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 static constexpr int digits = 0; 26 }; 27 28 // Only a few of the numeric_limits methods are implemented. 29 #define _PW_LIMITS_SPECIALIZATION( \ 30 type, val_signed, val_int, min_value, max_value, digits_value) \ 31 template <> \ 32 struct numeric_limits<type> { \ 33 static constexpr bool is_specialized = true; \ 34 \ 35 static constexpr bool is_signed = (val_signed); \ 36 static constexpr bool is_integer = (val_int); \ 37 \ 38 static constexpr int digits = (digits_value); \ 39 \ 40 static constexpr type min() noexcept { return (min_value); } \ 41 static constexpr type max() noexcept { return (max_value); } \ 42 } 43 44 #define _PW_INTEGRAL_LIMIT(type, sname, uname) \ 45 _PW_LIMITS_SPECIALIZATION(signed type, \ 46 true, \ 47 true, \ 48 sname##_MIN, \ 49 sname##_MAX, \ 50 CHAR_BIT * sizeof(type)); \ 51 _PW_LIMITS_SPECIALIZATION(unsigned type, \ 52 false, \ 53 true, \ 54 0u, \ 55 uname##_MAX, \ 56 CHAR_BIT * sizeof(type) - 1) 57 58 _PW_LIMITS_SPECIALIZATION(bool, false, true, false, true, 1); 59 _PW_LIMITS_SPECIALIZATION( 60 char, char(-1) < char(0), true, CHAR_MIN, CHAR_MAX, 1); 61 62 _PW_INTEGRAL_LIMIT(char, SCHAR, UCHAR); 63 _PW_INTEGRAL_LIMIT(short, SHRT, USHRT); 64 _PW_INTEGRAL_LIMIT(int, INT, UINT); 65 _PW_INTEGRAL_LIMIT(long, LONG, ULONG); 66 67 #ifndef LLONG_MIN 68 #define LLONG_MIN ((long long)(~0ull ^ (~0ull >> 1))) 69 #define LLONG_MAX ((long long)(~0ull >> 1)) 70 71 #define ULLONG_MIN (0ull) 72 #define ULLONG_MAX (~0ull) 73 #endif // LLONG_MIN 74 75 _PW_INTEGRAL_LIMIT(long long, LLONG, ULLONG); 76 77 #undef _PW_LIMITS_SPECIALIZATION 78 #undef _PW_INTEGRAL_LIMIT 79 80 _PW_POLYFILL_END_NAMESPACE_STD 81