LatinIME/java/src/com/android/inputmethod/latin/makedict/BinaryDictDecoderUtils.java
Yuichiro Hanada 77bce05e6f [Refactor] Rename BinaryDictReader and BinaryDictDecoder.
BinaryDictReader -> BinaryDictDecoder.
BinaryDictDecoder -> BianryDictDecoderUtils.

Change-Id: Iadf2153b379b760538ecda488dda4f17225e5f37
2013-08-19 19:36:31 +09:00

777 lines
33 KiB
Java

/*
* 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.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.PtNodeArray;
import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;
import com.android.inputmethod.latin.makedict.decoder.HeaderReader;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;
/**
* Decodes binary files for a FusionDictionary.
*
* All the methods in this class are static.
*
* TODO: Remove calls from classes except BinaryDictDecoder
* TODO: Move this file to makedict/internal.
*/
public final class BinaryDictDecoderUtils {
private static final boolean DBG = MakedictLog.DBG;
private BinaryDictDecoderUtils() {
// This utility class is not publicly instantiable.
}
private static final int MAX_JUMPS = 12;
@UsedForTesting
public interface DictBuffer {
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 ByteBufferDictBuffer implements DictBuffer {
private ByteBuffer mBuffer;
public ByteBufferDictBuffer(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.
*/
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.
*/
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.
*/
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.
*/
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 DictBuffer. This is the converse of the above method.
*/
static String readString(final DictBuffer dictBuffer) {
final StringBuilder s = new StringBuilder();
int character = readChar(dictBuffer);
while (character != FormatSpec.INVALID_CHARACTER) {
s.appendCodePoint(character);
character = readChar(dictBuffer);
}
return s.toString();
}
/**
* Reads a character from the buffer.
*
* This follows the character format documented earlier in this source file.
*
* @param dictBuffer the buffer, positioned over an encoded character.
* @return the character code.
*/
static int readChar(final DictBuffer dictBuffer) {
int character = dictBuffer.readUnsignedByte();
if (!fitsOnOneByte(character)) {
if (FormatSpec.GROUP_CHARACTERS_TERMINATOR == character) {
return FormatSpec.INVALID_CHARACTER;
}
character <<= 16;
character += dictBuffer.readUnsignedShort();
}
return character;
}
}
// Input methods: Read a binary dictionary to memory.
// readDictionaryBinary is the public entry point for them.
static int readChildrenAddress(final DictBuffer dictBuffer,
final int optionFlags, final FormatOptions options) {
if (options.mSupportsDynamicUpdate) {
final int address = dictBuffer.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 dictBuffer.readUnsignedByte();
case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_TWOBYTES:
return dictBuffer.readUnsignedShort();
case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_THREEBYTES:
return dictBuffer.readUnsignedInt24();
case FormatSpec.FLAG_GROUP_ADDRESS_TYPE_NOADDRESS:
default:
return FormatSpec.NO_CHILDREN_ADDRESS;
}
}
static int readParentAddress(final DictBuffer dictBuffer,
final FormatOptions formatOptions) {
if (BinaryDictIOUtils.supportsDynamicUpdate(formatOptions)) {
final int parentAddress = dictBuffer.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 DictBuffer dictBuffer,
final int originalGroupAddress, final FormatOptions options) {
int addressPointer = originalGroupAddress;
final int flags = dictBuffer.readUnsignedByte();
++addressPointer;
final int parentAddress = readParentAddress(dictBuffer, 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(dictBuffer);
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(dictBuffer);
addressPointer += CharEncoding.getCharSize(character);
}
characters = Arrays.copyOfRange(CHARACTER_BUFFER, 0, index);
} else {
final int character = CharEncoding.readChar(dictBuffer);
addressPointer += CharEncoding.getCharSize(character);
characters = new int[] { character };
}
final int frequency;
if (0 != (FormatSpec.FLAG_IS_TERMINAL & flags)) {
++addressPointer;
frequency = dictBuffer.readUnsignedByte();
} else {
frequency = CharGroup.NOT_A_TERMINAL;
}
int childrenAddress = readChildrenAddress(dictBuffer, flags, options);
if (childrenAddress != FormatSpec.NO_CHILDREN_ADDRESS) {
childrenAddress += addressPointer;
}
addressPointer += BinaryDictIOUtils.getChildrenAddressSize(flags, options);
ArrayList<WeightedString> shortcutTargets = null;
if (0 != (flags & FormatSpec.FLAG_HAS_SHORTCUT_TARGETS)) {
final int pointerBefore = dictBuffer.position();
shortcutTargets = new ArrayList<WeightedString>();
dictBuffer.readUnsignedShort(); // Skip the size
while (true) {
final int targetFlags = dictBuffer.readUnsignedByte();
final String word = CharEncoding.readString(dictBuffer);
shortcutTargets.add(new WeightedString(word,
targetFlags & FormatSpec.FLAG_ATTRIBUTE_FREQUENCY));
if (0 == (targetFlags & FormatSpec.FLAG_ATTRIBUTE_HAS_NEXT)) break;
}
addressPointer += dictBuffer.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 = dictBuffer.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 * dictBuffer.readUnsignedByte();
addressPointer += 1;
break;
case FormatSpec.FLAG_ATTRIBUTE_ADDRESS_TYPE_TWOBYTES:
bigramAddress += sign * dictBuffer.readUnsignedShort();
addressPointer += 2;
break;
case FormatSpec.FLAG_ATTRIBUTE_ADDRESS_TYPE_THREEBYTES:
final int offset = (dictBuffer.readUnsignedByte() << 16)
+ dictBuffer.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 DictBuffer dictBuffer) {
final int msb = dictBuffer.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)
+ dictBuffer.readUnsignedByte();
}
}
/**
* Finds, as a string, the word at the address passed as an argument.
