1 /*
2  * Copyright (C) 2013 Apple Inc. All rights reserved.
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5  * modification, are permitted provided that the following conditions
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9  * 2. Redistributions in binary form must reproduce the above copyright
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11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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25 
26 #include "third_party/blink/renderer/platform/wtf/text/string_hasher.h"
27 
28 #include "testing/gtest/include/gtest/gtest.h"
29 
30 namespace WTF {
31 
32 namespace {
33 
34 const LChar kNullLChars[2] = {0, 0};
35 const UChar kNullUChars[2] = {0, 0};
36 
37 const unsigned kEmptyStringHash = 0x4EC889EU;
38 const unsigned kSingleNullCharacterHash = 0x3D3ABF44U;
39 
40 const LChar kTestALChars[6] = {0x41, 0x95, 0xFF, 0x50, 0x01, 0};
41 const UChar kTestAUChars[6] = {0x41, 0x95, 0xFF, 0x50, 0x01, 0};
42 const UChar kTestBUChars[6] = {0x41, 0x95, 0xFFFF, 0x1080, 0x01, 0};
43 
44 const unsigned kTestAHash1 = 0xEA32B004;
45 const unsigned kTestAHash2 = 0x93F0F71E;
46 const unsigned kTestAHash3 = 0xCB609EB1;
47 const unsigned kTestAHash4 = 0x7984A706;
48 const unsigned kTestAHash5 = 0x0427561F;
49 
50 const unsigned kTestBHash1 = 0xEA32B004;
51 const unsigned kTestBHash2 = 0x93F0F71E;
52 const unsigned kTestBHash3 = 0x59EB1B2C;
53 const unsigned kTestBHash4 = 0xA7BCCC0A;
54 const unsigned kTestBHash5 = 0x79201649;
55 
56 }  // anonymous namespace
57 
TEST(StringHasherTest,StringHasher)58 TEST(StringHasherTest, StringHasher) {
59   StringHasher hasher;
60 
61   // The initial state of the hasher.
62   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
63   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
64 }
65 
TEST(StringHasherTest,StringHasher_addCharacter)66 TEST(StringHasherTest, StringHasher_addCharacter) {
67   StringHasher hasher;
68 
69   // Hashing a single character.
70   hasher = StringHasher();
71   hasher.AddCharacter(0);
72   EXPECT_EQ(kSingleNullCharacterHash, hasher.GetHash());
73   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
74             hasher.HashWithTop8BitsMasked());
75 
76   // Hashing five characters, checking the intermediate state after each is
77   // added.
78   hasher = StringHasher();
79   hasher.AddCharacter(kTestAUChars[0]);
80   EXPECT_EQ(kTestAHash1, hasher.GetHash());
81   EXPECT_EQ(kTestAHash1 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
82   hasher.AddCharacter(kTestAUChars[1]);
83   EXPECT_EQ(kTestAHash2, hasher.GetHash());
84   EXPECT_EQ(kTestAHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
85   hasher.AddCharacter(kTestAUChars[2]);
86   EXPECT_EQ(kTestAHash3, hasher.GetHash());
87   EXPECT_EQ(kTestAHash3 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
88   hasher.AddCharacter(kTestAUChars[3]);
89   EXPECT_EQ(kTestAHash4, hasher.GetHash());
90   EXPECT_EQ(kTestAHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
91   hasher.AddCharacter(kTestAUChars[4]);
92   EXPECT_EQ(kTestAHash5, hasher.GetHash());
93   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
94 
95   // Hashing a second set of five characters, including non-Latin-1 characters.
96   hasher = StringHasher();
97   hasher.AddCharacter(kTestBUChars[0]);
98   EXPECT_EQ(kTestBHash1, hasher.GetHash());
99   EXPECT_EQ(kTestBHash1 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
100   hasher.AddCharacter(kTestBUChars[1]);
101   EXPECT_EQ(kTestBHash2, hasher.GetHash());
102   EXPECT_EQ(kTestBHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
103   hasher.AddCharacter(kTestBUChars[2]);
104   EXPECT_EQ(kTestBHash3, hasher.GetHash());
105   EXPECT_EQ(kTestBHash3 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
106   hasher.AddCharacter(kTestBUChars[3]);
107   EXPECT_EQ(kTestBHash4, hasher.GetHash());
108   EXPECT_EQ(kTestBHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
109   hasher.AddCharacter(kTestBUChars[4]);
110   EXPECT_EQ(kTestBHash5, hasher.GetHash());
111   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
112 }
113 
TEST(StringHasherTest,StringHasher_addCharacters)114 TEST(StringHasherTest, StringHasher_addCharacters) {
115   StringHasher hasher;
116 
117   // Hashing zero characters.
