From bbfce66abc39c0c86767dba4f4a94db751fef0ca Mon Sep 17 00:00:00 2001
From: John Wellbelove <john.wellbelove@etlcpp.com>
Date: Tue, 28 May 2024 11:58:07 +0100
Subject: [PATCH] Added template parameter clamp functions

---
 include/etl/algorithm.h | 22 ++++++++++++++++++----
 test/test_algorithm.cpp | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/include/etl/algorithm.h b/include/etl/algorithm.h
index fb394f8f..844bc12f 100644
--- a/include/etl/algorithm.h
+++ b/include/etl/algorithm.h
@@ -2142,19 +2142,33 @@ namespace etl
   ///\ingroup algorithm
   //***************************************************************************
   template<typename T, typename TCompare>
-  ETL_CONSTEXPR 
-  const T& clamp(const T& value, const T& low, const T& high, TCompare compare)
+  ETL_CONSTEXPR
+  T clamp(const T& value, const T& low, const T& high, TCompare compare)
   {
     return compare(value, low) ? low : compare(high, value) ? high : value;
   }
   
   template <typename T>
-  ETL_CONSTEXPR 
-  const T& clamp(const T& value, const T& low, const T& high )
+  ETL_CONSTEXPR
+  T clamp(const T& value, const T& low, const T& high)
   {
     return clamp(value, low, high, etl::less<T>());
   }
 
+  template<typename T, T Low, T High, typename TCompare>
+  ETL_CONSTEXPR
+  T clamp(const T& value, TCompare compare)
+  {
+    return compare(value, Low) ? Low : compare(High, value) ? High : value;
+  }
+
+  template <typename T, T Low, T High>
+  ETL_CONSTEXPR
+  T clamp(const T& value)
+  {
+    return clamp<T, Low, High>(value, etl::less<T>());
+  }
+
   //***************************************************************************
   /// Remove
   ///\ingroup algorithm
diff --git a/test/test_algorithm.cpp b/test/test_algorithm.cpp
index 875884c6..43ff2379 100644
--- a/test/test_algorithm.cpp
+++ b/test/test_algorithm.cpp
@@ -2384,5 +2384,41 @@ namespace
         data = initial;
       }
     }
+
+    //*************************************************************************
+    TEST(clamp_run_time)
+    {
+      CHECK_EQUAL(5, etl::clamp(5, 0, 10));
+      CHECK_EQUAL(0, etl::clamp(-5, 0, 10));
+      CHECK_EQUAL(10, etl::clamp(15, 0, 10));
+    }
+
+    //*************************************************************************
+    TEST(clamp_compile_time)
+    {
+      CHECK_EQUAL(5,  (etl::clamp<int, 0, 10>(5)));
+      CHECK_EQUAL(0,  (etl::clamp<int, 0, 10>(-5)));
+      CHECK_EQUAL(10, (etl::clamp<int, 0, 10>(15)));
+    }
+
+    //*************************************************************************
+    TEST(clamp_constexpr)
+    {
+      constexpr int result1 = etl::clamp(5, 0, 10);
+      constexpr int result2 = etl::clamp(-5, 0, 10);
+      constexpr int result3 = etl::clamp(15, 0, 10);
+
+      constexpr int result4 = etl::clamp<int, 0, 10>(5);
+      constexpr int result5 = etl::clamp<int, 0, 10>(-5);
+      constexpr int result6 = etl::clamp<int, 0, 10>(15);
+
+      CHECK_EQUAL(5,  result1);
+      CHECK_EQUAL(0,  result2);
+      CHECK_EQUAL(10, result3);
+
+      CHECK_EQUAL(5, result4);
+      CHECK_EQUAL(0, result5);
+      CHECK_EQUAL(10, result6);
+    }
   };
 }