| /* |
| * Copyright 2012 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "SkChecksum.h" |
| #include "SkRandom.h" |
| #include "Test.h" |
| |
| |
| // Murmur3 has an optional third seed argument, so we wrap it to fit a uniform type. |
| static uint32_t murmur_noseed(const SkChecksum::FourByteAligned* d, size_t l) { |
| return SkChecksum::Murmur3(d, l); |
| } |
| |
| #define ASSERT(x) REPORTER_ASSERT(r, x) |
| |
| DEF_TEST(Checksum, r) { |
| // Algorithms to test. They're currently all uint32_t(const uint32_t*, size_t). |
| typedef uint32_t(*algorithmProc)(const SkChecksum::FourByteAligned*, size_t); |
| const algorithmProc kAlgorithms[] = { &SkChecksum::Compute, &murmur_noseed }; |
| |
| // Put 128 random bytes into two identical buffers. Any multiple of 4 will do. |
| const size_t kBytes = SkAlign4(128); |
| SkRandom rand; |
| uint32_t data[kBytes/4], tweaked[kBytes/4]; |
| for (size_t i = 0; i < SK_ARRAY_COUNT(tweaked); ++i) { |
| data[i] = tweaked[i] = rand.nextU(); |
| } |
| |
| // Test each algorithm. |
| for (size_t i = 0; i < SK_ARRAY_COUNT(kAlgorithms); ++i) { |
| const algorithmProc algorithm = kAlgorithms[i]; |
| |
| // Hash of NULL is always 0. |
| ASSERT(algorithm(NULL, 0) == 0); |
| |
| const uint32_t hash = algorithm(data, kBytes); |
| // Should be deterministic. |
| ASSERT(hash == algorithm(data, kBytes)); |
| |
| // Changing any single element should change the hash. |
| for (size_t j = 0; j < SK_ARRAY_COUNT(tweaked); ++j) { |
| const uint32_t saved = tweaked[j]; |
| tweaked[j] = rand.nextU(); |
| const uint32_t tweakedHash = algorithm(tweaked, kBytes); |
| ASSERT(tweakedHash != hash); |
| ASSERT(tweakedHash == algorithm(tweaked, kBytes)); |
| tweaked[j] = saved; |
| } |
| } |
| } |