Improve Vec3

Signed-off-by: Kamil Kopryk <kamil.kopryk@intel.com>
Related-To: NEO-4692

shared/source/helpers/vec.h

@@ -7,8 +7,16 @@
 
 #pragma once
 
+#include "shared/source/helpers/debug_helpers.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <type_traits>
+
 template <typename T>
 struct Vec3 {
+    static_assert(std::is_pod<T>::value);
+
     Vec3(T x, T y, T z) : x(x), y(y), z(z) {}
     Vec3(const Vec3 &v) : x(v.x), y(v.y), z(v.z) {}
     Vec3(const T *arr) {
@@ -43,6 +51,16 @@ struct Vec3 {
         return !operator==(vec);
     }
 
+    T &operator[](uint32_t i) {
+        UNRECOVERABLE_IF(i > 2);
+        return values[i];
+    }
+
+    T operator[](uint32_t i) const {
+        UNRECOVERABLE_IF(i > 2);
+        return values[i];
+    }
+
     unsigned int getSimplifiedDim() const {
         if (z > 1) {
             return 3;
@@ -56,7 +74,14 @@ struct Vec3 {
         return 0;
     }
 
-    T x;
-    T y;
-    T z;
+    union {
+        struct {
+            T x, y, z;
+        };
+        T values[3];
+    };
 };
+
+static_assert(offsetof(Vec3<size_t>, x) == offsetof(Vec3<size_t>, values[0]));
+static_assert(offsetof(Vec3<size_t>, y) == offsetof(Vec3<size_t>, values[1]));
+static_assert(offsetof(Vec3<size_t>, z) == offsetof(Vec3<size_t>, values[2]));

shared/test/unit_test/helpers/basic_math_tests.cpp

@@ -6,6 +6,7 @@
  */
 
 #include "shared/source/helpers/basic_math.h"
+#include "shared/source/helpers/vec.h"
 
 #include "gtest/gtest.h"
 
@@ -214,3 +215,28 @@ TEST(ffs, givenNonZeroThenReturnFirstSetBitIndex) {
     EXPECT_EQ(16ULL, ffs((1ULL << 63ULL) | (1ULL << 32ULL) | (1ULL << 16ULL)));
     EXPECT_EQ(63ULL, ffs(1ULL << 63ULL));
 }
+
+TEST(Vec3Tests, whenAccessingVec3ThenCorrectResultsAreReturned) {
+    Vec3<size_t> vec{1, 2, 3};
+
+    EXPECT_EQ(1u, vec[0]);
+    EXPECT_EQ(2u, vec[1]);
+    EXPECT_EQ(3u, vec[2]);
+    EXPECT_EQ(vec.x, vec[0]);
+    EXPECT_EQ(vec.y, vec[1]);
+    EXPECT_EQ(vec.z, vec[2]);
+
+    vec[0] = 10u;
+    vec[1] = 20u;
+    vec[2] = 30u;
+    EXPECT_EQ(10u, vec.x);
+    EXPECT_EQ(20u, vec.y);
+    EXPECT_EQ(30u, vec.z);
+    EXPECT_ANY_THROW(vec[3]);
+
+    const Vec3<size_t> vec2 = {1, 2, 3};
+    EXPECT_EQ(1u, vec2[0]);
+    EXPECT_EQ(2u, vec2[1]);
+    EXPECT_EQ(3u, vec2[2]);
+    EXPECT_ANY_THROW(vec2[3]);
+}