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Fix to_static_string and improve coverage

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This commit is contained in:
Krystian Stasiowski
2020-02-22 15:43:52 -05:00
parent 58661d6564
commit b8d458571c
2 changed files with 151 additions and 37 deletions
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115
include/boost/static_string/static_string.hpp
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@ -246,7 +246,7 @@ public:
Traits::assign(data_[size_], value_type());
}
size_type size_{0};
size_type size_ = 0;
#ifdef BOOST_STATIC_STRING_CPP20
value_type data_[N + 1];
#else
@ -336,9 +336,20 @@ integer_to_string(
}
if (value < 0)
{
value = -value;
const bool is_min = value == std::numeric_limits<Integer>::min();
// negation of a min value cannot be represented
if (is_min)
value = std::numeric_limits<Integer>::max();
else
value = -value;
const auto last_char = str_end - 1;
for (; value > 0; value /= 10)
Traits::assign(*--str_end, "0123456789"[value % 10]);
// minimum values are powers of 2, so it will
// never terminate with a 9.
if (is_min)
Traits::assign(*last_char, Traits::to_char_type(
Traits::to_int_type(*last_char) + 1));
Traits::assign(*--str_end, '-');
return str_end;
}
@ -380,9 +391,20 @@ integer_to_wstring(
}
if (value < 0)
{
value = -value;
const bool is_min = value == std::numeric_limits<Integer>::min();
// negation of a min value cannot be represented
if (is_min)
value = std::numeric_limits<Integer>::max();
else
value = -value;
const auto last_char = str_end - 1;
for (; value > 0; value /= 10)
Traits::assign(*--str_end, L"0123456789"[value % 10]);
// minimum values are powers of 2, so it will
// never terminate with a 9.
if (is_min)
Traits::assign(*last_char, Traits::to_char_type(
Traits::to_int_type(*last_char) + 1));
Traits::assign(*--str_end, L'-');
return str_end;
}
@ -433,6 +455,13 @@ to_static_wstring_int_impl(Integer value) noexcept
return static_wstring<N>(digits_begin, std::distance(digits_begin, digits_end));
}
BOOST_STATIC_STRING_CPP11_CONSTEXPR
inline
std::size_t count_digits(std::size_t value)
{
return value < 10 ? 1 : count_digits(value / 10) + 1;
}
template<std::size_t N>
inline
static_string<N>
@ -440,7 +469,27 @@ to_static_string_float_impl(double value) noexcept
{
// extra one needed for null terminator
char buffer[N + 1];
std::sprintf(buffer, "%f", value);
const auto write_count =
std::snprintf(buffer, N + 1, "%f", value);
// since our buffer has a fixed size, if the number of characters
// that would be written exceeds the size of the buffer,
// we need touse scientific notation instead.
// the number is converted into the format
// [-]d.ddde(+/-)dd; the exponent will contain at least
// 2 digits, the integral part will be 1 digit, the fractional
// part will be the length of the specified precision, and 3
// characters will be needed for e, the sign of the exponent
// and the potential sign of the integral part, total of 6 chars.
// we will reserve 7 characters just in case the size of the exponent
// is 3 characters.
