From 348254521f404f683d0230a84ae4943c9d20e51c Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Thu, 11 May 2017 10:42:15 +0100
Subject: [PATCH] rand.c, algorithms.py: Change how kinds of RNGs are
 distinguished.

Rather than a set of flags, assign them numbers and use `switch'.  It
doesn't seem like the flags are helpfully marking out sets of RNGs, and
this approach scales better to handling more kinds.
---
 algorithms.py |  8 ++++----
 rand.c        | 26 ++++++++++++++++++--------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/algorithms.py b/algorithms.py
index a2a468f..a7a2caa 100644
--- a/algorithms.py
+++ b/algorithms.py
@@ -73,14 +73,14 @@ print
 print '#define RNGS(_) \\'
 for i in (cross(prps, ['ofb', 'counter'])):
   print ('\t_("%(prim)s-%(mode)s", %(prim)s_keysz, ' +
-         '%(prim)s_%(mode)srand, 0, 0) \\') % \
+         '%(prim)s_%(mode)srand, RNG_PLAIN, 0) \\') % \
          {'prim': i[0], 'mode': i[1]}
 for i in (cross(hashes, 'mgf')):
   print ('\t_("%(prim)s-%(mode)s", %(prim)s_%(mode)skeysz, ' +
-         '%(prim)s_%(mode)srand, 0, 0) \\') % \
+         '%(prim)s_%(mode)srand, RNG_PLAIN, 0) \\') % \
          {'prim': i[0], 'mode': i[1]}
 print '\t_("rc4", rc4_keysz, rc4_rand, 0, 0) \\'
-print '\t_("seal", seal_keysz, seal_rand, RNGF_INT, 0) \\'
+print '\t_("seal", seal_keysz, seal_rand, RNG_SEAL, 0) \\'
 for i in latindances:
   for r in ['salsa20', 'xsalsa20', 'chacha', 'xchacha']:
     if i.startswith(r):
@@ -90,7 +90,7 @@ for i in latindances:
     raise ValueError, 'failed to find root name for %s' % i
   if i.endswith('-ietf'): root += '_ietf'
   print ('\t_("%(name)s", %(root)s_keysz, %(id)s_rand, ' +
-         'RNGF_NONCE | RNGF_LATIN, %(ROOT)s_NONCESZ) \\') % \
+         'RNG_LATIN, %(ROOT)s_NONCESZ) \\') % \
       {'name': i, 'id': i.translate(None, '/').replace('-', '_'),
        'root': root, 'ROOT': root.upper()}
 print '\t/* end */'
diff --git a/rand.c b/rand.c
index f163efa..5402737 100644
--- a/rand.c
+++ b/rand.c
@@ -591,9 +591,15 @@ typedef struct gccrand_info {
   gcrand_func *func;
 } gccrand_info;
 
-#define RNGF_INT 1u
-#define RNGF_NONCE 2u
-#define RNGF_LATIN 4u
+#define RNGF_MASK 255u
+
+enum {
+  RNG_PLAIN = 0,
+  RNG_SEAL,
+  RNG_LATIN,
+  RNG_SHAKE,
+  RNG_KMAC
+};
 
 typedef struct gccrand_pyobj {
   PyHeapTypeObject ty;
@@ -670,17 +676,21 @@ static PyObject *gccrand_pywrap(const gccrand_info *info)
   gccrand_pyobj *g = newtype(gccrand_pytype, 0, info->name);
   g->info = info;
   g->ty.ht_type.tp_basicsize = sizeof(grand_pyobj);
-  g->ty.ht_type.tp_base =
-    (info->f & RNGF_LATIN) ? gclatinrand_pytype : gcrand_pytype;
+  switch (info->f&RNGF_MASK) {
+    case RNG_LATIN: g->ty.ht_type.tp_base = gclatinrand_pytype; break;
+    default: g->ty.ht_type.tp_base = gcrand_pytype; break;
+  }
   Py_INCREF(g->ty.ht_type.tp_base);
   g->ty.ht_type.tp_flags = (Py_TPFLAGS_DEFAULT |
 			    Py_TPFLAGS_BASETYPE |
 			    Py_TPFLAGS_HEAPTYPE);
   g->ty.ht_type.tp_alloc = PyType_GenericAlloc;
   g->ty.ht_type.tp_free = 0;
-  if (info->f & RNGF_INT) g->ty.ht_type.tp_new = gcirand_pynew;
-  else if (info->f & RNGF_NONCE) g->ty.ht_type.tp_new = gcnrand_pynew;
-  else g->ty.ht_type.tp_new = gcrand_pynew;
+  switch (info->f&RNGF_MASK) {
+    case RNG_LATIN: g->ty.ht_type.tp_new = gcnrand_pynew; break;
+    case RNG_SEAL: g->ty.ht_type.tp_new = gcirand_pynew; break;
+    default: g->ty.ht_type.tp_new = gcrand_pynew; break;
+  }
   typeready(&g->ty.ht_type);
   return ((PyObject *)g);
 }
-- 
2.11.0