From 3bf42c6ff3805a0d42bbc661794a95ff31bedc26 Mon Sep 17 00:00:00 2001 From: untodesu Date: Sat, 15 Mar 2025 16:22:09 +0500 Subject: Add whatever I was working on for the last month --- deps/include/entt/core/algorithm.hpp | 143 +++++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 deps/include/entt/core/algorithm.hpp (limited to 'deps/include/entt/core/algorithm.hpp') diff --git a/deps/include/entt/core/algorithm.hpp b/deps/include/entt/core/algorithm.hpp new file mode 100644 index 0000000..35bdf94 --- /dev/null +++ b/deps/include/entt/core/algorithm.hpp @@ -0,0 +1,143 @@ +#ifndef ENTT_CORE_ALGORITHM_HPP +#define ENTT_CORE_ALGORITHM_HPP + +#include +#include +#include +#include +#include +#include "utility.hpp" + +namespace entt { + +/** + * @brief Function object to wrap `std::sort` in a class type. + * + * Unfortunately, `std::sort` cannot be passed as template argument to a class + * template or a function template.
+ * This class fills the gap by wrapping some flavors of `std::sort` in a + * function object. + */ +struct std_sort { + /** + * @brief Sorts the elements in a range. + * + * Sorts the elements in a range using the given binary comparison function. + * + * @tparam It Type of random access iterator. + * @tparam Compare Type of comparison function object. + * @tparam Args Types of arguments to forward to the sort function. + * @param first An iterator to the first element of the range to sort. + * @param last An iterator past the last element of the range to sort. + * @param compare A valid comparison function object. + * @param args Arguments to forward to the sort function, if any. + */ + template, typename... Args> + void operator()(It first, It last, Compare compare = Compare{}, Args &&...args) const { + std::sort(std::forward(args)..., std::move(first), std::move(last), std::move(compare)); + } +}; + +/*! @brief Function object for performing insertion sort. */ +struct insertion_sort { + /** + * @brief Sorts the elements in a range. + * + * Sorts the elements in a range using the given binary comparison function. + * + * @tparam It Type of random access iterator. + * @tparam Compare Type of comparison function object. + * @param first An iterator to the first element of the range to sort. + * @param last An iterator past the last element of the range to sort. + * @param compare A valid comparison function object. + */ + template> + void operator()(It first, It last, Compare compare = Compare{}) const { + if(first < last) { + for(auto it = first + 1; it < last; ++it) { + auto value = std::move(*it); + auto pre = it; + + // NOLINTBEGIN(cppcoreguidelines-pro-bounds-pointer-arithmetic) + for(; pre > first && compare(value, *(pre - 1)); --pre) { + *pre = std::move(*(pre - 1)); + } + // NOLINTEND(cppcoreguidelines-pro-bounds-pointer-arithmetic) + + *pre = std::move(value); + } + } + } +}; + +/** + * @brief Function object for performing LSD radix sort. + * @tparam Bit Number of bits processed per pass. + * @tparam N Maximum number of bits to sort. + */ +template +struct radix_sort { + static_assert((N % Bit) == 0, "The maximum number of bits to sort must be a multiple of the number of bits processed per pass"); + + /** + * @brief Sorts the elements in a range. + * + * Sorts the elements in a range using the given _getter_ to access the + * actual data to be sorted. + * + * This implementation is inspired by the online book + * [Physically Based Rendering](http://www.pbr-book.org/3ed-2018/Primitives_and_Intersection_Acceleration/Bounding_Volume_Hierarchies.html#RadixSort). + * + * @tparam It Type of random access iterator. + * @tparam Getter Type of _getter_ function object. + * @param first An iterator to the first element of the range to sort. + * @param last An iterator past the last element of the range to sort. + * @param getter A valid _getter_ function object. + */ + template + void operator()(It first, It last, Getter getter = Getter{}) const { + if(first < last) { + constexpr auto passes = N / Bit; + + using value_type = typename std::iterator_traits::value_type; + std::vector aux(std::distance(first, last)); + + auto part = [getter = std::move(getter)](auto from, auto to, auto out, auto start) { + constexpr auto mask = (1 << Bit) - 1; + constexpr auto buckets = 1 << Bit; + + // NOLINTNEXTLINE(cppcoreguidelines-avoid-c-arrays, modernize-avoid-c-arrays) + std::size_t count[buckets]{}; + + for(auto it = from; it != to; ++it) { + ++count[(getter(*it) >> start) & mask]; + } + + // NOLINTNEXTLINE(cppcoreguidelines-avoid-c-arrays, modernize-avoid-c-arrays) + std::size_t index[buckets]{}; + + for(std::size_t pos{}, end = buckets - 1u; pos < end; ++pos) { + index[pos + 1u] = index[pos] + count[pos]; + } + + for(auto it = from; it != to; ++it) { + out[index[(getter(*it) >> start) & mask]++] = std::move(*it); + } + }; + + for(std::size_t pass = 0; pass < (passes & ~1); pass += 2) { + part(first, last, aux.begin(), pass * Bit); + part(aux.begin(), aux.end(), first, (pass + 1) * Bit); + } + + if constexpr(passes & 1) { + part(first, last, aux.begin(), (passes - 1) * Bit); + std::move(aux.begin(), aux.end(), first); + } + } + } +}; + +} // namespace entt + +#endif -- cgit