1 // Copyright 2020 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include <limits.h> 17 18 #include "pw_polyfill/standard_library/namespace.h" 19 20 _PW_POLYFILL_BEGIN_NAMESPACE_STD 21 22 template <typename T> 23 struct numeric_limits { 24 static constexpr bool is_specialized = false; 25 }; 26 27 // Only a few of the numeric_limits methods are implemented. 28 #define _PW_LIMITS_SPECIALIZATION( \ 29 type, val_signed, val_int, min_value, max_value) \ 30 template <> \ 31 struct numeric_limits<type> { \ 32 static constexpr bool is_specialized = true; \ 33 \ 34 static constexpr bool is_signed = (val_signed); \ 35 static constexpr bool is_integer = (val_int); \ 36 \ 37 static constexpr type min() noexcept { return (min_value); } \ 38 static constexpr type max() noexcept { return (max_value); } \ 39 } 40 41 #define _PW_INTEGRAL_LIMIT(type, sname, uname) \ 42 _PW_LIMITS_SPECIALIZATION( \ 43 signed type, true, true, sname##_MIN, sname##_MAX); \ 44 _PW_LIMITS_SPECIALIZATION(unsigned type, false, true, 0u, uname##_MAX) 45 46 _PW_LIMITS_SPECIALIZATION(bool, false, true, false, true); 47 _PW_LIMITS_SPECIALIZATION(char, char(-1) < char(0), true, CHAR_MIN, CHAR_MAX); 48 49 _PW_INTEGRAL_LIMIT(char, SCHAR, UCHAR); 50 _PW_INTEGRAL_LIMIT(short, SHRT, USHRT); 51 _PW_INTEGRAL_LIMIT(int, INT, UINT); 52 _PW_INTEGRAL_LIMIT(long, LONG, ULONG); 53 54 #ifndef LLONG_MIN 55 #define LLONG_MIN ((long long)(~0ull ^ (~0ull >> 1))) 56 #define LLONG_MAX ((long long)(~0ull >> 1)) 57 58 #define ULLONG_MIN (0ull) 59 #define ULLONG_MAX (~0ull) 60 #endif // LLONG_MIN 61 62 _PW_INTEGRAL_LIMIT(long long, LLONG, ULLONG); 63 64 #undef _PW_LIMITS_SPECIALIZATION 65 #undef _PW_INTEGRAL_LIMIT 66 67 _PW_POLYFILL_END_NAMESPACE_STD 68