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-rw-r--r--absl/numeric/int128.h58
1 files changed, 53 insertions, 5 deletions
diff --git a/absl/numeric/int128.h b/absl/numeric/int128.h
index bc7dbb47ae81..e4f39c305152 100644
--- a/absl/numeric/int128.h
+++ b/absl/numeric/int128.h
@@ -219,21 +219,69 @@ std::ostream& operator<<(std::ostream& os, uint128 v);
 
 // TODO(strel) add operator>>(std::istream&, uint128)
 
+constexpr uint128 Uint128Max() {
+  return uint128(std::numeric_limits<uint64_t>::max(),
+                 std::numeric_limits<uint64_t>::max());
+}
+
+}  // namespace absl
+
+// Specialized numeric_limits for uint128.
+namespace std {
+template <>
+class numeric_limits<absl::uint128> {
+ public:
+  static constexpr bool is_specialized = true;
+  static constexpr bool is_signed = false;
+  static constexpr bool is_integer = true;
+  static constexpr bool is_exact = true;
+  static constexpr bool has_infinity = false;
+  static constexpr bool has_quiet_NaN = false;
+  static constexpr bool has_signaling_NaN = false;
+  static constexpr float_denorm_style has_denorm = denorm_absent;
+  static constexpr bool has_denorm_loss = false;
+  static constexpr float_round_style round_style = round_toward_zero;
+  static constexpr bool is_iec559 = false;
+  static constexpr bool is_bounded = true;
+  static constexpr bool is_modulo = true;
+  static constexpr int digits = 128;
+  static constexpr int digits10 = 38;
+  static constexpr int max_digits10 = 0;
+  static constexpr int radix = 2;
+  static constexpr int min_exponent = 0;
+  static constexpr int min_exponent10 = 0;
+  static constexpr int max_exponent = 0;
+  static constexpr int max_exponent10 = 0;
+#ifdef ABSL_HAVE_INTRINSIC_INT128
+  static constexpr bool traps = numeric_limits<unsigned __int128>::traps;
+#else   // ABSL_HAVE_INTRINSIC_INT128
+  static constexpr bool traps = numeric_limits<uint64_t>::traps;
+#endif  // ABSL_HAVE_INTRINSIC_INT128
+  static constexpr bool tinyness_before = false;
+
+  static constexpr absl::uint128 min() { return 0; }
+  static constexpr absl::uint128 lowest() { return 0; }
+  static constexpr absl::uint128 max() { return absl::Uint128Max(); }
+  static constexpr absl::uint128 epsilon() { return 0; }
+  static constexpr absl::uint128 round_error() { return 0; }
+  static constexpr absl::uint128 infinity() { return 0; }
+  static constexpr absl::uint128 quiet_NaN() { return 0; }
+  static constexpr absl::uint128 signaling_NaN() { return 0; }
+  static constexpr absl::uint128 denorm_min() { return 0; }
+};
+}  // namespace std
+
 // TODO(absl-team): Implement signed 128-bit type
 
 // --------------------------------------------------------------------------
 //                      Implementation details follow
 // --------------------------------------------------------------------------
+namespace absl {
 
 constexpr uint128 MakeUint128(uint64_t high, uint64_t low) {
   return uint128(high, low);
 }
 
-constexpr uint128 Uint128Max() {
-  return uint128(std::numeric_limits<uint64_t>::max(),
-                 std::numeric_limits<uint64_t>::max());
-}
-
 // Assignment from integer types.
 
 inline uint128& uint128::operator=(int v) { return *this = uint128(v); }