| /* |
| * 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 "include/core/SkTypes.h" |
| #include "include/private/SkChecksum.h" |
| #include "include/utils/SkRandom.h" |
| #include "src/core/SkOpts.h" |
| #include "tests/Test.h" |
| |
| DEF_TEST(Checksum, r) { |
| // 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(); |
| } |
| |
| // Hash of nullptr is always 0. |
| REPORTER_ASSERT(r, SkOpts::hash(nullptr, 0) == 0); |
| |
| const uint32_t hash = SkOpts::hash(data, kBytes); |
| // Should be deterministic. |
| REPORTER_ASSERT(r, hash == SkOpts::hash(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 = SkOpts::hash(tweaked, kBytes); |
| REPORTER_ASSERT(r, tweakedHash != hash); |
| REPORTER_ASSERT(r, tweakedHash == SkOpts::hash(tweaked, kBytes)); |
| tweaked[j] = saved; |
| } |
| } |
| |
| DEF_TEST(GoodHash, r) { |
| // 4 bytes --> hits SkChecksum::Mix fast path. |
| REPORTER_ASSERT(r, SkGoodHash()(( int32_t)4) == 614249093); |
| REPORTER_ASSERT(r, SkGoodHash()((uint32_t)4) == 614249093); |
| } |
| |
| DEF_TEST(ChecksumCollisions, r) { |
| // We noticed a few workloads that would cause hash collisions due to the way |
| // our optimized hashes split into three concurrent hashes and merge those hashes together. |
| // |
| // One of these two workloads ought to cause an unintentional hash collision on very similar |
| // data in those old algorithms, the float version on 32-bit x86 and double elsewhere. |
| { |
| float a[9] = { 0, 1, 2, |
| 3, 4, 5, |
| 6, 7, 8, }; |
| float b[9] = { 1, 2, 0, |
| 4, 5, 3, |
| 7, 8, 6, }; |
| |
| REPORTER_ASSERT(r, SkOpts::hash(a, sizeof(a)) != SkOpts::hash(b, sizeof(b))); |
| } |
| { |
| double a[9] = { 0, 1, 2, |
| 3, 4, 5, |
| 6, 7, 8, }; |
| double b[9] = { 1, 2, 0, |
| 4, 5, 3, |
| 7, 8, 6, }; |
| |
| REPORTER_ASSERT(r, SkOpts::hash(a, sizeof(a)) != SkOpts::hash(b, sizeof(b))); |
| } |
| } |
| |
| DEF_TEST(ChecksumConsistent, r) { |
| // We've decided to make SkOpts::hash() always return consistent results, so spot check a few: |
| uint8_t bytes[256]; |
| for (int i = 0; i < 256; i++) { |
| bytes[i] = i; |
| } |
| REPORTER_ASSERT(r, SkOpts::hash(bytes, 0) == 0x00000000, "%08x", SkOpts::hash(bytes, 0)); |
| REPORTER_ASSERT(r, SkOpts::hash(bytes, 1) == 0x00000000, "%08x", SkOpts::hash(bytes, 1)); |
| REPORTER_ASSERT(r, SkOpts::hash(bytes, 2) == 0xf26b8303, "%08x", SkOpts::hash(bytes, 2)); |
| REPORTER_ASSERT(r, SkOpts::hash(bytes, 7) == 0x18678721, "%08x", SkOpts::hash(bytes, 7)); |
| REPORTER_ASSERT(r, SkOpts::hash(bytes, 32) == 0x9d1ef96b, "%08x", SkOpts::hash(bytes, 32)); |
| REPORTER_ASSERT(r, SkOpts::hash(bytes, 63) == 0xc4b07d3a, "%08x", SkOpts::hash(bytes, 63)); |
| REPORTER_ASSERT(r, SkOpts::hash(bytes, 64) == 0x3535a461, "%08x", SkOpts::hash(bytes, 64)); |
| REPORTER_ASSERT(r, SkOpts::hash(bytes, 99) == 0x3f98a130, "%08x", SkOpts::hash(bytes, 99)); |
| REPORTER_ASSERT(r, SkOpts::hash(bytes,255) == 0x3b9ceab2, "%08x", SkOpts::hash(bytes,255)); |
| } |
| |
| DEF_TEST(ChecksumStrings, r) { |
| constexpr char kMessage[] = "Checksums are supported for SkString, string, and string_view."; |
| const uint32_t expectedHash = SkOpts::hash(kMessage, strlen(kMessage)); |
| |
| REPORTER_ASSERT(r, expectedHash == SkGoodHash()(SkString(kMessage))); |
| REPORTER_ASSERT(r, expectedHash == SkGoodHash()(std::string(kMessage))); |
| REPORTER_ASSERT(r, expectedHash == SkGoodHash()(std::string_view(kMessage))); |
| } |