neobytes/src/uint256.h

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_UINT256_H
#define BITCOIN_UINT256_H

#include <assert.h>
#include <stdexcept>
#include <stdint.h>
#include <stdio.h>
#include <string>
#include <string.h>
#include <vector>

extern const signed char p_util_hexdigit[256]; // defined in util.cpp

inline signed char HexDigit(char c)
{
    return p_util_hexdigit[(unsigned char)c];
}

class uint_error : public std::runtime_error {
public:
    explicit uint_error(const std::string& str) : std::runtime_error(str) {}
};

/** Template base class for unsigned big integers. */
template<unsigned int BITS>
class base_uint
{
private:
    enum { 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;
    }

    explicit base_uint(const std::string& str)
    {
        SetHex(str);
    }

    explicit base_uint(const std::vector<unsigned char>& vch)
    {
        if (vch.size() != sizeof(pn))
            throw uint_error("Converting vector of wrong size to base_uint");
        memcpy(pn, &vch[0], sizeof(pn));
    }

    bool operator!() const
    {
        for (int i = 0; i < WIDTH; i++)
            if (pn[i] != 0)
                return false;
        return true;
    }

    const base_uint operator~() const
    {
        base_uint ret;
        for (int i = 0; i < WIDTH; i++)
            ret.pn[i] = ~pn[i];
        return ret;
    }

    const 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
    {
        double ret = 0.0;
        double fact = 1.0;
        for (int i = 0; i < WIDTH; i++) {
            ret += fact * pn[i];
            fact *= 4294967296.0;
        }
        return ret;
    }

    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 a(*this);
        for (int i = 0; i < WIDTH; i++)
            pn[i] = 0;
        int k = shift / 32;
        shift = shift % 32;
        for (int i = 0; i < WIDTH; i++)
        {
            if (i+k+1 < WIDTH && shift != 0)
                pn[i+k+1] |= (a.pn[i] >> (32-shift));
            if (i+k < WIDTH)
                pn[i+k] |= (a.pn[i] << shift);
        }
        return *this;
    }

    base_uint& operator>>=(unsigned int shift)
    {
        base_uint a(*this);
        for (int i = 0; i < WIDTH; i++)
            pn[i] = 0;
        int k = shift / 32;
        shift = shift % 32;
        for (int i = 0; i < WIDTH; i++)
        {
            if (i-k-1 >= 0 && shift != 0)
                pn[i-k-1] |= (a.pn[i] << (32-shift));
            if (i-k >= 0)
                pn[i-k] |= (a.pn[i] >> shift);
        }
        return *this;
    }

    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++()
    {
        // prefix operator
        int i = 0;
        while (++pn[i] == 0 && i < WIDTH-1)
            i++;
        return *this;
    }

    const base_uint operator++(int)
    {
        // postfix operator
        const base_uint ret = *this;
        ++(*this);
        return ret;
    }

    base_uint& operator--()
    {
        // prefix operator
        int i = 0;
        while (--pn[i] == (uint32_t)-1 && i < WIDTH-1)
            i++;
        return *this;
    }

    const base_uint operator--(int)
    {
        // postfix operator
        const base_uint ret = *this;
        --(*this);
        return ret;
    }


    friend inline bool operator<(const base_uint& a, const base_uint& b)
    {
        for (int i = base_uint::WIDTH-1; i >= 0; i--)
        {
            if (a.pn[i] < b.pn[i])
                return true;
            else if (a.pn[i] > b.pn[i])
                return false;
        }
        return false;
    }

    friend inline bool operator<=(const base_uint& a, const base_uint& b)
    {
        for (int i = base_uint::WIDTH-1; i >= 0; i--)
        {
            if (a.pn[i] < b.pn[i])
                return true;
            else if (a.pn[i] > b.pn[i])
                return false;
        }
        return true;
    }

    friend inline bool operator>(const base_uint& a, const base_uint& b)
    {
        for (int i = base_uint::WIDTH-1; i >= 0; i--)
        {
            if (a.pn[i] > b.pn[i])
                return true;
            else if (a.pn[i] < b.pn[i])
                return false;
        }
        return false;
    }

    friend inline bool operator>=(const base_uint& a, const base_uint& b)
    {
        for (int i = base_uint::WIDTH-1; i >= 0; i--)
        {
            if (a.pn[i] > b.pn[i])
                return true;
            else if (a.pn[i] < b.pn[i])
                return false;
        }
        return true;
    }

    friend inline bool operator==(const base_uint& a, const base_uint& b)
    {
        for (int i = 0; i < base_uint::WIDTH; i++)
            if (a.pn[i] != b.pn[i])
                return false;
        return true;
    }

