xo-unit: + constexpr unit b/blocks (wip)

include/xo/unit/native_bpu2.hpp

@@ -0,0 +1,65 @@
+/** @file native_bpu2.hpp
+ *
+ *  Author: Roland Conybeare
+ **/
+
+#pragma once
+
+#include "basis_unit2.hpp"
+
+namespace xo {
+    namespace unit {
+        using bpu2_abbrev_type = flatstring<24>;
+
+        using power_ratio_type = xo::ratio::ratio<std::int64_t>;
+
+        /** @class native_bpu2
+         *
+         *  @brief represent product of a compile-time scale-factor with a rational power of a native unit
+         *
+         *  Example:
+         *  native_bpu<universal::time, ratio<1>, ratio<-1,2>> represents unit of 1/sqrt(t)
+         **/
+        template<typename Int>
+        struct bpu2 : basis_unit2 {
+        public:
+            constexpr bpu2(power_ratio_type power,
+                           dim native_dim,
+                           scalefactor_ratio_type scalefactor)
+                : basis_unit2(native_dim, scalefactor),
+                  power_{power}
+                {}
+
+            constexpr const power_ratio_type & power() const { return power_; }
+
+            /** @brief this unit represents native dimension taken to this power **/
+            power_ratio_type power_;
+        };
+
+        template <
+            dim BasisDim,
+            std::int64_t InnerScaleNum, std::int64_t InnerScaleDen,
+            std::int64_t PowerNum, std::int64_t PowerDen
+            >
+        constexpr bpu2_abbrev_type
+        bpu2_assemble_abbrev_helper()
+        {
+            return flatstring_concat
+                (units::scaled_native_unit2_abbrev_v<BasisDim, InnerScaleNum, InnerScaleDen>,
+                 flatstring_from_exponent<PowerNum, PowerDen>());
+        };
+
+        template < typename BPU >
+        constexpr auto bpu2_assemble_abbrev(const BPU & bpu) {
+            // bpu.power(), bpu.native_dim(), bpu.scalefactor()
+
+            return bpu2_assemble_abbrev_helper<
+                bpu.native_dim(),
+                bpu.scalefactor().num(), bpu.scalefactor().den(),
+                bpu.power().num(), bpu.power().den()>;
+        };
+    } /*namespace unit*/
+} /*namespace xo*/
+
+
+/** end native_bpu2.hpp **/