| // Copyright 2018 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "components/variations/variations_murmur_hash.h" |
| |
| #include <limits> |
| #include <vector> |
| |
| #include "build/build_config.h" |
| #include "testing/gtest/include/gtest/gtest.h" |
| #include "third_party/smhasher/src/MurmurHash3.h" |
| |
| namespace variations { |
| namespace internal { |
| |
| TEST(VariationsMurmurHashTest, StringToLE32) { |
| EXPECT_EQ(std::vector<uint32_t>(), |
| VariationsMurmurHash::StringToLE32("")); |
| EXPECT_EQ(std::vector<uint32_t>({0x00000061}), |
| VariationsMurmurHash::StringToLE32("a")); |
| EXPECT_EQ(std::vector<uint32_t>({0x00006261}), |
| VariationsMurmurHash::StringToLE32("ab")); |
| EXPECT_EQ(std::vector<uint32_t>({0x00636261}), |
| VariationsMurmurHash::StringToLE32("abc")); |
| EXPECT_EQ(std::vector<uint32_t>({0x64636261}), |
| VariationsMurmurHash::StringToLE32("abcd")); |
| EXPECT_EQ(std::vector<uint32_t>({0x64636261, 0x00000065}), |
| VariationsMurmurHash::StringToLE32("abcde")); |
| EXPECT_EQ(std::vector<uint32_t>({0x64636261, 0x00006665}), |
| VariationsMurmurHash::StringToLE32("abcdef")); |
| } |
| |
| // The tests inside this #if compare VariationsMurmurHash to the reference |
| // implementation, MurmurHash3_x86_32, which only works on little-endian. |
| #if defined(ARCH_CPU_LITTLE_ENDIAN) |
| |
| // Compare VariationsMurmurHash::Hash to MurmurHash3_x86_32 for every prefix of |
| // |data|, from the empty string to all of |data|. |
| TEST(VariationsMurmurHashTest, Hash) { |
| // Random bytes generated manually and hard-coded for reproducability |
| const std::vector<uint32_t> data({ |
| 2704264845, 2929902289, 1679431515, 1427187834, 1300338468, |
| 576307953, 1209988079, 1918627109, 3926412991, 74087765}); |
| |
| size_t max_size = data.size() * sizeof(uint32_t); |
| for (size_t size = 0; size <= max_size; size++) { |
| uint32_t expected; |
| MurmurHash3_x86_32(data.data(), size, /*seed=*/0, &expected); |
| EXPECT_EQ(expected, VariationsMurmurHash::Hash(data, size)) |
| << "size=" << size; |
| } |
| } |
| |
| TEST(VariationsMurmurHashTest, Hash16) { |
| // Pick some likely edge case values. |
| constexpr uint32_t max32 = std::numeric_limits<uint32_t>::max(); |
| uint32_t seeds[] = { |
| 0, max32 / 2 - 1, max32 - 2, |
| 1, max32 / 2, max32 - 1, |
| 2, max32 / 2 + 1, max32}; |
| |
| constexpr uint16_t max16 = std::numeric_limits<uint16_t>::max(); |
| uint16_t data[] = { |
| 0, max16 / 2 - 1, max16 - 2, |
| 1, max16 / 2, max16 - 1, |
| 2, max16 / 2 + 1, max16}; |
| |
| for (uint32_t seed : seeds) { |
| for (uint16_t datum : data) { |
| uint32_t expected; |
| MurmurHash3_x86_32(&datum, sizeof(datum), seed, &expected); |
| EXPECT_EQ(expected, VariationsMurmurHash::Hash16(seed, datum)) |
| << "seed=" << seed << ", datum=" << datum; |
| } |
| } |
| } |
| |
| #endif // defined(ARCH_CPU_LITTLE_ENDIAN) |
| |
| } // namespace internal |
| } // namespace variations |