    friend inline bool operator==(const base_uint& a, uint64_t b)
    {
        if (a.pn[0] != (unsigned int)b)
            return false;
        if (a.pn[1] != (unsigned int)(b >> 32))
            return false;
        for (int i = 2; i < base_uint::WIDTH; i++)
            if (a.pn[i] != 0)
                return false;
        return true;
    }

    friend inline bool operator!=(const base_uint& a, const base_uint& b)
    {
        return (!(a == b));
    }

    friend inline bool operator!=(const base_uint& a, uint64_t b)
    {
        return (!(a == b));
    }

    friend inline const base_uint operator+(const base_uint& a, const base_uint& b) { return base_uint(a) += b; }
    friend inline const base_uint operator-(const base_uint& a, const base_uint& b) { return base_uint(a) -= b; }
    friend inline const base_uint operator|(const base_uint& a, const base_uint& b) { return base_uint(a) |= b; }
    friend inline const base_uint operator&(const base_uint& a, const base_uint& b) { return base_uint(a) &= b; }
    friend inline const base_uint operator^(const base_uint& a, const base_uint& b) { return base_uint(a) ^= b; }
    friend inline const base_uint operator>>(const base_uint& a, int shift) { return base_uint(a) >>= shift; }
    friend inline const base_uint operator<<(const base_uint& a, int shift) { return base_uint(a) <<= shift; }

    std::string GetHex() const
    {
        char psz[sizeof(pn)*2 + 1];
        for (unsigned int i = 0; i < sizeof(pn); i++)
            sprintf(psz + i*2, "%02x", ((unsigned char*)pn)[sizeof(pn) - i - 1]);
        return std::string(psz, psz + sizeof(pn)*2);
    }

    void SetHex(const char* psz)
    {
        memset(pn,0,sizeof(pn));

        // skip leading spaces
        while (isspace(*psz))
            psz++;

        // skip 0x
        if (psz[0] == '0' && tolower(psz[1]) == 'x')
            psz += 2;

        // hex string to uint
        const char* pbegin = psz;
        while (::HexDigit(*psz) != -1)
            psz++;
        psz--;
        unsigned char* p1 = (unsigned char*)pn;
        unsigned char* pend = p1 + WIDTH * 4;
        while (psz >= pbegin && p1 < pend)
        {
            *p1 = ::HexDigit(*psz--);
            if (psz >= pbegin)
            {
                *p1 |= ((unsigned char)::HexDigit(*psz--) << 4);
                p1++;
            }
        }
    }

    void SetHex(const std::string& str)
    {
        SetHex(str.c_str());
    }

    std::string ToString() const
    {
        return (GetHex());
    }

    unsigned char* begin()
    {
        return (unsigned char*)&pn[0];
    }

    unsigned char* end()
    {
        return (unsigned char*)&pn[WIDTH];
    }

    const unsigned char* begin() const
    {
        return (unsigned char*)&pn[0];
    }

    const unsigned char* end() const
    {
        return (unsigned char*)&pn[WIDTH];
    }

    unsigned int size() const
    {
        return sizeof(pn);
    }

    uint64_t GetLow64() const
    {
        assert(WIDTH >= 2);
        return pn[0] | (uint64_t)pn[1] << 32;
    }

    unsigned int GetSerializeSize(int nType, int nVersion) const
    {
        return sizeof(pn);
    }

    template<typename Stream>
    void Serialize(Stream& s, int nType, int nVersion) const
    {
        s.write((char*)pn, sizeof(pn));
    }

    template<typename Stream>
    void Unserialize(Stream& s, int nType, int nVersion)
    {
        s.read((char*)pn, sizeof(pn));
    }
};

/** 160-bit unsigned big integer. */
class uint160 : public base_uint<160> {
public:
    uint160() {}
    uint160(const base_uint<160>& b) : base_uint<160>(b) {}
    uint160(uint64_t b) : base_uint<160>(b) {}
    explicit uint160(const std::string& str) : base_uint<160>(str) {}
    explicit uint160(const std::vector<unsigned char>& vch) : base_uint<160>(vch) {}
};

/** 256-bit unsigned big integer. */
class uint256 : public base_uint<256> {
public:
    uint256() {}
    uint256(const base_uint<256>& b) : base_uint<256>(b) {}
    uint256(uint64_t b) : base_uint<256>(b) {}
    explicit uint256(const std::string& str) : base_uint<256>(str) {}
    explicit uint256(const std::vector<unsigned char>& vch) : base_uint<256>(vch) {}
};

#endif