Prototype minimal icu integration

* TODO : Non icu-based default
* Support more units
* Detect supported units at compile time
* Support long names
* ratio ?

conanfile.py

@@ -46,7 +46,9 @@ class UnitsConan(ConanFile):
     settings = "os", "compiler", "build_type", "arch"
     requires = (
         "range-v3/0.9.1@ericniebler/stable",
-        "Catch2/2.10.0@catchorg/stable"
+        "Catch2/2.10.0@catchorg/stable",
+        "icu/64.2@bincrafters/stable",
+        "fmt/5.3.0@bincrafters/stable"
     )
     scm = {
         "type": "git",

src/CMakeLists.txt

@@ -54,7 +54,10 @@ target_compile_features(units INTERFACE cxx_std_20)
 target_link_libraries(units
     INTERFACE
         CONAN_PKG::range-v3
+        CONAN_PKG::fmt
+        CONAN_PKG::icu
 )
+
 target_include_directories(units
     INTERFACE
         $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>

src/include/units/bits/fmt.h

@@ -0,0 +1,40 @@
+#pragma once
+
+#include "unicode/uchriter.h"
+#include <fmt/format.h>
+#include <unicode/measfmt.h>
+#include <unicode/measunit.h>
+#include <limits.h>
+#include <cuchar>
+#include <locale>
+
+namespace units::details {
+
+  template<typename FormatContext>
+  auto format_localized_unit(const icu::Measure& m, FormatContext& ctx)
+  {
+    auto locale = ctx.locale().template get<std::locale>();
+
+    UErrorCode uc = {};
+    icu::MeasureFormat uFmt(locale.name() == "*" ? nullptr : locale.name().c_str(), UMEASFMT_WIDTH_SHORT, uc);
+    icu::UnicodeString s;
+    icu::FieldPosition p(icu::FieldPosition::DONT_CARE);
+    uFmt.formatMeasures(&m, 1, s, p, uc);
+    char out[MB_LEN_MAX]{};
+    icu::UCharCharacterIterator iter(s.getTerminatedBuffer(), s.length());
+    while(iter.hasNext()) {
+      std::mbstate_t state{};
+      auto c = iter.next32PostInc();
+      std::size_t rc = std::c32rtomb(out, c, &state);
+      if(rc != std::size_t(-1)) std::copy_n(std::begin(out), rc, ctx.out());
+    }
+    return ctx.out();
+  }
+
+  template<typename T>
+  icu::MeasureUnit* create_icu_unit(UErrorCode&)
+  {
+    return nullptr;
+  }
+
+}  // namespace units::details

src/include/units/dimensions/acceleration.h

@@ -22,6 +22,7 @@
 
 #pragma once
 
+#include <units/bits/fmt.h>
 #include <units/dimensions/velocity.h>
 
 namespace units {
@@ -41,4 +42,12 @@ namespace units {
 
   }  // namespace literals
 
+  namespace details {
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<metre_per_second_sq>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createMeterPerSecondSquared(uc);
+    }
+  }  // namespace details
+
 }  // namespace units

src/include/units/dimensions/area.h

@@ -23,6 +23,7 @@
 #pragma once
 
 #include <units/dimensions/length.h>
+#include <units/bits/fmt.h>
 
 namespace units {
 
@@ -61,4 +62,33 @@ namespace units {
 
   }  // namespace literals
 
-}  // namespace units
+
+  namespace details {
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<square_metre>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createSquareMeter(uc);
+    }
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<square_centimetre>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createSquareCentimeter(uc);
+    }
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<square_kilometre>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createSquareKilometer(uc);
+    }
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<square_foot>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createSquareFoot(uc);
+    }
+
+  }  // namespace details
+
+}  // namespace units

src/include/units/dimensions/current.h

@@ -42,4 +42,13 @@ namespace units {
 
   }
 
+
+  namespace details {
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<ampere>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createAmpere(uc);
+    }
+  }  // namespace details
+
 }  // namespace units

src/include/units/dimensions/energy.h

@@ -25,6 +25,7 @@
 #include <units/dimensions/base_dimensions.h>
 #include <units/dimensions/force.h>
 #include <units/dimensions/pressure.h>
+#include <units/bits/fmt.h>
 
