Added some assertions when the input to a NormalisableRange conversion function is outside of the expected range

modules/juce_core/maths/juce_NormalisableRange.h

@@ -143,9 +143,9 @@ public:
     ValueType convertTo0to1 (ValueType v) const noexcept
     {
         if (convertTo0To1Function != nullptr)
-            return convertTo0To1Function (start, end, v);
+            return clampTo0To1 (convertTo0To1Function (start, end, v));
 
-        auto proportion = (v - start) / (end - start);
+        auto proportion = clampTo0To1 ((v - start) / (end - start));
 
         if (skew == static_cast<ValueType> (1))
             return proportion;
@@ -166,6 +166,8 @@ public:
     */
     ValueType convertFrom0to1 (ValueType proportion) const noexcept
     {
+        proportion = clampTo0To1 (proportion);
+
         if (convertFrom0To1Function != nullptr)
             return convertFrom0To1Function (start, end, proportion);
 
@@ -261,6 +263,17 @@ private:
         jassert (skew > ValueType());
     }
 
+    static ValueType clampTo0To1 (ValueType value)
+    {
+        auto clampedValue = jlimit (static_cast<ValueType> (0), static_cast<ValueType> (1), value);
+
+        // If you his this assertion then either your normalisation function is not working
+        // correctly or your input is out of the expected bounds.
+        jassert (clampedValue == value);
+
+        return clampedValue;
+    }
+
     typedef std::function<ValueType(ValueType, ValueType, ValueType)> ConverstionFunction;
     ConverstionFunction convertFrom0To1Function  = {},
                         convertTo0To1Function    = {},