Merge pull request 'fix/zero_length_array' (#10) from fix/zero_length_array into master

Reviewed-on: http://git.mercurial-manifold.eu/an.tsouchlos/const_fmt/pulls/10

const_fmt/format.h

@@ -66,16 +66,13 @@ constexpr inline void format_arg(char* dest, const char* arg) {
 };
 
 
-// End of recursion
-template <auto ast>
-constexpr inline void format_args(char*) {
-}
-
 template <auto fmt_data_array, typename first_arg_t, typename... args_t>
 constexpr inline void format_args(char* dest, first_arg_t first_arg,
                                   args_t... args) {
     format_arg<fmt_data_array[0]>(dest + fmt_data_array[0].position, first_arg);
-    format_args<drop_first(fmt_data_array)>(dest, args...);
+
+    if constexpr(fmt_data_array.size() > 1)
+        format_args<drop_first(fmt_data_array)>(dest, args...);
 }
 
 

const_fmt/stdlib.h

@@ -4,9 +4,9 @@
 
 /*
  *
- * Disclaimer: Probably very bad implementation of some features of the C++
- * Standard Library. Not meant as a full-on stdlib implementation, only for
- * usage in this project (Underlined by the fact, that in this case the
+ * Disclaimer: Very bad (partially at least) implementation of some features of
+ * the C++ Standard Library. Not meant as a full-on stdlib implementation, only
+ * for usage in this project (Underlined by the fact, that in this case the
  * namespace std is actually const_fmt::std)
  *
  */
@@ -36,31 +36,105 @@ using size_t = uint16_t;
  */
 
 
-// clang-format off
-
-        template<typename T>
-        struct remove_reference {
-            using type = T;
-        };
-        template<typename T>
-        struct remove_reference<T &> {
-            using type = T;
-        };
-        template<typename T>
-        struct remove_reference<T &&> {
-            using type = T;
-        };
-
-        template<typename T>
-        using remove_reference_t = typename std::remove_reference<T>::type;
-
-// clang-format on
+// various
 
 
 constexpr inline bool is_constant_evaluated() noexcept {
     return __builtin_is_constant_evaluated();
 }
 
+struct true_type {
+    constexpr static bool value = true;
+};
+
+struct false_type {
+    constexpr static bool value = false;
+};
+
+
+// is_same
+
+
+template <typename fist_t, typename second_t>
+struct is_same : public false_type {};
+
+template <typename type_t>
+struct is_same<type_t, type_t> : public true_type {};
+
+
+// is_one_of
+
+
+template <typename...>
+struct is_one_of;
+template <typename type_t>
+struct is_one_of<type_t> {
+    constexpr static bool value = false;
+};
+template <typename type_t, typename first_t, typename... rest_t>
+struct is_one_of<type_t, first_t, rest_t...> {
+    constexpr static bool value = std::is_same<type_t, first_t>::value ||
+                                  is_one_of<type_t, rest_t...>::value;
+};
+
+
+// remove_x
+
+
+// clang-format off
+
+template <typename type_t> struct remove_cv                        { typedef type_t type; };
+template <typename type_t> struct remove_cv<const type_t>          { typedef type_t type; };
+template <typename type_t> struct remove_cv<volatile type_t>       { typedef type_t type; };
+template <typename type_t> struct remove_cv<const volatile type_t> { typedef type_t type; };
+
+template <typename type_t> struct remove_const                     { typedef type_t type; };
+template <typename type_t> struct remove_const<const type_t>       { typedef type_t type; };
+
+template <typename type_t> struct remove_volatile                  { typedef type_t type; };
+template <typename type_t> struct remove_volatile<volatile type_t> { typedef type_t type; };
+
+template <typename type_t> struct remove_reference                 { using type = type_t; };
+template <typename type_t> struct remove_reference<type_t &>       { using type = type_t; };
+template <typename type_t> struct remove_reference<type_t &&>      { using type = type_t; };
+
+template <typename type_t> using remove_reference_t = typename std::remove_reference<type_t>::type;
+template <typename type_t> using remove_cv_t        = typename std::remove_cv<type_t>::type;
+template <typename type_t> using remove_const_t     = typename std::remove_const<type_t>::type;
+template <typename type_t> using remove_volatile_t  = typename std::remove_volatile<type_t>::type;
+
+// clang-format on
+
+
+// is_integral
+
+
+template <typename type_t>
+using is_integral =
+    is_one_of<remove_cv_t<type_t>, bool, char, signed char, unsigned char,
+              wchar_t, char16_t, char32_t, short, unsigned short, int,
+              unsigned int, long, unsigned long, long long, unsigned long long>;
+
+
+// is_signed
+
+
+template <typename _Tp>
+using is_signed_integer = is_one_of<remove_cv_t<_Tp>, signed char, signed short,
+                                    signed int, signed long, signed long long>;
+
+
+
+// is_floating_point
+
+
+template <typename type_t>
+using is_floating_point =
+    is_one_of<remove_cv_t<type_t>, float, double, long double>;
+
+
+// make_unsigned
+
 
