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62 lines
2.0 KiB
C++
62 lines
2.0 KiB
C++
// Copyright 2025 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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//
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// See: https://github.com/boostorg/charconv/issues/280
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#include <boost/charconv.hpp>
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#include <boost/core/lightweight_test.hpp>
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#include <string>
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template <std::size_t precision>
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void test(const char* result_string)
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{
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constexpr double d = DBL_MIN;
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// for scientific, precision + 7 should suffice:
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// <digit> <.> <#precision digits> <e> <sign> <up to 3 digits>
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// 1 2 3 4 7
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constexpr size_t buf_size = precision + 7;
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char buf[buf_size];
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auto result = boost::charconv::to_chars(buf, buf + buf_size, d, boost::charconv::chars_format::scientific, precision);
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BOOST_TEST(result);
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// We have to use memcmp here since there is no space to null terminate
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BOOST_TEST(std::memcmp(buf, result_string, precision) == 0);
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}
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template <std::size_t precision>
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void test_negative(const char* result_string)
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{
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constexpr double d = -DBL_MIN;
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// for scientific, precision + 7 should suffice:
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// <digit> <.> <#precision digits> <e> <sign> <up to 3 digits>
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// 1 2 3 4 7
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constexpr size_t buf_size = 1 + precision + 7;
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char buf[buf_size];
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auto result = boost::charconv::to_chars(buf, buf + buf_size, d, boost::charconv::chars_format::scientific, precision);
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BOOST_TEST(result);
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// We have to use memcmp here since there is no space to null terminate
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BOOST_TEST(std::memcmp(buf, result_string, precision) == 0);
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}
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int main()
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{
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// DBL_MIN = 2.2250738585072013830902327173324040642192159804623318306e-308
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test<1>("2.2e-308");
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test<2>("2.23e-308");
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test<3>("2.225e-308");
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test<4>("2.2251e-308");
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test<5>("2.22507e-308");
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test_negative<1>("-2.2e-308");
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test_negative<2>("-2.23e-308");
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test_negative<3>("-2.225e-308");
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test_negative<4>("-2.2251e-308");
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test_negative<5>("-2.22507e-308");
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return boost::report_errors();
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}
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