118   hasher = StringHasher();
119   hasher.AddCharacters(static_cast<LChar*>(nullptr), 0);
120   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
121   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
122   hasher = StringHasher();
123   hasher.AddCharacters(kNullLChars, 0);
124   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
125   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
126   hasher = StringHasher();
127   hasher.AddCharacters(static_cast<UChar*>(nullptr), 0);
128   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
129   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
130   hasher = StringHasher();
131   hasher.AddCharacters(kNullUChars, 0);
132   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
133   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
134 
135   // Hashing one character.
136   hasher = StringHasher();
137   hasher.AddCharacters(kNullLChars, 1);
138   EXPECT_EQ(kSingleNullCharacterHash, hasher.GetHash());
139   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
140             hasher.HashWithTop8BitsMasked());
141   hasher = StringHasher();
142   hasher.AddCharacters(kNullUChars, 1);
143   EXPECT_EQ(kSingleNullCharacterHash, hasher.GetHash());
144   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
145             hasher.HashWithTop8BitsMasked());
146 
147   // Hashing five characters, all at once.
148   hasher = StringHasher();
149   hasher.AddCharacters(kTestALChars, 5);
150   EXPECT_EQ(kTestAHash5, hasher.GetHash());
151   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
152   hasher = StringHasher();
153   hasher.AddCharacters(kTestAUChars, 5);
154   EXPECT_EQ(kTestAHash5, hasher.GetHash());
155   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
156   hasher = StringHasher();
157   hasher.AddCharacters(kTestBUChars, 5);
158   EXPECT_EQ(kTestBHash5, hasher.GetHash());
159   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
160 
161   // Hashing five characters, in groups of two, then the last one.
162   hasher = StringHasher();
163   hasher.AddCharacters(kTestALChars, 2);
164   EXPECT_EQ(kTestAHash2, hasher.GetHash());
165   EXPECT_EQ(kTestAHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
166   hasher.AddCharacters(kTestALChars + 2, 2);
167   EXPECT_EQ(kTestAHash4, hasher.GetHash());
168   EXPECT_EQ(kTestAHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
169   hasher.AddCharacters(kTestALChars + 4, 1);
170   EXPECT_EQ(kTestAHash5, hasher.GetHash());
171   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
172   hasher = StringHasher();
173   hasher.AddCharacters(kTestALChars, 2);
174   hasher.AddCharacters(kTestALChars + 2, 2);
175   hasher.AddCharacters(kTestALChars + 4, 1);
176   EXPECT_EQ(kTestAHash5, hasher.GetHash());
177   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
178   hasher = StringHasher();
179   hasher.AddCharacters(kTestAUChars, 2);
180   EXPECT_EQ(kTestAHash2, hasher.GetHash());
181   EXPECT_EQ(kTestAHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
182   hasher.AddCharacters(kTestAUChars + 2, 2);
183   EXPECT_EQ(kTestAHash4, hasher.GetHash());
184   EXPECT_EQ(kTestAHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
185   hasher.AddCharacters(kTestAUChars + 4, 1);
186   EXPECT_EQ(kTestAHash5, hasher.GetHash());
187   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
188   hasher = StringHasher();
189   hasher.AddCharacters(kTestAUChars, 2);
190   hasher.AddCharacters(kTestAUChars + 2, 2);
191   hasher.AddCharacters(kTestAUChars + 4, 1);
192   EXPECT_EQ(kTestAHash5, hasher.GetHash());
193   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
194   hasher = StringHasher();
195   hasher.AddCharacters(kTestBUChars, 2);
196   EXPECT_EQ(kTestBHash2, hasher.GetHash());
197   EXPECT_EQ(kTestBHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
198   hasher.AddCharacters(kTestBUChars + 2, 2);
199   EXPECT_EQ(kTestBHash4, hasher.GetHash());
200   EXPECT_EQ(kTestBHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
201   hasher.AddCharacters(kTestBUChars + 4, 1);
202   EXPECT_EQ(kTestBHash5, hasher.GetHash());
203   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
204   hasher = StringHasher();
205   hasher.AddCharacters(kTestBUChars, 2);
206   hasher.AddCharacters(kTestBUChars + 2, 2);
207   hasher.AddCharacters(kTestBUChars + 4, 1);
208   EXPECT_EQ(kTestBHash5, hasher.GetHash());
209   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
210 
211   // Hashing five characters, the first three, then the last two.
