readInt();
-        public int position();
-        public void position(int newPosition);
-        public void put(final byte b);
-        public int limit();
-        @UsedForTesting
-        public int capacity();
-    }
-
-    public static final class ByteBufferWrapper implements FusionDictionaryBufferInterface {
-        private ByteBuffer mBuffer;
-
-        public ByteBufferWrapper(final ByteBuffer buffer) {
-            mBuffer = buffer;
-        }
-
-        @Override
-        public int readUnsignedByte() {
-            return mBuffer.get() & 0xFF;
-        }
-
-        @Override
-        public int readUnsignedShort() {
-            return mBuffer.getShort() & 0xFFFF;
-        }
-
-        @Override
-        public int readUnsignedInt24() {
-            final int retval = readUnsignedByte();
-            return (retval << 16) + readUnsignedShort();
-        }
-
-        @Override
-        public int readInt() {
-            return mBuffer.getInt();
-        }
-
-        @Override
-        public int position() {
-            return mBuffer.position();
-        }
-
-        @Override
-        public void position(int newPos) {
-            mBuffer.position(newPos);
-        }
-
-        @Override
-        public void put(final byte b) {
-            mBuffer.put(b);
-        }
-
-        @Override
-        public int limit() {
-            return mBuffer.limit();
-        }
-
-        @Override
-        public int capacity() {
-            return mBuffer.capacity();
-        }
-    }
-
-    /**
-     * A class grouping utility function for our specific character encoding.
-     */
-    static final class CharEncoding {
-        private static final int MINIMAL_ONE_BYTE_CHARACTER_VALUE = 0x20;
-        private static final int MAXIMAL_ONE_BYTE_CHARACTER_VALUE = 0xFF;
-
-        /**
-         * Helper method to find out whether this code fits on one byte
-         */
-        private static boolean fitsOnOneByte(final int character) {
-            return character >= MINIMAL_ONE_BYTE_CHARACTER_VALUE
-                    && character <= MAXIMAL_ONE_BYTE_CHARACTER_VALUE;
-        }
-
-        /**
-         * Compute the size of a character given its character code.
-         *
-         * Char format is:
-         * 1 byte = bbbbbbbb match
-         * case 000xxxxx: xxxxx << 16 + next byte << 8 + next byte
-         * else: if 00011111 (= 0x1F) : this is the terminator. This is a relevant choice because
-         *       unicode code points range from 0 to 0x10FFFF, so any 3-byte value starting with
-         *       00011111 would be outside unicode.
-         * else: iso-latin-1 code
-         * This allows for the whole unicode range to be encoded, including chars outside of
-         * the BMP. Also everything in the iso-latin-1 charset is only 1 byte, except control
-         * characters which should never happen anyway (and still work, but take 3 bytes).
-         *
-         * @param character the character code.
-         * @return the size in binary encoded-form, either 1 or 3 bytes.
-         */
-        static int getCharSize(final int character) {
-            // See char encoding in FusionDictionary.java
-            if (fitsOnOneByte(character)) return 1;
-            if (FormatSpec.INVALID_CHARACTER == character) return 1;
-            return 3;
-        }
-
-        /**
-         * Compute the byte size of a character array.
-         */
-        private static int getCharArraySize(final int[] chars) {
-            int size = 0;
-            for (int character : chars) size += getCharSize(character);
-            return size;
-        }
-
-        /**
-         * Writes a char array to a byte buffer.
-         *
-         * @param codePoints the code point array to write.
-         * @param buffer the byte buffer to write to.
-         * @param index the index in buffer to write the character array to.
-         * @return the index after the last character.
-         */
-        private static int writeCharArray(final int[] codePoints, final byte[] buffer, int index) {
-            for (int codePoint : codePoints) {
-                if (1 == getCharSize(codePoint)) {
-                    buffer[index++] = (byte)codePoint;
-                } else {
-                    buffer[index++] = (byte)(0xFF & (codePoint >> 16));
-                    buffer[index++] = (byte)(0xFF & (codePoint >> 8));
-                    buffer[index++] = (byte)(0xFF & codePoint);
-                }
-            }
-            return index;
-        }
-
-        /**
-         * Writes a string with our character format to a byte buffer.
-         *
-         * This will also write the terminator byte.
-         *
-         * @param buffer the byte buffer to write to.
-         * @param origin the offset to write from.
-         * @param word the string to write.
-         * @return the size written, in bytes.
-         */
-        private static int writeString(final byte[] buffer, final int origin,
-                final String word) {
-            final int length = word.length();
-            int index = origin;
-            for (int i = 0; i < length; i = word.offsetByCodePoints(i, 1)) {
-                final int codePoint = word.codePointAt(i);
-                if (1 == getCharSize(codePoint)) {
-                    buffer[index++] = (byte)codePoint;
-                } else {
-                    buffer[index++] = (byte)(0xFF & (codePoint >> 16));
-                    buffer[index++] = (byte)(0xFF & (codePoint >> 8));
-                    buffer[index++] = (byte)(0xFF & codePoint);
-                }
-            }
-            buffer[index++] = FormatSpec.GROUP_CHARACTERS_TERMINATOR;
-            return index - origin;
-        }
-
-        /**
-         * Writes a string with our character format to a ByteArrayOutputStream.
-         *
-         * This will also write the terminator byte.
-         *
-         * @param buffer the ByteArrayOutputStream to write to.
-         * @param word the string to write.
-         */
-        private static void writeString(final ByteArrayOutputStream buffer, final String word) {
-            final int length = word.length();
-            for (int i = 0; i < length; i = word.offsetByCodePoints(i, 1)) {
-                final int codePoint = word.codePointAt(i);
-                if (1 == getCharSize(codePoint)) {
-                    buffer.write((byte) codePoint);
-                } else {
-                    buffer.write((byte) (0xFF & (codePoint >> 16)));
-                    buffer.write((byte) (0xFF & (codePoint >> 8)));
-                    buffer.write((byte) (0xFF & codePoint));
-                }
-            }
-            buffer.write(FormatSpec.GROUP_CHARACTERS_TERMINATOR);
-        }
-
-        /**
-         * Reads a string from a buffer. This is the converse of the above method.
-         */
-        private static String readString(final FusionDictionaryBufferInterface buffer) {
-            final StringBuilder s = new StringBuilder();
-            int character = readChar(buffer);
-            while (character != FormatSpec.INVALID_CHARACTER) {
-                s.appendCodePoint(character);
-                character = readChar(buffer);
-            }
-            return s.toString();
-        }
-
-        /**
-         * Reads a character from the buffer.
-         *
-         * This follows the character format documented earlier in this source file.
-         *
-         * @param buffer the buffer, positioned over an encoded character.
-         * @return the character code.
-         */
-        static int readChar(final FusionDictionaryBufferInterface buffer) {
-            int character = buffer.readUnsignedByte();
-            if (!fitsOnOneByte(character)) {
-                if (FormatSpec.GROUP_CHARACTERS_TERMINATOR == character) {
-                    return FormatSpec.INVALID_CHARACTER;
-                }
-                character <<= 16;
-                character += buffer.readUnsignedShort();
-            }
-            return character;
-        }
-    }
-
-    /**
-     * Compute the binary size of the character array.
-     *
-     * If only one character, this is the size of this character. If many, it's the sum of their
-     * sizes + 1 byte for the terminator.
-     *
-     * @param characters the character array
-     * @return the size of the char array, including the terminator if any
-     */
-    static int getGroupCharactersSize(final int[] characters) {
-        int size = CharEncoding.getCharArraySize(characters);
-        if (characters.length > 1) size += FormatSpec.GROUP_TERMINATOR_SIZE;
-        return size;
-    }
-
-    /**
-     * Compute the binary size of the character array in a group
-     *
-     * If only one character, this is the size of this character. If many, it's the sum of their
-     * sizes + 1 byte for the terminator.
-     *
-     * @param group the group
-     * @return the size of the char array, including the terminator if any
-     */
-    private static int getGroupCharactersSize(final CharGroup group) {
-        return getGroupCharactersSize(group.mChars);
-    }
-
-    /**
-     * Compute the binary size of the group count for a node
-     * @param node the node
-     * @return the size of the group count, either 1 or 2 bytes.
-     */
-    private static int getGroupCountSize(final Node node) {
-        return BinaryDictIOUtils.getGroupCountSize(node.mData.size());
-    }
-
-    /**
-     * Compute the size of a shortcut in bytes.
-     */
-    private static int getShortcutSize(final WeightedString shortcut) {
-        int size = FormatSpec.GROUP_ATTRIBUTE_FLAGS_SIZE;
-        final String word = shortcut.mWord;
-        final int length = word.length();
-        for (int i = 0; i < length; i = word.offsetByCodePoints(i, 1)) {
-            final int codePoint = word.codePointAt(i);
-            size += CharEncoding.getCharSize(codePoint);
-        }
-        size += FormatSpec.GROUP_TERMINATOR_SIZE;
-        return size;
-    }
-
-    /**
-     * Compute the size of a shortcut list in bytes.
-     *
-     * This is known in advance and does not change according to position in the file
-     * like address lists do.
-     */
-    static int getShortcutListSize(final ArrayList<WeightedString> shortcutList) {
-        if (null == shortcutList) return 0;
-        int size = FormatSpec.GROUP_SHORTCUT_LIST_SIZE_SIZE;
-        for (final WeightedString shortcut : shortcutList) {
-            size += getShortcutSize(shortcut);
-        }
-        return size;
-    }
-
-    /**
-     * Compute the maximum size of a CharGroup, assuming 3-byte addresses for everything.
