diff options
| -rw-r--r-- | src/test/fuzz/addition_overflow.cpp | 17 | ||||
| -rw-r--r-- | src/test/util_tests.cpp | 16 | ||||
| -rw-r--r-- | src/util/overflow.h | 20 |
3 files changed, 48 insertions, 5 deletions
diff --git a/src/test/fuzz/addition_overflow.cpp b/src/test/fuzz/addition_overflow.cpp index cfad41659e..372c1a370e 100644 --- a/src/test/fuzz/addition_overflow.cpp +++ b/src/test/fuzz/addition_overflow.cpp @@ -26,6 +26,12 @@ void TestAdditionOverflow(FuzzedDataProvider& fuzzed_data_provider) const T i = fuzzed_data_provider.ConsumeIntegral<T>(); const T j = fuzzed_data_provider.ConsumeIntegral<T>(); const bool is_addition_overflow_custom = AdditionOverflow(i, j); + const auto maybe_add{CheckedAdd(i, j)}; + const auto sat_add{SaturatingAdd(i, j)}; + assert(is_addition_overflow_custom == !maybe_add.has_value()); + assert(is_addition_overflow_custom == AdditionOverflow(j, i)); + assert(maybe_add == CheckedAdd(j, i)); + assert(sat_add == SaturatingAdd(j, i)); #if defined(HAVE_BUILTIN_ADD_OVERFLOW) T result_builtin; const bool is_addition_overflow_builtin = __builtin_add_overflow(i, j, &result_builtin); @@ -33,11 +39,14 @@ void TestAdditionOverflow(FuzzedDataProvider& fuzzed_data_provider) if (!is_addition_overflow_custom) { assert(i + j == result_builtin); } -#else - if (!is_addition_overflow_custom) { - (void)(i + j); - } #endif + if (is_addition_overflow_custom) { + assert(sat_add == std::numeric_limits<T>::min() || sat_add == std::numeric_limits<T>::max()); + } else { + const auto add{i + j}; + assert(add == maybe_add.value()); + assert(add == sat_add); + } } } // namespace diff --git a/src/test/util_tests.cpp b/src/test/util_tests.cpp index 52b24327ec..22ce9b0582 100644 --- a/src/test/util_tests.cpp +++ b/src/test/util_tests.cpp @@ -1474,9 +1474,17 @@ static void TestAddMatrixOverflow() constexpr T MAXI{std::numeric_limits<T>::max()}; BOOST_CHECK(!CheckedAdd(T{1}, MAXI)); BOOST_CHECK(!CheckedAdd(MAXI, MAXI)); + BOOST_CHECK_EQUAL(MAXI, SaturatingAdd(T{1}, MAXI)); + BOOST_CHECK_EQUAL(MAXI, SaturatingAdd(MAXI, MAXI)); + BOOST_CHECK_EQUAL(0, CheckedAdd(T{0}, T{0}).value()); BOOST_CHECK_EQUAL(MAXI, CheckedAdd(T{0}, MAXI).value()); BOOST_CHECK_EQUAL(MAXI, CheckedAdd(T{1}, MAXI - 1).value()); + BOOST_CHECK_EQUAL(MAXI - 1, CheckedAdd(T{1}, MAXI - 2).value()); + BOOST_CHECK_EQUAL(0, SaturatingAdd(T{0}, T{0})); + BOOST_CHECK_EQUAL(MAXI, SaturatingAdd(T{0}, MAXI)); + BOOST_CHECK_EQUAL(MAXI, SaturatingAdd(T{1}, MAXI - 1)); + BOOST_CHECK_EQUAL(MAXI - 1, SaturatingAdd(T{1}, MAXI - 2)); } /* Check for overflow or underflow */ @@ -1488,9 +1496,17 @@ static void TestAddMatrix() constexpr T MAXI{std::numeric_limits<T>::max()}; BOOST_CHECK(!CheckedAdd(T{-1}, MINI)); BOOST_CHECK(!CheckedAdd(MINI, MINI)); + BOOST_CHECK_EQUAL(MINI, SaturatingAdd(T{-1}, MINI)); + BOOST_CHECK_EQUAL(MINI, SaturatingAdd(MINI, MINI)); + BOOST_CHECK_EQUAL(MINI, CheckedAdd(T{0}, MINI).value()); BOOST_CHECK_EQUAL(MINI, CheckedAdd(T{-1}, MINI + 1).value()); BOOST_CHECK_EQUAL(-1, CheckedAdd(MINI, MAXI).value()); + BOOST_CHECK_EQUAL(MINI + 1, CheckedAdd(T{-1}, MINI + 2).value()); + BOOST_CHECK_EQUAL(MINI, SaturatingAdd(T{0}, MINI)); + BOOST_CHECK_EQUAL(MINI, SaturatingAdd(T{-1}, MINI + 1)); + BOOST_CHECK_EQUAL(MINI + 1, SaturatingAdd(T{-1}, MINI + 2)); + BOOST_CHECK_EQUAL(-1, SaturatingAdd(MINI, MAXI)); } BOOST_AUTO_TEST_CASE(util_overflow) diff --git a/src/util/overflow.h b/src/util/overflow.h index c70a8b663e..6b7dd1e8fd 100644 --- a/src/util/overflow.h +++ b/src/util/overflow.h @@ -13,7 +13,7 @@ template <class T> [[nodiscard]] bool AdditionOverflow(const T i, const T j) noexcept { static_assert(std::is_integral<T>::value, "Integral required."); - if (std::numeric_limits<T>::is_signed) { + if constexpr (std::numeric_limits<T>::is_signed) { return (i > 0 && j > std::numeric_limits<T>::max() - i) || (i < 0 && j < std::numeric_limits<T>::min() - i); } @@ -29,4 +29,22 @@ template <class T> return i + j; } +template <class T> +[[nodiscard]] T SaturatingAdd(const T i, const T j) noexcept +{ + if constexpr (std::numeric_limits<T>::is_signed) { + if (i > 0 && j > std::numeric_limits<T>::max() - i) { + return std::numeric_limits<T>::max(); + } + if (i < 0 && j < std::numeric_limits<T>::min() - i) { + return std::numeric_limits<T>::min(); + } + } else { + if (std::numeric_limits<T>::max() - i < j) { + return std::numeric_limits<T>::max(); + } + } + return i + j; +} + #endif // BITCOIN_UTIL_OVERFLOW_H |