Refactor out headeronly ArrayRef (#164991)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/164991
Approved by: https://github.com/swolchok

test/cpp/aoti_abi_check/CMakeLists.txt

@@ -7,6 +7,7 @@ set(AOTI_ABI_CHECK_TEST_SRCS
   ${AOTI_ABI_CHECK_TEST_ROOT}/test_devicetype.cpp
   ${AOTI_ABI_CHECK_TEST_ROOT}/test_dtype.cpp
   ${AOTI_ABI_CHECK_TEST_ROOT}/test_exception.cpp
+  ${AOTI_ABI_CHECK_TEST_ROOT}/test_headeronlyarrayref.cpp
   ${AOTI_ABI_CHECK_TEST_ROOT}/test_macros.cpp
   ${AOTI_ABI_CHECK_TEST_ROOT}/test_math.cpp
   ${AOTI_ABI_CHECK_TEST_ROOT}/test_rand.cpp

test/cpp/aoti_abi_check/test_headeronlyarrayref.cpp

@@ -0,0 +1,52 @@
+#include <gtest/gtest.h>
+
+#include <torch/headeronly/util/HeaderOnlyArrayRef.h>
+
+#include <vector>
+
+using torch::headeronly::HeaderOnlyArrayRef;
+
+TEST(TestHeaderOnlyArrayRef, TestEmpty) {
+  HeaderOnlyArrayRef<float> arr;
+  ASSERT_TRUE(arr.empty());
+}
+
+TEST(TestHeaderOnlyArrayRef, TestSingleton) {
+  float val = 5.0f;
+  HeaderOnlyArrayRef<float> arr(val);
+  ASSERT_FALSE(arr.empty());
+  EXPECT_EQ(arr.size(), 1);
+  EXPECT_EQ(arr[0], val);
+}
+
+TEST(TestHeaderOnlyArrayRef, TestAPIs) {
+  std::vector<int> vec = {1, 2, 3, 4, 5, 6, 7};
+  HeaderOnlyArrayRef<int> arr(vec);
+  ASSERT_FALSE(arr.empty());
+  EXPECT_EQ(arr.size(), 7);
+  for (size_t i = 0; i < arr.size(); i++) {
+    EXPECT_EQ(arr[i], i + 1);
+    EXPECT_EQ(arr.at(i), i + 1);
+  }
+  EXPECT_EQ(arr.front(), 1);
+  EXPECT_EQ(arr.back(), 7);
+  ASSERT_TRUE(arr.slice(3, 4).equals(arr.slice(3)));
+}
+
+TEST(TestHeaderOnlyArrayRef, TestFromInitializerList) {
+  std::vector<int> vec = {1, 2, 3, 4, 5, 6, 7};
+  HeaderOnlyArrayRef<int> arr({1, 2, 3, 4, 5, 6, 7});
+  auto res_vec = arr.vec();
+  for (size_t i = 0; i < vec.size(); i++) {
+    EXPECT_EQ(vec[i], res_vec[i]);
+  }
+}
+
+TEST(TestHeaderOnlyArrayRef, TestFromRange) {
+  std::vector<int> vec = {1, 2, 3, 4, 5, 6, 7};
+  HeaderOnlyArrayRef<int> arr(vec.data() + 3, vec.data() + 7);
+  auto res_vec = arr.vec();
+  for (size_t i = 0; i < res_vec.size(); i++) {
+    EXPECT_EQ(vec[i + 3], res_vec[i]);
+  }
+}