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Simplify reverse tuple iteration #1161

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Merged
merged 3 commits into from
Mar 20, 2023
Merged

Simplify reverse tuple iteration #1161

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e730fee
Simplify reverse tuple iteration
vittorioromeo Mar 19, 2023
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vittorioromeo Mar 20, 2023
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vittorioromeo Mar 20, 2023
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34 changes: 0 additions & 34 deletions dev/functional/index_sequence_util.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3,9 +3,6 @@
#include <utility> // std::index_sequence, std::make_index_sequence

#include "../functional/cxx_universal.h"
#ifdef SQLITE_ORM_RELAXED_CONSTEXPR_SUPPORTED
#include <array>
#endif

namespace sqlite_orm {
namespace internal {
Expand All @@ -17,37 +14,6 @@ namespace sqlite_orm {
return I;
}

#ifdef SQLITE_ORM_RELAXED_CONSTEXPR_SUPPORTED
/**
* Reorder the values of an index_sequence according to the positions from a second sequence.
*/
template<size_t... Value, size_t... IdxOfValue>
SQLITE_ORM_CONSTEVAL auto reorder_index_sequence(std::index_sequence<Value...>,
std::index_sequence<IdxOfValue...>) {
constexpr std::array<size_t, sizeof...(Value)> values{Value...};
return std::index_sequence<values[sizeof...(Value) - 1u - IdxOfValue]...>{};
}

template<size_t Value, size_t IdxOfValue>
SQLITE_ORM_CONSTEVAL std::index_sequence<Value> reorder_index_sequence(std::index_sequence<Value>,
std::index_sequence<IdxOfValue>) {
return {};
}

inline SQLITE_ORM_CONSTEVAL std::index_sequence<> reorder_index_sequence(std::index_sequence<>,
std::index_sequence<>) {
return {};
}

/**
* Reverse the values of an index_sequence.
*/
template<size_t... Idx>
SQLITE_ORM_CONSTEVAL auto reverse_index_sequence(std::index_sequence<Idx...>) {
return reorder_index_sequence(std::index_sequence<Idx...>{}, std::make_index_sequence<sizeof...(Idx)>{});
}
#endif

template<class... Seq>
struct flatten_idxseq {
using type = std::index_sequence<>;
Expand Down
4 changes: 3 additions & 1 deletion dev/tuple_helper/tuple_iteration.h
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Expand Up @@ -33,7 +33,9 @@ namespace sqlite_orm {
template<bool reversed = false, class Tpl, size_t... Idx, class L>
void iterate_tuple(const Tpl& tpl, std::index_sequence<Idx...>, L&& lambda) {
if constexpr(reversed) {
iterate_tuple(tpl, reverse_index_sequence(std::index_sequence<Idx...>{}), std::forward<L>(lambda));
// nifty fold expression trick: make use of guaranteed right-to-left evaluation order when folding over operator=
int sink;
((lambda(std::get<Idx>(tpl)), sink) = ... = 0);
} else {
(lambda(std::get<Idx>(tpl)), ...);
}
Expand Down
39 changes: 3 additions & 36 deletions include/sqlite_orm/sqlite_orm.h
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Expand Up @@ -1114,10 +1114,6 @@ namespace sqlite_orm {

// #include "../functional/cxx_universal.h"

#ifdef SQLITE_ORM_RELAXED_CONSTEXPR_SUPPORTED
#include <array>
#endif

namespace sqlite_orm {
namespace internal {
/**
Expand All @@ -1128,37 +1124,6 @@ namespace sqlite_orm {
return I;
}

#ifdef SQLITE_ORM_RELAXED_CONSTEXPR_SUPPORTED
/**
* Reorder the values of an index_sequence according to the positions from a second sequence.
*/
template<size_t... Value, size_t... IdxOfValue>
SQLITE_ORM_CONSTEVAL auto reorder_index_sequence(std::index_sequence<Value...>,
std::index_sequence<IdxOfValue...>) {
constexpr std::array<size_t, sizeof...(Value)> values{Value...};
return std::index_sequence<values[sizeof...(Value) - 1u - IdxOfValue]...>{};
}

template<size_t Value, size_t IdxOfValue>
SQLITE_ORM_CONSTEVAL std::index_sequence<Value> reorder_index_sequence(std::index_sequence<Value>,
std::index_sequence<IdxOfValue>) {
return {};
}

inline SQLITE_ORM_CONSTEVAL std::index_sequence<> reorder_index_sequence(std::index_sequence<>,
std::index_sequence<>) {
return {};
}

/**
* Reverse the values of an index_sequence.
*/
template<size_t... Idx>
SQLITE_ORM_CONSTEVAL auto reverse_index_sequence(std::index_sequence<Idx...>) {
return reorder_index_sequence(std::index_sequence<Idx...>{}, std::make_index_sequence<sizeof...(Idx)>{});
}
#endif

template<class... Seq>
struct flatten_idxseq {
using type = std::index_sequence<>;
Expand Down Expand Up @@ -9574,7 +9539,9 @@ namespace sqlite_orm {
template<bool reversed = false, class Tpl, size_t... Idx, class L>
void iterate_tuple(const Tpl& tpl, std::index_sequence<Idx...>, L&& lambda) {
if constexpr(reversed) {
iterate_tuple(tpl, reverse_index_sequence(std::index_sequence<Idx...>{}), std::forward<L>(lambda));
// nifty fold expression trick: make use of guaranteed right-to-left evaluation order when folding over operator=
int sink;
((lambda(std::get<Idx>(tpl)), sink) = ... = 0);
} else {
(lambda(std::get<Idx>(tpl)), ...);
}
Expand Down