212   hasher = StringHasher();
213   hasher.AddCharacters(kTestALChars, 3);
214   EXPECT_EQ(kTestAHash3, hasher.GetHash());
215   EXPECT_EQ(kTestAHash3 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
216   hasher.AddCharacters(kTestALChars + 3, 2);
217   EXPECT_EQ(kTestAHash5, hasher.GetHash());
218   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
219   hasher = StringHasher();
220   hasher.AddCharacters(kTestALChars, 3);
221   EXPECT_EQ(kTestAHash3, hasher.GetHash());
222   EXPECT_EQ(kTestAHash3 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
223   hasher.AddCharacters(kTestALChars + 3, 2);
224   EXPECT_EQ(kTestAHash5, hasher.GetHash());
225   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
226   hasher = StringHasher();
227   hasher.AddCharacters(kTestAUChars, 3);
228   EXPECT_EQ(kTestAHash3, hasher.GetHash());
229   EXPECT_EQ(kTestAHash3 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
230   hasher.AddCharacters(kTestAUChars + 3, 2);
231   EXPECT_EQ(kTestAHash5, hasher.GetHash());
232   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
233   hasher = StringHasher();
234   hasher.AddCharacters(kTestAUChars, 3);
235   EXPECT_EQ(kTestAHash3, hasher.GetHash());
236   EXPECT_EQ(kTestAHash3 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
237   hasher.AddCharacters(kTestAUChars + 3, 2);
238   EXPECT_EQ(kTestAHash5, hasher.GetHash());
239   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
240   hasher = StringHasher();
241   hasher.AddCharacters(kTestBUChars, 3);
242   EXPECT_EQ(kTestBHash3, hasher.GetHash());
243   EXPECT_EQ(kTestBHash3 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
244   hasher.AddCharacters(kTestBUChars + 3, 2);
245   EXPECT_EQ(kTestBHash5, hasher.GetHash());
246   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
247   hasher = StringHasher();
248   hasher.AddCharacters(kTestBUChars, 3);
249   hasher.AddCharacters(kTestBUChars + 3, 2);
250   EXPECT_EQ(kTestBHash5, hasher.GetHash());
251   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
252 }
253 
TEST(StringHasherTest,StringHasher_addCharactersAssumingAligned)254 TEST(StringHasherTest, StringHasher_addCharactersAssumingAligned) {
255   StringHasher hasher;
256 
257   // Hashing zero characters.
258   hasher = StringHasher();
259   hasher.AddCharactersAssumingAligned(static_cast<LChar*>(nullptr), 0);
260   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
261   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
262   hasher = StringHasher();
263   hasher.AddCharactersAssumingAligned(kNullLChars, 0);
264   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
265   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
266   hasher = StringHasher();
267   hasher.AddCharactersAssumingAligned(static_cast<UChar*>(nullptr), 0);
268   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
269   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
270   hasher = StringHasher();
271   hasher.AddCharactersAssumingAligned(kNullUChars, 0);
272   EXPECT_EQ(kEmptyStringHash, hasher.GetHash());
273   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
274 
275   // Hashing one character.
276   hasher = StringHasher();
277   hasher.AddCharactersAssumingAligned(kNullLChars, 1);
278   EXPECT_EQ(kSingleNullCharacterHash, hasher.GetHash());
279   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
280             hasher.HashWithTop8BitsMasked());
281   hasher = StringHasher();
282   hasher.AddCharactersAssumingAligned(kNullUChars, 1);
283   EXPECT_EQ(kSingleNullCharacterHash, hasher.GetHash());
284   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
285             hasher.HashWithTop8BitsMasked());
286 
287   // Hashing five characters, all at once.
