luo980/json
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge 0132248b61 into 8215dbafbd

Browse Source
This commit is contained in:
Daniel Oberhoff 2025-02-22 06:11:49 +01:00 committed by GitHub
commit 9da75c17c5
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
5 changed files with 101 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
include/nlohmann/detail/conversions/to_chars.hpp
View File

@ -978,10 +978,11 @@ notation. Otherwise it will be printed in exponential notation.
JSON_HEDLEY_NON_NULL(1)
JSON_HEDLEY_RETURNS_NON_NULL
inline char* format_buffer(char* buf, int len, int decimal_exponent,
int min_exp, int max_exp)
int min_exp, int max_exp, size_t precision)
{
JSON_ASSERT(min_exp < 0);
JSON_ASSERT(max_exp > 0);
precision = (std::min)<size_t>(precision, std::numeric_limits<FloatType>::max_digits10);
const int k = len;
const int n = len + decimal_exponent;
@ -1009,6 +1010,9 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
JSON_ASSERT(k > n);
// truncate the digits by the precision
k = (std::min)(static_cast<size_t>(n) + precision, static_cast<size_t>(k));
std::memmove(buf + (static_cast<size_t>(n) + 1), buf + n, static_cast<size_t>(k) - static_cast<size_t>(n));
buf[n] = '.';
return buf + (static_cast<size_t>(k) + 1U);
@ -1023,7 +1027,8 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
buf[0] = '0';
buf[1] = '.';
std::memset(buf + 2, '0', static_cast<size_t>(-n));
return buf + (2U + static_cast<size_t>(-n) + static_cast<size_t>(k));
// truncate the reported buffer end by the precision
return buf + (std::min)(precision + 2, (2U + static_cast<size_t>(-n) + static_cast<size_t>(k)));
}
if (k == 1)
@ -1040,7 +1045,7 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
std::memmove(buf + 2, buf + 1, static_cast<size_t>(k) - 1);
buf[1] = '.';
buf += 1 + static_cast<size_t>(k);
buf += 1 + (std::min)(precision, static_cast<size_t>(k));
}
*buf++ = 'e';
@ -1062,7 +1067,7 @@ format. Returns an iterator pointing past-the-end of the decimal representation.
template<typename FloatType>
JSON_HEDLEY_NON_NULL(1, 2)
JSON_HEDLEY_RETURNS_NON_NULL
char* to_chars(char* first, const char* last, FloatType value)
char* to_chars(char* first, const char* last, FloatType value, size_t precision = std::numeric_limits<FloatType>::max_digits10)
{
static_cast<void>(last); // maybe unused - fix warning
JSON_ASSERT(std::isfinite(value));
@ -1111,7 +1116,7 @@ char* to_chars(char* first, const char* last, FloatType value)
JSON_ASSERT(last - first >= 2 + (-kMinExp - 1) + std::numeric_limits<FloatType>::max_digits10);
JSON_ASSERT(last - first >= std::numeric_limits<FloatType>::max_digits10 + 6);
return dtoa_impl::format_buffer(first, len, decimal_exponent, kMinExp, kMaxExp);
return dtoa_impl::format_buffer(first, len, decimal_exponent, kMinExp, kMaxExp, precision);
}
} // namespace detail

11
include/nlohmann/detail/output/serializer.hpp
View File

@ -64,13 +64,14 @@ class serializer
@param[in] ichar indentation character to use
@param[in] error_handler_ how to react on decoding errors
*/
serializer(output_adapter_t<char> s, const char ichar,
serializer(output_adapter_t<char> s, const char ichar, std::size_t prec = 1000,
error_handler_t error_handler_ = error_handler_t::strict)
: o(std::move(s))
, loc(std::localeconv())
, thousands_sep(loc->thousands_sep == nullptr ? '\0' : std::char_traits<char>::to_char_type(* (loc->thousands_sep)))
, decimal_point(loc->decimal_point == nullptr ? '\0' : std::char_traits<char>::to_char_type(* (loc->decimal_point)))
, indent_char(ichar)
, precision(prec)
, indent_string(512, indent_char)
, error_handler(error_handler_)
{}
@ -820,7 +821,7 @@ class serializer
void dump_float(number_float_t x, std::true_type /*is_ieee_single_or_double*/)
{
auto* begin = number_buffer.data();
auto* end = ::nlohmann::detail::to_chars(begin, begin + number_buffer.size(), x);
auto* end = ::nlohmann::detail::to_chars(begin, begin + number_buffer.size(), x, precision);
o->write_characters(begin, static_cast<size_t>(end - begin));
}
@ -828,10 +829,10 @@ class serializer
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
static constexpr auto d = std::numeric_limits<number_float_t>::max_digits10;
static constexpr int d_max = std::numeric_limits<number_float_t>::max_digits10;
int d = static_cast<int>((std::min)(precision, static_cast<std::size_t>(d_max)));
// the actual conversion
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
std::ptrdiff_t len = (std::snprintf)(number_buffer.data(), number_buffer.size(), "%.*g", d, x);
// negative value indicates an error
@ -977,6 +978,8 @@ class serializer
/// the indentation character
const char indent_char;
/// precision for floating point output
std::size_t precision;
/// the indentation string
string_t indent_string;

