Added is_kzg and is_lpc type_traits #309

Author: ETatuzova

include/nil/crypto3/zk/commitments/polynomial/kzg.hpp

@@ -325,7 +325,7 @@ namespace nil {
                 static void update_transcript(const typename KZG::public_key_type &public_key,
                                             typename KZG::transcript_type &transcript) {
 
-                    /* The procedure of updating the transcript is subject to review and change 
+                    /* The procedure of updating the transcript is subject to review and change
                      * #295 */
 
                     nil::marshalling::status_type status;
@@ -671,7 +671,7 @@ namespace nil {
                     }
 
                     void update_transcript(std::size_t batch_ind, typename KZGScheme::transcript_type &transcript) {
-                        /* The procedure of updating the transcript is subject to review and change 
+                        /* The procedure of updating the transcript is subject to review and change
                          * #295 */
 
                         // Push commitments to transcript
@@ -849,7 +849,7 @@ namespace nil {
                         typename KZGScheme::commitment_type,
                         typename KZGScheme::poly_type> {
                 public:
-                    constexpr static bool is_kzg_commitment_scheme_v2 = true;
+                    static constexpr bool is_kzg(){ return true; }
 
                     using curve_type = typename KZGScheme::curve_type;
                     using field_type = typename KZGScheme::field_type;
@@ -912,7 +912,7 @@ namespace nil {
                     }
 
                     void update_transcript(std::size_t batch_ind, typename KZGScheme::transcript_type &transcript) {
-                        /* The procedure of updating the transcript is subject to review and change 
+                        /* The procedure of updating the transcript is subject to review and change
                          * #295 */
 
                         // Push commitments to transcript

include/nil/crypto3/zk/commitments/polynomial/lpc.hpp

@@ -52,6 +52,8 @@ namespace nil {
                     typename LPCScheme::commitment_type, PolynomialType>{
 
                 public:
+                    static constexpr bool is_lpc(){return true;}
+
                     using field_type = typename LPCScheme::field_type;
                     using value_type = typename field_type::value_type;
                     using params_type = typename LPCScheme::params_type;
@@ -67,8 +69,6 @@ namespace nil {
                     using eval_storage_type = typename LPCScheme::eval_storage_type;
                     using preprocessed_data_type = std::map<std::size_t, std::vector<value_type>>;
 
-                    constexpr static bool is_lpc = true;
-
                 private:
                     std::map<std::size_t, precommitment_type> _trees;
                     typename fri_type::params_type _fri_params;

include/nil/crypto3/zk/commitments/type_traits.hpp

@@ -98,6 +98,45 @@ namespace nil {
                 constexpr static const bool value = !std::is_same<no, decltype(test<T>(nullptr))>::value;
             };
 
+            template<typename T>
+            class has_available_static_member_function_is_kzg {
+                struct no { };
+
+            protected:
+                template<typename C>
+                static void test(std::nullptr_t) {
+                    struct t {
+                        using C::is_kzg;
+                    };
+                }
+
+                template<typename>
+                static no test(...);
+
+            public:
+                constexpr static const bool value = !std::is_same<no, decltype(test<T>(nullptr))>::value;
+            };
+
+            template<typename T>
+            class has_available_static_member_function_is_lpc {
+                struct no { };
+
+            protected:
+                template<typename C>
+
+                static void test(std::nullptr_t) {
+                    struct t {
+                        using C::is_lpc;
+                    };
+                }
+
+                template<typename>
+                static no test(...);
+
+            public:
+                constexpr static const bool value = !std::is_same<no, decltype(test<T>(nullptr))>::value;
+            };
+
             template<typename T>
             struct is_commitment {
                 using commitment_type = typename member_type_commitment_type<T>::type;
@@ -109,12 +148,41 @@ namespace nil {
                 typedef T type;
             };
 
+            // An idea was copied from this example:
+            //    https://stackoverflow.com/questions/54920801/check-if-static-function-is-available-in-class-at-compile-time
+
+            template<typename T, typename Enable = void>
+            struct is_kzg_struct: std::false_type{
+                static const bool value = false;
+            };
+
+            template<class T>
+            struct is_kzg_struct<T, std::enable_if_t<std::is_invocable_r<bool, decltype(T::is_kzg)>::value>>
+            : std::integral_constant<bool, T::is_kzg()>
+            {};
+
+            template<class T>
+            constexpr bool is_kzg = is_kzg_struct<T>::value;
+
+
+            template<typename T, typename Enable = void>
+            struct is_lpc_struct: std::false_type{
+                static const bool value = false;
+            };
+
+            template<class T>
+            struct is_lpc_struct<T, std::enable_if_t<std::is_invocable_r<bool, decltype(T::is_lpc)>::value>>
+            : std::integral_constant<bool, T::is_lpc()>
+            {};
+
+            template<class T>
+            constexpr bool is_lpc = is_lpc_struct<T>::value;
+
             template<bool Condition, typename Type, std::size_t Size>
             struct select_container {
                 using type = typename std::
                     conditional<Condition, std::array<Type, Size>, std::vector<Type>>::type;
             };
-
         }    // namespace zk
     }        // namespace crypto3
 }    // namespace nil