From 325a7405b537f1c8ee3f3c7edef6886e0a6dec0f Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Fri, 1 Jul 2016 16:21:13 +1000
Subject: [PATCH] rand/lcg: add min/max/discard operations

---
 rand/lcg.cpp | 28 ++++++++++++++++++++++++++++
 rand/lcg.hpp |  9 ++++++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/rand/lcg.cpp b/rand/lcg.cpp
index 31d9887c..37937407 100644
--- a/rand/lcg.cpp
+++ b/rand/lcg.cpp
@@ -56,6 +56,34 @@ lcg<T,M,A,C>::operator() (void)
 }
 
 
+///////////////////////////////////////////////////////////////////////////////
+template <typename T, T M, T A, T C>
+typename lcg<T,M,A,C>::result_type
+lcg<T,M,A,C>::min (void)
+{
+    return std::numeric_limits<result_type>::min ();
+}
+
+
+//-----------------------------------------------------------------------------
+template <typename T, T M, T A, T C>
+typename lcg<T,M,A,C>::result_type
+lcg<T,M,A,C>::max (void)
+{
+    return std::numeric_limits<result_type>::max ();
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+template <typename T, T M, T A, T C>
+void
+lcg<T,M,A,C>::discard (unsigned count)
+{
+    while (count--)
+        (*this)();
+}
+
+
 ///////////////////////////////////////////////////////////////////////////////
 template struct util::rand::lcg<uint32_t, util::pow2(31), 1103515245, 12345>;
 template struct util::rand::lcg<uint64_t, 0ul, 6364136223846793005ul, 1ul>;
diff --git a/rand/lcg.hpp b/rand/lcg.hpp
index 8f2e74cc..e87ff243 100644
--- a/rand/lcg.hpp
+++ b/rand/lcg.hpp
@@ -30,11 +30,18 @@ namespace util { namespace rand {
     template <typename T, T M, T A, T C>
     struct lcg {
     public:
+        using result_type = T;
+
         static_assert (std::is_unsigned<T>::value,
                        "LCG generates integer overflow which is undefined behaviour for signed types");
         lcg (T seed);
 
-        T operator() (void);
+        result_type operator() (void);
+
+        static result_type min (void);
+        static result_type max (void);
+
+        void discard (unsigned);
 
     private:
         T m_x;