add compare_func() method so user-defined comparison functions are easier to use

This commit is contained in:
koe 2022-12-19 15:50:16 -06:00
parent 73298734d6
commit c60b11f3da
1 changed files with 14 additions and 0 deletions

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@ -47,7 +47,14 @@
namespace tools
{
/// convert a binary comparison function to a functor
template <typename T, typename ComparisonOpT = bool(const T &a, const T &b)>
inline auto compare_func(const ComparisonOpT &comparison_function)
{
return [&comparison_function](const T &a, const T &b) -> bool { return comparison_function(a, b); };
}
/// test if a container is sorted and unique according to a comparison criteria (defaults to operator<)
/// NOTE: ComparisonOpT must establish 'strict weak ordering' https://en.cppreference.com/w/cpp/named_req/Compare
template <typename T, typename ComparisonOpT = std::less<typename T::value_type>>
bool is_sorted_and_unique(const T &container, const ComparisonOpT &ComparisonOp = ComparisonOpT{})
{
@ -65,6 +72,13 @@ bool is_sorted_and_unique(const T &container, const ComparisonOpT &ComparisonOp
return true;
}
/// specialization for raw function pointers
template <typename T>
bool is_sorted_and_unique(const T &container,
bool (*const ComparisonOpFunc)(const typename T::value_type &a, const typename T::value_type &b))
{
return is_sorted_and_unique(container, compare_func<typename T::value_type>(ComparisonOpFunc));
}
/// convenience wrapper for checking if a mapped object is mapped to a key embedded in that object
/// example: std::unorderd_map<rct::key, std::pair<rct::key, rct::xmr_amount>> where the map key is supposed to
/// reproduce the pair's rct::key; use the predicate to get the pair's rct::key element