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Switch on precision rather than format

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This commit is contained in:
Matt Borland
2023-04-12 14:46:48 +02:00
parent 2084fc08bc
commit 96bb503485
2 changed files with 37 additions and 49 deletions
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84
src/to_chars.cpp
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@@ -327,70 +327,58 @@ boost::charconv::to_chars_result boost::charconv::to_chars(char* first, char* la
boost::charconv::to_chars_result boost::charconv::to_chars(char* first, char* last, double value, boost::charconv::chars_format fmt, int precision) noexcept
{
if (fmt == boost::charconv::chars_format::general || fmt == boost::charconv::chars_format::fixed)
// Unspecified precision so we always go with shortest representation
if (precision == -1)
{
const auto abs_value = std::abs(value);
if (abs_value >= 1 && abs_value < 1e16)
if (fmt == boost::charconv::chars_format::general || fmt == boost::charconv::chars_format::fixed)
{
auto value_struct = jkj::dragonbox::to_decimal(value);
if (value_struct.is_negative)
const auto abs_value = std::abs(value);
if (abs_value >= 1 && abs_value < 1e18) // 1 x 10^(max_digits10 + 1)
{
*first++ = '-';
}
auto value_struct = jkj::dragonbox::to_decimal(value);
if (value_struct.is_negative)
{
*first++ = '-';
}
auto r = boost::charconv::to_chars(first, last, value_struct.significand);
if (r.ec != 0)
{
return r;
}
std::memmove(r.ptr + value_struct.exponent + 1, r.ptr + value_struct.exponent, -value_struct.exponent);
std::memset(r.ptr + value_struct.exponent, '.', 1);
auto r = boost::charconv::to_chars(first, last, value_struct.significand);
if (r.ec != 0)
{
return r;
}
// Bounds check
if (value_struct.exponent < 0)
{
std::memmove(r.ptr + value_struct.exponent + 1, r.ptr + value_struct.exponent, -value_struct.exponent);
std::memset(r.ptr + value_struct.exponent, '.', 1);
}
return { r.ptr, 0 };
}
else if (abs_value >= 1e16 && abs_value < 1e20)
{
if (value < 0)
{
*first++ = '-';
return { r.ptr, 0 };
}
else
{
auto* ptr = jkj::dragonbox::to_chars(value, first);
return { ptr, 0 };
}
return boost::charconv::to_chars(first, last, static_cast<std::uint64_t>(abs_value));
}
else if (abs_value > 1e-288 && abs_value < 1e288)
else if (fmt == boost::charconv::chars_format::scientific)
{
auto* ptr = jkj::dragonbox::to_chars(value, first);
return { ptr, 0 };
}
else
}
else
{
if (fmt != boost::charconv::chars_format::hex)
{
if (precision == -1)
{
precision = std::numeric_limits<double>::max_digits10 - 1;
}
auto* ptr = boost::charconv::detail::floff<boost::charconv::detail::main_cache_full, boost::charconv::detail::extended_cache_long>(value, precision, first, fmt);
return { ptr, 0 };
}
}
else if (fmt == boost::charconv::chars_format::scientific)
{
if (precision == -1)
{
precision = std::numeric_limits<double>::max_digits10;
}
if (precision > static_cast<std::ptrdiff_t>(last - first))
{
return { first, EOVERFLOW };
}
auto* ptr = boost::charconv::detail::floff<boost::charconv::detail::main_cache_full, boost::charconv::detail::extended_cache_long>(value, precision, first, fmt);
return { ptr, 0 };
}
else if (fmt == boost::charconv::chars_format::hex)
{
return boost::charconv::detail::to_chars_hex(first, last, value, precision);
}
return { first + std::strlen(first), 0 };
// Hex handles both cases already
return boost::charconv::detail::to_chars_hex(first, last, value, precision);
}
boost::charconv::to_chars_result boost::charconv::to_chars( char* first, char* last, long double value ) noexcept