*
* @param dictBuffer 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 DictBuffer dictBuffer, final int headerSize, final int address,
final FormatOptions formatOptions) {
final WeightedString result;
final int originalPointer = dictBuffer.position();
dictBuffer.position(address);
if (BinaryDictIOUtils.supportsDynamicUpdate(formatOptions)) {
result = getWordAtAddressWithParentAddress(dictBuffer, headerSize, address,
formatOptions);
} else {
result = getWordAtAddressWithoutParentAddress(dictBuffer, headerSize, address,
formatOptions);
}
dictBuffer.position(originalPointer);
return result;
}
@SuppressWarnings("unused")
private static WeightedString getWordAtAddressWithParentAddress(
final DictBuffer dictBuffer, final int headerSize, final int address,
final FormatOptions options) {
int currentAddress = address;
int frequency = Integer.MIN_VALUE;
final StringBuilder builder = new StringBuilder();
// 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 {
dictBuffer.position(currentAddress + headerSize);
currentInfo = readCharGroup(dictBuffer, 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;
builder.insert(0,
new String(currentInfo.mCharacters, 0, currentInfo.mCharacters.length));
if (currentInfo.mParentAddress == FormatSpec.NO_PARENT_ADDRESS) break;
currentAddress = currentInfo.mParentAddress + currentInfo.mOriginalAddress;
}
return new WeightedString(builder.toString(), frequency);
}
private static WeightedString getWordAtAddressWithoutParentAddress(
final DictBuffer dictBuffer, final int headerSize, final int address,
final FormatOptions options) {
dictBuffer.position(headerSize);
final int count = readCharGroupCount(dictBuffer);
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(dictBuffer, 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));
dictBuffer.position(last.mChildrenAddress + headerSize);
i = readCharGroupCount(dictBuffer);
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));
dictBuffer.position(last.mChildrenAddress + headerSize);
i = readCharGroupCount(dictBuffer);
groupOffset = last.mChildrenAddress + BinaryDictIOUtils.getGroupCountSize(i);
last = null;
continue;
}
}
return result;
}
/**
* Reads a single node array from a buffer.
*
* This methods reads the file at the current position. A node array is fully expected to start
* at the current position.
* This will recursively read other node arrays into the structure, populating the reverse
* maps on the fly and using them to keep track of already read nodes.
*
* @param dictBuffer the buffer, correctly positioned at the start of a node array.
* @param headerSize the size, in bytes, of the file header.
* @param reverseNodeArrayMap a mapping from addresses to already read node arrays.
* @param reverseGroupMap a mapping from addresses to already read character groups.
* @param options file format options.
* @return the read node array with all his children already read.
*/
private static PtNodeArray readNodeArray(final DictBuffer dictBuffer,
final int headerSize, final Map<Integer, PtNodeArray> reverseNodeArrayMap,
final Map<Integer, CharGroup> reverseGroupMap, final FormatOptions options)
throws IOException {
final ArrayList<CharGroup> nodeArrayContents = new ArrayList<CharGroup>();
final int nodeArrayOrigin = dictBuffer.position() - headerSize;
do { // Scan the linked-list node.
final int nodeArrayHeadPosition = dictBuffer.position() - headerSize;
final int count = readCharGroupCount(dictBuffer);
int groupOffset = nodeArrayHeadPosition + BinaryDictIOUtils.getGroupCountSize(count);
for (int i = count; i > 0; --i) { // Scan the array of CharGroup.
