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 "SkRandom.h" 10 #include "Test.h" 11 12 13 // Murmur3 has an optional third seed argument, so we wrap it to fit a uniform type. 14 static uint32_t murmur_noseed(const uint32_t* d, size_t l) { return SkChecksum::Murmur3(d, l); } 15 16 #define ASSERT(x) REPORTER_ASSERT(r, x) 17 18 DEF_TEST(Checksum, r) { 19 // Algorithms to test. They're currently all uint32_t(const uint32_t*, size_t). 20 typedef uint32_t(*algorithmProc)(const uint32_t*, size_t); 21 const algorithmProc kAlgorithms[] = { &murmur_noseed }; 22 23 // Put 128 random bytes into two identical buffers. Any multiple of 4 will do. 24 const size_t kBytes = SkAlign4(128); 25 SkRandom rand; 26 uint32_t data[kBytes/4], tweaked[kBytes/4]; 27 for (size_t i = 0; i < SK_ARRAY_COUNT(tweaked); ++i) { 28 data[i] = tweaked[i] = rand.nextU(); 29 } 30 31 // Test each algorithm. 32 for (size_t i = 0; i < SK_ARRAY_COUNT(kAlgorithms); ++i) { 33 const algorithmProc algorithm = kAlgorithms[i]; 34 35 // Hash of nullptr is always 0. 36 ASSERT(algorithm(nullptr, 0) == 0); 37 38 const uint32_t hash = algorithm(data, kBytes); 39 // Should be deterministic. 40 ASSERT(hash == algorithm(data, kBytes)); 41 42 // Changing any single element should change the hash. 43 for (size_t j = 0; j < SK_ARRAY_COUNT(tweaked); ++j) { 44 const uint32_t saved = tweaked[j]; 45 tweaked[j] = rand.nextU(); 46 const uint32_t tweakedHash = algorithm(tweaked, kBytes); 47 ASSERT(tweakedHash != hash); 48 ASSERT(tweakedHash == algorithm(tweaked, kBytes)); 49 tweaked[j] = saved; 50 } 51 } 52 } 53 54 DEF_TEST(GoodHash, r) { 55 ASSERT(SkGoodHash()(( int32_t)4) == 614249093); // 4 bytes. Hits SkChecksum::Mix fast path. 56 ASSERT(SkGoodHash()((uint32_t)4) == 614249093); // (Ditto) 57 58 // None of these are 4 byte sized, so they use SkChecksum::Murmur3, not SkChecksum::Mix. 59 ASSERT(SkGoodHash()((uint64_t)4) == 3491892518); 60 ASSERT(SkGoodHash()((uint16_t)4) == 899251846); 61 ASSERT(SkGoodHash()( (uint8_t)4) == 962700458); 62 63 // Tests SkString is correctly specialized. 64 ASSERT(SkGoodHash()(SkString("Hi")) == 55667557); 65 } 66