288   hasher = StringHasher();
289   hasher.AddCharactersAssumingAligned(kTestALChars, 5);
290   EXPECT_EQ(kTestAHash5, hasher.GetHash());
291   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
292   hasher = StringHasher();
293   hasher.AddCharactersAssumingAligned(kTestAUChars, 5);
294   EXPECT_EQ(kTestAHash5, hasher.GetHash());
295   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
296   hasher = StringHasher();
297   hasher.AddCharactersAssumingAligned(kTestBUChars, 5);
298   EXPECT_EQ(kTestBHash5, hasher.GetHash());
299   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
300 
301   // Hashing five characters, in groups of two, then the last one.
302   hasher = StringHasher();
303   hasher.AddCharactersAssumingAligned(kTestALChars, 2);
304   EXPECT_EQ(kTestAHash2, hasher.GetHash());
305   EXPECT_EQ(kTestAHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
306   hasher.AddCharactersAssumingAligned(kTestALChars + 2, 2);
307   EXPECT_EQ(kTestAHash4, hasher.GetHash());
308   EXPECT_EQ(kTestAHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
309   hasher.AddCharactersAssumingAligned(kTestALChars + 4, 1);
310   EXPECT_EQ(kTestAHash5, hasher.GetHash());
311   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
312   hasher = StringHasher();
313   hasher.AddCharactersAssumingAligned(kTestALChars, 2);
314   hasher.AddCharactersAssumingAligned(kTestALChars + 2, 2);
315   hasher.AddCharactersAssumingAligned(kTestALChars + 4, 1);
316   EXPECT_EQ(kTestAHash5, hasher.GetHash());
317   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
318   hasher = StringHasher();
319   hasher.AddCharactersAssumingAligned(kTestAUChars, 2);
320   EXPECT_EQ(kTestAHash2, hasher.GetHash());
321   EXPECT_EQ(kTestAHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
322   hasher.AddCharactersAssumingAligned(kTestAUChars + 2, 2);
323   EXPECT_EQ(kTestAHash4, hasher.GetHash());
324   EXPECT_EQ(kTestAHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
325   hasher.AddCharactersAssumingAligned(kTestAUChars + 4, 1);
326   EXPECT_EQ(kTestAHash5, hasher.GetHash());
327   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
328   hasher = StringHasher();
329   hasher.AddCharactersAssumingAligned(kTestAUChars, 2);
330   hasher.AddCharactersAssumingAligned(kTestAUChars + 2, 2);
331   hasher.AddCharactersAssumingAligned(kTestAUChars + 4, 1);
332   EXPECT_EQ(kTestAHash5, hasher.GetHash());
333   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
334   hasher = StringHasher();
335   hasher.AddCharactersAssumingAligned(kTestBUChars, 2);
336   EXPECT_EQ(kTestBHash2, hasher.GetHash());
337   EXPECT_EQ(kTestBHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
338   hasher.AddCharactersAssumingAligned(kTestBUChars + 2, 2);
339   EXPECT_EQ(kTestBHash4, hasher.GetHash());
340   EXPECT_EQ(kTestBHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
341   hasher.AddCharactersAssumingAligned(kTestBUChars + 4, 1);
342   EXPECT_EQ(kTestBHash5, hasher.GetHash());
343   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
344   hasher = StringHasher();
345   hasher.AddCharactersAssumingAligned(kTestBUChars, 2);
346   hasher.AddCharactersAssumingAligned(kTestBUChars + 2, 2);
347   hasher.AddCharactersAssumingAligned(kTestBUChars + 4, 1);
348   EXPECT_EQ(kTestBHash5, hasher.GetHash());
349   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
350 
351   // Hashing five characters, first two characters one at a time,
352   // then two more, then the last one.