-     *
-     * @param group the CharGroup to compute the size of.
-     * @param options file format options.
-     * @return the maximum size of the group.
-     */
-    private static int getCharGroupMaximumSize(final CharGroup group, final FormatOptions options) {
-        int size = getGroupHeaderSize(group, options);
-        // If terminal, one byte for the frequency
-        if (group.isTerminal()) size += FormatSpec.GROUP_FREQUENCY_SIZE;
-        size += FormatSpec.GROUP_MAX_ADDRESS_SIZE; // For children address
-        size += getShortcutListSize(group.mShortcutTargets);
-        if (null != group.mBigrams) {
-            size += (FormatSpec.GROUP_ATTRIBUTE_FLAGS_SIZE
-                    + FormatSpec.GROUP_ATTRIBUTE_MAX_ADDRESS_SIZE)
-                    * group.mBigrams.size();
-        }
-        return size;
-    }
-
-    /**
-     * Compute the maximum size of a node, assuming 3-byte addresses for everything, and caches
-     * it in the 'actualSize' member of the node.
-     *
-     * @param node the node to compute the maximum size of.
-     * @param options file format options.
-     */
-    private static void calculateNodeMaximumSize(final Node node, final FormatOptions options) {
-        int size = getGroupCountSize(node);
-        for (CharGroup g : node.mData) {
-            final int groupSize = getCharGroupMaximumSize(g, options);
-            g.mCachedSize = groupSize;
-            size += groupSize;
-        }
-        if (options.mSupportsDynamicUpdate) {
-            size += FormatSpec.FORWARD_LINK_ADDRESS_SIZE;
-        }
-        node.mCachedSize = size;
-    }
-
-    /**
-     * Compute the size of the header (flag + [parent address] + characters size) of a CharGroup.
-     *
-     * @param group the group of which to compute the size of the header
-     * @param options file format options.
-     */
-    private static int getGroupHeaderSize(final CharGroup group, final FormatOptions options) {
-        if (BinaryDictIOUtils.supportsDynamicUpdate(options)) {
-            return FormatSpec.GROUP_FLAGS_SIZE + FormatSpec.PARENT_ADDRESS_SIZE
-                    + getGroupCharactersSize(group);
-        } else {
-            return FormatSpec.GROUP_FLAGS_SIZE + getGroupCharactersSize(group);
-        }
-    }
-
-    /**
-     * Compute the size, in bytes, that an address will occupy.
-     *
-     * This can be used either for children addresses (which are always positive) or for
-     * attribute, which may be positive or negative but
-     * store their sign bit separately.
-     *
-     * @param address the address
-     * @return the byte size.
-     */
-    static int getByteSize(final int address) {
-        assert(address <= FormatSpec.UINT24_MAX);
-        if (!BinaryDictIOUtils.hasChildrenAddress(address)) {
-            return 0;
-        } else if (Math.abs(address) <= FormatSpec.UINT8_MAX) {
-            return 1;
-        } else if (Math.abs(address) <= FormatSpec.UINT16_MAX) {
-            return 2;
-        } else {
-            return 3;
-        }
-    }
-
-    // End utility methods.
-
-    // This method is responsible for finding a nice ordering of the nodes that favors run-time
-    // cache performance and dictionary size.
-    /* package for tests */ static ArrayList<Node> flattenTree(final Node root) {
-        final int treeSize = FusionDictionary.countCharGroups(root);
-        MakedictLog.i("Counted nodes : " + treeSize);
-        final ArrayList<Node> flatTree = new ArrayList<Node>(treeSize);
-        return flattenTreeInner(flatTree, root);
-    }
-
-    private static ArrayList<Node> flattenTreeInner(final ArrayList<Node> list, final Node node) {
-        // Removing the node is necessary if the tails are merged, because we would then
-        // add the same node several times when we only want it once. A number of places in
-        // the code also depends on any node being only once in the list.
-        // Merging tails can only be done if there are no attributes. Searching for attributes
-        // in LatinIME code depends on a total breadth-first ordering, which merging tails
-        // breaks. If there are no attributes, it should be fine (and reduce the file size)
-        // to merge tails, and removing the node from the list would be necessary. However,
-        // we don't merge tails because breaking the breadth-first ordering would result in
-        // extreme overhead at bigram lookup time (it would make the search function O(n) instead
-        // of the current O(log(n)), where n=number of nodes in the dictionary which is pretty
-        // high).
-        // If no nodes are ever merged, we can't have the same node twice in the list, hence
-        // searching for duplicates in unnecessary. It is also very performance consuming,
-        // since `list' is an ArrayList so it's an O(n) operation that runs on all nodes, making
-        // this simple list.remove operation O(n*n) overall. On Android this overhead is very
-        // high.
-        // For future reference, the code to remove duplicate is a simple : list.remove(node);
-        list.add(node);
-        final ArrayList<CharGroup> branches = node.mData;
-        final int nodeSize = branches.size();
-        for (CharGroup group : branches) {
-            if (null != group.mChildren) flattenTreeInner(list, group.mChildren);
-        }
-        return list;
-    }
-
-    /**
-     * Get the offset from a position inside a current node to a target node, during update.
-     *
-     * If the current node is before the target node, the target node has not been updated yet,
-     * so we should return the offset from the old position of the current node to the old position
-     * of the target node. If on the other hand the target is before the current node, it already
-     * has been updated, so we should return the offset from the new position in the current node
-     * to the new position in the target node.
-     * @param currentNode the node containing the CharGroup where the offset will be written
-     * @param offsetFromStartOfCurrentNode the offset, in bytes, from the start of currentNode
-     * @param targetNode the target node to get the offset to
-     * @return the offset to the target node
-     */
-    private static int getOffsetToTargetNodeDuringUpdate(final Node currentNode,
-            final int offsetFromStartOfCurrentNode, final Node targetNode) {
-        final boolean isTargetBeforeCurrent = (targetNode.mCachedAddressBeforeUpdate
-                < currentNode.mCachedAddressBeforeUpdate);
-        if (isTargetBeforeCurrent) {
-            return targetNode.mCachedAddressAfterUpdate
-                    - (currentNode.mCachedAddressAfterUpdate + offsetFromStartOfCurrentNode);
-        } else {
-            return targetNode.mCachedAddressBeforeUpdate
-                    - (currentNode.mCachedAddressBeforeUpdate + offsetFromStartOfCurrentNode);
-        }
-    }
-
-    /**
-     * Get the offset from a position inside a current node to a target CharGroup, during update.
-     * @param currentNode the node containing the CharGroup where the offset will be written
-     * @param offsetFromStartOfCurrentNode the offset, in bytes, from the start of currentNode
-     * @param targetCharGroup the target CharGroup to get the offset to
-     * @return the offset to the target CharGroup
-     */
-    // TODO: is there any way to factorize this method with the one above?
-    private static int getOffsetToTargetCharGroupDuringUpdate(final Node currentNode,
-            final int offsetFromStartOfCurrentNode, final CharGroup targetCharGroup) {
-        final int oldOffsetBasePoint = currentNode.mCachedAddressBeforeUpdate
-                + offsetFromStartOfCurrentNode;
-        final boolean isTargetBeforeCurrent = (targetCharGroup.mCachedAddressBeforeUpdate
-                < oldOffsetBasePoint);
-        // If the target is before the current node, then its address has already been updated.
-        // We can use the AfterUpdate member, and compare it to our own member after update.
-        // Otherwise, the AfterUpdate member is not updated yet, so we need to use the BeforeUpdate
-        // member, and of course we have to compare this to our own address before update.
-        if (isTargetBeforeCurrent) {
-            final int newOffsetBasePoint = currentNode.mCachedAddressAfterUpdate
-                    + offsetFromStartOfCurrentNode;
-            return targetCharGroup.mCachedAddressAfterUpdate - newOffsetBasePoint;
-        } else {
-            return targetCharGroup.mCachedAddressBeforeUpdate - oldOffsetBasePoint;
-        }
-    }
-
-    /**
-     * Computes the actual node size, based on the cached addresses of the children nodes.
-     *
-     * Each node stores its tentative address. During dictionary address computing, these
-     * are not final, but they can be used to compute the node size (the node size depends
-     * on the address of the children because the number of bytes necessary to store an
-     * address depends on its numeric value. The return value indicates whether the node
-     * contents (as in, any of the addresses stored in the cache fields) have changed with
-     * respect to their previous value.
-     *
-     * @param node the node to compute the size of.
-     * @param dict the dictionary in which the word/attributes are to be found.
-     * @param formatOptions file format options.
-     * @return false if none of the cached addresses inside the node changed, true otherwise.
