amount.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2016 The Bitcoin Core developers
// Copyright (c) 2017-2019 The Bitcoin developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#ifndef BITCOIN_CONSENSUS_AMOUNT_H
#define BITCOIN_CONSENSUS_AMOUNT_H
 
#include <serialize.h>
#include <util/overflow.h>
 
#include <algorithm>
#include <cstdlib>
#include <optional>
#include <ostream>
#include <string>
#include <string_view>
#include <type_traits>
 
class UniValue;
 
struct Amount {
private:
    int64_t amount;
 
    explicit constexpr Amount(int64_t _amount) : amount(_amount) {}
 
public:
    constexpr Amount() noexcept : amount(0) {}
    operator UniValue() const;
 
    static constexpr Amount zero() noexcept { return Amount(0); }
    static constexpr Amount satoshi() noexcept { return Amount(1); }
 
    Amount &operator+=(const Amount a) {
        amount += a.amount;
        return *this;
    }
    Amount &operator-=(const Amount a) {
        amount -= a.amount;
        return *this;
    }
 
    friend constexpr bool operator==(const Amount a, const Amount b) {
        return a.amount == b.amount;
    }
    friend constexpr bool operator!=(const Amount a, const Amount b) {
        return !(a == b);
    }
 
    friend constexpr bool operator<(const Amount a, const Amount b) {
        return a.amount < b.amount;
    }
    friend constexpr bool operator>(const Amount a, const Amount b) {
        return b < a;
    }
    friend constexpr bool operator<=(const Amount a, const Amount b) {
        return !(a > b);
    }
    friend constexpr bool operator>=(const Amount a, const Amount b) {
        return !(a < b);
    }
 
    constexpr Amount operator-() const { return Amount(-amount); }
 
    friend constexpr Amount operator+(const Amount a, const Amount b) {
        return Amount(a.amount + b.amount);
    }
    friend constexpr Amount operator-(const Amount a, const Amount b) {
        return a + -b;
    }
    [[nodiscard]] std::optional<Amount>
    CheckedAdd(const Amount &other) const noexcept;
 
    void SaturatingAdd(const Amount &other) noexcept;
 
    friend constexpr Amount operator*(const int64_t a, const Amount b) {
        return Amount(a * b.amount);
    }
    friend constexpr Amount operator*(const int a, const Amount b) {
        return Amount(a * b.amount);
    }
 
    constexpr int64_t operator/(const Amount b) const {
        return amount / b.amount;
    }
    constexpr Amount operator/(const int64_t b) const {
        return Amount(amount / b);
    }
    constexpr Amount operator/(const int b) const { return Amount(amount / b); }
    Amount &operator/=(const int64_t n) {
        amount /= n;
        return *this;
    }
 
    constexpr Amount operator%(const Amount b) const {
        return Amount(amount % b.amount);
    }
    constexpr Amount operator%(const int64_t b) const {
        return Amount(amount % b);
    }
    constexpr Amount operator%(const int b) const { return Amount(amount % b); }
 
    friend constexpr Amount operator*(const double a, const Amount b) = delete;
    constexpr Amount operator/(const double b) const = delete;
    constexpr Amount operator%(const double b) const = delete;
 
    // ostream support
    friend std::ostream &operator<<(std::ostream &stream, const Amount &ca) {
        return stream << ca.amount;
    }
 
    std::string ToString() const;
 
    // serialization support
    SERIALIZE_METHODS(Amount, obj) { READWRITE(obj.amount); }
};
 
static constexpr Amount SATOSHI = Amount::satoshi();
static constexpr Amount COIN = 100000000 * SATOSHI;
 
struct Currency {
    Amount baseunit;
    Amount subunit;
    uint8_t decimals;
    std::string_view ticker;
 
    static const Currency &get();
    static std::string getTicker() { return std::string{get().ticker}; }
};
 
static constexpr Amount MAX_MONEY = 21000000 * COIN;
inline bool MoneyRange(const Amount nValue) {
    return nValue >= Amount::zero() && nValue <= MAX_MONEY;
}
 
inline Amount MoneyClamp(const Amount nValue) {
    return std::clamp(nValue, Amount::zero(), MAX_MONEY);
}
 
#endif // BITCOIN_CONSENSUS_AMOUNT_H