From bba65bd11506292aad0258ab516fe9eabf507e18 Mon Sep 17 00:00:00 2001
From: Eric Fiselier <ericwf@google.com>
Date: Wed, 28 Jun 2023 11:09:29 -0700
Subject: Refactor bit tests to allow for the testing of more types

PiperOrigin-RevId: 544107572
Change-Id: I8016ee690ad5df78bf80ba0786e528fba4e51907
---
 absl/numeric/bits.h       |  2 +-
 absl/numeric/bits_test.cc | 68 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/absl/numeric/bits.h b/absl/numeric/bits.h
index 5466af07..5ed36f52 100644
--- a/absl/numeric/bits.h
+++ b/absl/numeric/bits.h
@@ -49,8 +49,8 @@
 
 namespace absl {
 ABSL_NAMESPACE_BEGIN
-
 #if !(defined(__cpp_lib_bitops) && __cpp_lib_bitops >= 201907L)
+
 // rotating
 template <class T>
 ABSL_MUST_USE_RESULT constexpr
diff --git a/absl/numeric/bits_test.cc b/absl/numeric/bits_test.cc
index 7c942aae..14955eb3 100644
--- a/absl/numeric/bits_test.cc
+++ b/absl/numeric/bits_test.cc
@@ -15,6 +15,7 @@
 #include "absl/numeric/bits.h"
 
 #include <limits>
+#include <type_traits>
 
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
@@ -24,6 +25,73 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 namespace {
 
+template <typename IntT>
+class IntegerTypesTest : public ::testing::Test {};
+
+using OneByteIntegerTypes = ::testing::Types<
+    unsigned char,
+    uint8_t
+    >;
+
+TYPED_TEST_SUITE(IntegerTypesTest, OneByteIntegerTypes);
+
+TYPED_TEST(IntegerTypesTest, HandlesTypes) {
+  using UIntType = TypeParam;
+
+  EXPECT_EQ(rotl(UIntType{0x12}, 0), uint8_t{0x12});
+  EXPECT_EQ(rotr(UIntType{0x12}, -4), uint8_t{0x21});
+  static_assert(rotl(UIntType{0x12}, 0) == uint8_t{0x12}, "");
+
+  static_assert(rotr(UIntType{0x12}, 0) == uint8_t{0x12}, "");
+  EXPECT_EQ(rotr(UIntType{0x12}, 0), uint8_t{0x12});
+
+#if ABSL_INTERNAL_HAS_CONSTEXPR_CLZ
+  static_assert(countl_zero(UIntType{}) == 8, "");
+  static_assert(countl_zero(static_cast<UIntType>(-1)) == 0, "");
+
+  static_assert(countl_one(UIntType{}) == 0, "");
+  static_assert(countl_one(static_cast<UIntType>(-1)) == 8, "");
+
+  static_assert(countr_zero(UIntType{}) == 8, "");
+  static_assert(countr_zero(static_cast<UIntType>(-1)) == 0, "");
+
+  static_assert(countr_one(UIntType{}) == 0, "");
+  static_assert(countr_one(static_cast<UIntType>(-1)) == 8, "");
+
+  static_assert(popcount(UIntType{}) == 0, "");
+  static_assert(popcount(UIntType{1}) == 1, "");
+  static_assert(popcount(static_cast<UIntType>(-1)) == 8, "");
+
+  static_assert(bit_width(UIntType{}) == 0, "");
+  static_assert(bit_width(UIntType{1}) == 1, "");
+  static_assert(bit_width(UIntType{3}) == 2, "");
+  static_assert(bit_width(static_cast<UIntType>(-1)) == 8, "");
+#endif
+
+  EXPECT_EQ(countl_zero(UIntType{}), 8);
+  EXPECT_EQ(countl_zero(static_cast<UIntType>(-1)), 0);
+
+  EXPECT_EQ(countl_one(UIntType{}), 0);
+  EXPECT_EQ(countl_one(static_cast<UIntType>(-1)), 8);
+
+  EXPECT_EQ(countr_zero(UIntType{}), 8);
+  EXPECT_EQ(countr_zero(static_cast<UIntType>(-1)), 0);
+
+  EXPECT_EQ(countr_one(UIntType{}), 0);
+  EXPECT_EQ(countr_one(static_cast<UIntType>(-1)), 8);
+
+  EXPECT_EQ(popcount(UIntType{}), 0);
+  EXPECT_EQ(popcount(UIntType{1}), 1);
+
+  EXPECT_FALSE(has_single_bit(UIntType{}));
+  EXPECT_FALSE(has_single_bit(static_cast<UIntType>(-1)));
+
+  EXPECT_EQ(bit_width(UIntType{}), 0);
+  EXPECT_EQ(bit_width(UIntType{1}), 1);
+  EXPECT_EQ(bit_width(UIntType{3}), 2);
+  EXPECT_EQ(bit_width(static_cast<UIntType>(-1)), 8);
+}
+
 TEST(Rotate, Left) {
   static_assert(rotl(uint8_t{0x12}, 0) == uint8_t{0x12}, "");
   static_assert(rotl(uint16_t{0x1234}, 0) == uint16_t{0x1234}, "");
-- 
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