-     */
-    private static boolean computeActualNodeSize(final Node node, final FusionDictionary dict,
-            final FormatOptions formatOptions) {
-        boolean changed = false;
-        int size = getGroupCountSize(node);
-        for (CharGroup group : node.mData) {
-            group.mCachedAddressAfterUpdate = node.mCachedAddressAfterUpdate + size;
-            if (group.mCachedAddressAfterUpdate != group.mCachedAddressBeforeUpdate) {
-                changed = true;
-            }
-            int groupSize = getGroupHeaderSize(group, formatOptions);
-            if (group.isTerminal()) groupSize += FormatSpec.GROUP_FREQUENCY_SIZE;
-            if (null == group.mChildren && formatOptions.mSupportsDynamicUpdate) {
-                groupSize += FormatSpec.SIGNED_CHILDREN_ADDRESS_SIZE;
-            } else if (null != group.mChildren) {
-                if (formatOptions.mSupportsDynamicUpdate) {
-                    groupSize += FormatSpec.SIGNED_CHILDREN_ADDRESS_SIZE;
-                } else {
-                    groupSize += getByteSize(getOffsetToTargetNodeDuringUpdate(node,
-                            groupSize + size, group.mChildren));
-                }
-            }
-            groupSize += getShortcutListSize(group.mShortcutTargets);
-            if (null != group.mBigrams) {
-                for (WeightedString bigram : group.mBigrams) {
-                    final int offset = getOffsetToTargetCharGroupDuringUpdate(node,
-                            groupSize + size + FormatSpec.GROUP_FLAGS_SIZE,
-                            FusionDictionary.findWordInTree(dict.mRoot, bigram.mWord));
-                    groupSize += getByteSize(offset) + FormatSpec.GROUP_FLAGS_SIZE;
-                }
-            }
-            group.mCachedSize = groupSize;
-            size += groupSize;
-        }
-        if (formatOptions.mSupportsDynamicUpdate) {
-            size += FormatSpec.FORWARD_LINK_ADDRESS_SIZE;
-        }
-        if (node.mCachedSize != size) {
-            node.mCachedSize = size;
-            changed = true;
-        }
-        return changed;
-    }
-
-    /**
-     * Initializes the cached addresses of nodes from their size.
-     *
-     * @param flatNodes the array of nodes.
-     * @param formatOptions file format options.
-     * @return the byte size of the entire stack.
-     */
-    private static int initializeNodesCachedAddresses(final ArrayList<Node> flatNodes,
-            final FormatOptions formatOptions) {
-        int nodeOffset = 0;
-        for (final Node n : flatNodes) {
-            n.mCachedAddressBeforeUpdate = nodeOffset;
-            int groupCountSize = getGroupCountSize(n);
-            int groupOffset = 0;
-            for (final CharGroup g : n.mData) {
-                g.mCachedAddressBeforeUpdate = g.mCachedAddressAfterUpdate =
-                        groupCountSize + nodeOffset + groupOffset;
-                groupOffset += g.mCachedSize;
-            }
-            final int nodeSize = groupCountSize + groupOffset
-                    + (formatOptions.mSupportsDynamicUpdate
-                            ? FormatSpec.FORWARD_LINK_ADDRESS_SIZE : 0);
-            nodeOffset += n.mCachedSize;
-        }
-        return nodeOffset;
-    }
-
-    /**
-     * Updates the cached addresses of nodes after recomputing their new positions.
-     *
-     * @param flatNodes the array of nodes.
-     */
-    private static void updateNodeCachedAddresses(final ArrayList<Node> flatNodes) {
-        for (final Node n : flatNodes) {
-            n.mCachedAddressBeforeUpdate = n.mCachedAddressAfterUpdate;
-            for (final CharGroup g : n.mData) {
-                g.mCachedAddressBeforeUpdate = g.mCachedAddressAfterUpdate;
-            }
-        }
-    }
-
-    /**
-     * Compute the cached parent addresses after all has been updated.
-     *
-     * The parent addresses are used by some binary formats at write-to-disk time. Not all formats
-     * need them. In particular, version 2 does not need them, and version 3 does.
-     *
-     * @param flatNodes the flat array of nodes to fill in
-     */
-    private static void computeParentAddresses(final ArrayList<Node> flatNodes) {
-        for (final Node node : flatNodes) {
-            for (final CharGroup group : node.mData) {
-                if (null != group.mChildren) {
-                    // Assign my address to children's parent address
-                    // Here BeforeUpdate and AfterUpdate addresses have the same value, so it
-                    // does not matter which we use.
-                    group.mChildren.mCachedParentAddress = group.mCachedAddressAfterUpdate
-                            - group.mChildren.mCachedAddressAfterUpdate;
-                }
-            }
-        }
-    }
-
-    /**
-     * Compute the addresses and sizes of an ordered node array.
-     *
-     * This method takes a node array and will update its cached address and size values
-     * so that they can be written into a file. It determines the smallest size each of the
-     * nodes can be given the addresses of its children and attributes, and store that into
-     * each node.
-     * The order of the node is given by the order of the array. This method makes no effort
-     * to find a good order; it only mechanically computes the size this order results in.
-     *
-     * @param dict the dictionary
-     * @param flatNodes the ordered array of nodes
-     * @param formatOptions file format options.
-     * @return the same array it was passed. The nodes have been updated for address and size.
-     */
-    private static ArrayList<Node> computeAddresses(final FusionDictionary dict,
-            final ArrayList<Node> flatNodes, final FormatOptions formatOptions) {
-        // First get the worst possible sizes and offsets
-        for (final Node n : flatNodes) calculateNodeMaximumSize(n, formatOptions);
-        final int offset = initializeNodesCachedAddresses(flatNodes, formatOptions);
-
-        MakedictLog.i("Compressing the array addresses. Original size : " + offset);
-        MakedictLog.i("(Recursively seen size : " + offset + ")");
-
-        int passes = 0;
-        boolean changesDone = false;
-        do {
-            changesDone = false;
-            int nodeStartOffset = 0;
-            for (final Node n : flatNodes) {
-                n.mCachedAddressAfterUpdate = nodeStartOffset;
-                final int oldNodeSize = n.mCachedSize;
-                final boolean changed = computeActualNodeSize(n, dict, formatOptions);
-                final int newNodeSize = n.mCachedSize;
-                if (oldNodeSize < newNodeSize) throw new RuntimeException("Increased size ?!");
-                nodeStartOffset += newNodeSize;
-                changesDone |= changed;
-            }
-            updateNodeCachedAddresses(flatNodes);
-            ++passes;
-            if (passes > MAX_PASSES) throw new RuntimeException("Too many passes - probably a bug");
-        } while (changesDone);
-
-        if (formatOptions.mSupportsDynamicUpdate) {
-            computeParentAddresses(flatNodes);
-        }
-        final Node lastNode = flatNodes.get(flatNodes.size() - 1);
-        MakedictLog.i("Compression complete in " + passes + " passes.");
-        MakedictLog.i("After address compression : "
-                + (lastNode.mCachedAddressAfterUpdate + lastNode.mCachedSize));
-
-        return flatNodes;
-    }
-
-    /**
-     * Sanity-checking method.
-     *
-     * This method checks an array of node for juxtaposition, that is, it will do
-     * nothing if each node's cached address is actually the previous node's address
-     * plus the previous node's size.
-     * If this is not the case, it will throw an exception.
-     *
-     * @param array the array node to check
-     */
-    private static void checkFlatNodeArray(final ArrayList<Node> array) {
-        int offset = 0;
-        int index = 0;
-        for (final Node n : array) {
-            // BeforeUpdate and AfterUpdate addresses are the same here, so it does not matter
-            // which we use.
-            if (n.mCachedAddressAfterUpdate != offset) {
-                throw new RuntimeException("Wrong address for node " + index
-                        + " : expected " + offset + ", got " + n.mCachedAddressAfterUpdate);
-            }
-            ++index;
-            offset += n.mCachedSize;
-        }
-    }
-
-    /**
-     * Helper method to write a variable-size address to a file.
-     *
-     * @param buffer the buffer to write to.
-     * @param index the index in the buffer to write the address to.
-     * @param address the address to write.
-     * @return the size in bytes the address actually took.
-     */
-    private static int writeVariableAddress(final byte[] buffer, int index, final int address) {
-        switch (getByteSize(address)) {
-        case 1:
-            buffer[index++] = (byte)address;
-            return 1;
-        case 2:
-            buffer[index++] = (byte)(0xFF & (address >> 8));
-            buffer[index++] = (byte)(0xFF & address);
-            return 2;
-        case 3:
-            buffer[index++] = (byte)(0xFF & (address >> 16));
-            buffer[index++] = (byte)(0xFF & (address >> 8));
-            buffer[index++] = (byte)(0xFF & address);
-            return 3;
-        case 0:
-            return 0;
-        default:
-            throw new RuntimeException("Address " + address + " has a strange size");
-        }
-    }
-
-    /**
-     * Helper method to write a variable-size signed address to a file.
-     *
-     * @param buffer the buffer to write to.
-     * @param index the index in the buffer to write the address to.
-     * @param address the address to write.
-     * @return the size in bytes the address actually took.
-     */
-    private static int writeVariableSignedAddress(final byte[] buffer, int index,
-            final int address) {
-        if (!BinaryDictIOUtils.hasChildrenAddress(address)) {
-            buffer[index] = buffer[index + 1] = buffer[index + 2] = 0;
-        } else {
-            final int absAddress = Math.abs(address);
-            buffer[index++] =
-                    (byte)((address < 0 ? FormatSpec.MSB8 : 0) | (0xFF & (absAddress >> 16)));
-            buffer[index++] = (byte)(0xFF & (absAddress >> 8));
-            buffer[index++] = (byte)(0xFF & absAddress);
-        }
-        return 3;
-    }
-
-    /**
-     * Makes the flag value for a char group.
-     *
-     * @param hasMultipleChars whether the group has multiple chars.
-     * @param isTerminal whether the group is terminal.
-     * @param childrenAddressSize the size of a children address.
-     * @param hasShortcuts whether the group has shortcuts.
-     * @param hasBigrams whether the group has bigrams.
-     * @param isNotAWord whether the group is not a word.
-     * @param isBlackListEntry whether the group is a blacklist entry.
-     * @param formatOptions file format options.
