Fix random() for 64-bit values

Author: mikee47

Sming/Core/Data/Range.h

@@ -11,6 +11,7 @@
 #pragma once
 
 #include <WString.h>
+#include <limits>
 #include <esp_systemapi.h>
 
 /**
@@ -106,11 +107,14 @@ template <typename T> struct TRange {
 	 */
 	T random() const
 	{
-		auto n = 1 + max - min;
+		uint64_t n = 1 + max - min;
 		if(n == 0) {
 			return 0;
 		}
-		auto value = os_random();
+		T value = os_random();
+		if(n > std::numeric_limits<uint32_t>::max()) {
+			value |= uint64_t(os_random()) << 32;
+		}
 		return min + value % n;
 	}
 

tests/HostTests/modules/Range.cpp

@@ -19,6 +19,10 @@ class RangeTest : public TestGroup
 
 			constexpr int64_t tmp = 0x8000000000LL;
 			static_assert(!range.contains(tmp));
+
+			for(unsigned i = 0; i < 10; ++i) {
+				Serial << range.random() << endl;
+			}
 		}
 
 		TEST_CASE("truncation")
@@ -35,6 +39,14 @@ class RangeTest : public TestGroup
 			int val = 0x8000;
 			REQUIRE(!range.contains(val));
 		}
+
+		TEST_CASE("Random")
+		{
+			constexpr TRange<int64_t> range(-0x10000000000LL, 0x10000000000LL);
+			for(unsigned i = 0; i < 10; ++i) {
+				Serial << range.random() << endl;
+			}
+		}
 	}
 };