 // clang-format off
 
@@ -75,6 +149,16 @@ template <> struct make_unsigned<signed long long> { using type = unsigned long
 // clang-format on
 
 
+// value definitions
+
+template <typename type_t>
+inline constexpr bool is_integral_v = is_integral<type_t>::value;
+template <typename type_t>
+inline constexpr bool is_signed_integer_v = is_signed_integer<type_t>::value;
+template <typename type_t>
+inline constexpr bool is_floating_point_v = is_floating_point<type_t>::value;
+
+
 /*
  *
  * concepts
@@ -82,17 +166,17 @@ template <> struct make_unsigned<signed long long> { using type = unsigned long
  */
 
 
-//template <typename _Tp>
-//concept integral = is_integral_v<_Tp>;
-//
-//template <typename _Tp>
-//concept signed_integral = integral<_Tp> && is_signed_v<_Tp>;
-//
-//template <typename _Tp>
-//concept unsigned_integral = integral<_Tp> && !signed_integral<_Tp>;
-//
-//template <typename _Tp>
-//concept floating_point = is_floating_point_v<_Tp>;
+template <typename type_t>
+concept integral = is_integral_v<type_t>;
+
+template <typename type_t>
+concept signed_integral = is_signed_integer_v<type_t>;
+
+template <typename type_t>
+concept unsigned_integral = integral<type_t> && !signed_integral<type_t>;
+
+template <typename type_t>
+concept floating_point = is_floating_point_v<type_t>;
 
 
 /*
@@ -103,8 +187,11 @@ template <> struct make_unsigned<signed long long> { using type = unsigned long
 
 
 template <typename input_t, typename output_t>
-void copy(input_t* start, input_t* end, output_t* dest_start) {
-    memcpy(start, dest_start, end - start);
+constexpr inline void copy(const input_t* start, const input_t* end,
+                           output_t* dest_start) {
+    auto temp = start;
+    while (temp != end)
+        *(dest_start++) = *(temp++);
 }
 
 
@@ -121,7 +208,7 @@ std::remove_reference_t<T>&& move(T&& arg) noexcept {
 }
 
 template <typename T>
-void swap(T& t1, T& t2) {
+constexpr inline void swap(T& t1, T& t2) {
     T temp = std::move(t1);
     t1     = std::move(t2);
     t2     = std::move(temp);
@@ -150,14 +237,11 @@ public:
         static_assert(sizeof...(args) == t_size, "Invalid number of arguments");
     }
 
-    constexpr array() noexcept = default;
-
-    constexpr array(array&) = default;
-
-    constexpr array(array&&) = default;
-
-    constexpr array& operator=(array& other) = default;
+    constexpr array() noexcept    = default;
+    constexpr array(const array&) = default;
+    constexpr array(array&&)      = default;
 
+    constexpr array& operator=(const array& other) = default;
     constexpr array& operator=(array&& other) = default;
 
     constexpr void swap(array<data_t, t_size>& other) noexcept {
@@ -167,6 +251,9 @@ public:
         }
     }
 
+    constexpr std::size_t size() const noexcept {
+        return t_size;
+    }
 
     constexpr data_t& operator[](std::size_t index) noexcept {
         return m_data[index];
@@ -188,6 +275,14 @@ public:
         return (&(m_data[t_size - 1]) + 1);
     }
 
+    constexpr const_iterator begin() const noexcept {
+        return &(m_data[0]);
+    }
+
+    constexpr const_iterator end() const noexcept {
+        return (&(m_data[t_size - 1]) + 1);
+    }
+
     constexpr const_iterator cbegin() const noexcept {
         return &(m_data[0]);
     }