Add a heterogeneous container (with type list specified at compile-time) & tests

This commit is contained in:
Nikita Lisitsa 2020-11-26 22:01:57 +03:00
parent ccef8f91ea
commit d470fe7346
2 changed files with 534 additions and 0 deletions

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#pragma once
#include <psemek/util/flat_list.hpp>
#include <tuple>
#include <variant>
#include <any>
namespace psemek::util
{
namespace detail
{
constexpr std::size_t count_binary_digits(std::size_t n)
{
std::size_t result = 0;
for (; n > 0; n >>= 1)
++result;
return result;
}
template <typename T, typename ... Types>
struct one_of;
template <typename T>
struct one_of<T>
: std::false_type
{};
template <typename T, typename H, typename ... Types>
struct one_of<T, H, Types...>
: std::bool_constant<
std::is_same_v<T, H> ||
one_of<T, Types...>::value
>
{};
template <typename T, typename ... Types>
static constexpr bool one_of_v = one_of<T, Types...>::value;
template <typename T, typename ... Types>
struct index_of;
template <typename T>
struct index_of<T>
{
// there is no good value here, but we have to break recursion
static constexpr std::size_t value = -1;
};
template <typename T, typename H, typename ... Types>
struct index_of<T, H, Types...>
{
static constexpr std::size_t value =
std::is_same_v<T, H>
? 0
: 1 + index_of<T, Types...>::value;
};
template <typename T, typename ... Types>
static constexpr std::size_t index_of_v = index_of<T, Types...>::value;
template <typename F, typename T, std::size_t ... Is>
void tuple_for_each_impl(F && f, T & t, std::index_sequence<Is...>)
{
using expander = int[];
(void) expander { 0, (f(std::get<Is>(t), Is), 0) ... };
}
template <typename F, typename T>
void tuple_for_each(F && f, T & t)
{
tuple_for_each_impl(std::forward<F>(f), t, std::make_index_sequence<std::tuple_size_v<T>>{});
}
template <typename F, typename T, typename Seq>
struct tuple_apply_at_impl;
template <typename F, typename T>
struct tuple_apply_at_impl<F, T, std::index_sequence<>>
{
static decltype(auto) apply(F && f, T & t, std::size_t)
{
throw std::out_of_range("Bad tuple index");
return std::forward<F>(f)(std::get<0>(t));
}
};
template <typename F, typename T, std::size_t I, std::size_t ... Is>
struct tuple_apply_at_impl<F, T, std::index_sequence<I, Is...>>
{
static decltype(auto) apply(F && f, T & t, std::size_t i)
{
if (i == I)
{
return std::forward<F>(f)(std::get<I>(t));
}
return tuple_apply_at_impl<F, T, std::index_sequence<Is...>>::apply(std::forward<F>(f), t, i);
}
};
template <typename F, typename T>
decltype(auto) tuple_apply_at(F && f, T & t, std::size_t i)
{
if (i >= std::tuple_size_v<T>)
throw std::out_of_range("Bad tuple index");
return tuple_apply_at_impl<F, T, std::make_index_sequence<std::tuple_size_v<T>>>::apply(std::forward<F>(f), t, i);
}
}
struct bad_handle
: std::out_of_range
{
bad_handle()
: std::out_of_range("Bad handle")
{}
};
template <typename Handle, typename ... Types>
struct heterogeneous_container
{
using types = std::tuple<Types...>;
using any = std::variant<Types...>;
static constexpr std::size_t types_count = sizeof...(Types);
static_assert(types_count > 0);
using handle = Handle;
static_assert(std::is_integral_v<handle> && std::is_unsigned_v<handle>);
static std::size_t max_size()
{
return std::numeric_limits<handle>::max();
}
static std::size_t max_single_size()
{
return max_size() >> types_mask_bits;
}
template <typename T>
std::enable_if_t<detail::one_of_v<T, Types...>, handle>
insert(T value);
handle insert(any value);
void erase(handle h);
void clear();
any get(handle h) const;
template <typename T>
std::enable_if_t<detail::one_of_v<T, Types...>, T const &>
get(handle h) const;
template <typename T>
std::enable_if_t<detail::one_of_v<T, Types...>, T &>
get(handle h);
// TODO: arbitrary-arity visitors
template <typename F>
decltype(auto) visit(F && f, handle h1) const;
template <typename F>
decltype(auto) visit(F && f, handle h1, handle h2) const;
template <typename F>
decltype(auto) visit(F && f, handle h1);
template <typename F>
decltype(auto) visit(F && f, handle h1, handle h2);
std::size_t size() const;
bool empty() const;
private:
static constexpr std::size_t handle_bits = detail::count_binary_digits(static_cast<handle>(-1));
