Initial Commit

1 files changed, 107 insertions, 0 deletions

diff --git a/absl/base/bit_cast_test.cc b/absl/base/bit_cast_test.cc
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+++ b/absl/base/bit_cast_test.cc
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+// Copyright 2017 The Abseil Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Unit test for bit_cast template.
+
+#include <cstdint>
+#include <cstring>
+
+#include "gtest/gtest.h"
+#include "absl/base/casts.h"
+#include "absl/base/macros.h"
+
+namespace absl {
+namespace {
+
+template <int N>
+struct marshall { char buf[N]; };
+
+template <typename T>
+void TestMarshall(const T values[], int num_values) {
+  for (int i = 0; i < num_values; ++i) {
+    T t0 = values[i];
+    marshall<sizeof(T)> m0 = absl::bit_cast<marshall<sizeof(T)> >(t0);
+    T t1 = absl::bit_cast<T>(m0);
+    marshall<sizeof(T)> m1 = absl::bit_cast<marshall<sizeof(T)> >(t1);
+    ASSERT_EQ(0, memcmp(&t0, &t1, sizeof(T)));
+    ASSERT_EQ(0, memcmp(&m0, &m1, sizeof(T)));
+  }
+}
+
+// Convert back and forth to an integral type.  The C++ standard does
+// not guarantee this will work, but we test that this works on all the
+// platforms we support.
+//
+// Likewise, we below make assumptions about sizeof(float) and
+// sizeof(double) which the standard does not guarantee, but which hold on the
+// platforms we support.
+
+template <typename T, typename I>
+void TestIntegral(const T values[], int num_values) {
+  for (int i = 0; i < num_values; ++i) {
+    T t0 = values[i];
+    I i0 = absl::bit_cast<I>(t0);
+    T t1 = absl::bit_cast<T>(i0);
+    I i1 = absl::bit_cast<I>(t1);
+    ASSERT_EQ(0, memcmp(&t0, &t1, sizeof(T)));
+    ASSERT_EQ(i0, i1);
+  }
+}
+
+TEST(BitCast, Bool) {
+  static const bool bool_list[] = { false, true };
+  TestMarshall<bool>(bool_list, ABSL_ARRAYSIZE(bool_list));
+}
+
+TEST(BitCast, Int32) {
+  static const int32_t int_list[] =
+    { 0, 1, 100, 2147483647, -1, -100, -2147483647, -2147483647-1 };
+  TestMarshall<int32_t>(int_list, ABSL_ARRAYSIZE(int_list));
+}
+
+TEST(BitCast, Int64) {
+  static const int64_t int64_list[] =
+    { 0, 1, 1LL << 40, -1, -(1LL<<40) };
+  TestMarshall<int64_t>(int64_list, ABSL_ARRAYSIZE(int64_list));
+}
+
+TEST(BitCast, Uint64) {
+  static const uint64_t uint64_list[] =
+    { 0, 1, 1LLU << 40, 1LLU << 63 };
+  TestMarshall<uint64_t>(uint64_list, ABSL_ARRAYSIZE(uint64_list));
+}
+
+TEST(BitCast, Float) {
+  static const float float_list[] =
+    { 0.0f, 1.0f, -1.0f, 10.0f, -10.0f,
+      1e10f, 1e20f, 1e-10f, 1e-20f,
+      2.71828f, 3.14159f };
+  TestMarshall<float>(float_list, ABSL_ARRAYSIZE(float_list));
+  TestIntegral<float, int>(float_list, ABSL_ARRAYSIZE(float_list));
+  TestIntegral<float, unsigned>(float_list, ABSL_ARRAYSIZE(float_list));
+}
+
+TEST(BitCast, Double) {
+  static const double double_list[] =
+    { 0.0, 1.0, -1.0, 10.0, -10.0,
+      1e10, 1e100, 1e-10, 1e-100,
+      2.718281828459045,
+      3.141592653589793238462643383279502884197169399375105820974944 };
+  TestMarshall<double>(double_list, ABSL_ARRAYSIZE(double_list));
+  TestIntegral<double, int64_t>(double_list, ABSL_ARRAYSIZE(double_list));
+  TestIntegral<double, uint64_t>(double_list, ABSL_ARRAYSIZE(double_list));
+}
+
+}  // namespace
+}  // namespace absl