Merge pull request #260 from qxzkjp/master

Added get_randstate_t method to gmp_randclass

doc/mpir.texi

@@ -6849,6 +6849,18 @@ f = r.get_f();           // random number, 512 bits
 @end example
 @end deftypefun
 
+@deftypefun randstate_t gmp_randclass::get_randstate_t ()
+Get the underlying @code{randstate_t} from the object. This can be used to call a
+C function that doesn't have a C++ interface. For example, to check if an integer
+is prime,
+@example
+gmp_randclass r(gmp_randinit_mt);
+mpz_class p;
+// ... seed r and generate p ...
+is_prime = mpz_likely_prime_p(p.get_mpz_t(), r.get_randstate_t(), 0);
+@end example
+@end deftypefun
+
 
 
 @node C++ Interface Limitations,  , C++ Interface Random Numbers, C++ Class Interface

gmp-h.in

@@ -314,6 +314,8 @@ typedef __gmp_const __mpf_struct *mpf_srcptr;
 typedef __mpf_struct *mpf_ptr;
 typedef __gmp_const __mpq_struct *mpq_srcptr;
 typedef __mpq_struct *mpq_ptr;
+typedef __gmp_const __gmp_randstate_struct *randstate_srcptr;
+typedef __gmp_randstate_struct *randstate_ptr;
 
 
 #if __GMP_LIBGMP_DLL

mpirxx.h

@@ -3482,6 +3482,10 @@ class gmp_randclass
   void seed(mpir_ui s) { gmp_randseed_ui(state, s); }
   void seed(const mpz_class &z) { gmp_randseed(state, z.get_mpz_t()); }
 
+  //get randstate_t for compatibility with non-OO API functions
+  randstate_srcptr get_randstate_t() const { return this->state; }
+  randstate_ptr get_randstate_t() { return this->state; }
+
   // get random number
   __gmp_expr<mpz_t, __gmp_urandomb_value> get_z_bits(mp_bitcnt_t l)
   { return __gmp_expr<mpz_t, __gmp_urandomb_value>(state, l); }

tests/cxx/t-rand.cc

@@ -126,6 +126,31 @@ check_mpf (void)
   }
 }
 
+/*check that get_randstate_t really returns the randstate_t underlying a gmp_randclass*/
+void
+check_randstate_t(void)
+{
+  /*seed gmp_randclass r using its method, and seed gmp_randclass s using get_randstate_t
+    if they both generate the same sequence, then gmp_randstate_t must be returning the
+    underlying randstate_t of s */
+  {
+    gmp_randclass r(gmp_randinit_default);
+    gmp_randclass s(gmp_randinit_default);
+    __gmp_randstate_struct s_state = *s.get_randstate_t();
+
+    r.seed(0xdeadbeef);
+    gmp_randseed_ui(&s_state, 0xdeadbeef);
+
+    bool res = true;
+    for (int i = 0; i < 100; ++i)
+    {
+      mpz_class n1 = r.get_z_bits(32);
+      mpz_class n2 = s.get_z_bits(32);
+      ASSERT_ALWAYS (n1 == n2);
+    }
+  }
+}
+
 
 int
 main (void)
@@ -135,6 +160,7 @@ main (void)
   check_randinit();
   check_mpz();
   check_mpf();
+  check_randstate_t();
 
   tests_end();
   return 0;