-     * @return the flags
-     */
-    static int makeCharGroupFlags(final boolean hasMultipleChars, final boolean isTerminal,
-            final int childrenAddressSize, final boolean hasShortcuts, final boolean hasBigrams,
-            final boolean isNotAWord, final boolean isBlackListEntry,
-            final FormatOptions formatOptions) {
-        byte flags = 0;
-        if (hasMultipleChars) flags |= FormatSpec.FLAG_HAS_MULTIPLE_CHARS;
-        if (isTerminal) flags |= FormatSpec.FLAG_IS_TERMINAL;
-        if (formatOptions.mSupportsDynamicUpdate) {
-            flags |= FormatSpec.FLAG_IS_NOT_MOVED;
-        } else if (true) {
-            switch (childrenAddressSize) {
-                case 1:
-                    flags |= FormatSpec.FLAG_GROUP_ADDRESS_TYPE_ONEBYTE;
-                    break;
-                case 2:
-                    flags |= FormatSpec.FLAG_GROUP_ADDRESS_TYPE_TWOBYTES;
-                    break;
-                case 3:
-                    flags |= FormatSpec.FLAG_GROUP_ADDRESS_TYPE_THREEBYTES;
-                    break;
-                case 0:
-                    flags |= FormatSpec.FLAG_GROUP_ADDRESS_TYPE_NOADDRESS;
-                    break;
-                default:
-                    throw new RuntimeException("Node with a strange address");
-            }
-        }
-        if (hasShortcuts) flags |= FormatSpec.FLAG_HAS_SHORTCUT_TARGETS;
-        if (hasBigrams) flags |= FormatSpec.FLAG_HAS_BIGRAMS;
-        if (isNotAWord) flags |= FormatSpec.FLAG_IS_NOT_A_WORD;
-        if (isBlackListEntry) flags |= FormatSpec.FLAG_IS_BLACKLISTED;
-        return flags;
-    }
-
-    private static byte makeCharGroupFlags(final CharGroup group, final int groupAddress,
-            final int childrenOffset, final FormatOptions formatOptions) {
-        return (byte) makeCharGroupFlags(group.mChars.length > 1, group.mFrequency >= 0,
-                getByteSize(childrenOffset), group.mShortcutTargets != null, group.mBigrams != null,
-                group.mIsNotAWord, group.mIsBlacklistEntry, formatOptions);
-    }
-
-    /**
-     * Makes the flag value for a bigram.
-     *
-     * @param more whether there are more bigrams after this one.
-     * @param offset the offset of the bigram.
-     * @param bigramFrequency the frequency of the bigram, 0..255.
-     * @param unigramFrequency the unigram frequency of the same word, 0..255.
-     * @param word the second bigram, for debugging purposes
-     * @return the flags
-     */
-    private static final int makeBigramFlags(final boolean more, final int offset,
-            int bigramFrequency, final int unigramFrequency, final String word) {
-        int bigramFlags = (more ? FormatSpec.FLAG_ATTRIBUTE_HAS_NEXT : 0)
-                + (offset < 0 ? FormatSpec.FLAG_ATTRIBUTE_OFFSET_NEGATIVE : 0);
-        switch (getByteSize(offset)) {
-        case 1:
-            bigramFlags |= FormatSpec.FLAG_ATTRIBUTE_ADDRESS_TYPE_ONEBYTE;
-            break;
-        case 2:
-            bigramFlags |= FormatSpec.FLAG_ATTRIBUTE_ADDRESS_TYPE_TWOBYTES;
-            break;
-        case 3:
-            bigramFlags |= FormatSpec.FLAG_ATTRIBUTE_ADDRESS_TYPE_THREEBYTES;
-            break;
-        default:
-            throw new RuntimeException("Strange offset size");
-        }
-        if (unigramFrequency > bigramFrequency) {
-            MakedictLog.e("Unigram freq is superior to bigram freq for \"" + word
-                    + "\". Bigram freq is " + bigramFrequency + ", unigram freq for "
-                    + word + " is " + unigramFrequency);
-            bigramFrequency = unigramFrequency;
-        }
-        // We compute the difference between 255 (which means probability = 1) and the
-        // unigram score. We split this into a number of discrete steps.
-        // Now, the steps are numbered 0~15; 0 represents an increase of 1 step while 15
-        // represents an increase of 16 steps: a value of 15 will be interpreted as the median
-        // value of the 16th step. In all justice, if the bigram frequency is low enough to be
-        // rounded below the first step (which means it is less than half a step higher than the
-        // unigram frequency) then the unigram frequency itself is the best approximation of the
-        // bigram freq that we could possibly supply, hence we should *not* include this bigram
-        // in the file at all.
-        // until this is done, we'll write 0 and slightly overestimate this case.
-        // In other words, 0 means "between 0.5 step and 1.5 step", 1 means "between 1.5 step
-        // and 2.5 steps", and 15 means "between 15.5 steps and 16.5 steps". So we want to
-        // divide our range [unigramFreq..MAX_TERMINAL_FREQUENCY] in 16.5 steps to get the
-        // step size. Then we compute the start of the first step (the one where value 0 starts)
-        // by adding half-a-step to the unigramFrequency. From there, we compute the integer
-        // number of steps to the bigramFrequency. One last thing: we want our steps to include
-        // their lower bound and exclude their higher bound so we need to have the first step
-        // start at exactly 1 unit higher than floor(unigramFreq + half a step).
-        // Note : to reconstruct the score, the dictionary reader will need to divide
-        // MAX_TERMINAL_FREQUENCY - unigramFreq by 16.5 likewise to get the value of the step,
-        // and add (discretizedFrequency + 0.5 + 0.5) times this value to get the best
-        // approximation. (0.5 to get the first step start, and 0.5 to get the middle of the
-        // step pointed by the discretized frequency.
-        final float stepSize =
-                (FormatSpec.MAX_TERMINAL_FREQUENCY - unigramFrequency)
-                / (1.5f + FormatSpec.MAX_BIGRAM_FREQUENCY);
-        final float firstStepStart = 1 + unigramFrequency + (stepSize / 2.0f);
-        final int discretizedFrequency = (int)((bigramFrequency - firstStepStart) / stepSize);
-        // If the bigram freq is less than half-a-step higher than the unigram freq, we get -1
-        // here. The best approximation would be the unigram freq itself, so we should not
-        // include this bigram in the dictionary. For now, register as 0, and live with the
-        // small over-estimation that we get in this case. TODO: actually remove this bigram
-        // if discretizedFrequency < 0.
-        final int finalBigramFrequency = discretizedFrequency > 0 ? discretizedFrequency : 0;
-        bigramFlags += finalBigramFrequency & FormatSpec.FLAG_ATTRIBUTE_FREQUENCY;
-        return bigramFlags;
-    }
-
-    /**
-     * Makes the 2-byte value for options flags.
-     */
-    private static final int makeOptionsValue(final FusionDictionary dictionary,
-            final FormatOptions formatOptions) {
-        final DictionaryOptions options = dictionary.mOptions;
-        final boolean hasBigrams = dictionary.hasBigrams();
-        return (options.mFrenchLigatureProcessing ? FormatSpec.FRENCH_LIGATURE_PROCESSING_FLAG : 0)
-                + (options.mGermanUmlautProcessing ? FormatSpec.GERMAN_UMLAUT_PROCESSING_FLAG : 0)
-                + (hasBigrams ? FormatSpec.CONTAINS_BIGRAMS_FLAG : 0)
-                + (formatOptions.mSupportsDynamicUpdate ? FormatSpec.SUPPORTS_DYNAMIC_UPDATE : 0);
-    }
-
-    /**
-     * Makes the flag value for a shortcut.
-     *
-     * @param more whether there are more attributes after this one.
-     * @param frequency the frequency of the attribute, 0..15
-     * @return the flags
-     */
-    static final int makeShortcutFlags(final boolean more, final int frequency) {
-        return (more ? FormatSpec.FLAG_ATTRIBUTE_HAS_NEXT : 0)
-                + (frequency & FormatSpec.FLAG_ATTRIBUTE_FREQUENCY);
-    }
-
-    private static final int writeParentAddress(final byte[] buffer, final int index,
-            final int address, final FormatOptions formatOptions) {
-        if (BinaryDictIOUtils.supportsDynamicUpdate(formatOptions)) {
-            if (address == FormatSpec.NO_PARENT_ADDRESS) {
-                buffer[index] = buffer[index + 1] = buffer[index + 2] = 0;
-            } else {
-                final int absAddress = Math.abs(address);
-                assert(absAddress <= FormatSpec.SINT24_MAX);
-                buffer[index] = (byte)((address < 0 ? FormatSpec.MSB8 : 0)
-                        | ((absAddress >> 16) & 0xFF));
-                buffer[index + 1] = (byte)((absAddress >> 8) & 0xFF);
-                buffer[index + 2] = (byte)(absAddress & 0xFF);
-            }
-            return index + 3;
-        } else {
-            return index;
-        }
-    }
-
-    /**
-     * Write a node to memory. The node is expected to have its final position cached.
-     *
-     * This can be an empty map, but the more is inside the faster the lookups will be. It can
-     * be carried on as long as nodes do not move.
-     *
-     * @param dict the dictionary the node is a part of (for relative offsets).
-     * @param buffer the memory buffer to write to.
-     * @param node the node to write.
-     * @param formatOptions file format options.
-     * @return the address of the END of the node.
