79 lines
2.5 KiB
C++
79 lines
2.5 KiB
C++
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// Copyright 2023 Matt Borland
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// Distributed under the Boost Software License, Version 1.0.
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// https://www.boost.org/LICENSE_1_0.txt
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#ifndef BOOST_CHARCONV_DETAIL_MEMCPY_HPP
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#define BOOST_CHARCONV_DETAIL_MEMCPY_HPP
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#include <boost/charconv/detail/config.hpp>
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#include <cstring>
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#include <cstdint>
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// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89689
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// GCC 10 added checks for length of memcpy which yields the following warning (converted to error with -Werror)
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// /usr/include/x86_64-linux-gnu/bits/string_fortified.h:34:33: error:
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// ‘void* __builtin___memcpy_chk(void*, const void*, long unsigned int, long unsigned int)’ specified size between
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// 18446744071562067968 and 18446744073709551615 exceeds maximum object size 9223372036854775807 [-Werror=stringop-overflow=]
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//
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// memcpy is defined as taking a size_t for the count and the largest count this will recieve is the number of digits
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// in a 128-bit int (39) so we can safely ignore
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#if defined(__GNUC__) && __GNUC__ >= 10
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# pragma GCC diagnostic push
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# pragma GCC diagnostic ignored "-Wstringop-overflow"
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# define BOOST_CHARCONV_STRINGOP_OVERFLOW_DISABLED
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#endif
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namespace boost { namespace charconv { namespace detail {
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#if !defined(BOOST_CHARCONV_NO_CONSTEXPR_DETECTION) && defined(BOOST_CXX14_CONSTEXPR)
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#define BOOST_CHARCONV_CONSTEXPR constexpr
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constexpr char* memcpy(char* dest, const char* src, std::size_t count)
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{
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if (BOOST_CHARCONV_IS_CONSTANT_EVALUATED(count))
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{
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for (std::size_t i = 0; i < count; ++i)
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{
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*(dest + i) = *(src + i);
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}
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return dest;
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}
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else
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{
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// Workaround for GCC-11 because it does not honor GCC diagnostic ignored
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// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53431
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// Hopefully the optimizer turns this into memcpy
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#if defined(__GNUC__) && __GNUC__ == 11
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for (std::size_t i = 0; i < count; ++i)
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{
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*(dest + i) = *(src + i);
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}
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return dest;
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#else
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return static_cast<char*>(std::memcpy(dest, src, count));
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#endif
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}
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}
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#else // Either not C++14 or no way of telling if we are in a constexpr context
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#define BOOST_CHARCONV_CONSTEXPR inline
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inline void* memcpy(void* dest, const void* src, std::size_t count)
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{
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return std::memcpy(dest, src, count);
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}
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#endif
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}}} // Namespace boost::charconv::detail
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#ifdef BOOST_CHARCONV_STRINGOP_OVERFLOW_DISABLED
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# pragma GCC diagnostic pop
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#endif
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#endif // BOOST_CHARCONV_DETAIL_MEMCPY_HPP
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