Add support for built-in __int128 when available

include/fmt/chrono.h

@@ -582,7 +582,7 @@ struct chrono_formatter {
   void write(Rep value, int width) {
     write_sign();
     if (isnan(value)) return write_nan();
-    uint32_or_64_t<int> n = to_unsigned(
+    uint32_or_64_or_128_t<int> n = to_unsigned(
         to_nonnegative_int(value, (std::numeric_limits<int>::max)()));
     int num_digits = internal::count_digits(n);
     if (width > num_digits) out = std::fill_n(out, width - num_digits, '0');

include/fmt/core.h

@@ -645,6 +645,8 @@ enum type {
   uint_type,
   long_long_type,
   ulong_long_type,
+  int128_type,
+  uint128_type,
   bool_type,
   char_type,
   last_integer_type = char_type,
@@ -671,6 +673,10 @@ FMT_TYPE_CONSTANT(int, int_type);
 FMT_TYPE_CONSTANT(unsigned, uint_type);
 FMT_TYPE_CONSTANT(long long, long_long_type);
 FMT_TYPE_CONSTANT(unsigned long long, ulong_long_type);
+#if FMT_USE_INT128
+FMT_TYPE_CONSTANT(__int128_t, int128_type);
+FMT_TYPE_CONSTANT(__uint128_t, uint128_type);
+#endif
 FMT_TYPE_CONSTANT(bool, bool_type);
 FMT_TYPE_CONSTANT(Char, char_type);
 FMT_TYPE_CONSTANT(double, double_type);
@@ -710,6 +716,10 @@ template <typename Context> class value {
     unsigned uint_value;
     long long long_long_value;
     unsigned long long ulong_long_value;
+#if FMT_USE_INT128
+    __int128_t int128_value;
+    __uint128_t uint128_value;
+#endif
     bool bool_value;
     char_type char_value;
     double double_value;
@@ -724,6 +734,10 @@ template <typename Context> class value {
   FMT_CONSTEXPR value(unsigned val) : uint_value(val) {}
   value(long long val) : long_long_value(val) {}
   value(unsigned long long val) : ulong_long_value(val) {}
+#if FMT_USE_INT128
+  value(__int128_t val) : int128_value(val) {}
+  value(__uint128_t val) : uint128_value(val) {}
+#endif
   value(double val) : double_value(val) {}
   value(long double val) : long_double_value(val) {}
   value(bool val) : bool_value(val) {}
@@ -783,6 +797,10 @@ template <typename Context> struct arg_mapper {
   FMT_CONSTEXPR ulong_type map(unsigned long val) { return val; }
   FMT_CONSTEXPR long long map(long long val) { return val; }
   FMT_CONSTEXPR unsigned long long map(unsigned long long val) { return val; }
+#if FMT_USE_INT128
+  FMT_CONSTEXPR __int128_t map(__int128_t val) { return val; }
+  FMT_CONSTEXPR __uint128_t map(__uint128_t val) { return val; }
+#endif
   FMT_CONSTEXPR bool map(bool val) { return val; }
 
   template <typename T, FMT_ENABLE_IF(is_char<T>::value)>
@@ -943,6 +961,12 @@ FMT_CONSTEXPR auto visit_format_arg(Visitor&& vis,
     return vis(arg.value_.long_long_value);
   case internal::ulong_long_type:
     return vis(arg.value_.ulong_long_value);
+#if FMT_USE_INT128
+  case internal::int128_type:
+    return vis(arg.value_.int128_value);
+  case internal::uint128_type:
+    return vis(arg.value_.uint128_value);
+#endif
   case internal::bool_type:
     return vis(arg.value_.bool_value);
   case internal::char_type:

include/fmt/format-inl.h

@@ -158,7 +158,7 @@ FMT_FUNC void format_error_code(internal::buffer<char>& out, int error_code,
   static const char ERROR_STR[] = "error ";
   // Subtract 2 to account for terminating null characters in SEP and ERROR_STR.
   std::size_t error_code_size = sizeof(SEP) + sizeof(ERROR_STR) - 2;
-  auto abs_value = static_cast<uint32_or_64_t<int>>(error_code);
+  auto abs_value = static_cast<uint32_or_64_or_128_t<int>>(error_code);
   if (internal::is_negative(error_code)) {
     abs_value = 0 - abs_value;
     ++error_code_size;

include/fmt/format.h

@@ -636,11 +636,20 @@ FMT_CONSTEXPR bool is_negative(T) {
   return false;
 }
 
+#if FMT_USE_INT128
+// Smallest of uint32_t, uint64_t, unsigned __int128 that is large enough to
+// represent all values of T.
+template <typename T>
+using uint32_or_64_or_128_t = conditional_t<
+    std::numeric_limits<T>::digits <= 32, uint32_t,
+    conditional_t<std::numeric_limits<T>::digits <= 64, uint64_t, __uint128_t>>;
+#else
 // Smallest of uint32_t and uint64_t that is large enough to represent all
 // values of T.
 template <typename T>
-using uint32_or_64_t =
+using uint32_or_64_or_128_t =
     conditional_t<std::numeric_limits<T>::digits <= 32, uint32_t, uint64_t>;
+#endif
 
