Add unit tests for bx::bit_cast (#318)

tests/bitcast_test.cpp

@@ -0,0 +1,93 @@
+/*
+ * Copyright 2010-2024 Branimir Karadzic. All rights reserved.
+ * License: https://github.com/bkaradzic/bx/blob/master/LICENSE
+ */
+
+#include "test.h"
+#include <bx/bx.h>
+#include <string.h>
+
+namespace bx
+{
+	extern void memCopyRef(void* _dst, const void* _src, size_t _numBytes);
+}
+
+TEST_CASE("Bit cast round trip test using double to uint64_t")
+{
+	constexpr double d64v = 19880124.0;
+	REQUIRE(sizeof(double) == sizeof(uint64_t));
+
+	SECTION("bx::bit_cast")
+	{
+		const uint64_t u64v = bx::bit_cast<uint64_t>(d64v);
+		const double result = bx::bit_cast<double>(u64v);
+		REQUIRE(result == d64v);
+	}
+
+	SECTION("bx::memCopy")
+	{
+		uint64_t u64v = 0;
+		double result = 0;
+		bx::memCopy(&u64v, &d64v, sizeof(uint64_t));
+		bx::memCopy(&result, &u64v, sizeof(double));
+		REQUIRE(result == d64v);
+	}
+
+	SECTION("bx::memCopyRef")
+	{
+		uint64_t u64v = 0;
+		double result = 0;
+		bx::memCopyRef(&u64v, &d64v, sizeof(uint64_t));
+		bx::memCopyRef(&result, &u64v, sizeof(double));
+		REQUIRE(result == d64v);
+	}
+
+	SECTION("::memcpy")
+	{
+		uint64_t u64v = 0;
+		double result = 0;
+		::memcpy(&u64v, &d64v, sizeof(uint64_t));
+		::memcpy(&result, &u64v, sizeof(double));
+		REQUIRE(result == d64v);
+	}
+}
+
+TEST_CASE("Bit cast round trip test using uint64_t to double")
+{
+	constexpr uint64_t u64v = 0x3fe9000000000000ull;
+	REQUIRE(sizeof(uint64_t) == sizeof(double));
+
+	SECTION("bx::bit_cast")
+	{
+		const double d64v = bx::bit_cast<double>(u64v);
+		const uint64_t result = bx::bit_cast<uint64_t>(d64v);
+		REQUIRE(result == u64v);
+	}
+
+	SECTION("bx::memCopy")
+	{
+		double d64v = 0;
+		uint64_t result = 0;
+		bx::memCopy(&d64v, &u64v, sizeof(double));
+		bx::memCopy(&result, &d64v, sizeof(uint64_t));
+		REQUIRE(result == u64v);
+	}
+
+	SECTION("bx::memCopyRef")
+	{
+		double d64v = 0;
+		uint64_t result = 0;
+		bx::memCopyRef(&d64v, &u64v, sizeof(double));
+		bx::memCopyRef(&result, &d64v, sizeof(uint64_t));
+		REQUIRE(result == u64v);
+	}
+
+	SECTION("::memcpy")
+	{
+		double d64v = 0;
+		uint64_t result = 0;
+		::memcpy(&d64v, &u64v, sizeof(double));
+		::memcpy(&result, &d64v, sizeof(uint64_t));
+		REQUIRE(result == u64v);
+	}
+}