static constexpr std::size_t types_mask_bits = detail::count_binary_digits(std::max<std::size_t>(1, types_count - 1));
static constexpr handle type_mask = static_cast<handle>(-1) ^ (static_cast<handle>(-1) >> types_mask_bits);
std::tuple<flat_list<Types, handle>...> storage_;
static std::pair<std::size_t, handle> unpack_handle(handle h)
{
std::size_t const i = (h & type_mask) >> (handle_bits - types_mask_bits);
handle const hh = h & (~type_mask);
return {i, hh};
}
static handle pack_handle(std::size_t i, handle h)
{
return h | static_cast<handle>(i << (handle_bits - types_mask_bits));
}
};
template <typename Handle, typename ... Types>
template <typename T>
std::enable_if_t<detail::one_of_v<T, Types...>, Handle>
heterogeneous_container<Handle, Types...>::insert(T value)
{
static constexpr std::size_t i = detail::index_of_v<T, Types...>;
auto h = std::get<i>(storage_).insert(std::move(value));
return pack_handle(i, h);
}
template <typename Handle, typename ... Types>
Handle heterogeneous_container<Handle, Types...>::insert(any value)
{
std::visit([this](auto && value){ this->insert(value); }, value);
}
template <typename Handle, typename ... Types>
void heterogeneous_container<Handle, Types...>::erase(handle h)
{
auto [i, hh] = unpack_handle(h);
if (i >= types_count)
throw bad_handle{};
detail::tuple_apply_at([hh](auto & t) -> void {
t.erase(hh);
}, storage_, i);
}
template <typename Handle, typename ... Types>
void heterogeneous_container<Handle, Types...>::clear()
{
detail::tuple_for_each([](auto & t, auto){
t.clear();
}, storage_);
}
template <typename Handle, typename ... Types>
heterogeneous_container<Handle, Types...>::any heterogeneous_container<Handle, Types...>::get(handle h) const
{
auto [i, hh] = unpack_handle(h);
return detail::tuple_apply_at([hh](auto & t) -> any {
return t[hh];
}, storage_, i);
}
template <typename Handle, typename ... Types>
template <typename T>
std::enable_if_t<detail::one_of_v<T, Types...>, T const &>
heterogeneous_container<Handle, Types...>::get(handle h) const
{
T const * res = nullptr;
std::pair<std::size_t, handle> const p = unpack_handle(h);
std::size_t const i = p.first;
handle const hh = p.second;
detail::tuple_for_each([i, hh, &res](auto & t, std::size_t j){
if constexpr (std::is_same_v<std::decay_t<decltype(t[hh])>, T>)
{
if (i != j)
throw std::bad_any_cast{};
res = &t[hh];
}
}, storage_);
if (!res)
throw std::bad_any_cast{};
return *res;
}
template <typename Handle, typename ... Types>
template <typename T>
std::enable_if_t<detail::one_of_v<T, Types...>, T &>
heterogeneous_container<Handle, Types...>::get(handle h)
{
T * res = nullptr;
std::pair<std::size_t, handle> const p = unpack_handle(h);
std::size_t const i = p.first;
handle const hh = p.second;
detail::tuple_for_each([i, hh, &res](auto & t, std::size_t j){
if constexpr (std::is_same_v<std::decay_t<decltype(t[hh])>, T>)
{
if (i != j)
throw std::bad_any_cast{};
res = &t[hh];
}
}, storage_);
if (!res)
throw std::bad_any_cast{};
return *res;
}
template <typename Handle, typename ... Types>
template <typename F>
decltype(auto) heterogeneous_container<Handle, Types...>::visit(F && f, handle h1) const
{
std::pair<std::size_t, handle> const p1 = unpack_handle(h1);
std::size_t const i1 = p1.first;
handle const hh1 = p1.second;
return detail::tuple_apply_at([hh1, &f](auto & t1){
return std::forward<F>(f)(t1[hh1]);
}, storage_, i1);
}
template <typename Handle, typename ... Types>
template <typename F>
decltype(auto) heterogeneous_container<Handle, Types...>::visit(F && f, handle h1, handle h2) const
{
std::pair<std::size_t, handle> const p1 = unpack_handle(h1);
std::size_t const i1 = p1.first;
handle const hh1 = p1.second;
std::pair<std::size_t, handle> const p2 = unpack_handle(h2);
std::size_t const i2 = p2.first;
handle const hh2 = p2.second;
return detail::tuple_apply_at([i2, hh1, hh2, &f, this](auto & t1){
return detail::tuple_apply_at([hh1, hh2, &f, &t1](auto & t2){
return std::forward<F>(f)(t1[hh1], t2[hh2]);
}, storage_, i2);
}, storage_, i1);
}
template <typename Handle, typename ... Types>
template <typename F>
decltype(auto) heterogeneous_container<Handle, Types...>::visit(F && f, handle h1)
{
std::pair<std::size_t, handle> const p1 = unpack_handle(h1);
std::size_t const i1 = p1.first;
