我正在实现我自己的两个无序地图,一个是接收一个有3个参数的key,另一个是有2个参数的tuple。以下是我的代码。
#pragma once
#include <boost/functional/hash.hpp>
#include <unordered_map>
#include <tuple>
namespace Valk::ExchangeGateway::TupleMap
{
using boost::hash_value;
using boost::hash_combine;
template <typename T, typename U>
auto hashTuple = [](const std::tuple<T, U>& singleTuple) -> size_t
{
size_t seed{};
hash_combine(seed, hash_value(std::get<0>(singleTuple)));
hash_combine(seed, hash_value(std::get<1>(singleTuple)));
return seed;
};
template <typename T, typename U>
auto equalTuple = [](const std::tuple<T, U>& firstTuple, const std::tuple<T, U>& secondTuple) -> bool
{
return std::get<0>(firstTuple) == std::get<0>(secondTuple)
&& std::get<1>(firstTuple) == std::get<1>(secondTuple);
};
template <typename T, typename U, typename D>
auto hashTripleTuple = [](const std::tuple<T, U, D>& singleTuple) -> size_t
{
size_t seed{};
hash_combine(seed, hash_value(std::get<0>(singleTuple)));
hash_combine(seed, hash_value(std::get<1>(singleTuple)));
hash_combine(seed, hash_value(std::get<2>(singleTuple)));
return seed;
};
template <typename T, typename U, typename D>
auto equalTripleTuple =
[](const std::tuple<T, U, D>& firstTuple, const std::tuple<T, U, D>& secondTuple) -> bool
{
return std::get<0>(firstTuple) == std::get<0>(secondTuple)
&& std::get<1>(firstTuple) == std::get<1>(secondTuple)
&& std::get<2>(firstTuple) == std::get<2>(secondTuple);
};
using InstrumentFrequency = int;
using TotalDelta = double;
using FutureTupleUnorderedMap = std::unordered_map<std::tuple<TotalDelta, Instrument::InstrumentID, Platform::Price>,
InstrumentFrequency, decltype(hashTripleTuple<TotalDelta, Instrument::InstrumentID, Platform::Price>),
decltype(equalTripleTuple<TotalDelta, Instrument::InstrumentID, Platform::Price>)>;
using OptionTupleUnorderedMap = std::unordered_map<std::tuple<Platform::Quantity, Instrument::InstrumentID>,
InstrumentFrequency, decltype(hashTuple<Platform::Quantity, Instrument::InstrumentID>),
decltype(equalTuple<Platform::Quantity, Instrument::InstrumentID>)>;
}
你所看到的所有类型定义,例如 Platform::Quantity
和 Platform::Price
是基元类型的类型定义,如 long long
或 int
.
不知为什么,我得到了以下错误(截图比复制粘贴在这里容易),我不知道为什么。这里没有一个类的复制构造函数被删除或没有生成。
谢谢大家的帮助。
lambdas不是默认可构造的。所以,你需要传递哈希质量运算符。或者,你可以推导出lambda的命名类型,并添加默认可构造性。
最简单的方法是结合哈希分别平等运算符来处理双三元组。
struct HashTuple {
template <typename T, typename U>
auto operator()(const std::tuple<T, U>& singleTuple) const -> size_t
{
size_t seed{};
hash_combine(seed, hash_value(std::get<0>(singleTuple)));
hash_combine(seed, hash_value(std::get<1>(singleTuple)));
return seed;
}
template <typename T, typename U, typename D>
auto operator()(const std::tuple<T, U, D>& singleTuple) const -> size_t
{
size_t seed{};
hash_combine(seed, hash_value(std::get<0>(singleTuple)));
hash_combine(seed, hash_value(std::get<1>(singleTuple)));
hash_combine(seed, hash_value(std::get<2>(singleTuple)));
return seed;
}
};
struct EqualTuple {
template <typename... T>
auto operator()(const std::tuple<T...>& firstTuple, const std::tuple<T...>& secondTuple) const -> bool {
return firstTuple == secondTuple;
}
};
注意这使用了等价的
std::tuple::operator==
实施
现在,你可以简化类型。
std::unordered_map<std::tuple<double, int, double>, int, HashTuple, EqualTuple>
std::unordered_map<std::tuple<unsigned int, int>, int, HashTuple, EqualTuple>
我会用一个简单的助手来总结:
template <typename... Key> using FrequencyMap =
std::unordered_map<std::tuple<Key...>, InstrumentFrequency, HashTuple, EqualTuple>;
using FutureTupleUnorderedMap = FrequencyMap<TotalDelta, Instrument::InstrumentID, Platform::Price>;
using OptionTupleUnorderedMap = FrequencyMap<Platform::Quantity, Instrument::InstrumentID>;
现在我们有了一个完整的演示。
#include <boost/functional/hash.hpp>
#include <tuple>
#include <unordered_map>
struct Instrument {
using InstrumentID = int;
};
struct Platform {
using Quantity = unsigned;
using Price = double;
};
namespace Valk::ExchangeGateway::TupleMap {
struct HashTuple {
template <typename T, typename U>
auto operator()(const std::tuple<T, U>& singleTuple) const -> size_t
{
using boost::hash_value;
using boost::hash_combine;
size_t seed{};
hash_combine(seed, hash_value(std::get<0>(singleTuple)));
hash_combine(seed, hash_value(std::get<1>(singleTuple)));
return seed;
}
template <typename T, typename U, typename D>
auto operator()(const std::tuple<T, U, D>& singleTuple) const -> size_t
{
using boost::hash_value;
using boost::hash_combine;
size_t seed{};
hash_combine(seed, hash_value(std::get<0>(singleTuple)));
hash_combine(seed, hash_value(std::get<1>(singleTuple)));
hash_combine(seed, hash_value(std::get<2>(singleTuple)));
return seed;
}
};
struct EqualTuple {
template <typename... T>
auto operator()(const std::tuple<T...>& firstTuple, const std::tuple<T...>& secondTuple) const -> bool {
return firstTuple == secondTuple;
}
};
using InstrumentFrequency = int;
using TotalDelta = double;
template <typename... Key> using FrequencyMap =
std::unordered_map<std::tuple<Key...>, InstrumentFrequency, HashTuple, EqualTuple>;
using FutureTupleUnorderedMap = FrequencyMap<TotalDelta, Instrument::InstrumentID, Platform::Price>;
using OptionTupleUnorderedMap = FrequencyMap<Platform::Quantity, Instrument::InstrumentID>;
}
#include <boost/core/demangle.hpp>
#include <iostream>
int main() {
{
Valk::ExchangeGateway::TupleMap::FutureTupleUnorderedMap ftum;
std::cout << boost::core::demangle(typeid(ftum).name()) << "\n";
}
{
Valk::ExchangeGateway::TupleMap::OptionTupleUnorderedMap otum;
std::cout << boost::core::demangle(typeid(otum).name()) << "\n";
}
}
打印您在上面看到的类型名称。