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 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 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
