From 72e5eaed28381d9c6d5446fffea1cbe81cd4da38 Mon Sep 17 00:00:00 2001
From: Igor Zarzycki <izarzycki@dmcs.pl>
Date: Sat, 24 Aug 2024 01:44:10 +0200
Subject: [PATCH] Add hasFacet function checking numpunct.

---
 CMakeLists.txt                   |   1 +
 include/crap/locale              |   1 +
 include/crap/locale.d/hasfacet.h | 135 +++++++++++++++++++++++++++++++
 test/hasfacettest.cpp            |  24 ++++++
 4 files changed, 161 insertions(+)
 create mode 100644 include/crap/locale.d/hasfacet.h
 create mode 100644 test/hasfacettest.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5543148..b1f555c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,6 +20,7 @@ crap_test(countlzerovalue)
 crap_test(countronevalue)
 crap_test(countrzerovalue)
 crap_test(floortype)
+crap_test(hasfacet)
 crap_test(hassinglebitvalue)
 crap_test(innerproductvalue)
 crap_test(isheapuntilltype)
diff --git a/include/crap/locale b/include/crap/locale
index 2c75b33..5b6dd4a 100644
--- a/include/crap/locale
+++ b/include/crap/locale
@@ -1,6 +1,7 @@
 #ifndef CRAP_LOCALE
 #define CRAP_LOCALE
 
+#include "locale.d/hasfacet.h"
 #include "locale.d/isalnumvalue.h"
 #include "locale.d/isalphavalue.h"
 #include "locale.d/isblankvalue.h"
diff --git a/include/crap/locale.d/hasfacet.h b/include/crap/locale.d/hasfacet.h
new file mode 100644
index 0000000..6ee86e3
--- /dev/null
+++ b/include/crap/locale.d/hasfacet.h
@@ -0,0 +1,135 @@
+#ifndef CRAP_LOCALE_HASFACET
+#define CRAP_LOCALE_HASFACET
+
+#include <locale>
+#include <tuple>
+#include <type_traits>
+#include <utility>
+
+#include "numpunct.h"
+#include "../algorithm.d/countiftype.h"
+#include "../type_traits.d/voidt.h"
+#include "../version.d/libintegralconstantcallable.h"
+
+namespace crap
+{
+ template <class, class> struct hasFacet;
+
+ template <class CharType, class Locale> struct hasFacet<std :: numpunct<CharType>, Locale>
+ {
+  private:
+  template <class Type> struct isNumpunct;
+  template <bool, template <class> class> struct isLocaleHaving;
+  template <template <class> class IsNumpunct> struct isLocaleHaving<true, IsNumpunct> : std :: true_type {};
+  template <template <class> class IsNumpunct> struct isLocaleHaving<false, IsNumpunct>;
+  public:
+  constexpr const static bool value = isLocaleHaving <isNumpunct <Locale> :: value, isNumpunct> :: value;
+  using value_type = decltype(value);
+  constexpr operator value_type () const noexcept;
+#if (crap_lib_integral_constant_callable >= 201304L)
+  constexpr value_type operator () () const noexcept;
+#endif
+ };
+
+ template <class CharType, class Locale>
+	 struct hasFacet<numpunct<CharType>, Locale> : hasFacet<std :: numpunct<CharType>, Locale> {};
+
+ template <class CharType, class Locale>
+	 template <class Type>
+ struct hasFacet <std :: numpunct<CharType>, Locale> :: isNumpunct
+ { //Check if has numpunct interface.
+  private:
+  //Type fields verifiers.
+  template <class, class = void> struct hasDecimalPoint : std :: false_type {};
+  template <class SubType> struct hasDecimalPoint<SubType, voidT<typename SubType :: decimalPoint_t> >
+	  : std :: true_type {};
+  template <class, class = void> struct hasThousandsSep : std :: false_type {};
+  template <class SubType> struct hasThousandsSep<SubType, voidT<typename SubType :: thousandsSep_t> >
+	  : std :: true_type {};
+  template <class, class = void> struct hasGrouping : std :: false_type {};
+  template <class SubType> struct hasGrouping<SubType, voidT<typename SubType :: grouping_t> >
+	  : std :: true_type {};
+  template <class, class = void> struct hasTruename : std :: false_type {};
+  template <class SubType> struct hasTruename<SubType, voidT<typename SubType :: truename_t> >
+	  : std :: true_type {};
+  template <class, class = void> struct hasFalsename : std :: false_type {};
+  template <class SubType> struct hasFalsename<SubType, voidT<typename SubType :: falsename_t> >
+	  : std :: true_type {};
+  //Generic type verifiers.
+  template <class> struct isConstant : std :: false_type {};
+  template <class SubCharType, SubCharType Char> struct isConstant<std :: integral_constant<SubCharType, Char> >
+	  : std :: true_type {};
+  template <class> struct isString : std :: false_type {};
+  template <class SubCharType, SubCharType ... Chars> struct isString<string<SubCharType, Chars...> > : std :: true_type {};
+  //Detailed type verifiers.
