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Clarify matters of syntax

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ckormanyos
2025-09-06 13:51:02 +02:00
parent 2f07bf5e26
commit 16992622e9
2 changed files with 40 additions and 13 deletions
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13
include/boost/multiprecision/cpp_dec_float.hpp
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@@ -1932,8 +1932,17 @@ std::string cpp_dec_float<Digits10, ExponentType, Allocator>::str(std::intmax_t
}
else if (f & std::ios_base::scientific)
++number_of_digits;
// Determine the number of elements needed to provide the requested digits from cpp_dec_float<Digits10, ExponentType, Allocator>.
const std::size_t number_of_elements = (std::min)(static_cast<std::size_t>(static_cast<std::size_t>(number_of_digits / static_cast<std::intmax_t>(cpp_dec_float_elem_digits10)) + 2u),
// Determine the number of elements needed to provide the requested
// digits from cpp_dec_float<Digits10, ExponentType, Allocator>.
const std::intmax_t
number_of_elements_signed
{
(std::max)(static_cast<std::intmax_t>(number_of_digits / static_cast<std::intmax_t>(cpp_dec_float_elem_digits10) + 2),
std::intmax_t { INT8_C(0) })
};
const std::size_t number_of_elements = (std::min)(static_cast<std::size_t>(number_of_elements_signed),
static_cast<std::size_t>(cpp_dec_float_elem_number));
// Extract the remaining digits from cpp_dec_float<Digits10, ExponentType, Allocator> after the decimal point.

40
test/git_issue_734.cpp
View File

@@ -10,6 +10,7 @@
#include <iomanip>
#include <iostream>
#include <sstream>
#include <typeinfo>
namespace local {
@@ -18,11 +19,17 @@ auto my_stringify_via_top_level_number(const std::streamsize strm_size) -> std::
{
using float_type = boost::multiprecision::number<BackendType, boost::multiprecision::et_off>;
#if defined(BOOST_MSVC)
using streamsize_type = std::streamsize;
#else
using streamsize_type = int;
#endif
float_type x("0.0000000000000000222222222222222");
std::stringstream strm { };
strm << std::setprecision(strm_size) << std::fixed;
strm << std::setprecision(static_cast<streamsize_type>(strm_size)) << std::fixed;
strm << x;
return strm.str();
@@ -33,11 +40,17 @@ auto my_stringify_via_str_and_backend_str(const std::streamsize strm_size) -> st
{
using float_type = boost::multiprecision::number<BackendType, boost::multiprecision::et_off>;
#if defined(BOOST_MSVC)
using streamsize_type = std::streamsize;
#else
using streamsize_type = int;
#endif
float_type x("0.0000000000000000222222222222222");
std::stringstream strm { };
strm << std::setprecision(strm_size) << std::fixed;
strm << std::setprecision(static_cast<streamsize_type>(strm_size)) << std::fixed;
return x.str(strm_size, strm.flags());
}
@@ -45,15 +58,17 @@ auto my_stringify_via_str_and_backend_str(const std::streamsize strm_size) -> st
template<typename BackendType>
auto test() -> void
{
BOOST_TEST(my_stringify_via_top_level_number<BackendType>(0) == "0");
BOOST_TEST(my_stringify_via_top_level_number<BackendType>(8) == "0.00000000");
BOOST_TEST(my_stringify_via_top_level_number<BackendType>(12) == "0.000000000000");
BOOST_TEST(my_stringify_via_top_level_number<BackendType>(31) == "0.0000000000000000222222222222222");
std::cout << "Testing type of test: " << typeid(BackendType).name() << std::endl;
BOOST_TEST(my_stringify_via_str_and_backend_str<BackendType>(0) == "0");
BOOST_TEST(my_stringify_via_str_and_backend_str<BackendType>(8) == "0.00000000");
BOOST_TEST(my_stringify_via_str_and_backend_str<BackendType>(12) == "0.000000000000");
BOOST_TEST(my_stringify_via_str_and_backend_str<BackendType>(31) == "0.0000000000000000222222222222222");
BOOST_TEST(my_stringify_via_top_level_number<BackendType>(std::streamsize { INT8_C(0) }) == "0");
BOOST_TEST(my_stringify_via_top_level_number<BackendType>(std::streamsize { INT8_C(8) }) == "0.00000000");
BOOST_TEST(my_stringify_via_top_level_number<BackendType>(std::streamsize { INT8_C(12) }) == "0.000000000000");
BOOST_TEST(my_stringify_via_top_level_number<BackendType>(std::streamsize { INT8_C(31) }) == "0.0000000000000000222222222222222");
BOOST_TEST(my_stringify_via_str_and_backend_str<BackendType>(std::streamsize { INT8_C(0) }) == "0");
BOOST_TEST(my_stringify_via_str_and_backend_str<BackendType>(std::streamsize { INT8_C(8) }) == "0.00000000");
BOOST_TEST(my_stringify_via_str_and_backend_str<BackendType>(std::streamsize { INT8_C(12) }) == "0.000000000000");
BOOST_TEST(my_stringify_via_str_and_backend_str<BackendType>(std::streamsize { INT8_C(31) }) == "0.0000000000000000222222222222222");
}
} // namespace local
@@ -62,7 +77,10 @@ auto main() -> int
{
local::test<boost::multiprecision::cpp_bin_float<32>>();
local::test<boost::multiprecision::cpp_dec_float<32>>();
local::test<boost::multiprecision::cpp_double_fp_backend<double>>();
BOOST_IF_CONSTEXPR(std::numeric_limits<double>::digits >= 53)
{
local::test<boost::multiprecision::cpp_double_fp_backend<double>>();
}
return boost::report_errors();
}