handle const hh1 = p1.second;
return detail::tuple_apply_at([hh1, &f](auto & t1){
return std::forward<F>(f)(t1[hh1]);
}, storage_, i1);
}
template <typename Handle, typename ... Types>
template <typename F>
decltype(auto) heterogeneous_container<Handle, Types...>::visit(F && f, handle h1, handle h2)
{
std::pair<std::size_t, handle> const p1 = unpack_handle(h1);
std::size_t const i1 = p1.first;
handle const hh1 = p1.second;
std::pair<std::size_t, handle> const p2 = unpack_handle(h2);
std::size_t const i2 = p2.first;
handle const hh2 = p2.second;
return detail::tuple_apply_at([i2, hh1, hh2, &f, this](auto & t1){
return detail::tuple_apply_at([hh1, hh2, &f, &t1](auto & t2){
return std::forward<F>(f)(t1[hh1], t2[hh2]);
}, storage_, i2);
}, storage_, i1);
}
template <typename Handle, typename ... Types>
std::size_t heterogeneous_container<Handle, Types...>::size() const
{
std::size_t res = 0;
detail::tuple_for_each([&res](auto & t, auto){ res += t.size(); }, storage_);
return res;
}
template <typename Handle, typename ... Types>
bool heterogeneous_container<Handle, Types...>::empty() const
{
bool res = true;
detail::tuple_for_each([&res](auto & t, auto){ res &= t.empty(); }, storage_);
return res;
}
}

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#include <psemek/test/test.hpp>
#include <psemek/util/heterogeneous_container.hpp>
using namespace psemek::util;
using container = heterogeneous_container<std::uint32_t, char, int, float, double>;
test_case(util_heterogeneous__container_empty)
{
container c;
expect(c.empty());
expect_equal(c.size(), 0);
}
test_case(util_heterogeneous__container_max__size)
{
container c;
expect_gequal(c.max_single_size(), 1 << 20);
}
test_case(util_heterogeneous__container_size)
{
container c;
auto c0 = c.insert('0');
expect_equal(c.size(), 1);
expect(!c.empty());
auto c1 = c.insert('1');
expect_equal(c.size(), 2);
expect(!c.empty());
auto c2 = c.insert('2');
expect_equal(c.size(), 3);
expect(!c.empty());
auto d0 = c.insert(0.0);
expect_equal(c.size(), 4);
expect(!c.empty());
auto d1 = c.insert(1.0);
expect_equal(c.size(), 5);
expect(!c.empty());
auto d2 = c.insert(2.0);
expect_equal(c.size(), 6);
expect(!c.empty());
c.erase(c2);
expect_equal(c.size(), 5);
expect(!c.empty());
c.erase(d1);
expect_equal(c.size(), 4);
expect(!c.empty());
c.erase(d0);
expect_equal(c.size(), 3);
expect(!c.empty());
c.erase(c0);
expect_equal(c.size(), 2);
expect(!c.empty());
c.erase(d2);
expect_equal(c.size(), 1);
expect(!c.empty());
c.erase(c1);
expect_equal(c.size(), 0);
expect(c.empty());
}
test_case(util_heterogeneous__container_get)
{
container c;
auto c0 = c.insert('0');
expect_equal(c.get<char>(c0), '0');
expect_equal(c.get(c0).index(), 0);
expect_equal(std::get<0>(c.get(c0)), '0');
expect_equal(std::get<char>(c.get(c0)), '0');
auto c1 = c.insert('1');
expect_equal(c.get<char>(c1), '1');
expect_equal(c.get(c1).index(), 0);
expect_equal(std::get<0>(c.get(c1)), '1');
expect_equal(std::get<char>(c.get(c1)), '1');
auto f0 = c.insert(3.14f);
expect_equal(c.get<float>(f0), 3.14f);
expect_equal(c.get(f0).index(), 2);
expect_equal(std::get<2>(c.get(f0)), 3.14f);
expect_equal(std::get<float>(c.get(f0)), 3.14f);
expect_throw(c.get<float>(c0), std::bad_any_cast);
expect_throw(c.get<float>(c1), std::bad_any_cast);
expect_throw(c.get<char>(f0), std::bad_any_cast);
}
test_case(util_heterogeneous__container_visit)
{
container c;
auto c0 = c.insert('0');
auto f0 = c.insert(3.14f);
c.visit([](auto const & v){
if constexpr (std::is_same_v<std::decay_t<decltype(v)>, char>)
{
expect_equal(v, '0');
}
else
{
expect(false);
}
}, c0);
c.visit([](auto const & v){
if constexpr (std::is_same_v<std::decay_t<decltype(v)>, float>)
{
expect_equal(v, 3.14f);
}
else
{
expect(false);
}
}, f0);
c.visit([](auto const & vc, auto const & vf){
if constexpr (std::is_same_v<std::decay_t<decltype(vc)>, char> && std::is_same_v<std::decay_t<decltype(vf)>, float>)
{
expect_equal(vc, '0');
expect_equal(vf, 3.14f);
}
else
{
expect(false);
}
}, c0, f0);
c.visit([](auto const & vf, auto const & vc){
if constexpr (std::is_same_v<std::decay_t<decltype(vc)>, char> && std::is_same_v<std::decay_t<decltype(vf)>, float>)
{
expect_equal(vc, '0');
expect_equal(vf, 3.14f);
}
else
{
expect(false);
}
}, f0, c0);
}