-     */
-    @SuppressWarnings("unused")
-    private static int writePlacedNode(final FusionDictionary dict, byte[] buffer,
-            final Node node, final FormatOptions formatOptions) {
-        // TODO: Make the code in common with BinaryDictIOUtils#writeCharGroup
-        int index = node.mCachedAddressAfterUpdate;
-
-        final int groupCount = node.mData.size();
-        final int countSize = getGroupCountSize(node);
-        final int parentAddress = node.mCachedParentAddress;
-        if (1 == countSize) {
-            buffer[index++] = (byte)groupCount;
-        } else if (2 == countSize) {
-            // We need to signal 2-byte size by setting the top bit of the MSB to 1, so
-            // we | 0x80 to do this.
-            buffer[index++] = (byte)((groupCount >> 8) | 0x80);
-            buffer[index++] = (byte)(groupCount & 0xFF);
-        } else {
-            throw new RuntimeException("Strange size from getGroupCountSize : " + countSize);
-        }
-        int groupAddress = index;
-        for (int i = 0; i < groupCount; ++i) {
-            final CharGroup group = node.mData.get(i);
-            if (index != group.mCachedAddressAfterUpdate) {
-                throw new RuntimeException("Bug: write index is not the same as the cached address "
-                        + "of the group : " + index + " <> " + group.mCachedAddressAfterUpdate);
-            }
-            groupAddress += getGroupHeaderSize(group, formatOptions);
-            // Sanity checks.
-            if (DBG && group.mFrequency > FormatSpec.MAX_TERMINAL_FREQUENCY) {
-                throw new RuntimeException("A node has a frequency > "
-                        + FormatSpec.MAX_TERMINAL_FREQUENCY
-                        + " : " + group.mFrequency);
-            }
-            if (group.mFrequency >= 0) groupAddress += FormatSpec.GROUP_FREQUENCY_SIZE;
-            final int childrenOffset = null == group.mChildren
-                    ? FormatSpec.NO_CHILDREN_ADDRESS
-                            : group.mChildren.mCachedAddressAfterUpdate - groupAddress;
-            buffer[index++] =
-                    makeCharGroupFlags(group, groupAddress, childrenOffset, formatOptions);
-
-            if (parentAddress == FormatSpec.NO_PARENT_ADDRESS) {
-                index = writeParentAddress(buffer, index, parentAddress, formatOptions);
-            } else {
-                index = writeParentAddress(buffer, index, parentAddress
-                        + (node.mCachedAddressAfterUpdate - group.mCachedAddressAfterUpdate),
-                        formatOptions);
-            }
-
-            index = CharEncoding.writeCharArray(group.mChars, buffer, index);
-            if (group.hasSeveralChars()) {
-                buffer[index++] = FormatSpec.GROUP_CHARACTERS_TERMINATOR;
-            }
-            if (group.mFrequency >= 0) {
-                buffer[index++] = (byte) group.mFrequency;
-            }
-
-            final int shift;
-            if (formatOptions.mSupportsDynamicUpdate) {
-                shift = writeVariableSignedAddress(buffer, index, childrenOffset);
-            } else {
-                shift = writeVariableAddress(buffer, index, childrenOffset);
-            }
-            index += shift;
-            groupAddress += shift;
-
-            // Write shortcuts
-            if (null != group.mShortcutTargets) {
-                final int indexOfShortcutByteSize = index;
-                index += FormatSpec.GROUP_SHORTCUT_LIST_SIZE_SIZE;
-                groupAddress += FormatSpec.GROUP_SHORTCUT_LIST_SIZE_SIZE;
-                final Iterator<WeightedString> shortcutIterator = group.mShortcutTargets.iterator();
-                while (shortcutIterator.hasNext()) {
-                    final WeightedString target = shortcutIterator.next();
-                    ++groupAddress;
-                    int shortcutFlags = makeShortcutFlags(shortcutIterator.hasNext(),
-                            target.mFrequency);
-                    buffer[index++] = (byte)shortcutFlags;
-                    final int shortcutShift = CharEncoding.writeString(buffer, index, target.mWord);
-                    index += shortcutShift;
-                    groupAddress += shortcutShift;
-                }
-                final int shortcutByteSize = index - indexOfShortcutByteSize;
-                if (shortcutByteSize > 0xFFFF) {
-                    throw new RuntimeException("Shortcut list too large");
-                }
-                buffer[indexOfShortcutByteSize] = (byte)(shortcutByteSize >> 8);
-                buffer[indexOfShortcutByteSize + 1] = (byte)(shortcutByteSize & 0xFF);
-            }
-            // Write bigrams
-            if (null != group.mBigrams) {
-                final Iterator<WeightedString> bigramIterator = group.mBigrams.iterator();
-                while (bigramIterator.hasNext()) {
-                    final WeightedString bigram = bigramIterator.next();
-                    final CharGroup target =
-                            FusionDictionary.findWordInTree(dict.mRoot, bigram.mWord);
-                    final int addressOfBigram = target.mCachedAddressAfterUpdate;
-                    final int unigramFrequencyForThisWord = target.mFrequency;
-                    ++groupAddress;
-                    final int offset = addressOfBigram - groupAddress;
-                    int bigramFlags = makeBigramFlags(bigramIterator.hasNext(), offset,
-                            bigram.mFrequency, unigramFrequencyForThisWord, bigram.mWord);
-                    buffer[index++] = (byte)bigramFlags;
-                    final int bigramShift = writeVariableAddress(buffer, index, Math.abs(offset));
-                    index += bigramShift;
-                    groupAddress += bigramShift;
-                }
-            }
-
-        }
-        if (formatOptions.mSupportsDynamicUpdate) {
-            buffer[index] = buffer[index + 1] = buffer[index + 2]
-                    = FormatSpec.NO_FORWARD_LINK_ADDRESS;
-            index += FormatSpec.FORWARD_LINK_ADDRESS_SIZE;
-        }
-        if (index != node.mCachedAddressAfterUpdate + node.mCachedSize) throw new RuntimeException(
-                "Not the same size : written "
-                + (index - node.mCachedAddressAfterUpdate) + " bytes from a node that should have "
-                + node.mCachedSize + " bytes");
-        return index;
-    }
-
-    /**
-     * Dumps a collection of useful statistics about a node array.
-     *
-     * This prints purely informative stuff, like the total estimated file size, the
-     * number of nodes, of character groups, the repartition of each address size, etc
-     *
-     * @param nodes the node array.
-     */
-    private static void showStatistics(ArrayList<Node> nodes) {
-        int firstTerminalAddress = Integer.MAX_VALUE;
-        int lastTerminalAddress = Integer.MIN_VALUE;
-        int size = 0;
-        int charGroups = 0;
-        int maxGroups = 0;
-        int maxRuns = 0;
-        for (final Node n : nodes) {
-            if (maxGroups < n.mData.size()) maxGroups = n.mData.size();
-            for (final CharGroup cg : n.mData) {
-                ++charGroups;
-                if (cg.mChars.length > maxRuns) maxRuns = cg.mChars.length;
-                if (cg.mFrequency >= 0) {
-                    if (n.mCachedAddressAfterUpdate < firstTerminalAddress)
-                        firstTerminalAddress = n.mCachedAddressAfterUpdate;
-                    if (n.mCachedAddressAfterUpdate > lastTerminalAddress)
-                        lastTerminalAddress = n.mCachedAddressAfterUpdate;
-                }
-            }
-            if (n.mCachedAddressAfterUpdate + n.mCachedSize > size) {
-                size = n.mCachedAddressAfterUpdate + n.mCachedSize;
-            }
-        }
-        final int[] groupCounts = new int[maxGroups + 1];
-        final int[] runCounts = new int[maxRuns + 1];
-        for (final Node n : nodes) {
-            ++groupCounts[n.mData.size()];
-            for (final CharGroup cg : n.mData) {
-                ++runCounts[cg.mChars.length];
-            }
-        }
-
-        MakedictLog.i("Statistics:\n"
-                + "  total file size " + size + "\n"
-                + "  " + nodes.size() + " nodes\n"
-                + "  " + charGroups + " groups (" + ((float)charGroups / nodes.size())
-                        + " groups per node)\n"
-                + "  first terminal at " + firstTerminalAddress + "\n"
-                + "  last terminal at " + lastTerminalAddress + "\n"
-                + "  Group stats : max = " + maxGroups);
-        for (int i = 0; i < groupCounts.length; ++i) {
-            MakedictLog.i("    " + i + " : " + groupCounts[i]);
-        }
-        MakedictLog.i("  Character run stats : max = " + maxRuns);
-        for (int i = 0; i < runCounts.length; ++i) {
-            MakedictLog.i("    " + i + " : " + runCounts[i]);
-        }
-    }
-
-    /**
-     * Dumps a FusionDictionary to a file.
-     *
-     * This is the public entry point to write a dictionary to a file.
-     *
-     * @param destination the stream to write the binary data to.
-     * @param dict the dictionary to write.
-     * @param formatOptions file format options.
-     */
-    public static void writeDictionaryBinary(final OutputStream destination,
-            final FusionDictionary dict, final FormatOptions formatOptions)
-            throws IOException, UnsupportedFormatException {
-
-        // Addresses are limited to 3 bytes, but since addresses can be relative to each node, the
-        // structure itself is not limited to 16MB. However, if it is over 16MB deciding the order
-        // of the nodes becomes a quite complicated problem, because though the dictionary itself
-        // does not have a size limit, each node must still be within 16MB of all its children and
-        // parents. As long as this is ensured, the dictionary file may grow to any size.