8
include/nlohmann/json.hpp
View File

@ -1299,10 +1299,11 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
string_t dump(const int indent = -1,
const char indent_char = ' ',
const bool ensure_ascii = false,
const error_handler_t error_handler = error_handler_t::strict) const
const error_handler_t error_handler = error_handler_t::strict,
const size_t precision = std::numeric_limits<size_t>::max()) const
{
string_t result;
serializer s(detail::output_adapter<char, string_t>(result), indent_char, error_handler);
serializer s(detail::output_adapter<char, string_t>(result), indent_char, precision, error_handler);
if (indent >= 0)
{
@ -4010,8 +4011,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
o.width(0);
// do the actual serialization
serializer s(detail::output_adapter<char>(o), o.fill());
serializer s(detail::output_adapter<char>(o), o.fill(), static_cast<size_t>(o.precision())).;
s.dump(j, pretty_print, false, static_cast<unsigned int>(indentation));
return o;
}

35
single_include/nlohmann/json.hpp
View File

@ -18583,10 +18583,11 @@ notation. Otherwise it will be printed in exponential notation.
JSON_HEDLEY_NON_NULL(1)
JSON_HEDLEY_RETURNS_NON_NULL
inline char* format_buffer(char* buf, int len, int decimal_exponent,
int min_exp, int max_exp)
int min_exp, int max_exp, size_t precision)
{
JSON_ASSERT(min_exp < 0);
JSON_ASSERT(max_exp > 0);
precision = std::min<size_t>(precision, 1000);
const int k = len;
const int n = len + decimal_exponent;
@ -18616,7 +18617,7 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
std::memmove(buf + (static_cast<size_t>(n) + 1), buf + n, static_cast<size_t>(k) - static_cast<size_t>(n));
buf[n] = '.';
return buf + (static_cast<size_t>(k) + 1U);
return buf + (std::min(n + precision, static_cast<size_t>(k)) + 1U);
}
if (min_exp < n && n <= 0)
@ -18628,7 +18629,7 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
buf[0] = '0';
buf[1] = '.';
std::memset(buf + 2, '0', static_cast<size_t>(-n));
return buf + (2U + static_cast<size_t>(-n) + static_cast<size_t>(k));
return buf + std::min(precision + 2, (2U + static_cast<size_t>(-n) + static_cast<size_t>(k)));
}
if (k == 1)
@ -18645,7 +18646,7 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
std::memmove(buf + 2, buf + 1, static_cast<size_t>(k) - 1);
buf[1] = '.';
buf += 1 + static_cast<size_t>(k);
buf += 1 + std::min(precision, static_cast<size_t>(k));
}
*buf++ = 'e';
@ -18667,7 +18668,7 @@ format. Returns an iterator pointing past-the-end of the decimal representation.
template<typename FloatType>
JSON_HEDLEY_NON_NULL(1, 2)
JSON_HEDLEY_RETURNS_NON_NULL
char* to_chars(char* first, const char* last, FloatType value)
char* to_chars(char* first, const char* last, FloatType value, size_t precision = std::numeric_limits<FloatType>::max_digits10)
{
static_cast<void>(last); // maybe unused - fix warning
JSON_ASSERT(std::isfinite(value));
@ -18716,7 +18717,7 @@ char* to_chars(char* first, const char* last, FloatType value)
JSON_ASSERT(last - first >= 2 + (-kMinExp - 1) + std::numeric_limits<FloatType>::max_digits10);
JSON_ASSERT(last - first >= std::numeric_limits<FloatType>::max_digits10 + 6);
return dtoa_impl::format_buffer(first, len, decimal_exponent, kMinExp, kMaxExp);
return dtoa_impl::format_buffer(first, len, decimal_exponent, kMinExp, kMaxExp, precision);
}
} // namespace detail
@ -18770,13 +18771,14 @@ class serializer
@param[in] ichar indentation character to use
@param[in] error_handler_ how to react on decoding errors
*/
serializer(output_adapter_t<char> s, const char ichar,
serializer(output_adapter_t<char> s, const char ichar, size_t precision = 1000,
error_handler_t error_handler_ = error_handler_t::strict)