if (write_count > N)
{
const auto period =
std::char_traits<char>::find(buffer, N, '.');
// we want at least 2 decimal places
if (!period || std::size_t(period - buffer) > N - 3)
std::snprintf(buffer, N + 1, "%.*e", int(N > 7 ? N - 7 : 0), value);
}
// this will not throw
return static_string<N>(buffer);
}
@ -452,7 +501,17 @@ to_static_string_float_impl(long double value) noexcept
{
// extra one needed for null terminator
char buffer[N + 1];
std::sprintf(buffer, "%Lf", value);
// number of characters written
const auto write_count =
std::snprintf(buffer, N + 1, "%Lf", value);
if (write_count > N)
{
const auto period =
std::char_traits<char>::find(buffer, N, '.');
// we want at least 2 decimal places
if (!period || std::size_t(period - buffer) > N - 3)
std::snprintf(buffer, N + 1, "%.*e", int(N > 7 ? N - 7 : 0), value);
}
// this will not throw
return static_string<N>(buffer);
}
@ -464,7 +523,16 @@ to_static_wstring_float_impl(double value) noexcept
{
// extra one needed for null terminator
wchar_t buffer[N + 1];
std::swprintf(buffer, N + 1, L"%f", value);
const auto write_count =
std::swprintf(buffer, N + 1, L"%f", value);
if (write_count > N)
{
const auto period =
std::char_traits<wchar_t>::find(buffer, N, '.');
// we want at least 2 decimal places
if (!period || std::size_t(period - buffer) > N - 3)
std::swprintf(buffer, N + 1, L"%.*e", int(N > 7 ? N - 7 : 0), value);
}
// this will not throw
return static_wstring<N>(buffer);
}
@ -476,7 +544,16 @@ to_static_wstring_float_impl(long double value) noexcept
{
// extra one needed for null terminator
wchar_t buffer[N + 1];
std::swprintf(buffer, N + 1, L"%Lf", value);
const auto write_count =
std::swprintf(buffer, N + 1, L"%Lf", value);
if (write_count > N)
{
const auto period =
std::char_traits<wchar_t>::find(buffer, N, '.');
// we want at least 2 decimal places
if (!period || std::size_t(period - buffer) > N - 3)
std::swprintf(buffer, N + 1, L"%.*e", int(N > 7 ? N - 7 : 0), value);
}
// this will not throw
return static_wstring<N>(buffer);
}
@ -4510,30 +4587,30 @@ operator<<(
//------------------------------------------------------------------------------
/// Converts `value` to a `static_string`
static_string<std::numeric_limits<int>::digits10 + 1>
static_string<std::numeric_limits<int>::digits10 + 2>
inline
to_static_string(int value) noexcept
{
return detail::to_static_string_int_impl<
std::numeric_limits<int>::digits10 + 1>(value);
std::numeric_limits<int>::digits10 + 2>(value);
}
/// Converts `value` to a `static_string`
static_string<std::numeric_limits<long>::digits10 + 1>
static_string<std::numeric_limits<long>::digits10 + 2>
inline
to_static_string(long value) noexcept
{
return detail::to_static_string_int_impl<
std::numeric_limits<long>::digits10 + 1>(value);
std::numeric_limits<long>::digits10 + 2>(value);
}
/// Converts `value` to a `static_string`
static_string<std::numeric_limits<long long>::digits10 + 1>
static_string<std::numeric_limits<long long>::digits10 + 2>
inline
to_static_string(long long value) noexcept
{
return detail::to_static_string_int_impl<
std::numeric_limits<long long>::digits10 + 1>(value);
std::numeric_limits<long long>::digits10 + 2>(value);
}
/// Converts `value` to a `static_string`
@ -4591,30 +4668,30 @@ to_static_string(long double value) noexcept
}
/// Converts `value` to a `static_wstring`
static_wstring<std::numeric_limits<int>::digits10 + 1>
static_wstring<std::numeric_limits<int>::digits10 + 2>
inline
to_static_wstring(int value) noexcept
{
return detail::to_static_wstring_int_impl<
std::numeric_limits<int>::digits10 + 1>(value);
std::numeric_limits<int>::digits10 + 2>(value);
}
/// Converts `value` to a `static_wstring`
static_wstring<std::numeric_limits<long>::digits10 + 1>
static_wstring<std::numeric_limits<long>::digits10 + 2>
inline
to_static_wstring(long value) noexcept
{
return detail::to_static_wstring_int_impl<
std::numeric_limits<long>::digits10 + 1>(value);
std::numeric_limits<long>::digits10 + 2>(value);
}
/// Converts `value` to a `static_wstring`
static_wstring<std::numeric_limits<long long>::digits10 + 1>
static_wstring<std::numeric_limits<long long>::digits10 + 2>
inline
to_static_wstring(long long value) noexcept
{
return detail::to_static_wstring_int_impl<
std::numeric_limits<long long>::digits10 + 1>(value);
std::numeric_limits<long long>::digits10 + 2>(value);
}
/// Converts `value` to a `static_wstring`