CharGroupInfo info = readCharGroup(dictBuffer, 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(
dictBuffer, headerSize, bigram.mAddress, options);
final int reconstructedFrequency =
BinaryDictIOUtils.reconstructBigramFrequency(word.mFrequency,
bigram.mFrequency);
bigrams.add(new WeightedString(word.mWord, reconstructedFrequency));
}
}
if (BinaryDictIOUtils.hasChildrenAddress(info.mChildrenAddress)) {
PtNodeArray children = reverseNodeArrayMap.get(info.mChildrenAddress);
if (null == children) {
final int currentPosition = dictBuffer.position();
dictBuffer.position(info.mChildrenAddress + headerSize);
children = readNodeArray(dictBuffer, headerSize, reverseNodeArrayMap,
reverseGroupMap, options);
dictBuffer.position(currentPosition);
}
nodeArrayContents.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 {
nodeArrayContents.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 = dictBuffer.readUnsignedInt24();
if (nextAddress >= 0 && nextAddress < dictBuffer.limit()) {
dictBuffer.position(nextAddress);
} else {
break;
}
}
} while (options.mSupportsDynamicUpdate &&
dictBuffer.position() != FormatSpec.NO_FORWARD_LINK_ADDRESS);
final PtNodeArray nodeArray = new PtNodeArray(nodeArrayContents);
nodeArray.mCachedAddressBeforeUpdate = nodeArrayOrigin;
nodeArray.mCachedAddressAfterUpdate = nodeArrayOrigin;
reverseNodeArrayMap.put(nodeArray.mCachedAddressAfterUpdate, nodeArray);
return nodeArray;
}
/**
* Helper function to get the binary format version from the header.
* @throws IOException
*/
private static int getFormatVersion(final DictBuffer dictBuffer)
throws IOException {
final int magic = dictBuffer.readInt();
if (FormatSpec.MAGIC_NUMBER == magic) return dictBuffer.readUnsignedShort();
return FormatSpec.NOT_A_VERSION_NUMBER;
}
/**
* Helper function to get and validate the binary format version.
* @throws UnsupportedFormatException
* @throws IOException
*/
static int checkFormatVersion(final DictBuffer dictBuffer)
throws IOException, UnsupportedFormatException {
final int version = getFormatVersion(dictBuffer);
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 headerReader the header reader
* @throws IOException
* @throws UnsupportedFormatException
*/
public static FileHeader readHeader(final HeaderReader headerReader)
throws IOException, UnsupportedFormatException {
final int version = headerReader.readVersion();
final int optionsFlags = headerReader.readOptionFlags();
final int headerSize = headerReader.readHeaderSize();
if (headerSize < 0) {
throw new UnsupportedFormatException("header size can't be negative.");
}
final HashMap<String, String> attributes = headerReader.readAttributes(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 DictBuffer dictBuffer,
final int headerSize, final HashMap<String, String> options) {
while (dictBuffer.position() < headerSize) {
final String key = CharEncoding.readString(dictBuffer);
final String value = CharEncoding.readString(dictBuffer);
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 dictDecoder the dict decoder.
* @param dict an optional dictionary to add words to, or null.
* @return the created (or merged) dictionary.
*/
@UsedForTesting
public static FusionDictionary readDictionaryBinary(final BinaryDictDecoder dictDecoder,
final FusionDictionary dict) throws FileNotFoundException, IOException,
UnsupportedFormatException {
// if the buffer has not been opened, open the buffer with bytebuffer.
if (dictDecoder.getDictBuffer() == null) dictDecoder.openDictBuffer(
new BinaryDictDecoder.DictionaryBufferFromReadOnlyByteBufferFactory());
if (dictDecoder.getDictBuffer() == null) {
MakedictLog.e("Cannot open the buffer");
}
// Read header
final FileHeader fileHeader = readHeader(dictDecoder);
Map<Integer, PtNodeArray> reverseNodeArrayMapping = new TreeMap<Integer, PtNodeArray>();
Map<Integer, CharGroup> reverseGroupMapping = new TreeMap<Integer, CharGroup>();
final PtNodeArray root = readNodeArray(dictDecoder.getDictBuffer(), fileHeader.mHeaderSize,
reverseNodeArrayMapping, reverseGroupMapping, fileHeader.mFormatOptions);
FusionDictionary newDict = new FusionDictionary(root, fileHeader.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 ByteBufferDictBuffer(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
}
}
}
}
}