From 85b62bfa0154f30a9359831663f45e8f6bbe3fe6 Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Mon, 25 Nov 2019 13:07:34 +0000
Subject: [PATCH] rand.c: Implement the `passes' property of the `DSARand'
 generator.

This has always been present in the C library, but wasn't surfaced in
Python, which seems like a poor show.
---
 rand.c      | 35 ++++++++++++++++++++++++++++++++---
 t/t-rand.py |  8 ++++++--
 2 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/rand.c b/rand.c
index ada2baa..e72f450 100644
--- a/rand.c
+++ b/rand.c
@@ -1120,12 +1120,18 @@ static const PyTypeObject tlsprf_pytype_skel = {
 static PyObject *dsarand_pynew(PyTypeObject *ty, PyObject *arg, PyObject *kw)
 {
   struct bin in;
+  unsigned passes = 1;
+  grand *r;
   PyObject *rc = 0;
-  static const char *const kwlist[] = { "seed", 0 };
+  static const char *const kwlist[] = { "seed", "passes", 0 };
 
-  if (!PyArg_ParseTupleAndKeywords(arg, kw, "O&:new", KWLIST, convbin, &in))
+  if (!PyArg_ParseTupleAndKeywords(arg, kw, "O&|O&:new", KWLIST,
+				   convbin, &in, convuint, &passes))
     goto end;
-  rc = grand_dopywrap(ty, dsarand_create(in.p, in.sz), f_freeme);
+  if (!passes) VALERR("must be positive");
+  r = dsarand_create(in.p, in.sz);
+  if (passes != 1) r->ops->misc(r, DSARAND_PASSES, passes);
+  rc = grand_dopywrap(ty, r, f_freeme);
 end:
   return (rc);
 }
@@ -1139,9 +1145,32 @@ static PyObject *drget_seed(PyObject *me, void *hunoz)
   return (rc);
 }
 
+static PyObject *drget_passes(PyObject *me, void *hunoz)
+{
+  grand *r = GRAND_R(me);
+  return (PyInt_FromLong(r->ops->misc(r, DSARAND_PASSES, 0)));
+}
+
+static int drset_passes(PyObject *me, PyObject *val, void *hunoz)
+{
+  grand *r = GRAND_R(me);
+  long n;
+  int rc = -1;
+
+  if (!val) NIERR("__del__");
+  n = PyInt_AsLong(val); if (n == -1 && PyErr_Occurred()) goto end;
+  if (n <= 0) VALERR("must be positive");
+  if (n > ULONG_MAX) VALERR("out of range");
+  r->ops->misc(r, DSARAND_PASSES, (unsigned)n);
+  rc = 0;
+end:
+  return (rc);
+}
+
 static const PyGetSetDef dsarand_pygetset[] = {
 #define GETSETNAME(op, name) dr##op##_##name
   GET	(seed,		"R.seed -> current generator seed")
+  GETSET(passes,	"R.passes -> number of passes to create output")
 #undef GETSETNAME
   { 0 }
 };
diff --git a/t/t-rand.py b/t/t-rand.py
index 0ad92dc..9acf693 100644
--- a/t/t-rand.py
+++ b/t/t-rand.py
@@ -122,9 +122,13 @@ class TestRandomGenerator (U.TestCase):
   def test_dsarand(me):
     seed = T.span(16)
     n = C.MP.loadb(seed)
-    rng = C.DSARand(seed)
+    rng = C.DSARand(seed, passes = 2)
     me.check_rand(rng)
-    me.assertEqual(rng.seed, (n + 153 + 3).storeb(16))
+    me.assertEqual(rng.seed, (n + 2*153).storeb(16))
+    me.assertEqual(rng.passes, 2);
+    rng.passes = 1
+    me.check_rand(rng)
+    me.assertEqual(rng.seed, (n + 3*153 + 1).storeb(16))
 
   def test_bbs(me):
     ev = T.EventRecorder()
-- 
2.11.0