switch to if constexpr (..) to remove clutter

2 files changed, 17 insertions, 70 deletions

diff --git a/aesxx/include/aesxx/api.hpp b/aesxx/include/aesxx/api.hpp
index 1797a85..70891c9 100644
--- a/aesxx/include/aesxx/api.hpp
+++ b/aesxx/include/aesxx/api.hpp
@@ -48,72 +48,32 @@ void derive_decryption_keys(
     typename Types<algorithm>::RoundKeys& decryption_keys
 );
 
-template <
-    Algorithm algorithm,
-    Mode mode,
-    typename std::enable_if<ModeRequiresInitVector<mode>::value>::type* = nullptr>
+template <Algorithm algorithm, Mode mode>
 void encrypt_block(
     const typename Types<algorithm>::Block& plaintext,
     const typename Types<algorithm>::RoundKeys& round_keys,
     typename Types<algorithm>::Block& iv,
     typename Types<algorithm>::Block& ciphertext
-);
-
-template <
-    Algorithm algorithm,
-    Mode mode,
-    typename std::enable_if<!ModeRequiresInitVector<mode>::value>::type* = nullptr>
-void encrypt_block(
-    const typename Types<algorithm>::Block& plaintext,
-    const typename Types<algorithm>::RoundKeys& round_keys,
-    typename Types<algorithm>::Block& ciphertext
-);
-
-template <
-    Algorithm algorithm,
-    Mode mode,
-    typename std::enable_if<!ModeRequiresInitVector<mode>::value>::type* = nullptr>
-void encrypt_block(
-    const typename Types<algorithm>::Block& plaintext,
-    const typename Types<algorithm>::RoundKeys& round_keys,
-    typename Types<algorithm>::Block&,
-    typename Types<algorithm>::Block& ciphertext
 ) {
-    encrypt_block<algorithm, mode>(plaintext, round_keys, ciphertext);
+    if constexpr (mode_requires_init_vector(mode)) {
+        encrypt_block(plaintext, round_keys, iv, ciphertext);
+    } else {
+        encrypt_block(plaintext, round_keys, ciphertext);
+    }
 }
 
-template <
-    Algorithm algorithm,
-    Mode mode,
-    typename std::enable_if<ModeRequiresInitVector<mode>::value>::type* = nullptr>
+template <Algorithm algorithm, Mode mode>
 void decrypt_block(
     const typename Types<algorithm>::Block& ciphertext,
     const typename Types<algorithm>::RoundKeys& round_keys,
     typename Types<algorithm>::Block& iv,
     typename Types<algorithm>::Block& plaintext
-);
-
-template <
-    Algorithm algorithm,
-    Mode mode,
-    typename std::enable_if<!ModeRequiresInitVector<mode>::value>::type* = nullptr>
-void decrypt_block(
-    const typename Types<algorithm>::Block& ciphertext,
-    const typename Types<algorithm>::RoundKeys& round_keys,
-    typename Types<algorithm>::Block& plaintext
-);
-
-template <
-    Algorithm algorithm,
-    Mode mode,
-    typename std::enable_if<!ModeRequiresInitVector<mode>::value>::type* = nullptr>
-void decrypt_block(
-    const typename Types<algorithm>::Block& ciphertext,
-    const typename Types<algorithm>::RoundKeys& round_keys,
-    typename Types<algorithm>::Block&,
-    typename Types<algorithm>::Block& plaintext
 ) {
-    decrypt_block<algorithm, mode>(ciphertext, round_keys, plaintext);
+    if constexpr (mode_requires_init_vector(mode)) {
+        encrypt_block(plaintext, round_keys, iv, ciphertext);
+    } else {
+        encrypt_block(plaintext, round_keys, ciphertext);
+    }
 }
 
 template <Algorithm algorithm, Mode mode>
@@ -147,7 +107,7 @@ struct DecryptWrapper {
         typename Types<algorithm>::RoundKeys encryption_keys;
         expand_key<algorithm>(key, encryption_keys);
 
-        if (ModeUsesEncryptionKeysOnly<mode>::value) {
+        if constexpr (mode_uses_encryption_keys_only(mode)) {
             decryption_keys = encryption_keys;
         } else {
             derive_decryption_keys<algorithm>(encryption_keys, decryption_keys);
diff --git a/aesxx/include/aesxx/mode.hpp b/aesxx/include/aesxx/mode.hpp
index e4391a4..9fbcaae 100644
--- a/aesxx/include/aesxx/mode.hpp
+++ b/aesxx/include/aesxx/mode.hpp
@@ -13,26 +13,11 @@ namespace aes {
 
 typedef AES_Mode Mode;
 
-template <Mode mode>
-struct ModeRequiresInitVector : public std::true_type {};
-
-template <>
-struct ModeRequiresInitVector<AES_ECB> : public std::false_type {};
-
-template <Mode mode>
-struct ModeUsesEncryptionKeysOnly : public std::true_type {};
-
-inline bool mode_requires_init_vector(Mode mode) {
+inline constexpr bool mode_requires_init_vector(Mode mode) {
     return mode != AES_ECB;
 }
 
-template <>
-struct ModeUsesEncryptionKeysOnly<AES_ECB> : public std::false_type {};
-
-template <>
-struct ModeUsesEncryptionKeysOnly<AES_CBC> : public std::false_type {};
-
-inline bool mode_uses_encryption_keys_only(Mode mode) {
+inline constexpr bool mode_uses_encryption_keys_only(Mode mode) {
     return mode != AES_ECB && mode != AES_CBC;
 }
 
@@ -41,6 +26,7 @@ inline bool mode_uses_encryption_keys_only(Mode mode) {
     inline void encrypt_block<AES_##prefix, AES_ECB>(                               \
         const typename Types<AES_##prefix>::Block& plaintext,                       \
         const typename Types<AES_##prefix>::RoundKeys& encryption_keys,             \
+        typename Types<AES_##prefix>::Block&,                                       \
         typename Types<AES_##prefix>::Block& ciphertext                             \
     ) {                                                                             \
         ciphertext = aes_##prefix##_encrypt_block_ECB(plaintext, &encryption_keys); \
@@ -51,6 +37,7 @@ inline bool mode_uses_encryption_keys_only(Mode mode) {
     inline void decrypt_block<AES_##prefix, AES_ECB>(                               \
         const typename Types<AES_##prefix>::Block& ciphertext,                      \
         const typename Types<AES_##prefix>::RoundKeys& decryption_keys,             \
+        typename Types<AES_##prefix>::Block&,                                       \
         typename Types<AES_##prefix>::Block& plaintext                              \
     ) {                                                                             \
         plaintext = aes_##prefix##_decrypt_block_ECB(ciphertext, &decryption_keys); \