 // Static data is placed in this class template for the header-only config.
 template <typename T = void> struct FMT_EXTERN_TEMPLATE_API basic_data {
@@ -689,6 +698,23 @@ inline int count_digits(uint64_t n) {
 }
 #endif
 
+#if FMT_USE_INT128
+inline int count_digits(__uint128_t n) {
+  int count = 1;
+  for (;;) {
+    // Integer division is slow so do it for a group of four digits instead
+    // of for every digit. The idea comes from the talk by Alexandrescu
+    // "Three Optimization Tips for C++". See speed-test for a comparison.
+    if (n < 10) return count;
+    if (n < 100) return count + 1;
+    if (n < 1000) return count + 2;
+    if (n < 10000) return count + 3;
+    n /= 10000u;
+    count += 4;
+  }
+}
+#endif
+
 // Counts the number of digits in n. BITS = log2(radix).
 template <unsigned BITS, typename UInt> inline int count_digits(UInt n) {
   int num_digits = 0;
@@ -818,12 +844,22 @@ inline Char* format_decimal(Char* buffer, UInt value, int num_digits,
   return end;
 }
 
+template <typename Int> constexpr int digits10() noexcept {
+  return std::numeric_limits<Int>::digits10;
+}
+
+#if FMT_USE_INT128
+template <> constexpr int digits10<__int128_t>() noexcept { return 38; }
+
+template <> constexpr int digits10<__uint128_t>() noexcept { return 38; }
+#endif
+
 template <typename Char, typename UInt, typename Iterator, typename F>
 inline Iterator format_decimal(Iterator out, UInt value, int num_digits,
                                F add_thousands_sep) {
   FMT_ASSERT(num_digits >= 0, "invalid digit count");
   // Buffer should be large enough to hold all digits (<= digits10 + 1).
-  enum { max_size = std::numeric_limits<UInt>::digits10 + 1 };
+  enum { max_size = digits10<UInt>() + 1 };
   Char buffer[max_size + max_size / 3];
   auto end = format_decimal(buffer, value, num_digits, add_thousands_sep);
   return internal::copy_str<Char>(buffer, end, out);
@@ -1324,7 +1360,7 @@ template <typename Range> class basic_writer {
 
   // Writes a decimal integer.
   template <typename Int> void write_decimal(Int value) {
-    auto abs_value = static_cast<uint32_or_64_t<Int>>(value);
+    auto abs_value = static_cast<uint32_or_64_or_128_t<Int>>(value);
     bool is_negative = internal::is_negative(value);
     if (is_negative) abs_value = 0 - abs_value;
     int num_digits = internal::count_digits(abs_value);
@@ -1336,7 +1372,7 @@ template <typename Range> class basic_writer {
 
   // The handle_int_type_spec handler that writes an integer.
   template <typename Int, typename Specs> struct int_writer {
-    using unsigned_type = uint32_or_64_t<Int>;
+    using unsigned_type = uint32_or_64_or_128_t<Int>;
 
     basic_writer<Range>& writer;
     const Specs& specs;
@@ -1608,10 +1644,16 @@ template <typename Range> class basic_writer {
   void write(int value) { write_decimal(value); }
   void write(long value) { write_decimal(value); }
   void write(long long value) { write_decimal(value); }
+#if FMT_USE_INT128
+  void write(__int128_t value) { write_decimal(value); }
+#endif
 
   void write(unsigned value) { write_decimal(value); }
   void write(unsigned long value) { write_decimal(value); }
   void write(unsigned long long value) { write_decimal(value); }
+#if FMT_USE_INT128
+  void write(__uint128_t value) { write_decimal(value); }
+#endif
 
   // Writes a formatted integer.
   template <typename T, typename Spec>
@@ -1694,6 +1736,14 @@ template <typename Range> class basic_writer {
 
 using writer = basic_writer<buffer_range<char>>;
 
