arith_uint256.h

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2022 The Bitcoin Core developers
 
// modified version of https://github.com/bitcoin/bitcoin/blob/master/src/arith_uint256.h
 
#pragma once
 
#include <cstring>
#include <limits>
#include <stdexcept>
#include <stdint.h>
#include <string>
 
class uint_error : public std::runtime_error
{
  public:
    explicit uint_error(const std::string &str) : std::runtime_error(str)
    {
    }
};
 
template <unsigned int BITS> class base_uint
{
  protected:
    static_assert(BITS / 32 > 0 && BITS % 32 == 0, "Template parameter BITS must be a positive multiple of 32.");
    static constexpr int WIDTH = BITS / 32;
    uint32_t pn[WIDTH];
 
  public:
    base_uint()
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] = 0;
    }
 
    base_uint(const base_uint &b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] = b.pn[i];
    }
 
    base_uint &operator=(const base_uint &b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] = b.pn[i];
        return *this;
    }
 
    base_uint(uint64_t b)
    {
        pn[0] = (unsigned int)b;
        pn[1] = (unsigned int)(b >> 32);
        for (int i = 2; i < WIDTH; i++)
            pn[i] = 0;
    }
 
    base_uint operator~() const
    {
        base_uint ret;
        for (int i = 0; i < WIDTH; i++)
            ret.pn[i] = ~pn[i];
        return ret;
    }
 
    base_uint operator-() const
    {
        base_uint ret;
        for (int i = 0; i < WIDTH; i++)
            ret.pn[i] = ~pn[i];
        ++ret;
        return ret;
    }
 
    double getdouble() const;
 
    base_uint &operator=(uint64_t b)
    {
        pn[0] = (unsigned int)b;
        pn[1] = (unsigned int)(b >> 32);
        for (int i = 2; i < WIDTH; i++)
            pn[i] = 0;
        return *this;
    }
 
    base_uint &operator^=(const base_uint &b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] ^= b.pn[i];
        return *this;
    }
 
    base_uint &operator&=(const base_uint &b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] &= b.pn[i];
        return *this;
    }
 
    base_uint &operator|=(const base_uint &b)
    {
        for (int i = 0; i < WIDTH; i++)
            pn[i] |= b.pn[i];
        return *this;
    }
 
    base_uint &operator^=(uint64_t b)
    {
        pn[0] ^= (unsigned int)b;
        pn[1] ^= (unsigned int)(b >> 32);
        return *this;
    }
 
    base_uint &operator|=(uint64_t b)
    {
        pn[0] |= (unsigned int)b;
        pn[1] |= (unsigned int)(b >> 32);
        return *this;
    }
 
    base_uint &operator<<=(unsigned int shift);
    base_uint &operator>>=(unsigned int shift);
 
    base_uint &operator+=(const base_uint &b)
    {
        uint64_t carry = 0;
        for (int i = 0; i < WIDTH; i++)
        {
            uint64_t n = carry + pn[i] + b.pn[i];
            pn[i] = n & 0xffffffff;
            carry = n >> 32;
        }
        return *this;
    }
 
    base_uint &operator-=(const base_uint &b)
    {
        *this += -b;
        return *this;
    }
 
    base_uint &operator+=(uint64_t b64)
    {
        base_uint b;
        b = b64;
        *this += b;
        return *this;
    }
 
    base_uint &operator-=(uint64_t b64)
    {
        base_uint b;
        b = b64;
        *this += -b;
        return *this;
    }
 
    base_uint &operator*=(uint32_t b32);
    base_uint &operator*=(const base_uint &b);
    base_uint &operator/=(const base_uint &b);
 
    base_uint &operator++()
    {
        // prefix operator
        int i = 0;
        while (i < WIDTH && ++pn[i] == 0)
            i++;
        return *this;
    }
 
    base_uint operator++(int)
    {
        // postfix operator
        const base_uint ret = *this;
        ++(*this);
        return ret;
    }
 
    base_uint &operator--()
    {
        // prefix operator
        int i = 0;
        while (i < WIDTH && --pn[i] == std::numeric_limits<uint32_t>::max())
            i++;
        return *this;
    }
 
    base_uint operator--(int)
    {
        // postfix operator
        const base_uint ret = *this;
        --(*this);
        return ret;
    }
 
    int CompareTo(const base_uint &b) const;
    bool EqualTo(uint64_t b) const;
 
    friend inline base_uint operator+(const base_uint &a, const base_uint &b)
    {
        return base_uint(a) += b;
    }
    friend inline base_uint operator-(const base_uint &a, const base_uint &b)
    {
        return base_uint(a) -= b;
    }
    friend inline base_uint operator*(const base_uint &a, const base_uint &b)
    {
        return base_uint(a) *= b;
    }
    friend inline base_uint operator/(const base_uint &a, const base_uint &b)
    {
        return base_uint(a) /= b;
    }
    friend inline base_uint operator|(const base_uint &a, const base_uint &b)
    {
        return base_uint(a) |= b;
    }
    friend inline base_uint operator&(const base_uint &a, const base_uint &b)
    {
        return base_uint(a) &= b;
    }
    friend inline base_uint operator^(const base_uint &a, const base_uint &b)
    {
        return base_uint(a) ^= b;
    }
    friend inline base_uint operator>>(const base_uint &a, int shift)
    {
        return base_uint(a) >>= shift;
    }
    friend inline base_uint operator<<(const base_uint &a, int shift)
    {
        return base_uint(a) <<= shift;
    }
    friend inline base_uint operator*(const base_uint &a, uint32_t b)
    {
        return base_uint(a) *= b;
    }
    friend inline bool operator==(const base_uint &a, const base_uint &b)
    {
        return memcmp(a.pn, b.pn, sizeof(a.pn)) == 0;
    }
    friend inline bool operator!=(const base_uint &a, const base_uint &b)
    {
        return memcmp(a.pn, b.pn, sizeof(a.pn)) != 0;
    }
    friend inline bool operator>(const base_uint &a, const base_uint &b)
    {
        return a.CompareTo(b) > 0;
    }
    friend inline bool operator<(const base_uint &a, const base_uint &b)
    {
        return a.CompareTo(b) < 0;
    }
    friend inline bool operator>=(const base_uint &a, const base_uint &b)
    {
        return a.CompareTo(b) >= 0;
    }
    friend inline bool operator<=(const base_uint &a, const base_uint &b)
    {
        return a.CompareTo(b) <= 0;
    }
    friend inline bool operator==(const base_uint &a, uint64_t b)
    {
        return a.EqualTo(b);
    }
    friend inline bool operator!=(const base_uint &a, uint64_t b)
    {
        return !a.EqualTo(b);
    }
 
    unsigned int size() const
    {
        return sizeof(pn);
    }
 
    unsigned int bits() const;
 
    uint64_t GetLow64() const
    {
        static_assert(WIDTH >= 2, "Assertion WIDTH >= 2 failed (WIDTH = BITS / 32). BITS is a template parameter.");
        return pn[0] | (uint64_t)pn[1] << 32;
    }
};