Remove both default arguments to the constructor of ANSI_X931_RNG.

If the second argument was NULL, it would default to a new Randpool.
But this introduces an annoying dependency: really it is the caller who
is relying on Randpool. Make this explicit by passing a new Randpool
pointer to the constructor in Library_State.

This will break all callers using ANSI_X931_RNG's constructors with
default arguments. To regain the previous behavior, change:
  ANSI_X931_RNG rng;
  ANSI_X931_RNG rng("/*cipher name*/");
to
  ANSI_X931_RNG rng(/*cipher name, default was AES-256 */, new Randpool);

You are free to pass another PRNG object if you like.

This make require inclusion of <botan/randpool.h>

2 files changed, 7 insertions, 7 deletions

diff --git a/src/libstate.cpp b/src/libstate.cpp
index db2d124a8..b988625ce 100644
--- a/src/libstate.cpp
+++ b/src/libstate.cpp
@@ -11,6 +11,7 @@
 #include <botan/mutex.h>
 #include <botan/charset.h>
 #include <botan/x931_rng.h>
+#include <botan/randpool.h>
 #include <botan/selftest.h>
 #include <algorithm>
 
@@ -272,7 +273,7 @@ void Library_State::initialize(const InitializerOptions& args,
    for(u32bit j = 0; j != sources.size(); ++j)
       add_entropy_source(sources[j]);
 
-   set_prng(new ANSI_X931_RNG);
+   set_prng(new ANSI_X931_RNG("AES-256", new Randpool));
 
    if(args.seed_rng())
       {
diff --git a/src/x931_rng.cpp b/src/x931_rng.cpp
index 01b8c33d2..94d5f9247 100644
--- a/src/x931_rng.cpp
+++ b/src/x931_rng.cpp
@@ -108,18 +108,17 @@ std::string ANSI_X931_RNG::name() const
 ANSI_X931_RNG::ANSI_X931_RNG(const std::string& cipher_name,
                              RandomNumberGenerator* prng_ptr)
    {
-   if(cipher_name == "")
-      cipher = get_block_cipher("AES-256");
-   else
-      cipher = get_block_cipher(cipher_name);
+   if(!prng_ptr)
+      throw Invalid_Argument("ANSI_X931_RNG constructor: NULL prng");
+
+   prng = prng_ptr;
+   cipher = get_block_cipher(cipher_name);
 
    const u32bit BLOCK_SIZE = cipher->BLOCK_SIZE;
 
    V.create(BLOCK_SIZE);
    R.create(BLOCK_SIZE);
 
-   prng = (prng_ptr ? prng_ptr : new Randpool);
-
    position = 0;
    }