1 // Copyright 2014 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/hash/hash.h"
6
7 #include <string>
8 #include <vector>
9
10 #include "testing/gtest/include/gtest/gtest.h"
11
12 namespace base {
13
TEST(HashTest,DeprecatedHashFromString)14 TEST(HashTest, DeprecatedHashFromString) {
15 std::string str;
16 // Empty string (should hash to 0).
17 str = "";
18 EXPECT_EQ(0u, Hash(str));
19
20 // Simple test.
21 str = "hello world";
22 EXPECT_EQ(2794219650u, Hash(str));
23
24 // Change one bit.
25 str = "helmo world";
26 EXPECT_EQ(1006697176u, Hash(str));
27
28 // Insert a null byte.
29 str = "hello world";
30 str[5] = '\0';
31 EXPECT_EQ(2319902537u, Hash(str));
32
33 // Test that the bytes after the null contribute to the hash.
34 str = "hello worle";
35 str[5] = '\0';
36 EXPECT_EQ(553904462u, Hash(str));
37
38 // Extremely long string.
39 // Also tests strings with high bit set, and null byte.
40 std::vector<char> long_string_buffer;
41 for (int i = 0; i < 4096; ++i)
42 long_string_buffer.push_back((i % 256) - 128);
43 str.assign(&long_string_buffer.front(), long_string_buffer.size());
44 EXPECT_EQ(2797962408u, Hash(str));
45
46 // All possible lengths (mod 4). Tests separate code paths. Also test with
47 // final byte high bit set (regression test for http://crbug.com/90659).
48 // Note that the 1 and 3 cases have a weird bug where the final byte is
49 // treated as a signed char. It was decided on the above bug discussion to
50 // enshrine that behaviour as "correct" to avoid invalidating existing hashes.
51
52 // Length mod 4 == 0.
53 str = "hello w\xab";
54 EXPECT_EQ(615571198u, Hash(str));
55 // Length mod 4 == 1.
56 str = "hello wo\xab";
57 EXPECT_EQ(623474296u, Hash(str));
58 // Length mod 4 == 2.
59 str = "hello wor\xab";
60 EXPECT_EQ(4278562408u, Hash(str));
61 // Length mod 4 == 3.
62 str = "hello worl\xab";
63 EXPECT_EQ(3224633008u, Hash(str));
64 }
65
TEST(HashTest,DeprecatedHashFromCString)66 TEST(HashTest, DeprecatedHashFromCString) {
67 const char* str;
68 // Empty string (should hash to 0).
69 str = "";
70 EXPECT_EQ(0u, Hash(str));
71
72 // Simple test.
73 str = "hello world";
74 EXPECT_EQ(2794219650u, Hash(str));
75 }
76
TEST(HashTest,PersistentHashFromSpan)77 TEST(HashTest, PersistentHashFromSpan) {
78 // Empty span (should hash to 0).
79 EXPECT_EQ(0u, PersistentHash(base::span<const uint8_t>()));
80
81 // Simple test.
82 const char* str = "hello world";
83 EXPECT_EQ(2794219650u, PersistentHash(as_byte_span(std::string(str))));
84 }
85
TEST(HashTest,FastHash)86 TEST(HashTest, FastHash) {
87 std::string s;
88 constexpr char kEmptyString[] = "";
89 EXPECT_EQ(FastHash(s), FastHash(kEmptyString));
90 }
91
92 } // namespace base
93