| // Copyright 2018 The Fuchsia Authors |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #pragma once |
| |
| // TODO(https://fxbug.dev/42106615): The libc++ <limits> defines specializations for |
| // floating-point types, which in GCC is incompatible with the command-line |
| // switches used for the kernel. So this header fakes out the other libc++ |
| // headers with a std::numeric_limits that is close enough. |
| |
| #include <limits.h> |
| |
| namespace std { |
| |
| template <class T> |
| class numeric_limits {}; |
| |
| #define SPECIALIZE_INT(type, sign, modulo, digits_, min_, max_) \ |
| template <> \ |
| class numeric_limits<type> { \ |
| public: \ |
| static constexpr bool is_specialized = true; \ |
| static constexpr bool is_signed = (sign); \ |
| 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 bool has_denorm = false; \ |
| static constexpr bool has_denorm_loss = false; \ |
| static constexpr bool round_style = false; \ |
| static constexpr bool is_iec559 = false; \ |
| static constexpr bool is_bounded = true; \ |
| static constexpr bool is_modulo = (modulo); \ |
| static constexpr int digits = (digits_); \ |
| static constexpr int digits10 = (digits_) * 3 / 10; \ |
| 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; \ |
| static constexpr bool traps = false; \ |
| static constexpr bool tinyness_before = false; \ |
| static constexpr type min() { \ |
| return (min_); \ |
| } \ |
| static constexpr type lowest() { \ |
| return (min_); \ |
| } \ |
| static constexpr type max() { \ |
| return (max_); \ |
| } \ |
| static constexpr type epsilon() { \ |
| return 0; \ |
| } \ |
| static constexpr type round_error() { \ |
| return 0; \ |
| } \ |
| static constexpr type infinity() { \ |
| return 0; \ |
| } \ |
| static constexpr type quiet_NaN() { \ |
| return 0; \ |
| } \ |
| static constexpr type signaling_NaN() { \ |
| return 0; \ |
| } \ |
| static constexpr type denorm_min() { \ |
| return 0; \ |
| } \ |
| } |
| |
| #define SPECIALIZE_SIGNED(type, min, max) \ |
| SPECIALIZE_INT(type, true, false, CHAR_BIT * sizeof(type) - 1, min, max) |
| |
| #define SPECIALIZE_UNSIGNED(type, min, max) \ |
| SPECIALIZE_INT(type, false, true, CHAR_BIT * sizeof(type), min, max) |
| |
| SPECIALIZE_INT(bool, false, true, 1, false, true); |
| #if CHAR_MIN == 0 |
| SPECIALIZE_SIGNED(char, CHAR_MIN, CHAR_MAX); |
| #else |
| SPECIALIZE_UNSIGNED(char, CHAR_MIN, CHAR_MAX); |
| #endif |
| SPECIALIZE_SIGNED(signed char, SCHAR_MIN, SCHAR_MAX); |
| SPECIALIZE_UNSIGNED(unsigned char, 0, UCHAR_MAX); |
| |
| SPECIALIZE_SIGNED(short, SHRT_MIN, SHRT_MAX); |
| SPECIALIZE_UNSIGNED(unsigned short, 0, USHRT_MAX); |
| SPECIALIZE_SIGNED(int, INT_MIN, INT_MAX); |
| SPECIALIZE_UNSIGNED(unsigned int, 0, UINT_MAX); |
| SPECIALIZE_SIGNED(long, LONG_MIN, LONG_MAX); |
| SPECIALIZE_UNSIGNED(unsigned long, 0, ULONG_MAX); |
| SPECIALIZE_SIGNED(long long, (-__LONG_LONG_MAX__ - 1LL), __LONG_LONG_MAX__); |
| SPECIALIZE_UNSIGNED(unsigned long long, 0, (__LONG_LONG_MAX__ * 2ULL + 1ULL)); |
| |
| #ifdef __SIZEOF_INT128__ |
| SPECIALIZE_SIGNED(__int128_t, (__int128_t{1} << 127), (~__uint128_t{0} ^ (__int128_t{1} << 127))); |
| SPECIALIZE_UNSIGNED(__uint128_t, 0, (~__uint128_t{0})); |
| #endif |
| |
| #undef SPECIALIZE_SIGNED |
| #undef SPECIALIZE_UNSIGNED |
| #undef SPECIALIZE_INT |
| |
| } // namespace std |