+  template <bool, class> struct isDecimalPointOkType : std :: false_type {};
+  template <class SubType> struct isDecimalPointOkType <true, SubType>
+	  : isConstant<typename SubType :: decimalPoint_t> {};
+  template <bool, class> struct isThousandsSepOkType : std :: false_type {};
+  template <class SubType> struct isThousandsSepOkType <true, SubType>
+	  : isConstant<typename SubType :: thousandsSep_t> {};
+  template <bool, class> struct isGroupingOkType : std :: false_type {};
+  template <class SubType> struct isGroupingOkType <true, SubType>
+	  : isString<typename SubType :: grouping_t> {};
+  template <bool, class> struct isTruenameOkType : std :: false_type {};
+  template <class SubType> struct isTruenameOkType <true, SubType>
+	  : isString<typename SubType :: truename_t> {};
+  template <bool, class> struct isFalsenameOkType : std :: false_type {};
+  template <class SubType> struct isFalsenameOkType <true, SubType>
+	  : isString<typename SubType :: falsename_t> {};
+  //Functionalities.
+  constexpr const static auto decimalPointFine =
+	  isDecimalPointOkType<hasDecimalPoint <Type> :: value, Type> :: value;
+  constexpr const static auto thousandsSepFine =
+	  isThousandsSepOkType<hasThousandsSep <Type> :: value, Type> :: value;
+  constexpr const static auto groupingFine =
+	  isGroupingOkType<hasGrouping <Type> :: value, Type> :: value;
+  constexpr const static auto truenameFine =
+	  isTruenameOkType<hasTruename <Type> :: value, Type> :: value;
+  constexpr const static auto falsenameFine =
+	  isFalsenameOkType<hasFalsename <Type> :: value, Type> :: value;
+  public:
+  constexpr const static auto value =
+	  decimalPointFine && thousandsSepFine && groupingFine && truenameFine && falsenameFine;
+ };
+
+ template <class CharType, class Locale>
+	 template <template <class> class IsNumpunct>
+ struct hasFacet <std :: numpunct<CharType>, Locale> :: isLocaleHaving<false, IsNumpunct>
+ { //Check if has locale interface.
+  private:
+  //Check if has "facet" field.
+  template <class, class = void> struct hasFacetField : std :: false_type {};
+  template <class Type> struct hasFacetField<Type, voidT<typename Type :: facet> > : std :: true_type {};
+  constexpr const static auto hasFacetField_v = hasFacetField <Locale> :: value;
+  //Check possible "facet" field types.
+  template <class Type> struct isProperFacet : IsNumpunct<Type> {};
+  template <class ... Types> struct isProperFacet<std :: tuple<Types...> >
+	  : std :: integral_constant<bool, (countIfType <IsNumpunct, Types...> :: value == 1u)> {};
+  template <class Type1, class Type2> struct isProperFacet<std :: pair<Type1, Type2> >
+	  : std :: integral_constant<bool, (countIfType <IsNumpunct, Type1, Type2> :: value == 1u)> {};
+  //Check if "facet" field is proper collection.
+  template <bool, class> struct checkFacet : std :: false_type {};
+  template <class Type> struct checkFacet<true, Type> : isProperFacet<typename Type :: facet> {};
+  public:
+  constexpr const static auto value = checkFacet <hasFacetField_v, Locale> :: value;
+ };
+}
+
+template <class CharType, class Locale>
+	inline constexpr crap :: hasFacet <std :: numpunct<CharType>, Locale> :: operator
+	typename crap :: hasFacet <std :: numpunct<CharType>, Locale> :: value_type () const noexcept
+{
+ return crap :: hasFacet <std :: numpunct<CharType>, Locale> :: value;
+};
+#if (crap_lib_integral_constant_callable >= 201304L)
+
+template <class CharType, class Locale>
+	inline constexpr typename crap :: hasFacet <std :: numpunct<CharType>, Locale> :: value_type
+	crap :: hasFacet <std :: numpunct<CharType>, Locale> :: operator () () const noexcept
+{
+ return crap :: hasFacet <std :: numpunct<CharType>, Locale> :: value;
+}
+#endif
+#endif
+
diff --git a/test/hasfacettest.cpp b/test/hasfacettest.cpp
new file mode 100644
index 0000000..a835916
--- /dev/null
+++ b/test/hasfacettest.cpp
@@ -0,0 +1,24 @@
+#include "../include/crap/locale.d/hasfacet.h"
+
+#include <tuple>
+#include <utility>
+
+#include "../include/crap/locale.d/numpunct.h"
+
+struct empty {};
+
+template <class Type> struct testFacet
+{
+ using facet = Type;
+};
+
+template <class Type> void test_hasFacetNumpunct()
+{
+ static_assert(!(crap :: hasFacet <crap :: numpunct<Type>, void> :: value), "Void has no facet.");
+}
+
+int main()
+{
+ test_hasFacetNumpunct<char>();
+ return EXIT_SUCCESS;
+}