68 lines
2.4 KiB
C++
68 lines
2.4 KiB
C++
// Copyright 2020 The Pigweed Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not
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// use this file except in compliance with the License. You may obtain a copy of
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// the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations under
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// the License.
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#pragma once
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#include <limits.h>
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#include "pw_polyfill/standard_library/namespace.h"
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_PW_POLYFILL_BEGIN_NAMESPACE_STD
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template <typename T>
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struct numeric_limits {
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static constexpr bool is_specialized = false;
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};
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// Only a few of the numeric_limits methods are implemented.
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#define _PW_LIMITS_SPECIALIZATION( \
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type, val_signed, val_int, min_value, max_value) \
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template <> \
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struct numeric_limits<type> { \
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static constexpr bool is_specialized = true; \
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\
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static constexpr bool is_signed = (val_signed); \
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static constexpr bool is_integer = (val_int); \
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\
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static constexpr type min() noexcept { return (min_value); } \
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static constexpr type max() noexcept { return (max_value); } \
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}
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#define _PW_INTEGRAL_LIMIT(type, sname, uname) \
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_PW_LIMITS_SPECIALIZATION( \
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signed type, true, true, sname##_MIN, sname##_MAX); \
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_PW_LIMITS_SPECIALIZATION(unsigned type, false, true, 0u, uname##_MAX)
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_PW_LIMITS_SPECIALIZATION(bool, false, true, false, true);
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_PW_LIMITS_SPECIALIZATION(char, char(-1) < char(0), true, CHAR_MIN, CHAR_MAX);
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_PW_INTEGRAL_LIMIT(char, SCHAR, UCHAR);
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_PW_INTEGRAL_LIMIT(short, SHRT, USHRT);
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_PW_INTEGRAL_LIMIT(int, INT, UINT);
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_PW_INTEGRAL_LIMIT(long, LONG, ULONG);
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#ifndef LLONG_MIN
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#define LLONG_MIN ((long long)(~0ull ^ (~0ull >> 1)))
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#define LLONG_MAX ((long long)(~0ull >> 1))
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#define ULLONG_MIN (0ull)
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#define ULLONG_MAX (~0ull)
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#endif // LLONG_MIN
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_PW_INTEGRAL_LIMIT(long long, LLONG, ULLONG);
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#undef _PW_LIMITS_SPECIALIZATION
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#undef _PW_INTEGRAL_LIMIT
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_PW_POLYFILL_END_NAMESPACE_STD
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