-
-        final int version = formatOptions.mVersion;
-        if (version < FormatSpec.MINIMUM_SUPPORTED_VERSION
-                || version > FormatSpec.MAXIMUM_SUPPORTED_VERSION) {
-            throw new UnsupportedFormatException("Requested file format version " + version
-                    + ", but this implementation only supports versions "
-                    + FormatSpec.MINIMUM_SUPPORTED_VERSION + " through "
-                    + FormatSpec.MAXIMUM_SUPPORTED_VERSION);
-        }
-
-        ByteArrayOutputStream headerBuffer = new ByteArrayOutputStream(256);
-
-        // The magic number in big-endian order.
-        // Magic number for all versions.
-        headerBuffer.write((byte) (0xFF & (FormatSpec.MAGIC_NUMBER >> 24)));
-        headerBuffer.write((byte) (0xFF & (FormatSpec.MAGIC_NUMBER >> 16)));
-        headerBuffer.write((byte) (0xFF & (FormatSpec.MAGIC_NUMBER >> 8)));
-        headerBuffer.write((byte) (0xFF & FormatSpec.MAGIC_NUMBER));
-        // Dictionary version.
-        headerBuffer.write((byte) (0xFF & (version >> 8)));
-        headerBuffer.write((byte) (0xFF & version));
-
-        // Options flags
-        final int options = makeOptionsValue(dict, formatOptions);
-        headerBuffer.write((byte) (0xFF & (options >> 8)));
-        headerBuffer.write((byte) (0xFF & options));
-        final int headerSizeOffset = headerBuffer.size();
-        // Placeholder to be written later with header size.
-        for (int i = 0; i < 4; ++i) {
-            headerBuffer.write(0);
-        }
-        // Write out the options.
-        for (final String key : dict.mOptions.mAttributes.keySet()) {
-            final String value = dict.mOptions.mAttributes.get(key);
-            CharEncoding.writeString(headerBuffer, key);
-            CharEncoding.writeString(headerBuffer, value);
-        }
-        final int size = headerBuffer.size();
-        final byte[] bytes = headerBuffer.toByteArray();
-        // Write out the header size.
-        bytes[headerSizeOffset] = (byte) (0xFF & (size >> 24));
-        bytes[headerSizeOffset + 1] = (byte) (0xFF & (size >> 16));
-        bytes[headerSizeOffset + 2] = (byte) (0xFF & (size >> 8));
-        bytes[headerSizeOffset + 3] = (byte) (0xFF & (size >> 0));
-        destination.write(bytes);
-
-        headerBuffer.close();
-
-        // Leave the choice of the optimal node order to the flattenTree function.
-        MakedictLog.i("Flattening the tree...");
-        ArrayList<Node> flatNodes = flattenTree(dict.mRoot);
-
-        MakedictLog.i("Computing addresses...");
-        computeAddresses(dict, flatNodes, formatOptions);
-        MakedictLog.i("Checking array...");
-        if (DBG) checkFlatNodeArray(flatNodes);
-
-        // Create a buffer that matches the final dictionary size.
-        final Node lastNode = flatNodes.get(flatNodes.size() - 1);
-        final int bufferSize = lastNode.mCachedAddressAfterUpdate + lastNode.mCachedSize;
-        final byte[] buffer = new byte[bufferSize];
-        int index = 0;
-
-        MakedictLog.i("Writing file...");
-        int dataEndOffset = 0;
-        for (Node n : flatNodes) {
-            dataEndOffset = writePlacedNode(dict, buffer, n, formatOptions);
-        }
-
-        if (DBG) showStatistics(flatNodes);
-
-        destination.write(buffer, 0, dataEndOffset);
-
-        destination.close();
-        MakedictLog.i("Done");
-    }
-
-
-    // Input methods: Read a binary dictionary to memory.
-    // readDictionaryBinary is the public entry point for them.
-
-    static int getChildrenAddressSize(final int optionFlags,
-            final FormatOptions formatOptions) {
-        if (formatOptions.mSupportsDynamicUpdate) return FormatSpec.SIGNED_CHILDREN_ADDRESS_SIZE;
-        switch (optionFlags & FormatSpec.MASK_GROUP_ADDRESS_TYPE) {
-            case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_ONEBYTE:
-                return 1;
-            case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_TWOBYTES:
-                return 2;
-            case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_THREEBYTES:
-                return 3;
-            case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_NOADDRESS:
-            default:
-                return 0;
-        }
-    }
-
-    static int readChildrenAddress(final FusionDictionaryBufferInterface buffer,
-            final int optionFlags, final FormatOptions options) {
-        if (options.mSupportsDynamicUpdate) {
-            final int address = buffer.readUnsignedInt24();
-            if (address == 0) return FormatSpec.NO_CHILDREN_ADDRESS;
-            if ((address & FormatSpec.MSB24) != 0) {
-                return -(address & FormatSpec.SINT24_MAX);
-            } else {
-                return address;
-            }
-        }
-        int address;
-        switch (optionFlags & FormatSpec.MASK_GROUP_ADDRESS_TYPE) {
-            case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_ONEBYTE:
-                return buffer.readUnsignedByte();
-            case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_TWOBYTES:
-                return buffer.readUnsignedShort();
-            case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_THREEBYTES:
-                return buffer.readUnsignedInt24();
-            case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_NOADDRESS:
-            default:
-                return FormatSpec.NO_CHILDREN_ADDRESS;
-        }
-    }
-
-    static int readParentAddress(final FusionDictionaryBufferInterface buffer,
-            final FormatOptions formatOptions) {
-        if (BinaryDictIOUtils.supportsDynamicUpdate(formatOptions)) {
-            final int parentAddress = buffer.readUnsignedInt24();
-            final int sign = ((parentAddress & FormatSpec.MSB24) != 0) ? -1 : 1;
-            return sign * (parentAddress & FormatSpec.SINT24_MAX);
-        } else {
-            return FormatSpec.NO_PARENT_ADDRESS;
-        }
-    }
-
-    private static final int[] CHARACTER_BUFFER = new int[FormatSpec.MAX_WORD_LENGTH];
-    public static CharGroupInfo readCharGroup(final FusionDictionaryBufferInterface buffer,
-            final int originalGroupAddress, final FormatOptions options) {
-        int addressPointer = originalGroupAddress;
-        final int flags = buffer.readUnsignedByte();
-        ++addressPointer;
-
-        final int parentAddress = readParentAddress(buffer, options);
-        if (BinaryDictIOUtils.supportsDynamicUpdate(options)) {
-            addressPointer += 3;
-        }
-
-        final int characters[];
-        if (0 != (flags & FormatSpec.FLAG_HAS_MULTIPLE_CHARS)) {
-            int index = 0;
-            int character = CharEncoding.readChar(buffer);
-            addressPointer += CharEncoding.getCharSize(character);
-            while (-1 != character) {
-                // FusionDictionary is making sure that the length of the word is smaller than
-                // MAX_WORD_LENGTH.
-                // So we'll never write past the end of CHARACTER_BUFFER.
-                CHARACTER_BUFFER[index++] = character;
-                character = CharEncoding.readChar(buffer);
-                addressPointer += CharEncoding.getCharSize(character);
-            }
-            characters = Arrays.copyOfRange(CHARACTER_BUFFER, 0, index);
-        } else {
-            final int character = CharEncoding.readChar(buffer);
-            addressPointer += CharEncoding.getCharSize(character);
-            characters = new int[] { character };
-        }
-        final int frequency;
-        if (0 != (FormatSpec.FLAG_IS_TERMINAL & flags)) {
-            ++addressPointer;
-            frequency = buffer.readUnsignedByte();
-        } else {
-            frequency = CharGroup.NOT_A_TERMINAL;
-        }
-        int childrenAddress = readChildrenAddress(buffer, flags, options);
-        if (childrenAddress != FormatSpec.NO_CHILDREN_ADDRESS) {
-            childrenAddress += addressPointer;
-        }
-        addressPointer += getChildrenAddressSize(flags, options);
-        ArrayList<WeightedString> shortcutTargets = null;
-        if (0 != (flags & FormatSpec.FLAG_HAS_SHORTCUT_TARGETS)) {
-            final int pointerBefore = buffer.position();
-            shortcutTargets = new ArrayList<WeightedString>();
-            buffer.readUnsignedShort(); // Skip the size
-            while (true) {
-                final int targetFlags = buffer.readUnsignedByte();
-                final String word = CharEncoding.readString(buffer);
-                shortcutTargets.add(new WeightedString(word,
-                        targetFlags & FormatSpec.FLAG_ATTRIBUTE_FREQUENCY));
-                if (0 == (targetFlags & FormatSpec.FLAG_ATTRIBUTE_HAS_NEXT)) break;
-            }
-            addressPointer += buffer.position() - pointerBefore;
-        }
-        ArrayList<PendingAttribute> bigrams = null;
-        if (0 != (flags & FormatSpec.FLAG_HAS_BIGRAMS)) {
-            bigrams = new ArrayList<PendingAttribute>();
-            int bigramCount = 0;
-            while (bigramCount++ < FormatSpec.MAX_BIGRAMS_IN_A_GROUP) {
-                final int bigramFlags = buffer.readUnsignedByte();
-                ++addressPointer;
-                final int sign = 0 == (bigramFlags & FormatSpec.FLAG_ATTRIBUTE_OFFSET_NEGATIVE)
-                        ? 1 : -1;
-                int bigramAddress = addressPointer;
-                switch (bigramFlags & FormatSpec.MASK_ATTRIBUTE_ADDRESS_TYPE) {
-                case FormatSpec.FLAG_ATTRIBUTE_ADDRESS_TYPE_ONEBYTE:
-                    bigramAddress += sign * buffer.readUnsignedByte();
-                    addressPointer += 1;
-                    break;
-                case FormatSpec.FLAG_ATTRIBUTE_ADDRESS_TYPE_TWOBYTES:
-                    bigramAddress += sign * buffer.readUnsignedShort();
-                    addressPointer += 2;
-                    break;
-                case FormatSpec.FLAG_ATTRIBUTE_ADDRESS_TYPE_THREEBYTES:
-                    final int offset = (buffer.readUnsignedByte() << 16)
-                            + buffer.readUnsignedShort();
-                    bigramAddress += sign * offset;
-                    addressPointer += 3;
-                    break;
-                default:
-                    throw new RuntimeException("Has bigrams with no address");
-                }
-                bigrams.add(new PendingAttribute(bigramFlags & FormatSpec.FLAG_ATTRIBUTE_FREQUENCY,
-                        bigramAddress));
-                if (0 == (bigramFlags & FormatSpec.FLAG_ATTRIBUTE_HAS_NEXT)) break;
-            }
-            if (bigramCount >= FormatSpec.MAX_BIGRAMS_IN_A_GROUP) {
-                MakedictLog.d("too many bigrams in a group.");
-            }
-        }
-        return new CharGroupInfo(originalGroupAddress, addressPointer, flags, characters, frequency,
-                parentAddress, childrenAddress, shortcutTargets, bigrams);
-    }
-
-    /**
-     * Reads and returns the char group count out of a buffer and forwards the pointer.
