pw_checksum: Add CRC32 support
Change-Id: Ife7a384658e1515aff2a096e3890bac6d0accfa7
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/12843
Reviewed-by: Wyatt Hepler <hepler@google.com>
Commit-Queue: Zihan Chen <zihanchen@google.com>
diff --git a/pw_checksum/crc32_test.cc b/pw_checksum/crc32_test.cc
new file mode 100644
index 0000000..87b8430
--- /dev/null
+++ b/pw_checksum/crc32_test.cc
@@ -0,0 +1,88 @@
+// Copyright 2020 The Pigweed 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 "pw_checksum/crc32.h"
+
+#include <span>
+#include <string_view>
+
+#include "gtest/gtest.h"
+
+namespace pw::checksum {
+namespace {
+
+// The expected CRC32 values were calculated using
+//
+// http://www.sunshine2k.de/coding/javascript/crc/crc_js.html
+//
+// with polynomial 0x4C11DB7, initial value 0xFFFFFFFF.
+
+constexpr uint8_t kBytes[] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
+constexpr uint8_t kBytesPart0[] = {1, 2, 3, 4, 5};
+constexpr uint8_t kBytesPart1[] = {6, 7, 8, 9};
+constexpr uint32_t kBufferCrc = 0x40EFAB9E;
+
+constexpr std::string_view kString =
+ "In the beginning the Universe was created. This has made a lot of "
+ "people very angry and been widely regarded as a bad move.";
+constexpr uint32_t kStringCrc = 0x9EC87F88;
+
+TEST(Crc32, Empty) {
+ EXPECT_EQ(Crc32(std::span<std::byte>()), ~kCrc32InitialValue);
+}
+
+TEST(Crc32, ByteByByte) {
+ uint32_t crc;
+ crc = Crc32(std::byte{kBytes[0]});
+ for (size_t i = 1; i < sizeof(kBytes); i++) {
+ crc = Crc32(std::byte{kBytes[i]}, crc);
+ }
+ EXPECT_EQ(crc, kBufferCrc);
+}
+
+TEST(Crc32, Buffer) {
+ EXPECT_EQ(Crc32(as_bytes(std::span(kBytes))), kBufferCrc);
+}
+
+TEST(Crc32, BufferAppend) {
+ uint32_t crc = Crc32(as_bytes(std::span(kBytesPart0)));
+ EXPECT_EQ(Crc32(as_bytes(std::span(kBytesPart1)), crc), kBufferCrc);
+}
+
+TEST(Crc32, String) {
+ EXPECT_EQ(Crc32(as_bytes(std::span(kString))), kStringCrc);
+}
+
+extern "C" uint32_t CallChecksumCrc32(const void* data, size_t size_bytes);
+extern "C" uint32_t CallChecksumCrc32Append(const void* data,
+ size_t size_bytes);
+
+TEST(Crc32FromC, Buffer) {
+ EXPECT_EQ(CallChecksumCrc32(kBytes, sizeof(kBytes)), kBufferCrc);
+}
+
+TEST(Crc32FromC, String) {
+ EXPECT_EQ(CallChecksumCrc32(kString.data(), kString.size()), kStringCrc);
+}
+
+TEST(Crc32AppendFromC, Buffer) {
+ EXPECT_EQ(CallChecksumCrc32(kBytes, sizeof(kBytes)), kBufferCrc);
+}
+
+TEST(Crc32AppendFromC, String) {
+ EXPECT_EQ(CallChecksumCrc32Append(kString.data(), kString.size()),
+ kStringCrc);
+}
+
+} // namespace
+} // namespace pw::checksum