amount.h

//------------------------------------------------------------------------------
/*
  This file is part of rippled: https://github.com/ripple/rippled
  Copyright (c) 2012-2015 Ripple Labs Inc.
 
  Permission to use, copy, modify, and/or distribute this software for any
  purpose  with  or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.
 
  THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
  MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_TEST_JTX_AMOUNT_H_INCLUDED
#define RIPPLE_TEST_JTX_AMOUNT_H_INCLUDED
 
#include <ripple/basics/FeeUnits.h>
#include <ripple/basics/contract.h>
#include <ripple/protocol/Issue.h>
#include <ripple/protocol/STAmount.h>
#include <cstdint>
#include <ostream>
#include <string>
#include <test/jtx/Account.h>
#include <test/jtx/amount.h>
#include <test/jtx/tags.h>
#include <type_traits>
 
namespace ripple {
namespace test {
namespace jtx {
 
/*
 
The decision was made to accept amounts of drops and XRP
using an int type, since the range of XRP is 100 billion
and having both signed and unsigned overloads creates
tricky code leading to overload resolution ambiguities.
 
*/
 
struct AnyAmount;
 
// Represents "no amount" of a currency
// This is distinct from zero or a balance.
// For example, no USD means the trust line
// doesn't even exist. Using this in an
// inappropriate context will generate a
// compile error.
//
struct None
{
    Issue issue;
};
 
//------------------------------------------------------------------------------
 
// This value is also defined in SystemParameters.h. It's
// duplicated here to catch any possible future errors that
// could change that value (however unlikely).
constexpr XRPAmount dropsPerXRP{1'000'000};
 
struct PrettyAmount
{
private:
    // VFALCO TODO should be Amount
    STAmount amount_;
    std::string name_;
 
public:
    PrettyAmount() = default;
    PrettyAmount(PrettyAmount const&) = default;
    PrettyAmount&
    operator=(PrettyAmount const&) = default;
 
    PrettyAmount(STAmount const& amount, std::string const& name)
        : amount_(amount), name_(name)
    {
    }
 
    template <class T>
    PrettyAmount(
        T v,
        std::enable_if_t<
            sizeof(T) >= sizeof(int) && std::is_integral_v<T> &&
            std::is_signed_v<T>>* = nullptr)
        : amount_((v > 0) ? v : -v, v < 0)
    {
    }
 
    template <class T>
    PrettyAmount(
        T v,
        std::enable_if_t<sizeof(T) >= sizeof(int) && std::is_unsigned_v<T>>* =
            nullptr)
        : amount_(v)
    {
    }
 
    PrettyAmount(XRPAmount v) : amount_(v)
    {
    }
 
    std::string const&
    name() const
    {
        return name_;
    }
 
    STAmount const&
    value() const
    {
        return amount_;
    }
 
    operator STAmount const &() const
    {
        return amount_;
    }
 
    operator AnyAmount() const;
};
 
inline bool
operator==(PrettyAmount const& lhs, PrettyAmount const& rhs)
{
    return lhs.value() == rhs.value();
}
 
inline bool
operator!=(PrettyAmount const& lhs, PrettyAmount const& rhs)
{
    return !operator==(lhs, rhs);
}
 
std::ostream&
operator<<(std::ostream& os, PrettyAmount const& amount);
 
//------------------------------------------------------------------------------
 
// Specifies an order book
struct BookSpec
{
    AccountID account;
    ripple::Currency currency;
 
    BookSpec(AccountID const& account_, ripple::Currency const& currency_)
        : account(account_), currency(currency_)
    {
    }
};
 
//------------------------------------------------------------------------------
 
struct XRP_t
{
    operator Issue() const
    {
        return xrpIssue();
    }
 
    template <class T, class = std::enable_if_t<std::is_integral_v<T>>>
    PrettyAmount
    operator()(T v) const
    {
        using TOut = std::
            conditional_t<std::is_signed_v<T>, std::int64_t, std::uint64_t>;
        return {TOut{v} * dropsPerXRP};
    }
 
    PrettyAmount
    operator()(double v) const
    {
        auto const c = dropsPerXRP.drops();
        if (v >= 0)
        {
            auto const d = std::uint64_t(std::round(v * c));
            if (double(d) / c != v)
                Throw<std::domain_error>("unrepresentable");
            return {d};
        }
        auto const d = std::int64_t(std::round(v * c));
        if (double(d) / c != v)
            Throw<std::domain_error>("unrepresentable");
        return {d};
    }
    None operator()(none_t) const
    {
        return {xrpIssue()};
    }
 
    friend BookSpec
    operator~(XRP_t const&)
    {
        return BookSpec(xrpAccount(), xrpCurrency());
    }
};
 
extern XRP_t const XRP;
 
template <class Integer, class = std::enable_if_t<std::is_integral_v<Integer>>>
PrettyAmount
drops(Integer i)
{
    return {i};
}
 
inline PrettyAmount
drops(XRPAmount i)
{
    return {i};
}
 
//------------------------------------------------------------------------------
 
namespace detail {
 
struct epsilon_multiple
{
    std::size_t n;
};
 
}  // namespace detail
 
// The smallest possible IOU STAmount
struct epsilon_t
{
    epsilon_t()
    {
    }
 
    detail::epsilon_multiple
    operator()(std::size_t n) const
    {
        return {n};
    }
};
 
static epsilon_t const epsilon;
 
class IOU
{
public:
    Account account;
    ripple::Currency currency;
 
    IOU(Account const& account_, ripple::Currency const& currency_)
        : account(account_), currency(currency_)
    {
    }
 
    Issue
    issue() const
    {
        return {currency, account.id()};
    }
 
    operator Issue() const
    {
        return issue();
    }
 
    template <
        class T,
        class = std::enable_if_t<
            sizeof(T) >= sizeof(int) && std::is_arithmetic<T>::value>>
    PrettyAmount
    operator()(T v) const
    {
        // VFALCO NOTE Should throw if the
        //             representation of v is not exact.
        return {amountFromString(issue(), std::to_string(v)), account.name()};
    }
 
    PrettyAmount operator()(epsilon_t) const;
    PrettyAmount operator()(detail::epsilon_multiple) const;
 
    // VFALCO TODO
    // STAmount operator()(char const* s) const;
 
    None operator()(none_t) const
    {
        return {issue()};
    }
 
    friend BookSpec
    operator~(IOU const& iou)
    {
        return BookSpec(iou.account.id(), iou.currency);
    }
};
 
std::ostream&
operator<<(std::ostream& os, IOU const& iou);
 
//------------------------------------------------------------------------------
 
struct any_t
{
    inline AnyAmount
    operator()(STAmount const& sta) const;
};
 
struct AnyAmount
{
    bool is_any;
    STAmount value;
 
    AnyAmount() = delete;
    AnyAmount(AnyAmount const&) = default;
    AnyAmount&
    operator=(AnyAmount const&) = default;
 
    AnyAmount(STAmount const& amount) : is_any(false), value(amount)
    {
    }
 
    AnyAmount(STAmount const& amount, any_t const*)
        : is_any(true), value(amount)
    {
    }
 
    // Reset the issue to a specific account
    void
    to(AccountID const& id)
    {
        if (!is_any)
            return;
        value.setIssuer(id);
    }
};
 
inline AnyAmount
any_t::operator()(STAmount const& sta) const
{
    return AnyAmount(sta, this);
}
 
extern any_t const any;
 
}  // namespace jtx
}  // namespace test
}  // namespace ripple
 
#endif