Add a runtime map of string->func() which when called return

Transforms and BlockCiphers. Registration for all types is done at
startup but is very cheap as just a std::function and a std::map entry
are created, no actual objects are created until needed. This is a
huge improvement over Algorithm_Factory which used T::clone() as the
function and thus kept a prototype object of each type in memory.

Replace existing lookup mechanisms for ciphers, AEADs, and compression
to use the transform lookup. The existing Engine framework remains in
place for BlockCipher, but the engines now just call to the registry
instead of having hardcoded lookups.

s/Transformation/Transform/ with typedefs for compatability.

Remove lib/selftest code (for runtime selftesting): not the right approach.

2 files changed, 22 insertions, 0 deletions

diff --git a/src/lib/modes/mode_pad/mode_pad.cpp b/src/lib/modes/mode_pad/mode_pad.cpp
index 946cd92c7..ecf241821 100644
--- a/src/lib/modes/mode_pad/mode_pad.cpp
+++ b/src/lib/modes/mode_pad/mode_pad.cpp
@@ -10,6 +10,26 @@
 
 namespace Botan {
 
+/**
+* Get a block cipher padding method by name
+*/
+BlockCipherModePaddingMethod* get_bc_pad(const std::string& algo_spec)
+   {
+   if(algo_spec == "NoPadding")
+      return new Null_Padding;
+
+   if(algo_spec == "PKCS7")
+      return new PKCS7_Padding;
+
+   if(algo_spec == "OneAndZeros")
+      return new OneAndZeros_Padding;
+
+   if(algo_spec == "X9.23")
+      return new ANSI_X923_Padding;
+
+   return nullptr;
+   }
+
 /*
 * Pad with PKCS #7 Method
 */
diff --git a/src/lib/modes/mode_pad/mode_pad.h b/src/lib/modes/mode_pad/mode_pad.h
index c60e25849..c4d5baf2e 100644
--- a/src/lib/modes/mode_pad/mode_pad.h
+++ b/src/lib/modes/mode_pad/mode_pad.h
@@ -119,6 +119,8 @@ class BOTAN_DLL Null_Padding : public BlockCipherModePaddingMethod
       std::string name() const { return "NoPadding"; }
    };
 
+BlockCipherModePaddingMethod* get_bc_pad(const std::string& algo_spec);
+
 }
 
 #endif