math: add

Signed-off-by: Simon Rozman <simon@rozman.si>

UnitTests/UnitTests.vcxproj

@@ -116,6 +116,7 @@
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" />
   <ItemGroup>
     <ClCompile Include="ios.cpp" />
+    <ClCompile Include="math.cpp" />
     <ClCompile Include="parser.cpp" />
     <ClCompile Include="pch.cpp">
       <PrecompiledHeader>Create</PrecompiledHeader>

UnitTests/UnitTests.vcxproj.filters

@@ -27,6 +27,9 @@
     <ClCompile Include="ios.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="math.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="pch.h">

UnitTests/math.cpp

@@ -0,0 +1,42 @@
+/*
+	SPDX-License-Identifier: MIT
+	Copyright © 2023 Amebis
+*/
+
+#include "pch.h"
+
+using namespace std;
+using namespace Microsoft::VisualStudio::CppUnitTestFramework;
+
+namespace UnitTests
+{
+	TEST_CLASS(math)
+	{
+	public:
+		TEST_METHOD(mul)
+		{
+			Assert::AreEqual<size_t>(10, stdex::mul(2, 5));
+			Assert::AreEqual<size_t>(10, stdex::mul(5, 2));
+			Assert::AreEqual<size_t>(0, stdex::mul(0, 10));
+			Assert::AreEqual<size_t>(0, stdex::mul(10, 0));
+			Assert::AreEqual<size_t>(0, stdex::mul(SIZE_MAX, 0));
+			Assert::AreEqual<size_t>(0, stdex::mul(0, SIZE_MAX));
+			Assert::AreEqual<size_t>(SIZE_MAX, stdex::mul(SIZE_MAX, 1));
+			Assert::AreEqual<size_t>(SIZE_MAX, stdex::mul(1, SIZE_MAX));
+			Assert::ExpectException<std::invalid_argument>([] { stdex::mul(SIZE_MAX, 2); });
+			Assert::ExpectException<std::invalid_argument>([] { stdex::mul(2, SIZE_MAX); });
+		}
+
+		TEST_METHOD(add)
+		{
+			Assert::AreEqual<size_t>(7, stdex::add(2, 5));
+			Assert::AreEqual<size_t>(7, stdex::add(5, 2));
+			Assert::AreEqual<size_t>(10, stdex::add(0, 10));
+			Assert::AreEqual<size_t>(10, stdex::add(10, 0));
+			Assert::AreEqual<size_t>(SIZE_MAX, stdex::add(SIZE_MAX, 0));
+			Assert::AreEqual<size_t>(SIZE_MAX, stdex::add(0, SIZE_MAX));
+			Assert::ExpectException<std::invalid_argument>([] { stdex::add(SIZE_MAX, 1); });
+			Assert::ExpectException<std::invalid_argument>([] { stdex::add(1, SIZE_MAX); });
+		}
+	};
+}

UnitTests/pch.h

@@ -16,6 +16,7 @@
 #include <stdex/interval.hpp>
 #include <stdex/ios.hpp>
 #include <stdex/mapping.hpp>
+#include <stdex/math.hpp>
 #include <stdex/parser.hpp>
 #include <stdex/progress.hpp>
 #include <stdex/sal.hpp>

include/stdex/math.hpp

@@ -0,0 +1,49 @@
+/*
+	SPDX-License-Identifier: MIT
+	Copyright © 2023 Amebis
+*/
+
+#pragma once
+
+#include "sal.hpp"
+#include "system.hpp"
+#include <stdexcept>
+
+namespace stdex
+{
+	inline size_t mul(size_t a, size_t b)
+	{
+#if _MSC_VER >= 1300
+		SIZE_T result;
+		if (SUCCEEDED(SIZETMult(a, b, &result)))
+			return result;
+#elif defined(_MSC_VER)
+		if (a == 0)
+			return 0;
+		if (b <= SIZE_MAX / a)
+			return a * b;
+#else
+		size_t result;
+		if (!__builtin_mul_overflow(a, b, &result))
+			return result;
+#endif
+		throw std::invalid_argument("multiply overflow");
+	}
+
+	inline size_t add(size_t a, size_t b)
+	{
+#if _MSC_VER >= 1300
+		SIZE_T result;
+		if (SUCCEEDED(SIZETAdd(a, b, &result)))
+			return result;
+#elif defined(_MSC_VER)
+		if (a <= SIZE_MAX - b)
+			return a + b;
+#else
+		size_t result;
+		if (!__builtin_add_overflow(a, b, &result))
+			return result;
+#endif
+		throw std::invalid_argument("add overflow");
+	}
+}