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
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
|
// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/zucchini/patch_utils.h"
#include <stdint.h>
#include <iterator>
#include <vector>
#include "testing/gtest/include/gtest/gtest.h"
namespace zucchini {
constexpr int RADIUS = 4;
template <class T, class EncodeFunc, class DecodeFunc>
void TestEncodeDecodeImpl(const std::vector<T>& centers,
EncodeFunc encode_func,
DecodeFunc decode_func) {
std::vector<uint8_t> buffer;
std::vector<T> values;
for (T center : centers) {
// Test the neighborhood values |centers|.
T start = center - RADIUS;
for (int inc = 0; inc <= (RADIUS * 2); ++inc) {
T value = start + inc;
encode_func(value, std::back_inserter(buffer));
values.push_back(value);
}
}
auto it = buffer.begin();
for (T expected : values) {
T value = T(-1); // Fill with 1-bits to ensure proper overwrite.
auto res = decode_func(it, buffer.end(), &value);
EXPECT_NE(0, res);
EXPECT_EQ(expected, value);
it += res;
}
EXPECT_EQ(it, buffer.end());
T value = T(-1);
auto res = decode_func(it, buffer.end(), &value);
EXPECT_EQ(0, res);
EXPECT_EQ(T(-1), value);
}
template <class T>
void TestEncodeDecodeVarUInt(const std::vector<T>& centers) {
TestEncodeDecodeImpl<T>(
centers, [](T value, auto dst) { return EncodeVarUInt<T>(value, dst); },
[](auto first, auto last, T* value) {
return DecodeVarUInt<T>(first, last, value);
});
}
template <class T>
void TestEncodeDecodeVarInt(const std::vector<T>& centers) {
TestEncodeDecodeImpl<T>(
centers, [](T value, auto dst) { return EncodeVarInt<T>(value, dst); },
[](auto first, auto last, T* value) {
return DecodeVarInt<T>(first, last, value);
});
}
template <class T>
void PushPowersOf2AndNegations(int lo_bit,
int hi_bit,
T subtract_from,
std::vector<T>* out) {
for (int bit = lo_bit; bit <= hi_bit; ++bit) {
T v = static_cast<T>(1) << bit;
DCHECK_GT(v, static_cast<T>(RADIUS));
out->push_back(v);
out->push_back(subtract_from - v);
}
}
// "Center" values of EncodeDecode*() tests are chosen to avoid underflow /
// overflow when shifted by [-RADIUS, RADIUS].
TEST(PatchUtilsTest, EncodeDecodeVarUInt32) {
std::vector<uint32_t> centers = {RADIUS, UINT32_MAX - RADIUS};
PushPowersOf2AndNegations<uint32_t>(3, 30, UINT32_MAX, ¢ers);
centers.push_back(UINT32_MAX >> 1);
TestEncodeDecodeVarUInt<uint32_t>(centers);
}
TEST(PatchUtilsTest, EncodeDecodeVarInt32) {
std::vector<int32_t> centers = {RADIUS, -1 - RADIUS};
PushPowersOf2AndNegations<int32_t>(3, 30, 0, ¢ers);
centers.push_back(INT32_MIN + RADIUS);
centers.push_back(INT32_MAX - RADIUS);
TestEncodeDecodeVarInt<int32_t>(centers);
}
TEST(PatchUtilsTest, EncodeDecodeVarUInt64) {
std::vector<uint64_t> centers = {RADIUS, UINT64_MAX - RADIUS};
PushPowersOf2AndNegations<uint64_t>(3, 62, UINT64_MAX, ¢ers);
centers.push_back(UINT64_MAX >> 1);
TestEncodeDecodeVarUInt<uint64_t>(centers);
}
TEST(PatchUtilsTest, EncodeDecodeVarInt64) {
std::vector<int64_t> centers = {RADIUS, -1LL - RADIUS};
PushPowersOf2AndNegations<int64_t>(3, 62, 0LL, ¢ers);
centers.push_back(INT64_MIN + RADIUS);
centers.push_back(INT64_MAX - RADIUS);
TestEncodeDecodeVarInt<int64_t>(centers);
}
TEST(PatchUtilsTest, DecodeVarUInt32Malformed) {
constexpr uint32_t kUninit = static_cast<uint32_t>(-1LL);
// Output variable to ensure that on failure, the output variable is not
// written to.
uint32_t value = uint32_t(-1);
auto TestDecodeVarInt = [&value](const std::vector<uint8_t>& buffer) {
value = kUninit;
return DecodeVarUInt(buffer.begin(), buffer.end(), &value);
};
// Exhausted.
EXPECT_EQ(0, TestDecodeVarInt(std::vector<uint8_t>{}));
EXPECT_EQ(kUninit, value);
EXPECT_EQ(0, TestDecodeVarInt(std::vector<uint8_t>(4, 128)));
EXPECT_EQ(kUninit, value);
// Overflow.
EXPECT_EQ(0, TestDecodeVarInt(std::vector<uint8_t>(6, 128)));
EXPECT_EQ(kUninit, value);
EXPECT_EQ(0, TestDecodeVarInt({128, 128, 128, 128, 128, 42}));
EXPECT_EQ(kUninit, value);
// Following are pathological cases that are not handled for simplicity,
// hence decoding is expected to be successful.
EXPECT_NE(0, TestDecodeVarInt({128, 128, 128, 128, 16}));
EXPECT_EQ(uint32_t(0), value);
EXPECT_NE(0, TestDecodeVarInt({128, 128, 128, 128, 32}));
EXPECT_EQ(uint32_t(0), value);
EXPECT_NE(0, TestDecodeVarInt({128, 128, 128, 128, 64}));
EXPECT_EQ(uint32_t(0), value);
}
TEST(PatchUtilsTest, DecodeVarUInt64Malformed) {
constexpr uint64_t kUninit = static_cast<uint64_t>(-1);
uint64_t value = kUninit;
auto TestDecodeVarInt = [&value](const std::vector<uint8_t>& buffer) {
value = kUninit;
return DecodeVarUInt(buffer.begin(), buffer.end(), &value);
};
// Exhausted.
EXPECT_EQ(0, TestDecodeVarInt(std::vector<uint8_t>{}));
EXPECT_EQ(kUninit, value);
EXPECT_EQ(0, TestDecodeVarInt(std::vector<uint8_t>(9, 128)));
EXPECT_EQ(kUninit, value);
// Overflow.
EXPECT_EQ(0, TestDecodeVarInt(std::vector<uint8_t>(10, 128)));
EXPECT_EQ(kUninit, value);
EXPECT_EQ(0, TestDecodeVarInt(
{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 42}));
EXPECT_EQ(kUninit, value);
}
} // namespace zucchini
|
