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109 lines
4.4 KiB
C++
109 lines
4.4 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// Copyright (c) Microsoft Corporation.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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// Copyright 2018 Ulf Adams
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// Copyright (c) Microsoft Corporation. All rights reserved.
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// Boost Software License - Version 1.0 - August 17th, 2003
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// Permission is hereby granted, free of charge, to any person or organization
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// obtaining a copy of the software and accompanying documentation covered by
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// this license (the "Software") to use, reproduce, display, distribute,
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// execute, and transmit the Software, and to prepare derivative works of the
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// Software, and to permit third-parties to whom the Software is furnished to
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// do so, all subject to the following:
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// The copyright notices in the Software and this entire statement, including
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// the above license grant, this restriction and the following disclaimer,
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// must be included in all copies of the Software, in whole or in part, and
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// all derivative works of the Software, unless such copies or derivative
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// works are solely in the form of machine-executable object code generated by
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// a source language processor.
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
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// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
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// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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#ifndef _LIBCPP_SRC_INCLUDE_RYU_COMMON_H
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#define _LIBCPP_SRC_INCLUDE_RYU_COMMON_H
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// Avoid formatting to keep the changes with the original code minimal.
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// clang-format off
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#include <__assert>
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#include <__config>
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#include <cstring>
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_LIBCPP_BEGIN_NAMESPACE_STD
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __decimalLength9(const uint32_t __v) {
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// Function precondition: __v is not a 10-digit number.
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// (f2s: 9 digits are sufficient for round-tripping.)
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// (d2fixed: We print 9-digit blocks.)
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_LIBCPP_ASSERT_INTERNAL(__v < 1000000000, "");
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if (__v >= 100000000) { return 9; }
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if (__v >= 10000000) { return 8; }
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if (__v >= 1000000) { return 7; }
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if (__v >= 100000) { return 6; }
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if (__v >= 10000) { return 5; }
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if (__v >= 1000) { return 4; }
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if (__v >= 100) { return 3; }
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if (__v >= 10) { return 2; }
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return 1;
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}
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// Returns __e == 0 ? 1 : ceil(log_2(5^__e)).
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline int32_t __pow5bits(const int32_t __e) {
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// This approximation works up to the point that the multiplication overflows at __e = 3529.
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// If the multiplication were done in 64 bits, it would fail at 5^4004 which is just greater
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// than 2^9297.
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_LIBCPP_ASSERT_INTERNAL(__e >= 0, "");
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_LIBCPP_ASSERT_INTERNAL(__e <= 3528, "");
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return static_cast<int32_t>(((static_cast<uint32_t>(__e) * 1217359) >> 19) + 1);
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}
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// Returns floor(log_10(2^__e)).
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __log10Pow2(const int32_t __e) {
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// The first value this approximation fails for is 2^1651 which is just greater than 10^297.
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_LIBCPP_ASSERT_INTERNAL(__e >= 0, "");
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_LIBCPP_ASSERT_INTERNAL(__e <= 1650, "");
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return (static_cast<uint32_t>(__e) * 78913) >> 18;
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}
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// Returns floor(log_10(5^__e)).
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __log10Pow5(const int32_t __e) {
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// The first value this approximation fails for is 5^2621 which is just greater than 10^1832.
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_LIBCPP_ASSERT_INTERNAL(__e >= 0, "");
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_LIBCPP_ASSERT_INTERNAL(__e <= 2620, "");
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return (static_cast<uint32_t>(__e) * 732923) >> 20;
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}
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint32_t __float_to_bits(const float __f) {
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uint32_t __bits = 0;
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std::memcpy(&__bits, &__f, sizeof(float));
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return __bits;
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}
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI inline uint64_t __double_to_bits(const double __d) {
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uint64_t __bits = 0;
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std::memcpy(&__bits, &__d, sizeof(double));
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return __bits;
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}
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_LIBCPP_END_NAMESPACE_STD
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// clang-format on
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#endif // _LIBCPP_SRC_INCLUDE_RYU_COMMON_H
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