-     */
-    public static int readCharGroupCount(final FusionDictionaryBufferInterface buffer) {
-        final int msb = buffer.readUnsignedByte();
-        if (FormatSpec.MAX_CHARGROUPS_FOR_ONE_BYTE_CHARGROUP_COUNT >= msb) {
-            return msb;
-        } else {
-            return ((FormatSpec.MAX_CHARGROUPS_FOR_ONE_BYTE_CHARGROUP_COUNT & msb) << 8)
-                    + buffer.readUnsignedByte();
-        }
-    }
-
-    // The word cache here is a stopgap bandaid to help the catastrophic performance
-    // of this method. Since it performs direct, unbuffered random access to the file and
-    // may be called hundreds of thousands of times, the resulting performance is not
-    // reasonable without some kind of cache. Thus:
-    private static TreeMap<Integer, WeightedString> wordCache =
-            new TreeMap<Integer, WeightedString>();
-    /**
-     * Finds, as a string, the word at the address passed as an argument.
-     *
-     * @param buffer the buffer to read from.
-     * @param headerSize the size of the header.
-     * @param address the address to seek.
-     * @param formatOptions file format options.
-     * @return the word with its frequency, as a weighted string.
-     */
-    /* package for tests */ static WeightedString getWordAtAddress(
-            final FusionDictionaryBufferInterface buffer, final int headerSize, final int address,
-            final FormatOptions formatOptions) {
-        final WeightedString cachedString = wordCache.get(address);
-        if (null != cachedString) return cachedString;
-
-        final WeightedString result;
-        final int originalPointer = buffer.position();
-        buffer.position(address);
-
-        if (BinaryDictIOUtils.supportsDynamicUpdate(formatOptions)) {
-            result = getWordAtAddressWithParentAddress(buffer, headerSize, address, formatOptions);
-        } else {
-            result = getWordAtAddressWithoutParentAddress(buffer, headerSize, address,
-                    formatOptions);
-        }
-
-        wordCache.put(address, result);
-        buffer.position(originalPointer);
-        return result;
-    }
-
-    // TODO: static!? This will behave erratically when used in multi-threaded code.
-    // We need to fix this
-    private static int[] sGetWordBuffer = new int[FormatSpec.MAX_WORD_LENGTH];
-    @SuppressWarnings("unused")
-    private static WeightedString getWordAtAddressWithParentAddress(
-            final FusionDictionaryBufferInterface buffer, final int headerSize, final int address,
-            final FormatOptions options) {
-        int currentAddress = address;
-        int index = FormatSpec.MAX_WORD_LENGTH - 1;
-        int frequency = Integer.MIN_VALUE;
-        // the length of the path from the root to the leaf is limited by MAX_WORD_LENGTH
-        for (int count = 0; count < FormatSpec.MAX_WORD_LENGTH; ++count) {
-            CharGroupInfo currentInfo;
-            int loopCounter = 0;
-            do {
-                buffer.position(currentAddress + headerSize);
-                currentInfo = readCharGroup(buffer, currentAddress, options);
-                if (BinaryDictIOUtils.isMovedGroup(currentInfo.mFlags, options)) {
-                    currentAddress = currentInfo.mParentAddress + currentInfo.mOriginalAddress;
-                }
-                if (DBG && loopCounter++ > MAX_JUMPS) {
-                    MakedictLog.d("Too many jumps - probably a bug");
-                }
-            } while (BinaryDictIOUtils.isMovedGroup(currentInfo.mFlags, options));
-            if (Integer.MIN_VALUE == frequency) frequency = currentInfo.mFrequency;
-            for (int i = 0; i < currentInfo.mCharacters.length; ++i) {
-                sGetWordBuffer[index--] =
-                        currentInfo.mCharacters[currentInfo.mCharacters.length - i - 1];
-            }
-            if (currentInfo.mParentAddress == FormatSpec.NO_PARENT_ADDRESS) break;
-            currentAddress = currentInfo.mParentAddress + currentInfo.mOriginalAddress;
-        }
-
-        return new WeightedString(
-                new String(sGetWordBuffer, index + 1, FormatSpec.MAX_WORD_LENGTH - index - 1),
-                        frequency);
-    }
-
-    private static WeightedString getWordAtAddressWithoutParentAddress(
-            final FusionDictionaryBufferInterface buffer, final int headerSize, final int address,
-            final FormatOptions options) {
-        buffer.position(headerSize);
-        final int count = readCharGroupCount(buffer);
-        int groupOffset = BinaryDictIOUtils.getGroupCountSize(count);
-        final StringBuilder builder = new StringBuilder();
-        WeightedString result = null;
-
-        CharGroupInfo last = null;
-        for (int i = count - 1; i >= 0; --i) {
-            CharGroupInfo info = readCharGroup(buffer, groupOffset, options);
-            groupOffset = info.mEndAddress;
-            if (info.mOriginalAddress == address) {
-                builder.append(new String(info.mCharacters, 0, info.mCharacters.length));
-                result = new WeightedString(builder.toString(), info.mFrequency);
-                break; // and return
-            }
-            if (BinaryDictIOUtils.hasChildrenAddress(info.mChildrenAddress)) {
-                if (info.mChildrenAddress > address) {
-                    if (null == last) continue;
-                    builder.append(new String(last.mCharacters, 0, last.mCharacters.length));
-                    buffer.position(last.mChildrenAddress + headerSize);
-                    i = readCharGroupCount(buffer);
-                    groupOffset = last.mChildrenAddress + BinaryDictIOUtils.getGroupCountSize(i);
-                    last = null;
-                    continue;
-                }
-                last = info;
-            }
-            if (0 == i && BinaryDictIOUtils.hasChildrenAddress(last.mChildrenAddress)) {
-                builder.append(new String(last.mCharacters, 0, last.mCharacters.length));
-                buffer.position(last.mChildrenAddress + headerSize);
-                i = readCharGroupCount(buffer);
-                groupOffset = last.mChildrenAddress + BinaryDictIOUtils.getGroupCountSize(i);
-                last = null;
-                continue;
-            }
-        }
-        return result;
-    }
-
-    /**
-     * Reads a single node from a buffer.
-     *
-     * This methods reads the file at the current position. A node is fully expected to start at
-     * the current position.
-     * This will recursively read other nodes into the structure, populating the reverse
-     * maps on the fly and using them to keep track of already read nodes.
-     *
-     * @param buffer the buffer, correctly positioned at the start of a node.
-     * @param headerSize the size, in bytes, of the file header.
-     * @param reverseNodeMap a mapping from addresses to already read nodes.
-     * @param reverseGroupMap a mapping from addresses to already read character groups.
-     * @param options file format options.
-     * @return the read node with all his children already read.
-     */
-    private static Node readNode(final FusionDictionaryBufferInterface buffer, final int headerSize,
-            final Map<Integer, Node> reverseNodeMap, final Map<Integer, CharGroup> reverseGroupMap,
-            final FormatOptions options)
-            throws IOException {
-        final ArrayList<CharGroup> nodeContents = new ArrayList<CharGroup>();
-        final int nodeOrigin = buffer.position() - headerSize;
-
-        do { // Scan the linked-list node.
-            final int nodeHeadPosition = buffer.position() - headerSize;
-            final int count = readCharGroupCount(buffer);
-            int groupOffset = nodeHeadPosition + BinaryDictIOUtils.getGroupCountSize(count);
-            for (int i = count; i > 0; --i) { // Scan the array of CharGroup.
