| // 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_UNSIGNED(char, CHAR_MIN, CHAR_MAX); | |
| #else | |
| SPECIALIZE_SIGNED(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 |