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Diffstat (limited to 'absl/crc/crc32c_test.cc')
| -rw-r--r-- | absl/crc/crc32c_test.cc | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/absl/crc/crc32c_test.cc b/absl/crc/crc32c_test.cc new file mode 100644 index 00000000..98e5fea3 --- /dev/null +++ b/absl/crc/crc32c_test.cc @@ -0,0 +1,186 @@ +// Copyright 2022 The Abseil Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// https://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +#include "absl/crc/crc32c.h" + +#include <algorithm> +#include <cstdint> +#include <cstring> +#include <string> + +#include "gtest/gtest.h" +#include "absl/crc/internal/crc32c.h" +#include "absl/strings/str_cat.h" +#include "absl/strings/string_view.h" + +namespace { + +TEST(CRC32C, RFC3720) { + // Test the results of the vectors from + // https://www.rfc-editor.org/rfc/rfc3720#appendix-B.4 + char data[32]; + + // 32 bytes of ones. + memset(data, 0, sizeof(data)); + EXPECT_EQ(absl::ComputeCrc32c(absl::string_view(data, sizeof(data))), + absl::ToCrc32c(0x8a9136aa)); + + // 32 bytes of ones. + memset(data, 0xff, sizeof(data)); + EXPECT_EQ(absl::ComputeCrc32c(absl::string_view(data, sizeof(data))), + absl::ToCrc32c(0x62a8ab43)); + + // 32 incrementing bytes. + for (int i = 0; i < 32; ++i) data[i] = static_cast<char>(i); + EXPECT_EQ(absl::ComputeCrc32c(absl::string_view(data, sizeof(data))), + absl::ToCrc32c(0x46dd794e)); + + // 32 decrementing bytes. + for (int i = 0; i < 32; ++i) data[i] = static_cast<char>(31 - i); + EXPECT_EQ(absl::ComputeCrc32c(absl::string_view(data, sizeof(data))), + absl::ToCrc32c(0x113fdb5c)); + + // An iSCSI - SCSI Read (10) Command PDU. + constexpr uint8_t cmd[48] = { + 0x01, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, + 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x18, 0x28, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + }; + EXPECT_EQ(absl::ComputeCrc32c(absl::string_view( + reinterpret_cast<const char*>(cmd), sizeof(cmd))), + absl::ToCrc32c(0xd9963a56)); +} + +std::string TestString(size_t len) { + std::string result; + result.reserve(len); + for (size_t i = 0; i < len; ++i) { + result.push_back(static_cast<char>(i % 256)); + } + return result; +} + +TEST(CRC32C, Compute) { + EXPECT_EQ(absl::ComputeCrc32c(""), absl::ToCrc32c(0)); + EXPECT_EQ(absl::ComputeCrc32c("hello world"), absl::ToCrc32c(0xc99465aa)); +} + +TEST(CRC32C, Extend) { + uint32_t base = 0xC99465AA; // CRC32C of "Hello World" + std::string extension = "Extension String"; + + EXPECT_EQ( + absl::ExtendCrc32c(absl::ToCrc32c(base), extension), + absl::ToCrc32c(0xD2F65090)); // CRC32C of "Hello WorldExtension String" +} + +TEST(CRC32C, ExtendByZeroes) { + std::string base = "hello world"; + absl::crc32c_t base_crc = absl::ToCrc32c(0xc99465aa); + + for (const size_t extend_by : {100, 10000, 100000}) { + SCOPED_TRACE(extend_by); + absl::crc32c_t crc2 = absl::ExtendCrc32cByZeroes(base_crc, extend_by); + EXPECT_EQ(crc2, absl::ComputeCrc32c(base + std::string(extend_by, '\0'))); + } +} + +TEST(CRC32C, UnextendByZeroes) { + for (auto seed_crc : {absl::ToCrc32c(0), absl::ToCrc32c(0xc99465aa)}) { + SCOPED_TRACE(seed_crc); + for (const size_t size_1 : {2, 200, 20000, 200000, 20000000}) { + for (const size_t size_2 : {0, 100, 10000, 100000, 10000000}) { + size_t extend_size = std::max(size_1, size_2); + size_t unextend_size = std::min(size_1, size_2); + SCOPED_TRACE(extend_size); + SCOPED_TRACE(unextend_size); + + // Extending by A zeroes an unextending by B<A zeros should be identical + // to extending by A-B zeroes. + absl::crc32c_t crc1 = seed_crc; + crc1 = absl::ExtendCrc32cByZeroes(crc1, extend_size); + crc1 = absl::crc_internal::UnextendCrc32cByZeroes(crc1, unextend_size); + + absl::crc32c_t crc2 = seed_crc; + crc2 = absl::ExtendCrc32cByZeroes(crc2, extend_size - unextend_size); + + EXPECT_EQ(crc1, crc2); + } + } + } + for (const size_t size : {0, 1, 100, 10000}) { + SCOPED_TRACE(size); + std::string string_before = TestString(size); + std::string string_after = string_before + std::string(size, '\0'); + + absl::crc32c_t crc_before = absl::ComputeCrc32c(string_before); + absl::crc32c_t crc_after = absl::ComputeCrc32c(string_after); + + EXPECT_EQ(crc_before, + absl::crc_internal::UnextendCrc32cByZeroes(crc_after, size)); + } +} + +TEST(CRC32C, Concat) { + std::string hello = "Hello, "; + std::string world = "world!"; + std::string hello_world = absl::StrCat(hello, world); + + absl::crc32c_t crc_a = absl::ComputeCrc32c(hello); + absl::crc32c_t crc_b = absl::ComputeCrc32c(world); + absl::crc32c_t crc_ab = absl::ComputeCrc32c(hello_world); + + EXPECT_EQ(absl::ConcatCrc32c(crc_a, crc_b, world.size()), crc_ab); +} + +TEST(CRC32C, Memcpy) { + for (size_t bytes : {0, 1, 20, 500, 100000}) { + SCOPED_TRACE(bytes); + std::string sample_string = TestString(bytes); + std::string target_buffer = std::string(bytes, '\0'); + + absl::crc32c_t memcpy_crc = + absl::MemcpyCrc32c(&(target_buffer[0]), sample_string.data(), bytes); + absl::crc32c_t compute_crc = absl::ComputeCrc32c(sample_string); + + EXPECT_EQ(memcpy_crc, compute_crc); + EXPECT_EQ(sample_string, target_buffer); + } +} + +TEST(CRC32C, RemovePrefix) { + std::string hello = "Hello, "; + std::string world = "world!"; + std::string hello_world = absl::StrCat(hello, world); + + absl::crc32c_t crc_a = absl::ComputeCrc32c(hello); + absl::crc32c_t crc_b = absl::ComputeCrc32c(world); + absl::crc32c_t crc_ab = absl::ComputeCrc32c(hello_world); + + EXPECT_EQ(absl::RemoveCrc32cPrefix(crc_a, crc_ab, world.size()), crc_b); +} + +TEST(CRC32C, RemoveSuffix) { + std::string hello = "Hello, "; + std::string world = "world!"; + std::string hello_world = absl::StrCat(hello, world); + + absl::crc32c_t crc_a = absl::ComputeCrc32c(hello); + absl::crc32c_t crc_b = absl::ComputeCrc32c(world); + absl::crc32c_t crc_ab = absl::ComputeCrc32c(hello_world); + + EXPECT_EQ(absl::RemoveCrc32cSuffix(crc_ab, crc_b, world.size()), crc_a); +} +} // namespace |