Speed up `FastIntToBuffer`.

PiperOrigin-RevId: 560038034
Change-Id: I2c74d271b52faeefb6e8627d9830b2b53de64e73

1 files changed, 22 insertions, 0 deletions

diff --git a/absl/strings/numbers_test.cc b/absl/strings/numbers_test.cc
index a450b99e..75c2dcf2 100644
--- a/absl/strings/numbers_test.cc
+++ b/absl/strings/numbers_test.cc
@@ -63,6 +63,7 @@ using absl::strings_internal::strtouint32_test_cases;
 using absl::strings_internal::strtouint64_test_cases;
 using testing::Eq;
 using testing::MatchesRegex;
+using testing::Pointee;
 
 // Number of floats to test with.
 // 5,000,000 is a reasonable default for a test that only takes a few seconds.
@@ -1715,4 +1716,25 @@ TEST(FastHexToBufferZeroPad16, Smoke) {
   }
 }
 
+template <typename Int>
+void ExpectWritesNull() {
+  {
+    char buf[absl::numbers_internal::kFastToBufferSize];
+    Int x = std::numeric_limits<Int>::min();
+    EXPECT_THAT(absl::numbers_internal::FastIntToBuffer(x, buf), Pointee('\0'));
+  }
+  {
+    char buf[absl::numbers_internal::kFastToBufferSize];
+    Int x = std::numeric_limits<Int>::max();
+    EXPECT_THAT(absl::numbers_internal::FastIntToBuffer(x, buf), Pointee('\0'));
+  }
+}
+
+TEST(FastIntToBuffer, WritesNull) {
+  ExpectWritesNull<int32_t>();
+  ExpectWritesNull<uint32_t>();
+  ExpectWritesNull<int64_t>();
+  ExpectWritesNull<uint32_t>();
+}
+
 }  // namespace