: o(std::move(s))
, loc(std::localeconv())
, thousands_sep(loc->thousands_sep == nullptr ? '\0' : std::char_traits<char>::to_char_type(* (loc->thousands_sep)))
, decimal_point(loc->decimal_point == nullptr ? '\0' : std::char_traits<char>::to_char_type(* (loc->decimal_point)))
, indent_char(ichar)
, precision(precision)
, indent_string(512, indent_char)
, error_handler(error_handler_)
{}
@ -19526,7 +19528,7 @@ class serializer
void dump_float(number_float_t x, std::true_type /*is_ieee_single_or_double*/)
{
auto* begin = number_buffer.data();
auto* end = ::nlohmann::detail::to_chars(begin, begin + number_buffer.size(), x);
auto* end = ::nlohmann::detail::to_chars(begin, begin + number_buffer.size(), x, precision);
o->write_characters(begin, static_cast<size_t>(end - begin));
}
@ -19538,6 +19540,8 @@ class serializer
// the actual conversion
// NOLINTNEXTLINE(cppcoreguidelines-pro-type-vararg,hicpp-vararg)
char format[100];
snprintf(format, 100, "%%.%dg", precision);
std::ptrdiff_t len = (std::snprintf)(number_buffer.data(), number_buffer.size(), "%.*g", d, x);
// negative value indicates an error
@ -19683,6 +19687,8 @@ class serializer
/// the indentation character
const char indent_char;
/// precision for floating point output
size_t precision;
/// the indentation string
string_t indent_string;
@ -21298,10 +21304,11 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
string_t dump(const int indent = -1,
const char indent_char = ' ',
const bool ensure_ascii = false,
const error_handler_t error_handler = error_handler_t::strict) const
const error_handler_t error_handler = error_handler_t::strict,
const size_t precision = std::numeric_limits<size_t>::max()) const
{
string_t result;
serializer s(detail::output_adapter<char, string_t>(result), indent_char, error_handler);
serializer s(detail::output_adapter<char, string_t>(result), indent_char, precision, error_handler);
if (indent >= 0)
{
@ -24002,15 +24009,17 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
friend std::ostream& operator<<(std::ostream& o, const basic_json& j)
{
// read width member and use it as indentation parameter if nonzero
const bool pretty_print = o.width() > 0;
const auto indentation = pretty_print ? o.width() : 0;
const auto width = o.width();
const bool pretty_print = width > 0;
const auto indentation = pretty_print ? width : 0;
// reset width to 0 for subsequent calls to this stream
o.width(0);
// do the actual serialization
serializer s(detail::output_adapter<char>(o), o.fill());
serializer s(detail::output_adapter<char>(o), o.fill(), o.precision());
s.dump(j, pretty_print, false, static_cast<unsigned int>(indentation));
return o;
}

57
tests/src/unit-precision.cpp Normal file
View File

@ -0,0 +1,57 @@
/*
__ _____ _____ _____
__| | __| | | | JSON for Modern C++ (test suite)
| | |__ | | | | | | version 3.10.5
|_____|_____|_____|_|___| https://github.com/nlohmann/json
Licensed under the MIT License <http://opensource.org/licenses/MIT>.
SPDX-License-Identifier: MIT
Copyright (c) 2013-2022 Niels Lohmann <http://nlohmann.me>.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
#include "doctest_compatibility.h"
#include <cmath>
#include <iomanip>
#include <nlohmann/json.hpp>
#include <sstream>
#include <string>
using json = nlohmann::json;
#include <set>
TEST_CASE("precision<nlohmann::json>")
{
json j;
j = M_PI;
auto to_string = [](const nlohmann::json & j, size_t precision)
{
std::stringstream ss;
ss << std::setprecision(precision) << j;
return ss.str();
};
auto s1 = to_string(j, 1);
auto s2 = to_string(j, 2);
auto s3 = to_string(j, 3);
CHECK(s1 == "3.1");
CHECK(s2 == "3.14");
CHECK(s3 == "3.141");
}