static bool
HashTxSorter(TransactionFramePtr const& tx1, TransactionFramePtr const& tx2)
{
    // need to use the hash of whole tx here since multiple txs could have
    // the same Contents
    return tx1->getFullHash() < tx2->getFullHash();
}
 bool operator()(TransactionFramePtr const& tx1,
                 TransactionFramePtr const& tx2) const
 {
     // need to use the hash of whole tx here since multiple txs could have
     // the same Contents
     return lessThanXored(tx1->getFullHash(), tx2->getFullHash(), mSetHash);
 }
    bool operator()(TransactionFramePtr const& tx1,
                    TransactionFramePtr const& tx2) const
    {
        // need to use the hash of whole tx here since multiple txs could have
        // the same Contents
        Hash h1 = tx1->getFullHash();
        Hash h2 = tx2->getFullHash();
        Hash v1, v2;
        for (int n = 0; n < 32; n++)
        {
            v1[n] = mSetHash[n] ^ h1[n];
            v2[n] = mSetHash[n] ^ h2[n];
        }

        return v1 < v2;
    }