Implement AbslStringify for crc32c_t in order to support absl::StrFormat natively

PiperOrigin-RevId: 552940359
Change-Id: I925764757404c0c9f2a13ed729190d51f4ac46cf

absl/crc/BUILD.bazel

@@ -106,6 +106,7 @@ cc_test(
     deps = [
         ":crc32c",
         "//absl/strings",
+        "//absl/strings:str_format",
         "@com_google_googletest//:gtest_main",
     ],
 )

absl/crc/CMakeLists.txt

@@ -91,6 +91,7 @@ absl_cc_test(
   DEPS
     absl::crc32c
     absl::strings
+    absl::str_format
     GTest::gtest_main
 )
 

absl/crc/crc32c.h

@@ -62,6 +62,11 @@ class crc32c_t final {
 
   friend bool operator!=(crc32c_t lhs, crc32c_t rhs) { return !(lhs == rhs); }
 
+  template <typename Sink>
+  friend void AbslStringify(Sink& sink, crc32c_t crc) {
+    absl::Format(&sink, "%08x", static_cast<uint32_t>(crc));
+  }
+
  private:
   uint32_t crc_;
 };

absl/crc/crc32c_test.cc

@@ -24,6 +24,7 @@
 #include "gtest/gtest.h"
 #include "absl/crc/internal/crc32c.h"
 #include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
 #include "absl/strings/string_view.h"
 
 namespace {
@@ -210,4 +211,17 @@ TEST(CRC32C, InsertionOperator) {
     EXPECT_EQ(buf.str(), "00000011");
   }
 }
+
+TEST(CRC32C, AbslStringify) {
+  // StrFormat
+  EXPECT_EQ(absl::StrFormat("%v", absl::crc32c_t{0xc99465aa}), "c99465aa");
+  EXPECT_EQ(absl::StrFormat("%v", absl::crc32c_t{0}), "00000000");
+  EXPECT_EQ(absl::StrFormat("%v", absl::crc32c_t{17}), "00000011");
+
+  // StrCat
+  EXPECT_EQ(absl::StrCat(absl::crc32c_t{0xc99465aa}), "c99465aa");
+  EXPECT_EQ(absl::StrCat(absl::crc32c_t{0}), "00000000");
+  EXPECT_EQ(absl::StrCat(absl::crc32c_t{17}), "00000011");
+}
+
 }  // namespace