Coverage Improvements

include/boost/int128/format.hpp

@@ -12,6 +12,7 @@
 #include <boost/int128/int128.hpp>
 #include <string>
 #include <format>
+#include <tuple>
 
 #define BOOST_INT128_HAS_FORMAT
 

include/boost/int128/numeric.hpp

@@ -313,17 +313,11 @@ constexpr uint128_t gcd(uint128_t a, uint128_t b) noexcept
         }
 
         b -= a;
+    } while (b != 0U && (a.high | b.high) > 0U);
 
-        // Stop doing 128-bit math as soon as we can
-        if (a.high == 0U && b.high == 0U)
-        {
-            const auto g {detail::gcd64(a.low, b.low)};
-            return uint128_t{0, g} << shift;
-        }
-
-    } while (b != 0U);
-
-    return a << shift; // LCOV_EXCL_LINE : Should be unreachable, but this is also the correct answer
+    // Stop doing 128-bit math as soon as we can
+    const auto g {detail::gcd64(a.low, b.low)};
+    return uint128_t{0, g} << shift;
 }
 
 constexpr int128_t gcd(const int128_t a, const int128_t b) noexcept

test/limits_link_2.cpp

@@ -9,9 +9,9 @@
 void test_odr_use( int const* );
 void test_odr_use( std::size_t const* );
 
-template<typename T> void test()
+template<typename T> void test()                        // LCOV_EXCL_LINE
 {
-    test_odr_use( &std::numeric_limits<T>::digits10 );
+    test_odr_use( &std::numeric_limits<T>::digits10 );  // LCOV_EXCL_LINE
 }
 
 void f2()

test/limits_link_3.cpp

@@ -18,6 +18,6 @@ void test_odr_use( int const* )
 {
 }
 
-void test_odr_use ( std::size_t const* )
+void test_odr_use ( std::size_t const* )    // LCOV_EXCL_LINE
 {
 }

test/test_num_digits.cpp

@@ -2,9 +2,51 @@
 // Distributed under the Boost Software License, Version 1.0.
 // https://www.boost.org/LICENSE_1_0.txt
 
+#ifndef BOOST_INT128_ALLOW_SIGN_CONVERSION
+#  define BOOST_INT128_ALLOW_SIGN_CONVERSION
+#endif
+
 #include <boost/int128.hpp>
 #include <boost/int128/charconv.hpp>
 #include <boost/core/lightweight_test.hpp>
+#include <random>
+#include <array>
+
+#ifdef __clang__
+#  pragma clang diagnostic push
+#  pragma clang diagnostic ignored "-Wold-style-cast"
+#endif
+
+#include <boost/random/uniform_int_distribution.hpp>
+
+#ifdef __clang__
+#  pragma clang diagnostic pop
+#endif
+
+static std::mt19937_64 rng{42};
+boost::random::uniform_int_distribution<boost::int128::uint128_t> dist(std::numeric_limits<boost::int128::uint128_t>::min(),
+                                                                       std::numeric_limits<boost::int128::uint128_t>::max());
+
+constexpr std::array<boost::int128::uint128_t, 5> edge_cases {{
+    boost::int128::uint128_t{1, 0},
+    boost::int128::uint128_t{1, 1},
+    boost::int128::uint128_t{2, 0},
+    boost::int128::uint128_t{2, UINT64_MAX - 1U},
+    boost::int128::uint128_t{4, 0},
+}};
+
+constexpr int trivial_num_digits(boost::int128::uint128_t x) noexcept
+{
+    int digits = 0;
+
+    while (x)
+    {
+        x /= UINT64_C(10);
+        ++digits;
+    }
+
+    return digits;
+}
 
 void test()
 {
@@ -14,6 +56,30 @@ void test()
         const auto current_val_digits {boost::charconv::detail::num_digits(current_val)};
         BOOST_TEST_EQ(current_val_digits, i + 1);
     }
+
+    for (int i {1}; i < 39; ++i)
+    {
+        const auto current_val {boost::charconv::detail::int128_pow10[static_cast<std::size_t>(i)] - 1U};
+        const auto current_val_digits {boost::charconv::detail::num_digits(current_val)};
+        BOOST_TEST_EQ(current_val_digits, i);
+    }
+
+    for (int i {}; i < 1024; ++i)
+    {
+        const auto value {dist(rng)};
+        const auto current_val_digits {boost::charconv::detail::num_digits(value)};
+        const auto trivial_digits {trivial_num_digits(value)};
+
+        BOOST_TEST_EQ(current_val_digits, trivial_digits);
+    }
+
+    for (const auto value : edge_cases)
+    {
+        const auto current_val_digits {boost::charconv::detail::num_digits(value)};
+        const auto trivial_digits {trivial_num_digits(value)};
+
+        BOOST_TEST_EQ(current_val_digits, trivial_digits);
+    }
 }
 
 int main()