+template <typename T> struct is_integral : std::is_integral<T> {};
+
+#if FMT_USE_INT128
+template <> struct is_integral<__int128_t> : std::true_type {};
+
+template <> struct is_integral<__uint128_t> : std::true_type {};
+#endif
+
 template <typename Range, typename ErrorHandler = internal::error_handler>
 class arg_formatter_base {
  public:
@@ -1756,7 +1806,7 @@ class arg_formatter_base {
     return out();
   }
 
-  template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
+  template <typename T, FMT_ENABLE_IF(is_integral<T>::value)>
   iterator operator()(T value) {
     if (specs_)
       writer_.write_int(value, *specs_);
@@ -1888,7 +1938,7 @@ template <typename Context> class custom_formatter {
 
 template <typename T>
 using is_integer =
-    bool_constant<std::is_integral<T>::value && !std::is_same<T, bool>::value &&
+    bool_constant<is_integral<T>::value && !std::is_same<T, bool>::value &&
                   !std::is_same<T, char>::value &&
                   !std::is_same<T, wchar_t>::value>;
 
@@ -2947,6 +2997,8 @@ struct formatter<T, Char,
     case internal::uint_type:
     case internal::long_long_type:
     case internal::ulong_long_type:
+    case internal::int128_type:
+    case internal::uint128_type:
     case internal::bool_type:
       handle_int_type_spec(specs_.type,
                            internal::int_type_checker<decltype(eh)>(eh));

include/fmt/printf.h

@@ -158,7 +158,7 @@ template <typename Char> class printf_width_handler {
 
   template <typename T, FMT_ENABLE_IF(std::is_integral<T>::value)>
   unsigned operator()(T value) {
-    auto width = static_cast<uint32_or_64_t<T>>(value);
+    auto width = static_cast<uint32_or_64_or_128_t<T>>(value);
     if (internal::is_negative(value)) {
       specs_.align = align::left;
       width = 0 - width;

test/format-impl-test.cc

@@ -149,6 +149,17 @@ template <typename T> struct value_extractor {
   template <typename U> FMT_NORETURN T operator()(U) {
     throw std::runtime_error(fmt::format("invalid type {}", typeid(U).name()));
   }
+
+#ifdef __apple_build_version__
+  // Apple Clang does not define typeid for __int128_t and __uint128_t.
+  FMT_NORETURN T operator()(__int128_t) {
+    throw std::runtime_error(fmt::format("invalid type {}", "__int128_t"));
+  }
+
+  FMT_NORETURN T operator()(__uint128_t) {
+    throw std::runtime_error(fmt::format("invalid type {}", "__uint128_t"));
+  }
+#endif
 };
 
 TEST(FormatTest, ArgConverter) {

test/format-test.cc

@@ -1333,6 +1333,14 @@ TEST(FormatterTest, FormatBin) {
             format("{0:b}", std::numeric_limits<uint32_t>::max()));
 }
 
