fixedpoint_util.h

// Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
//
// 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.

#pragma once

#include <cmath>
#include <iostream>

#include "prng_utils.h"

namespace aby3 {
template<typename T, size_t N>
class FixedPointUtil {
public:

    static double reveal(T* shares[3]) {
        //reveal
        T sum = *shares[0] + *shares[1] + *shares[2];
        return sum / pow(2, N);
    }

    static void share(double input, T* ret[3]) {
        T ll_in = (T) (input * pow(2, N));
        //share
        *ret[0] = _s_prng.get<T>();
        *ret[1] = _s_prng.get<T>();
        *ret[2] = ll_in - *ret[0] - *ret[1];
    }

    static PseudorandomNumberGenerator _s_prng;
};

template<typename T, size_t N>
PseudorandomNumberGenerator FixedPointUtil<T, N>::_s_prng(block_from_dev_urandom());

} //namespace aby3