Skip to content

Simplify reverse tuple iteration #1161

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
Mar 20, 2023
Merged

Simplify reverse tuple iteration #1161

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
e730fee
Simplify reverse tuple iteration
vittorioromeo Mar 19, 2023
1dc9cdc
Apply review suggestions
vittorioromeo Mar 20, 2023
e64e23b
Apply review suggestions
vittorioromeo Mar 20, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
31 changes: 0 additions & 31 deletions dev/functional/index_sequence_util.h
View file
Open in desktop
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

BTW, we might implement first_index_sequence_value() as follows. What do you think?

template<size_t... Idx>
SQLITE_ORM_CONSTEVAL size_t first_index_sequence_value(std::index_sequence<Idx...>) {
    static_assert(sizeof...(Idx) > 0);
    size_t result;
    ((result = Idx, true) || ...);
    return result;
}

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Compared to the current implementation, I'm not sure it's going to be faster. I would recommend a benchmark on https://www.build-bench.com/

Original file line number Diff line number Diff line change
Expand Up @@ -17,37 +17,6 @@ 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
3 changes: 2 additions & 1 deletion dev/tuple_helper/tuple_iteration.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,8 @@ 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));
int sink;
((lambda(std::get<Idx>(tpl)), sink) = ... = 0);
} else {
(lambda(std::get<Idx>(tpl)), ...);
}
Expand Down
34 changes: 2 additions & 32 deletions include/sqlite_orm/sqlite_orm.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1128,37 +1128,6 @@ 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 +9543,8 @@ 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));
int sink;
((lambda(std::get<Idx>(tpl)), sink) = ... = 0);
} else {
(lambda(std::get<Idx>(tpl)), ...);
}
Expand Down