Add a new subclass for BlockCipher BlockCipher_Fixed_Block_Size, which

sets the block size statically and also creates an enum with the
size. Use the enum instead of calling block_size() where possible,
since that uses two virtual function calls per block which is quite
unfortunate. The real advantages here as compared to the previous
version which kept the block size as a per-object u32bit:

 - The compiler can inline the constant as an immediate operand
   (previously it would load the value via an indirection on this)

 - Removes 32 bits per object overhead (except in cases with actually
   variable block sizes, which are very few and rarely used)

2 files changed, 6 insertions, 6 deletions

diff --git a/src/block/mars/mars.cpp b/src/block/mars/mars.cpp
index 5864ac49b..fa73e564f 100644
--- a/src/block/mars/mars.cpp
+++ b/src/block/mars/mars.cpp
@@ -267,8 +267,8 @@ void MARS::encrypt_n(const byte in[], byte out[], size_t blocks) const
 
       store_le(out, A, B, C, D);
 
-      in += block_size();
-      out += block_size();
+      in += BLOCK_SIZE;
+      out += BLOCK_SIZE;
       }
    }
 
@@ -310,8 +310,8 @@ void MARS::decrypt_n(const byte in[], byte out[], size_t blocks) const
 
       store_le(out, D, C, B, A);
 
-      in += block_size();
-      out += block_size();
+      in += BLOCK_SIZE;
+      out += BLOCK_SIZE;
       }
    }
 
diff --git a/src/block/mars/mars.h b/src/block/mars/mars.h
index a61f475f2..7a53d116b 100644
--- a/src/block/mars/mars.h
+++ b/src/block/mars/mars.h
@@ -15,7 +15,7 @@ namespace Botan {
 /**
 * MARS, IBM's candidate for AES
 */
-class BOTAN_DLL MARS : public BlockCipher
+class BOTAN_DLL MARS : public BlockCipher_Fixed_Block_Size<16>
    {
    public:
       void encrypt_n(const byte in[], byte out[], size_t blocks) const;
@@ -25,7 +25,7 @@ class BOTAN_DLL MARS : public BlockCipher
       std::string name() const { return "MARS"; }
       BlockCipher* clone() const { return new MARS; }
 
-      MARS() : BlockCipher(16, 16, 32, 4), EK(40) {}
+      MARS() : BlockCipher_Fixed_Block_Size(16, 32, 4), EK(40) {}
    private:
       void key_schedule(const byte[], size_t);