1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
// 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
//
// https://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
|
