thehub/libs/utils/primitives/ScriptBigNum_p.h

/*
 * This file is part of the Flowee project
 * Copyright (C) 2009-2010 Satoshi Nakamoto
 * Copyright (C) 2009-2015 The Bitcoin Core developers
 * Copyright (C) 2021 Tom Zander <tom@flowee.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef FLOWEE_SCRIPT_BIGNUM_H
#define FLOWEE_SCRIPT_BIGNUM_H

#include "script.h"
#include "ScriptDefines.h"
#include <optional>

#include <boost/multiprecision/cpp_int.hpp>

class ScriptBigNum
{
public:
    using BigInt = boost::multiprecision::cpp_int;

    static const size_t MAXIMUM_ELEMENT_SIZE_BIG_INT = may2025::MAX_SCRIPT_ELEMENT_SIZE;
    static const size_t MAX_BIG_INT_BITS = MAXIMUM_ELEMENT_SIZE_BIG_INT * 8 - 1;

    explicit ScriptBigNum(int64_t value = 0);
    explicit ScriptBigNum(const BigInt &value);
    explicit ScriptBigNum(BigInt &&value);
    explicit ScriptBigNum(const std::vector<unsigned char> &vch, bool fRequireMinimal,
                          size_t maxIntegerSize = MAXIMUM_ELEMENT_SIZE_BIG_INT);

    static size_t absValNumBits(const BigInt &value);
    static bool validRange(const BigInt &value);

    bool safeIncr();
    bool safeDecr();
    bool safeAddInPlace(const ScriptBigNum &rhs);
    bool safeAddInPlace(int64_t rhs);
    bool safeSubInPlace(const ScriptBigNum &rhs);
    bool safeSubInPlace(int64_t rhs);
    bool safeMulInPlace(const ScriptBigNum &rhs);
    bool safeMulInPlace(int64_t rhs);

    ScriptBigNum& operator/=(const ScriptBigNum &rhs);
    ScriptBigNum& operator%=(const ScriptBigNum &rhs);
    ScriptBigNum& negate();

    bool checkedLeftShift(unsigned bitcount);
    bool checkedRightShift(unsigned bitcount);
    bool isZero() const;

    int32_t getint32() const;
    std::optional<int64_t> getint64() const;
    std::vector<unsigned char> getvch() const;
    size_t absValNumBits() const;

    int compare(const ScriptBigNum &rhs) const;

    bool operator==(const ScriptBigNum &rhs) const { return compare(rhs) == 0; }
    bool operator!=(const ScriptBigNum &rhs) const { return compare(rhs) != 0; }
    bool operator<(const ScriptBigNum &rhs) const { return compare(rhs) < 0; }
    bool operator<=(const ScriptBigNum &rhs) const { return compare(rhs) <= 0; }
    bool operator>(const ScriptBigNum &rhs) const { return compare(rhs) > 0; }
    bool operator>=(const ScriptBigNum &rhs) const { return compare(rhs) >= 0; }

private:
    BigInt m_value;

    static BigInt set_vch(const std::vector<unsigned char> &vch);
    static std::vector<unsigned char> serialize(const BigInt &value);
};

#endif