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// Copyright 2023 Peter Dimov
// Copyright 2023 Matt Borland
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
#include <boost/charconv/detail/config.hpp>
#include <ostream>
#ifdef BOOST_CHARCONV_HAS_STDFLOAT128
#include <charconv>
std::ostream& operator<<( std::ostream& os, std::float128_t v)
{
char buffer [ 256 ] {};
std::to_chars(buffer, buffer + sizeof(buffer), v);
os << buffer;
return os;
}
#endif
#include <boost/charconv/to_chars.hpp>
#include <boost/core/type_name.hpp>
#include <boost/core/detail/splitmix64.hpp>
#include <boost/config.hpp>
#include <type_traits>
#include <chrono>
#include <cstdio>
#include <iostream>
#include <iomanip>
#include <charconv>
constexpr unsigned N = 2'000'000;
constexpr int K = 10;
template<class T> static BOOST_NOINLINE void init_input_data( std::vector<T>& data )
{
data.reserve( N );
boost::detail::splitmix64 rng;
for( unsigned i = 0; i < N; ++i )
{
std::uint64_t tmp = rng();
T x;
std::memcpy( &x, &tmp, sizeof(x) );
if( !std::isfinite(x) ) continue;
data.push_back( x );
}
}
#ifdef BOOST_CHARCONV_HAS_STDFLOAT128
template<> BOOST_NOINLINE void init_input_data<std::float128_t>( std::vector<std::float128_t>& data )
{
data.reserve( N );
boost::detail::splitmix64 rng;
for( unsigned i = 0; i < N; ++i )
{
boost::charconv::detail::uint128 tmp {rng(), rng()};
boost::uint128_type temp {tmp};
std::float128_t x;
std::memcpy( &x, &temp, sizeof(x) );
if( !std::isfinite(x) ) continue;
data.push_back( x );
}
}
#endif
using namespace std::chrono_literals;
template<class T> static BOOST_NOINLINE void test_snprintf( std::vector<T> const& data, bool general, char const* label, int precision )
{
auto t1 = std::chrono::steady_clock::now();
std::size_t s = 0;
char const* format = general? "%.*g": "%.*e";
int prec = precision;
if( prec == 0 )
{
prec = 16;
BOOST_IF_CONSTEXPR( std::is_same<T, float>::value )
{
prec = 8;
}
}
for( int i = 0; i < K; ++i )
{
char buffer[ 22 ];
for( auto x: data )
{
auto r = std::snprintf( buffer, sizeof( buffer ), format, prec, x );
s += r;
s += static_cast<unsigned char>( buffer[0] );
}
}
auto t2 = std::chrono::steady_clock::now();
std::cout << " std::snprintf<" << boost::core::type_name<T>() << ">, " << label << ", " << precision << ": " << std::setw( 5 ) << ( t2 - t1 ) / 1ms << " ms (s=" << s << ")\n";
}
template<class T> static BOOST_NOINLINE void test_std_to_chars( std::vector<T> const& data, bool general, char const* label, int precision )
{
auto t1 = std::chrono::steady_clock::now();
std::size_t s = 0;
for( int i = 0; i < K; ++i )
{
char buffer[ 21 ];
for( auto x: data )
{
std::chars_format fmt = general? std::chars_format::general: std::chars_format::scientific;
auto r = precision == 0?
std::to_chars( buffer, buffer + sizeof( buffer ), x, fmt ):
std::to_chars( buffer, buffer + sizeof( buffer ), x, fmt, precision );
s += static_cast<std::size_t>( r.ptr - buffer );
s += static_cast<unsigned char>( buffer[0] );
}
}
auto t2 = std::chrono::steady_clock::now();
std::cout << " std::to_chars<" << boost::core::type_name<T>() << ">, " << label << ", " << precision << ": " << std::setw( 5 ) << ( t2 - t1 ) / 1ms << " ms (s=" << s << ")\n";
}
template<class T> static BOOST_NOINLINE void test_boost_to_chars( std::vector<T> const& data, bool general, char const* label, int precision )
{
auto t1 = std::chrono::steady_clock::now();
std::size_t s = 0;
for( int i = 0; i < K; ++i )
{
char buffer[ 21 ];
for( auto x: data )
{
boost::charconv::chars_format fmt = general? boost::charconv::chars_format::general: boost::charconv::chars_format::scientific;
auto r = precision == 0?
boost::charconv::to_chars( buffer, buffer + sizeof( buffer ), x, fmt ):
boost::charconv::to_chars( buffer, buffer + sizeof( buffer ), x, fmt, precision );
s += static_cast<std::size_t>( r.ptr - buffer );
s += static_cast<unsigned char>( buffer[0] );
}
}
auto t2 = std::chrono::steady_clock::now();
std::cout << "boost::charconv::to_chars<" << boost::core::type_name<T>() << ">, " << label << ", " << precision << ": " << std::setw( 5 ) << ( t2 - t1 ) / 1ms << " ms (s=" << s << ")\n";
}
template<class T> static void test()
{
std::vector<T> data;
init_input_data( data );
test_snprintf( data, false, "scientific", 0 );
test_std_to_chars( data, false, "scientific", 0 );
test_boost_to_chars( data, false, "scientific", 0 );
std::cout << std::endl;
test_snprintf( data, false, "scientific", 6 );
test_std_to_chars( data, false, "scientific", 6 );
test_boost_to_chars( data, false, "scientific", 6 );
std::cout << std::endl;
test_snprintf( data, true, "general", 0 );
test_std_to_chars( data, true, "general", 0 );
test_boost_to_chars( data, true, "general", 0 );
std::cout << std::endl;
test_snprintf( data, true, "general", 6 );
test_std_to_chars( data, true, "general", 6 );
test_boost_to_chars( data, true, "general", 6 );
std::cout << std::endl;
}
#ifdef BOOST_CHARCONV_HAS_STDFLOAT128
template<> void test<std::float128_t>()
{
std::vector<std::float128_t> data;
init_input_data( data );
test_std_to_chars( data, false, "scientific", 0 );
test_boost_to_chars( data, false, "scientific", 0 );
std::cout << std::endl;
test_std_to_chars( data, false, "scientific", 6 );
test_boost_to_chars( data, false, "scientific", 6 );
std::cout << std::endl;
test_std_to_chars( data, true, "general", 0 );
test_boost_to_chars( data, true, "general", 0 );
std::cout << std::endl;
test_std_to_chars( data, true, "general", 6 );
test_boost_to_chars( data, true, "general", 6 );
std::cout << std::endl;
}
#endif
int main()
{
std::cout << BOOST_COMPILER << "\n";
std::cout << BOOST_STDLIB << "\n\n";
test<float>();
test<double>();
#ifdef BOOST_CHARCONV_HAS_STDFLOAT128
test<std::float128_t>();
#endif
}
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