From e01da5638274dee81238fa1272bb138bf3586f00 Mon Sep 17 00:00:00 2001
From: Egor Tensin <egor@tensin.name>
Date: Mon, 20 Jul 2026 18:32:43 +0200
Subject: aesxx: use if constexpr for get_number_of_rounds

---
 aesxx/include/aesxx/aes.hpp | 15 ---------------
 aesxx/include/aesxx/api.hpp | 10 +++++++++-
 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
@@ -32,11 +32,6 @@ struct Types<AES_AES128> {
     typedef aes128::Key Key;
 };
 
-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{});
@@ -107,11 +102,6 @@ struct Types<AES_AES192> {
     typedef aes192::Key Key;
 };
 
-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{});
@@ -182,11 +172,6 @@ struct Types<AES_AES256> {
     typedef aes256::Key Key;
 };
 
-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);
-- 
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