+#if FMT_USE_INT128
+constexpr auto INT128_MAX = static_cast<__int128_t>(
+    (static_cast<__uint128_t>(1) << ((__SIZEOF_INT128__ * CHAR_BIT) - 1)) - 1);
+constexpr auto INT128_MIN = -INT128_MAX - 1;
+
+constexpr auto UINT128_MAX = ~static_cast<__uint128_t>(0);
+#endif
+
 TEST(FormatterTest, FormatDec) {
   EXPECT_EQ("0", format("{0}", 0));
   EXPECT_EQ("42", format("{0}", 42));
@@ -1341,6 +1349,23 @@ TEST(FormatterTest, FormatDec) {
   EXPECT_EQ("-42", format("{0}", -42));
   EXPECT_EQ("12345", format("{0}", 12345));
   EXPECT_EQ("67890", format("{0}", 67890));
+#if FMT_USE_INT128
+  EXPECT_EQ("0", format("{0}", static_cast<__int128_t>(0)));
+  EXPECT_EQ("0", format("{0}", static_cast<__uint128_t>(0)));
+  EXPECT_EQ("9223372036854775808",
+            format("{0}", static_cast<__int128_t>(INT64_MAX) + 1));
+  EXPECT_EQ("-9223372036854775809",
+            format("{0}", static_cast<__int128_t>(INT64_MIN) - 1));
+  EXPECT_EQ("18446744073709551616",
+            format("{0}", static_cast<__int128_t>(UINT64_MAX) + 1));
+  EXPECT_EQ("170141183460469231731687303715884105727",
+            format("{0}", INT128_MAX));
+  EXPECT_EQ("-170141183460469231731687303715884105728",
+            format("{0}", INT128_MIN));
+  EXPECT_EQ("340282366920938463463374607431768211455",
+            format("{0}", UINT128_MAX));
+#endif
+
   char buffer[BUFFER_SIZE];
   safe_sprintf(buffer, "%d", INT_MIN);
   EXPECT_EQ(buffer, format("{0}", INT_MIN));
@@ -1365,6 +1390,19 @@ TEST(FormatterTest, FormatHex) {
   EXPECT_EQ("90abcdef", format("{0:x}", 0x90abcdef));
   EXPECT_EQ("12345678", format("{0:X}", 0x12345678));
   EXPECT_EQ("90ABCDEF", format("{0:X}", 0x90ABCDEF));
+#if FMT_USE_INT128
+  EXPECT_EQ("0", format("{0:x}", static_cast<__int128_t>(0)));
+  EXPECT_EQ("0", format("{0:x}", static_cast<__uint128_t>(0)));
+  EXPECT_EQ("8000000000000000",
+            format("{0:x}", static_cast<__int128_t>(INT64_MAX) + 1));
+  EXPECT_EQ("-8000000000000001",
+            format("{0:x}", static_cast<__int128_t>(INT64_MIN) - 1));
+  EXPECT_EQ("10000000000000000",
+            format("{0:x}", static_cast<__int128_t>(UINT64_MAX) + 1));
+  EXPECT_EQ("7fffffffffffffffffffffffffffffff", format("{0:x}", INT128_MAX));
+  EXPECT_EQ("-80000000000000000000000000000000", format("{0:x}", INT128_MIN));
+  EXPECT_EQ("ffffffffffffffffffffffffffffffff", format("{0:x}", UINT128_MAX));
+#endif
 
   char buffer[BUFFER_SIZE];
   safe_sprintf(buffer, "-%x", 0 - static_cast<unsigned>(INT_MIN));
@@ -1387,6 +1425,23 @@ TEST(FormatterTest, FormatOct) {
   EXPECT_EQ("42", format("{0:o}", 042u));
   EXPECT_EQ("-42", format("{0:o}", -042));
   EXPECT_EQ("12345670", format("{0:o}", 012345670));
+#if FMT_USE_INT128
+  EXPECT_EQ("0", format("{0:o}", static_cast<__int128_t>(0)));
+  EXPECT_EQ("0", format("{0:o}", static_cast<__uint128_t>(0)));
+  EXPECT_EQ("1000000000000000000000",
+            format("{0:o}", static_cast<__int128_t>(INT64_MAX) + 1));
+  EXPECT_EQ("-1000000000000000000001",
+            format("{0:o}", static_cast<__int128_t>(INT64_MIN) - 1));
+  EXPECT_EQ("2000000000000000000000",
+            format("{0:o}", static_cast<__int128_t>(UINT64_MAX) + 1));
+  EXPECT_EQ("1777777777777777777777777777777777777777777",
+            format("{0:o}", INT128_MAX));
+  EXPECT_EQ("-2000000000000000000000000000000000000000000",
+            format("{0:o}", INT128_MIN));
+  EXPECT_EQ("3777777777777777777777777777777777777777777",
+            format("{0:o}", UINT128_MAX));
+#endif
+
   char buffer[BUFFER_SIZE];
   safe_sprintf(buffer, "-%o", 0 - static_cast<unsigned>(INT_MIN));
   EXPECT_EQ(buffer, format("{0:o}", INT_MIN));
@@ -1923,7 +1978,11 @@ using buffer_range = fmt::buffer_range<char>;
 class mock_arg_formatter
     : public fmt::internal::arg_formatter_base<buffer_range> {
  private:
+#if FMT_USE_INT128
+  MOCK_METHOD1(call, void(__int128_t value));
+#else
   MOCK_METHOD1(call, void(long long value));
+#endif
 
  public:
   typedef fmt::internal::arg_formatter_base<buffer_range> base;
@@ -1936,14 +1995,14 @@ class mock_arg_formatter
   }
 
   template <typename T>
-  typename std::enable_if<std::is_integral<T>::value, iterator>::type
+  typename std::enable_if<fmt::internal::is_integral<T>::value, iterator>::type
   operator()(T value) {
     call(value);
     return base::operator()(value);
   }
 
   template <typename T>
-  typename std::enable_if<!std::is_integral<T>::value, iterator>::type
+  typename std::enable_if<!fmt::internal::is_integral<T>::value, iterator>::type
   operator()(T value) {
     return base::operator()(value);
   }