353   hasher = StringHasher();
354   hasher.AddCharacter(kTestBUChars[0]);
355   EXPECT_EQ(kTestBHash1, hasher.GetHash());
356   EXPECT_EQ(kTestBHash1 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
357   hasher.AddCharacter(kTestBUChars[1]);
358   EXPECT_EQ(kTestBHash2, hasher.GetHash());
359   EXPECT_EQ(kTestBHash2 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
360   hasher.AddCharactersAssumingAligned(kTestBUChars[2], kTestBUChars[3]);
361   EXPECT_EQ(kTestBHash4, hasher.GetHash());
362   EXPECT_EQ(kTestBHash4 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
363   hasher.AddCharactersAssumingAligned(kTestBUChars + 4, 1);
364   EXPECT_EQ(kTestBHash5, hasher.GetHash());
365   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, hasher.HashWithTop8BitsMasked());
366 }
367 
TEST(StringHasherTest,StringHasher_computeHash)368 TEST(StringHasherTest, StringHasher_computeHash) {
369   EXPECT_EQ(kEmptyStringHash,
370             StringHasher::ComputeHash(static_cast<LChar*>(nullptr), 0));
371   EXPECT_EQ(kEmptyStringHash, StringHasher::ComputeHash(kNullLChars, 0));
372   EXPECT_EQ(kEmptyStringHash,
373             StringHasher::ComputeHash(static_cast<UChar*>(nullptr), 0));
374   EXPECT_EQ(kEmptyStringHash, StringHasher::ComputeHash(kNullUChars, 0));
375 
376   EXPECT_EQ(kSingleNullCharacterHash,
377             StringHasher::ComputeHash(kNullLChars, 1));
378   EXPECT_EQ(kSingleNullCharacterHash,
379             StringHasher::ComputeHash(kNullUChars, 1));
380 
381   EXPECT_EQ(kTestAHash5, StringHasher::ComputeHash(kTestALChars, 5));
382   EXPECT_EQ(kTestAHash5, StringHasher::ComputeHash(kTestAUChars, 5));
383   EXPECT_EQ(kTestBHash5, StringHasher::ComputeHash(kTestBUChars, 5));
384 }
385 
TEST(StringHasherTest,StringHasher_computeHashAndMaskTop8Bits)386 TEST(StringHasherTest, StringHasher_computeHashAndMaskTop8Bits) {
387   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF,
388             StringHasher::ComputeHashAndMaskTop8Bits(
389                 static_cast<LChar*>(nullptr), 0));
390   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF,
391             StringHasher::ComputeHashAndMaskTop8Bits(kNullLChars, 0));
392   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF,
393             StringHasher::ComputeHashAndMaskTop8Bits(
394                 static_cast<UChar*>(nullptr), 0));
395   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF,
396             StringHasher::ComputeHashAndMaskTop8Bits(kNullUChars, 0));
397 
398   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
399             StringHasher::ComputeHashAndMaskTop8Bits(kNullLChars, 1));
400   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
401             StringHasher::ComputeHashAndMaskTop8Bits(kNullUChars, 1));
402 
403   EXPECT_EQ(kTestAHash5 & 0xFFFFFF,
404             StringHasher::ComputeHashAndMaskTop8Bits(kTestALChars, 5));
405   EXPECT_EQ(kTestAHash5 & 0xFFFFFF,
406             StringHasher::ComputeHashAndMaskTop8Bits(kTestAUChars, 5));
407   EXPECT_EQ(kTestBHash5 & 0xFFFFFF,
408             StringHasher::ComputeHashAndMaskTop8Bits(kTestBUChars, 5));
409 }
410 
TEST(StringHasherTest,StringHasher_hashMemory)411 TEST(StringHasherTest, StringHasher_hashMemory) {
412   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, StringHasher::HashMemory(nullptr, 0));
413   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF,
414             StringHasher::HashMemory(kNullUChars, 0));
415   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF, StringHasher::HashMemory<0>(nullptr));
416   EXPECT_EQ(kEmptyStringHash & 0xFFFFFF,
417             StringHasher::HashMemory<0>(kNullUChars));
418 
419   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
420             StringHasher::HashMemory(kNullUChars, 2));
421   EXPECT_EQ(kSingleNullCharacterHash & 0xFFFFFF,
422             StringHasher::HashMemory<2>(kNullUChars));
423 
424   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, StringHasher::HashMemory(kTestAUChars, 10));
425   EXPECT_EQ(kTestAHash5 & 0xFFFFFF, StringHasher::HashMemory<10>(kTestAUChars));
426   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, StringHasher::HashMemory(kTestBUChars, 10));
427   EXPECT_EQ(kTestBHash5 & 0xFFFFFF, StringHasher::HashMemory<10>(kTestBUChars));
428 }
429 
430 }  // namespace WTF
431