aesxx: use if constexpr for get_number_of_rounds

2 files changed, 9 insertions, 16 deletions

diff --git a/aesxx/include/aesxx/aes.hpp b/aesxx/include/aesxx/aes.hpp
index 241e051..1b5aefa 100644
--- a/aesxx/include/aesxx/aes.hpp
+++ b/aesxx/include/aesxx/aes.hpp
@@ -33,11 +33,6 @@ struct Types<AES_AES128> {
 };
 
 template <>
-inline std::size_t get_number_of_rounds<AES_AES128>() {
-    return 11;
-}
-
-template <>
 inline void from_string<AES_AES128>(aes128::Block& dest, std::string_view src) {
     aes_AES128_parse_block(&dest, src.data(), ErrorDetailsThrowsInDestructor{});
 }
@@ -108,11 +103,6 @@ struct Types<AES_AES192> {
 };
 
 template <>
-inline std::size_t get_number_of_rounds<AES_AES192>() {
-    return 13;
-}
-
-template <>
 inline void from_string<AES_AES192>(aes192::Block& dest, std::string_view src) {
     aes_AES192_parse_block(&dest, src.data(), ErrorDetailsThrowsInDestructor{});
 }
@@ -183,11 +173,6 @@ struct Types<AES_AES256> {
 };
 
 template <>
-inline std::size_t get_number_of_rounds<AES_AES256>() {
-    return 15;
-}
-
-template <>
 inline void from_string<AES_AES256>(aes256::Block& dest, std::string_view src) {
     aes_AES256_parse_block(&dest, src.data(), ErrorDetailsThrowsInDestructor{});
 }
diff --git a/aesxx/include/aesxx/api.hpp b/aesxx/include/aesxx/api.hpp
index 70891c9..131e5e5 100644
--- a/aesxx/include/aesxx/api.hpp
+++ b/aesxx/include/aesxx/api.hpp
@@ -19,7 +19,15 @@ template <Algorithm algorithm>
 struct Types;
 
 template <Algorithm algorithm>
-std::size_t get_number_of_rounds();
+std::size_t get_number_of_rounds() {
+    if constexpr (algorithm == AES_AES128)
+        return 11;
+    if constexpr (algorithm == AES_AES192)
+        return 13;
+    if constexpr (algorithm == AES_AES256)
+        return 15;
+    static_assert("Unrecognized algorithm");
+}
 
 template <Algorithm algorithm>
 void from_string(typename Types<algorithm>::Block&, std::string_view);