-                CharGroupInfo info = readCharGroup(buffer, groupOffset, options);
-                if (BinaryDictIOUtils.isMovedGroup(info.mFlags, options)) continue;
-                ArrayList<WeightedString> shortcutTargets = info.mShortcutTargets;
-                ArrayList<WeightedString> bigrams = null;
-                if (null != info.mBigrams) {
-                    bigrams = new ArrayList<WeightedString>();
-                    for (PendingAttribute bigram : info.mBigrams) {
-                        final WeightedString word = getWordAtAddress(
-                                buffer, headerSize, bigram.mAddress, options);
-                        final int reconstructedFrequency =
-                                reconstructBigramFrequency(word.mFrequency, bigram.mFrequency);
-                        bigrams.add(new WeightedString(word.mWord, reconstructedFrequency));
-                    }
-                }
-                if (BinaryDictIOUtils.hasChildrenAddress(info.mChildrenAddress)) {
-                    Node children = reverseNodeMap.get(info.mChildrenAddress);
-                    if (null == children) {
-                        final int currentPosition = buffer.position();
-                        buffer.position(info.mChildrenAddress + headerSize);
-                        children = readNode(
-                                buffer, headerSize, reverseNodeMap, reverseGroupMap, options);
-                        buffer.position(currentPosition);
-                    }
-                    nodeContents.add(
-                            new CharGroup(info.mCharacters, shortcutTargets, bigrams,
-                                    info.mFrequency,
-                                    0 != (info.mFlags & FormatSpec.FLAG_IS_NOT_A_WORD),
-                                    0 != (info.mFlags & FormatSpec.FLAG_IS_BLACKLISTED), children));
-                } else {
-                    nodeContents.add(
-                            new CharGroup(info.mCharacters, shortcutTargets, bigrams,
-                                    info.mFrequency,
-                                    0 != (info.mFlags & FormatSpec.FLAG_IS_NOT_A_WORD),
-                                    0 != (info.mFlags & FormatSpec.FLAG_IS_BLACKLISTED)));
-                }
-                groupOffset = info.mEndAddress;
-            }
-
-            // reach the end of the array.
-            if (options.mSupportsDynamicUpdate) {
-                final int nextAddress = buffer.readUnsignedInt24();
-                if (nextAddress >= 0 && nextAddress < buffer.limit()) {
-                    buffer.position(nextAddress);
-                } else {
-                    break;
-                }
-            }
-        } while (options.mSupportsDynamicUpdate &&
-                buffer.position() != FormatSpec.NO_FORWARD_LINK_ADDRESS);
-
-        final Node node = new Node(nodeContents);
-        node.mCachedAddressBeforeUpdate = nodeOrigin;
-        node.mCachedAddressAfterUpdate = nodeOrigin;
-        reverseNodeMap.put(node.mCachedAddressAfterUpdate, node);
-        return node;
-    }
-
-    /**
-     * Helper function to get the binary format version from the header.
-     * @throws IOException
-     */
-    private static int getFormatVersion(final FusionDictionaryBufferInterface buffer)
-            throws IOException {
-        final int magic = buffer.readInt();
-        if (FormatSpec.MAGIC_NUMBER == magic) return buffer.readUnsignedShort();
-        return FormatSpec.NOT_A_VERSION_NUMBER;
-    }
-
-    /**
-     * Helper function to get and validate the binary format version.
-     * @throws UnsupportedFormatException
-     * @throws IOException
-     */
-    private static int checkFormatVersion(final FusionDictionaryBufferInterface buffer)
-            throws IOException, UnsupportedFormatException {
-        final int version = getFormatVersion(buffer);
-        if (version < FormatSpec.MINIMUM_SUPPORTED_VERSION
-                || version > FormatSpec.MAXIMUM_SUPPORTED_VERSION) {
-            throw new UnsupportedFormatException("This file has version " + version
-                    + ", but this implementation does not support versions above "
-                    + FormatSpec.MAXIMUM_SUPPORTED_VERSION);
-        }
-        return version;
-    }
-
-    /**
-     * Reads a header from a buffer.
-     * @param buffer the buffer to read.
-     * @throws IOException
-     * @throws UnsupportedFormatException
-     */
-    public static FileHeader readHeader(final FusionDictionaryBufferInterface buffer)
-            throws IOException, UnsupportedFormatException {
-        final int version = checkFormatVersion(buffer);
-        final int optionsFlags = buffer.readUnsignedShort();
-
-        final HashMap<String, String> attributes = new HashMap<String, String>();
-        final int headerSize;
-        headerSize = buffer.readInt();
-
-        if (headerSize < 0) {
-            throw new UnsupportedFormatException("header size can't be negative.");
-        }
-
-        populateOptions(buffer, headerSize, attributes);
-        buffer.position(headerSize);
-
-        final FileHeader header = new FileHeader(headerSize,
-                new FusionDictionary.DictionaryOptions(attributes,
-                        0 != (optionsFlags & FormatSpec.GERMAN_UMLAUT_PROCESSING_FLAG),
-                        0 != (optionsFlags & FormatSpec.FRENCH_LIGATURE_PROCESSING_FLAG)),
-                new FormatOptions(version,
-                        0 != (optionsFlags & FormatSpec.SUPPORTS_DYNAMIC_UPDATE)));
-        return header;
-    }
-
-    /**
-     * Reads options from a buffer and populate a map with their contents.
-     *
-     * The buffer is read at the current position, so the caller must take care the pointer
-     * is in the right place before calling this.
-     */
-    public static void populateOptions(final FusionDictionaryBufferInterface buffer,
-            final int headerSize, final HashMap<String, String> options) {
-        while (buffer.position() < headerSize) {
-            final String key = CharEncoding.readString(buffer);
-            final String value = CharEncoding.readString(buffer);
-            options.put(key, value);
-        }
-    }
-
-    /**
-     * Reads a buffer and returns the memory representation of the dictionary.
-     *
-     * This high-level method takes a buffer and reads its contents, populating a
-     * FusionDictionary structure. The optional dict argument is an existing dictionary to
-     * which words from the buffer should be added. If it is null, a new dictionary is created.
-     *
-     * @param reader the reader.
-     * @param dict an optional dictionary to add words to, or null.
-     * @return the created (or merged) dictionary.
-     */
-    @UsedForTesting
-    public static FusionDictionary readDictionaryBinary(final BinaryDictReader reader,
-            final FusionDictionary dict) throws FileNotFoundException, IOException,
-            UnsupportedFormatException {
-        // clear cache
-        wordCache.clear();
-
-        // if the buffer has not been opened, open the buffer with bytebuffer.
-        if (reader.getBuffer() == null) reader.openBuffer(
-                new BinaryDictReader.FusionDictionaryBufferFromByteBufferFactory());
-        if (reader.getBuffer() == null) {
-            MakedictLog.e("Cannot open the buffer");
-        }
-
-        // Read header
-        final FileHeader header = readHeader(reader.getBuffer());
-
-        Map<Integer, Node> reverseNodeMapping = new TreeMap<Integer, Node>();
-        Map<Integer, CharGroup> reverseGroupMapping = new TreeMap<Integer, CharGroup>();
-        final Node root = readNode(reader.getBuffer(), header.mHeaderSize, reverseNodeMapping,
-                reverseGroupMapping, header.mFormatOptions);
-
-        FusionDictionary newDict = new FusionDictionary(root, header.mDictionaryOptions);
-        if (null != dict) {
-            for (final Word w : dict) {
-                if (w.mIsBlacklistEntry) {
-                    newDict.addBlacklistEntry(w.mWord, w.mShortcutTargets, w.mIsNotAWord);
-                } else {
-                    newDict.add(w.mWord, w.mFrequency, w.mShortcutTargets, w.mIsNotAWord);
-                }
-            }
-            for (final Word w : dict) {
-                // By construction a binary dictionary may not have bigrams pointing to
-                // words that are not also registered as unigrams so we don't have to avoid
-                // them explicitly here.
-                for (final WeightedString bigram : w.mBigrams) {
-                    newDict.setBigram(w.mWord, bigram.mWord, bigram.mFrequency);
-                }
-            }
-        }
-
-        return newDict;
-    }
-
-    /**
-     * Helper method to pass a file name instead of a File object to isBinaryDictionary.
-     */
-    public static boolean isBinaryDictionary(final String filename) {
-        final File file = new File(filename);
-        return isBinaryDictionary(file);
-    }
-
-    /**
-     * Basic test to find out whether the file is a binary dictionary or not.
-     *
-     * Concretely this only tests the magic number.
-     *
-     * @param file The file to test.
-     * @return true if it's a binary dictionary, false otherwise
-     */
-    public static boolean isBinaryDictionary(final File file) {
-        FileInputStream inStream = null;
-        try {
-            inStream = new FileInputStream(file);
-            final ByteBuffer buffer = inStream.getChannel().map(
-                    FileChannel.MapMode.READ_ONLY, 0, file.length());
-            final int version = getFormatVersion(new ByteBufferWrapper(buffer));
-            return (version >= FormatSpec.MINIMUM_SUPPORTED_VERSION
-                    && version <= FormatSpec.MAXIMUM_SUPPORTED_VERSION);
-        } catch (FileNotFoundException e) {
-            return false;
-        } catch (IOException e) {
-            return false;
-        } finally {
-            if (inStream != null) {
-                try {
-                    inStream.close();
-                } catch (IOException e) {
-                    // do nothing
-                }
-            }
-        }
-    }
-
-    /**
-     * Calculate bigram frequency from compressed value
-     *
-     * @see #makeBigramFlags
-     *
-     * @param unigramFrequency
-     * @param bigramFrequency compressed frequency
-     * @return approximate bigram frequency
-     */
-    public static int reconstructBigramFrequency(final int unigramFrequency,
-            final int bigramFrequency) {
-        final float stepSize = (FormatSpec.MAX_TERMINAL_FREQUENCY - unigramFrequency)
-                / (1.5f + FormatSpec.MAX_BIGRAM_FREQUENCY);
-        final float resultFreqFloat = unigramFrequency + stepSize * (bigramFrequency + 1.0f);
-        return (int)resultFreqFloat;
-    }
-}