Merge pull request #6 from elbeno/add-unit-udls

✨ Add UDLs for useful byte sizes
intel · Sep 12, 2023 · 9a47918 · 9a47918
2 parents c1d7cb7 + f64f51b
commit 9a47918
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diff --git a/docs/utility.adoc b/docs/utility.adoc
@@ -45,3 +45,20 @@ using my_type_without_X = my_type<"X"_false>;
 using my_type_with_X_alt = my_type<"X"_b>;
 using my_type_without_X_alt = my_type<not "X"_b>;
 ----
+
+And some UDLs that are useful when specifying sizes in bytes:
+
+[source,cpp]
+----
+using namespace stdx::literals;
+
+// decimal SI prefixes
+constexpr auto a = 1_k;  // 1,000
+constexpr auto b = 1_M;  // 1,000,000
+constexpr auto c = 1_G;  // 1,000,000,000
+
+// binary equivalents
+constexpr auto d = 1_ki; // 1,024
+constexpr auto e = 1_Mi; // 1,048,567
+constexpr auto f = 1_Gi; // 1,073,741,824
+----
diff --git a/include/stdx/utility.hpp b/include/stdx/utility.hpp
@@ -23,6 +23,34 @@ CONSTEVAL auto operator""_true(char const *, std::size_t) -> bool {
 CONSTEVAL auto operator""_false(char const *, std::size_t) -> bool {
     return false;
 }
+
+// NOLINTBEGIN(google-runtime-int)
+CONSTEVAL auto operator""_k(unsigned long long int n)
+    -> unsigned long long int {
+    return n * 1'000u;
+}
+CONSTEVAL auto operator""_M(unsigned long long int n)
+    -> unsigned long long int {
+    return n * 1'000'000u;
+}
+CONSTEVAL auto operator""_G(unsigned long long int n)
+    -> unsigned long long int {
+    return n * 1'000'000'000u;
+}
+
+CONSTEVAL auto operator""_ki(unsigned long long int n)
+    -> unsigned long long int {
+    return n * 1'024u;
+}
+CONSTEVAL auto operator""_Mi(unsigned long long int n)
+    -> unsigned long long int {
+    return n * 1'024ull * 1'024ull;
+}
+CONSTEVAL auto operator""_Gi(unsigned long long int n)
+    -> unsigned long long int {
+    return n * 1'024ull * 1'024ull * 1'024ull;
+}
+// NOLINTEND(google-runtime-int)
 } // namespace literals
 
 [[noreturn]] inline auto unreachable() -> void { __builtin_unreachable(); }

diff --git a/test/udls.cpp b/test/udls.cpp
@@ -10,3 +10,17 @@ TEST_CASE("compile-time named bools", "[utility]") {
     static_assert("variable"_true);
     static_assert(not "variable"_false);
 }
+
+TEST_CASE("decimal units", "[units]") {
+    using namespace stdx::literals;
+    static_assert(1_k == 1'000ull);
+    static_assert(1_M == 1'000'000ull);
+    static_assert(1_G == 1'000'000'000ull);
+}
+
+TEST_CASE("binary units", "[units]") {
+    using namespace stdx::literals;
+    static_assert(1_ki == 1'024ull);
+    static_assert(1_Mi == 1'024ull * 1'024ull);
+    static_assert(1_Gi == 1'024ull * 1'024ull * 1'024ull);
+}