 namespace units {
 
@@ -63,4 +64,19 @@ namespace units {
 
   }  // namespace literals
 
+  namespace details {
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<joule>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createJoule(uc);
+    }
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<kilojoule>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createKilojoule(uc);
+    }
+  }  // namespace details
+
 }  // namespace units

src/include/units/dimensions/force.h

@@ -43,4 +43,13 @@ namespace units {
 
   }  // namespace literals
 
+
+  namespace details {
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<newton>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createNewton(uc);
+    }
+  }  // namespace details
+
 }  // namespace units

src/include/units/dimensions/frequency.h

@@ -22,6 +22,7 @@
 
 #pragma once
 
+#include <units/bits/fmt.h>
 #include <units/dimensions/base_dimensions.h>
 #include <units/dimensions/time.h>
 
@@ -67,4 +68,33 @@ namespace units {
 
   }  // namespace literals
 
+
+  namespace details {
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<hertz>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createHertz(uc);
+    }
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<kilohertz>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createKilohertz(uc);
+    }
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<megahertz>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createMegahertz(uc);
+    }
+
+    template<>
+    inline icu::MeasureUnit* create_icu_unit<gigahertz>(UErrorCode& uc)
+    {
+      return icu::MeasureUnit::createGigahertz(uc);
+    }
+
+  }  // namespace details
+
 }  // namespace units

src/include/units/format.h

@@ -23,6 +23,10 @@
 #pragma once
 
 #include <units/quantity.h>
+#include <fmt/format.h>
+#include <unicode/measunit.h>
+#include <unicode/measfmt.h>
+#include <unicode/measure.h>
 
 namespace units {
 

src/include/units/quantity.h

@@ -22,10 +22,13 @@
 
 #pragma once
 
+#include <units/bits/fmt.h>
 #include <units/bits/concepts.h>
 #include <units/prefix.h>
 #include <limits>
 #include <ostream>
+#include <unicode/measunit.h>
+
 
 namespace units {
 
@@ -471,3 +474,25 @@ namespace units {
   }
 
 }  // namespace units
+
+namespace fmt {
+  template<typename Qty, typename T>
+  struct formatter<units::quantity<Qty, T>> {
+    template<typename ParseContext>
+    constexpr auto parse(ParseContext& ctx)
+    {
+      return ctx.begin();
+    }
+
+    template<typename FormatContext>
+    auto format(const units::quantity<Qty, T>& sm, FormatContext& ctx)
+    {
+      auto locale = ctx.locale().template get<std::locale>();
+
+      UErrorCode uc;
+      icu::MeasureUnit* unit = units::details::create_icu_unit<Qty>(uc);
+      icu::Measure m(sm.count(), unit, uc);
+      return units::details::format_localized_unit(m, ctx);
+    }
+  };
+}  // namespace fmt

test/unit_test/runtime/CMakeLists.txt

@@ -25,6 +25,7 @@ add_executable(unit_tests_runtime
     digital_information_test.cpp
     math_test.cpp
     text_test.cpp
+    fmt_test.cpp
 )
 target_link_libraries(unit_tests_runtime
     PRIVATE

test/unit_test/runtime/catch_main.cpp

@@ -1,2 +1,8 @@
-#define CATCH_CONFIG_MAIN
+#define CATCH_CONFIG_RUNNER
 #include <catch2/catch.hpp>
+
+int main( int argc, char* argv[] ) {
+  setlocale(LC_CTYPE, "C.UTF-8");
+  int result = Catch::Session().run( argc, argv );
+  return result;
+}

test/unit_test/runtime/fmt_test.cpp

@@ -0,0 +1,42 @@
+// The MIT License (MIT)
+//
+// Copyright (c) 2018 Mateusz Pusz
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#include "units/dimensions/area.h"
+#include "units/dimensions/frequency.h"
+#include "units/dimensions/power.h"
+#include "units/dimensions/velocity.h"
+#include "units/dimensions/volume.h"
+#include "units/math.h"
+#include <catch2/catch.hpp>
+#include <fmt/locale.h>
+
+using namespace units;
+
+TEST_CASE("fmt on a quantity", "[text][fmt]")
+{
+  SECTION("quantity with a predefined unit")
+  {
+    std::locale ru_loc("ru_RU.UTF-8");
+    REQUIRE(fmt::format(ru_loc, "{}", 2sq_m) == "2 м²");
+    REQUIRE(fmt::format("{}", 2GHz) == "2 GHz");
+  }
+}