1 /*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "SkChecksum.h"
9 #include "SkOpts.h"
10 #include "SkRandom.h"
11 #include "Test.h"
12
DEF_TEST(Checksum,r)13 DEF_TEST(Checksum, r) {
14 // Put 128 random bytes into two identical buffers. Any multiple of 4 will do.
15 const size_t kBytes = SkAlign4(128);
16 SkRandom rand;
17 uint32_t data[kBytes/4], tweaked[kBytes/4];
18 for (size_t i = 0; i < SK_ARRAY_COUNT(tweaked); ++i) {
19 data[i] = tweaked[i] = rand.nextU();
20 }
21
22 // Hash of nullptr is always 0.
23 REPORTER_ASSERT(r, SkOpts::hash(nullptr, 0) == 0);
24
25 const uint32_t hash = SkOpts::hash(data, kBytes);
26 // Should be deterministic.
27 REPORTER_ASSERT(r, hash == SkOpts::hash(data, kBytes));
28
29 // Changing any single element should change the hash.
30 for (size_t j = 0; j < SK_ARRAY_COUNT(tweaked); ++j) {
31 const uint32_t saved = tweaked[j];
32 tweaked[j] = rand.nextU();
33 const uint32_t tweakedHash = SkOpts::hash(tweaked, kBytes);
34 REPORTER_ASSERT(r, tweakedHash != hash);
35 REPORTER_ASSERT(r, tweakedHash == SkOpts::hash(tweaked, kBytes));
36 tweaked[j] = saved;
37 }
38 }
39
DEF_TEST(GoodHash,r)40 DEF_TEST(GoodHash, r) {
41 // 4 bytes --> hits SkChecksum::Mix fast path.
42 REPORTER_ASSERT(r, SkGoodHash()(( int32_t)4) == 614249093);
43 REPORTER_ASSERT(r, SkGoodHash()((uint32_t)4) == 614249093);
44 }
45