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♻️ replace snprintf with stream

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Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2025-05-17 17:49:45 +02:00
parent dfb9eb6eec
commit b6d265367b
2 changed files with 14 additions and 96 deletions
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55
include/nlohmann/detail/output/serializer.hpp
View File

@@ -17,6 +17,7 @@
#include <cstdint> // uint8_t #include <cstdint> // uint8_t
#include <cstdio> // snprintf #include <cstdio> // snprintf
#include <limits> // numeric_limits #include <limits> // numeric_limits
#include <sstream> // string_stream
#include <string> // string, char_traits #include <string> // string, char_traits
#include <iomanip> // setfill, setw #include <iomanip> // setfill, setw
#include <type_traits> // is_same #include <type_traits> // is_same
@@ -827,55 +828,13 @@ class serializer
void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/) void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/)
{ {
// get number of digits for a float -> text -> float round-trip std::ostringstream oss;
static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10; oss.precision(std::numeric_limits<number_float_t>::max_digits10);
oss.imbue(std::locale::classic());
oss << std::defaultfloat << x;
// the actual conversion (Note that is_ieee_single_or_double==false const auto s = oss.str();
// rules out that number_float_t is double or long double. Therefore, o->write_characters(s.c_str(), s.size());
// we need to cast the argument x to double to be able to use snprintf.)
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
std::ptrdiff_t len = (std::snprintf)(number_buffer.data(), number_buffer.size(), "%.*g", d, static_cast<double>(x));
// negative value indicates an error
JSON_ASSERT(len > 0);
// check if buffer was large enough
JSON_ASSERT(static_cast<std::size_t>(len) < number_buffer.size());
// erase thousands separator
if (thousands_sep != '\0')
{
// NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::remove returns an iterator, see https://github.com/nlohmann/json/issues/3081
const auto end = std::remove(number_buffer.begin(), number_buffer.begin() + len, thousands_sep);
std::fill(end, number_buffer.end(), '\0');
JSON_ASSERT((end - number_buffer.begin()) <= len);
len = (end - number_buffer.begin());
}
// convert decimal point to '.'
if (decimal_point != '\0' && decimal_point != '.')
{
// NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::find returns an iterator, see https://github.com/nlohmann/json/issues/3081
const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
if (dec_pos != number_buffer.end())
{
*dec_pos = '.';
}
}
o->write_characters(number_buffer.data(), static_cast<std::size_t>(len));
// determine if we need to append ".0"
const bool value_is_int_like =
std::none_of(number_buffer.begin(), number_buffer.begin() + len + 1,
[](char c)
{
return c == '.' || c == 'e';
});
if (value_is_int_like)
{
o->write_characters(".0", 2);
}
} }
/*! /*!

55
single_include/nlohmann/json.hpp
View File

@@ -17625,6 +17625,7 @@ NLOHMANN_JSON_NAMESPACE_END
#include <cstdint> // uint8_t #include <cstdint> // uint8_t
#include <cstdio> // snprintf #include <cstdio> // snprintf
#include <limits> // numeric_limits #include <limits> // numeric_limits
#include <sstream> // string_stream
#include <string> // string, char_traits #include <string> // string, char_traits
#include <iomanip> // setfill, setw #include <iomanip> // setfill, setw
#include <type_traits> // is_same #include <type_traits> // is_same
@@ -19562,55 +19563,13 @@ class serializer
void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/) void dump_float(number_float_t x, std::false_type /*is_ieee_single_or_double*/)
{ {
// get number of digits for a float -> text -> float round-trip std::ostringstream oss;
static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10; oss.precision(std::numeric_limits<number_float_t>::max_digits10);
oss.imbue(std::locale::classic());
oss << std::defaultfloat << x;
// the actual conversion (Note that is_ieee_single_or_double==false const auto s = oss.str();
// rules out that number_float_t is double or long double. Therefore, o->write_characters(s.c_str(), s.size());
// we need to cast the argument x to double to be able to use snprintf.)
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
std::ptrdiff_t len = (std::snprintf)(number_buffer.data(), number_buffer.size(), "%.*g", d, static_cast<double>(x));
// negative value indicates an error
JSON_ASSERT(len > 0);
// check if buffer was large enough
JSON_ASSERT(static_cast<std::size_t>(len) < number_buffer.size());
// erase thousands separator
if (thousands_sep != '\0')
{
// NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::remove returns an iterator, see https://github.com/nlohmann/json/issues/3081
const auto end = std::remove(number_buffer.begin(), number_buffer.begin() + len, thousands_sep);
std::fill(end, number_buffer.end(), '\0');
JSON_ASSERT((end - number_buffer.begin()) <= len);
len = (end - number_buffer.begin());
}
// convert decimal point to '.'
if (decimal_point != '\0' && decimal_point != '.')
{
// NOLINTNEXTLINE(readability-qualified-auto,llvm-qualified-auto): std::find returns an iterator, see https://github.com/nlohmann/json/issues/3081
const auto dec_pos = std::find(number_buffer.begin(), number_buffer.end(), decimal_point);
if (dec_pos != number_buffer.end())
{
*dec_pos = '.';
}
}
o->write_characters(number_buffer.data(), static_cast<std::size_t>(len));
// determine if we need to append ".0"
const bool value_is_int_like =
std::none_of(number_buffer.begin(), number_buffer.begin() + len + 1,
[](char c)
{
return c == '.' || c == 'e';
});
if (value_is_int_like)
{
o->write_characters(".0", 2);
}
} }
/*! /*!