1 files changed, 159 insertions, 0 deletions
diff --git a/lib/collections.h b/lib/collections.h
new file mode 100644
index 0000000..8f5a43d
--- /dev/null
+++ b/lib/collections.h
@@ -0,0 +1,159 @@
+#pragma once
+
+#include <algorithm>
+#include <array>
+#include <span>
+#include <utility>
+#include <vector>
+
+template<typename T, typename E>
+concept SequentialCollection = requires(T c) {
+								   {
+									   c.size()
+									   } -> std::integral;
+								   {
+									   c.data()
+									   } -> std::same_as<const E *>;
+							   };
+template<typename T>
+concept IterableCollection = std::is_same_v<decltype(std::declval<T>().begin()), decltype(std::declval<T>().end())>;
+
+template<typename T, std::size_t first, std::size_t second>
+[[nodiscard]] constexpr std::array<T, first + second>
+operator+(const std::array<T, first> & a, const std::array<T, second> & b)
+{
+	std::array<T, first + second> r;
+	auto out = r.begin();
+	out = std::copy(a.begin(), a.end(), out);
+	std::copy(b.begin(), b.end(), out);
+	return r;
+}
+
+template<typename T, typename V, std::size_t first, std::size_t second>
+[[nodiscard]] constexpr std::array<std::pair<T, V>, first * second>
+operator*(const std::array<T, first> & a, const std::array<V, second> & b)
+{
+	std::array<std::pair<T, V>, first * second> r;
+	auto out = r.begin();
+	for (const auto & ae : a) {
+		for (const auto & be : b) {
+			*out++ = {ae, be};
+		}
+	}
+	return r;
+}
+
+template<typename T, std::size_t N>
+[[nodiscard]] constexpr auto
+operator*(const std::array<T, N> & in, auto && f)
+{
+	std::array<decltype(f(in[0])), N> out;
+
+	for (auto outitr = out.begin(); const auto & v : in) {
+		*outitr++ = f(v);
+	}
+	return out;
+}
+
+constexpr auto &
+operator*=(IterableCollection auto & in, auto && f)
+{
+	for (auto & v : in) {
+		f(v);
+	}
+	return in;
+}
+
+template<template<typename...> typename C, typename... T>
+	requires IterableCollection<C<T...>>
+[[nodiscard]] constexpr auto
+operator*(const C<T...> & in, auto && f)
+{
+	C<decltype(f(*in.begin()))> out;
+	if constexpr (requires { out.reserve(in.size()); }) {
+		out.reserve(in.size());
+	}
+
+	std::transform(in.begin(), in.end(), std::inserter(out, out.end()), f);
+	return out;
+}
+
+template<typename T, std::size_t N>
+[[nodiscard]] constexpr auto
+operator*(const std::span<T, N> in, auto && f)
+{
+	std::array<decltype(f(std::declval<T>())), N> out;
+
+	std::transform(in.begin(), in.end(), out.begin(), f);
+	return out;
+}
+
+template<typename T>
+[[nodiscard]] constexpr auto
+operator*(const std::span<T, std::dynamic_extent> in, auto && f)
+{
+	std::vector<decltype(f(std::declval<T>()))> out;
+
+	out.reserve(in.size());
+	std::transform(in.begin(), in.end(), std::inserter(out, out.end()), f);
+	return out;
+}
+
+template<typename... T>
+constexpr auto &
+operator+=(std::vector<T...> & in, std::vector<T...> && src)
+{
+	in.reserve(in.size() + src.size());
+	std::move(src.begin(), src.end(), std::back_inserter(in));
+	return in;
+}
+
+template<typename... T, typename Vn>
+[[nodiscard]] constexpr auto
+operator+(const std::vector<T...> & in, Vn && vn)
+{
+	auto out(in);
+	out.emplace_back(std::forward<Vn>(vn));
+	return out;
+}
+
+template<template<typename> typename Direction = std::plus, typename T = unsigned int>
+[[nodiscard]] static auto
+vectorOfN(std::integral auto N, T start = {}, T step = 1)
+{
+	std::vector<T> v;
+	v.resize(N);
+	std::generate_n(v.begin(), N, [&start, step, adj = Direction {}]() {
+		return std::exchange(start, adj(start, step));
+	});
+	return v;
+}
+
+template<template<typename...> typename Rtn = std::vector, IterableCollection In>
+[[nodiscard]] auto
+materializeRange(In && in)
+{
+	return Rtn(in.begin(), in.end());
+}
+
+template<template<typename...> typename Rtn = std::vector, typename In>
+[[nodiscard]] auto
+materializeRange(const std::pair<In, In> & in)
+{
+	return Rtn(in.first, in.second);
+}
+
+template<typename T> struct pair_range {
+	constexpr auto &
+	begin() const noexcept
+	{
+		return pair.first;
+	}
+	constexpr auto &
+	end() const noexcept
+	{
+		return pair.second;
+	}
+	const std::pair<T, T> & pair;
+};
+template<typename T> pair_range(std::pair<T, T>) -> pair_range<T>;