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145 lines
4.0 KiB
C++
145 lines
4.0 KiB
C++
//------------------------------------------------------------------------------
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/*
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This file is part of rippled: https://github.com/ripple/rippled
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Copyright (c) 2012, 2013 Ripple Labs Inc.
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Permission to use, copy, modify, and/or distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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//==============================================================================
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#ifndef RIPPLE_APP_BOOK_QUALITY_H_INCLUDED
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#define RIPPLE_APP_BOOK_QUALITY_H_INCLUDED
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#include <ripple/app/book/Amount.h>
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#include <ripple/app/book/Amounts.h>
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#include <cstdint>
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#include <ostream>
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namespace ripple {
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namespace core {
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// Ripple specific constant used for parsing qualities and other things
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#define QUALITY_ONE 1000000000 // 10e9
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/** Represents the logical ratio of output currency to input currency.
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Internally this is stored using a custom floating point representation,
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as the inverse of the ratio, so that quality will be descending in
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a sequence of actual values that represent qualities.
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*/
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class Quality
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{
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public:
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// Type of the internal representation. Higher qualities
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// have lower unsigned integer representations.
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typedef std::uint64_t value_type;
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private:
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value_type m_value;
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public:
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Quality() = default;
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/** Create a quality from the integer encoding of an Amount */
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explicit
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Quality (std::uint64_t value);
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/** Create a quality from the ratio of two amounts. */
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explicit
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Quality (Amounts const& amount);
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/** Advances to the next higher quality level. */
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/** @{ */
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Quality&
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operator++();
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Quality
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operator++ (int);
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/** @} */
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/** Advances to the next lower quality level. */
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/** @{ */
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Quality&
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operator--();
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Quality
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operator-- (int);
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/** @} */
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/** Returns the quality as Amount. */
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Amount
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rate () const
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{
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return amountFromQuality (m_value);
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}
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/** Returns the scaled amount with in capped.
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Math is avoided if the result is exact. The output is clamped
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to prevent money creation.
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*/
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Amounts
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ceil_in (Amounts const& amount, Amount const& limit) const;
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/** Returns the scaled amount with out capped.
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Math is avoided if the result is exact. The input is clamped
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to prevent money creation.
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*/
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Amounts
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ceil_out (Amounts const& amount, Amount const& limit) const;
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/** Returns `true` if lhs is lower quality than `rhs`.
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Lower quality means the taker receives a worse deal.
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Higher quality is better for the taker.
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*/
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friend
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bool
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operator< (Quality const& lhs, Quality const& rhs) noexcept
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{
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return lhs.m_value > rhs.m_value;
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}
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friend
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bool
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operator== (Quality const& lhs, Quality const& rhs) noexcept
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{
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return lhs.m_value == rhs.m_value;
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}
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friend
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bool
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operator!= (Quality const& lhs, Quality const& rhs) noexcept
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{
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return ! (lhs == rhs);
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}
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friend
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std::ostream&
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operator<< (std::ostream& os, Quality const& quality)
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{
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os << quality.m_value;
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return os;
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}
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};
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/** Calculate the quality of a two-hop path given the two hops.
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@param lhs The first leg of the path: input to intermediate.
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@param rhs The second leg of the path: intermediate to output.
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*/
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Quality
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composed_quality (Quality const& lhs, Quality const& rhs);
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}
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}
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#endif
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