const ProbabilityEntry ProbabilityDictContent::getProbabilityEntry(const int terminalId) const {
    if (terminalId < 0 || terminalId >= mSize) {
        // This method can be called with invalid terminal id during GC.
        return ProbabilityEntry(0 /* flags */, NOT_A_PROBABILITY);
    }
    const BufferWithExtendableBuffer *const buffer = getBuffer();
    int entryPos = getEntryPos(terminalId);
    const int flags = buffer->readUintAndAdvancePosition(
            Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE, &entryPos);
    const int probability = buffer->readUintAndAdvancePosition(
            Ver4DictConstants::PROBABILITY_SIZE, &entryPos);
    if (mHasHistoricalInfo) {
        const int timestamp = buffer->readUintAndAdvancePosition(
                Ver4DictConstants::TIME_STAMP_FIELD_SIZE, &entryPos);
        const int level = buffer->readUintAndAdvancePosition(
                Ver4DictConstants::WORD_LEVEL_FIELD_SIZE, &entryPos);
        const int count = buffer->readUintAndAdvancePosition(
                Ver4DictConstants::WORD_COUNT_FIELD_SIZE, &entryPos);
        // Hack for better migration.
        const HistoricalInfo historicalInfo(timestamp, level, count + level);
        return ProbabilityEntry(flags, probability, &historicalInfo);
    } else {
        return ProbabilityEntry(flags, probability);
    }
}
bool TerminalPositionLookupTable::setTerminalPtNodePosition(
        const int terminalId, const int terminalPtNodePos) {
    if (terminalId < 0) {
        return NOT_A_DICT_POS;
    }
    while (terminalId >= mSize) {
        // Write new entry.
        if (!getWritableBuffer()->writeUint(Ver4DictConstants::NOT_A_TERMINAL_ADDRESS,
                Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(mSize))) {
            return false;
        }
        mSize++;
    }
    const int terminalPos = (terminalPtNodePos != NOT_A_DICT_POS) ?
            terminalPtNodePos : Ver4DictConstants::NOT_A_TERMINAL_ADDRESS;
    return getWritableBuffer()->writeUint(terminalPos,
            Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(terminalId));
}
int TerminalPositionLookupTable::getTerminalPtNodePosition(const int terminalId) const {
    if (terminalId < 0 || terminalId >= mSize) {
        return NOT_A_DICT_POS;
    }
    const int terminalPos = getBuffer()->readUint(
            Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(terminalId));
    return (terminalPos == Ver4DictConstants::NOT_A_TERMINAL_ADDRESS) ?
            NOT_A_DICT_POS : terminalPos;
}
bool TerminalPositionLookupTable::runGCTerminalIds(TerminalIdMap *const terminalIdMap) {
    int removedEntryCount = 0;
    int nextNewTerminalId = 0;
    for (int i = 0; i < mSize; ++i) {
        const int terminalPos = getBuffer()->readUint(
                Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(i));
        if (terminalPos == Ver4DictConstants::NOT_A_TERMINAL_ADDRESS) {
            // This entry is a garbage.
            removedEntryCount++;
        } else {
            // Give a new terminal id to the entry.
            if (!getWritableBuffer()->writeUint(terminalPos,
                    Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE,
                    getEntryPos(nextNewTerminalId))) {
                return false;
            }
            // Memorize the mapping to the old terminal id to the new terminal id.
            terminalIdMap->insert(TerminalIdMap::value_type(i, nextNewTerminalId));
            nextNewTerminalId++;
        }
    }
    mSize = nextNewTerminalId;
    return true;
}
bool ProbabilityDictContent::flushToFile(const char *const dictPath) const {
    if (getEntryPos(mSize) < getBuffer()->getTailPosition()) {
        ProbabilityDictContent probabilityDictContentToWrite(mHasHistoricalInfo);
        for (int i = 0; i < mSize; ++i) {
            const ProbabilityEntry probabilityEntry = getProbabilityEntry(i);
            if (!probabilityDictContentToWrite.setProbabilityEntry(i, &probabilityEntry)) {
                AKLOGE("Cannot set probability entry in flushToFile. terminalId: %d", i);
                return false;
            }
        }
        return probabilityDictContentToWrite.flush(dictPath,
                Ver4DictConstants::FREQ_FILE_EXTENSION);
    } else {
        return flush(dictPath, Ver4DictConstants::FREQ_FILE_EXTENSION);
    }
}
bool TerminalPositionLookupTable::flushToFile(FILE *const file) const {
    // If the used buffer size is smaller than the actual buffer size, regenerate the lookup
    // table and write the new table to the file.
    if (getEntryPos(mSize) < getBuffer()->getTailPosition()) {
        TerminalPositionLookupTable lookupTableToWrite;
        for (int i = 0; i < mSize; ++i) {
            const int terminalPtNodePosition = getTerminalPtNodePosition(i);
            if (!lookupTableToWrite.setTerminalPtNodePosition(i, terminalPtNodePosition)) {
                AKLOGE("Cannot set terminal position to lookupTableToWrite."
                        " terminalId: %d, position: %d", i, terminalPtNodePosition);
                return false;
            }
        }
        return lookupTableToWrite.flush(file);
    } else {
        // We can simply use this lookup table because the buffer size has not been
        // changed.
        return flush(file);
    }
}
bool ProbabilityDictContent::setProbabilityEntry(const int terminalId,
        const ProbabilityEntry *const probabilityEntry) {
    if (terminalId < 0) {
        return false;
    }
    const int entryPos = getEntryPos(terminalId);
    if (terminalId >= mSize) {
        ProbabilityEntry dummyEntry;
        // Write new entry.
        int writingPos = getBuffer()->getTailPosition();
        while (writingPos <= entryPos) {
            // Fulfilling with dummy entries until writingPos.
            if (!writeEntry(&dummyEntry, writingPos)) {
                AKLOGE("Cannot write dummy entry. pos: %d, mSize: %d", writingPos, mSize);
                return false;
            }
            writingPos += getEntrySize();
        }
        mSize = terminalId + 1;
    }
    return writeEntry(probabilityEntry, entryPos);
}