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