Added locale-independent numtostr
This commit is contained in:
Alex Astashyn
parent
bc28942101
commit
21cae35930
2 changed files with 286 additions and 72 deletions
179
src/json.hpp
179
src/json.hpp
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@ -2180,14 +2180,6 @@ class basic_json
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string_t dump(const int indent = -1) const
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{
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std::stringstream ss;
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// fix locale problems
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ss.imbue(std::locale::classic());
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// 6, 15 or 16 digits of precision allows round-trip IEEE 754
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// string->float->string, string->double->string or string->long
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// double->string; to be safe, we read this value from
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// std::numeric_limits<number_float_t>::digits10
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ss.precision(std::numeric_limits<double>::digits10);
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if (indent >= 0)
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{
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@ -5878,10 +5870,6 @@ class basic_json
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`std::setw(4)` on @a o sets the indentation level to `4` and the
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serialization result is the same as calling `dump(4)`.
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@note During serializaion, the locale and the precision of the output
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stream @a o are changed. The original values are restored when the
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function returns.
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@param[in,out] o stream to serialize to
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@param[in] j JSON value to serialize
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@ -5903,22 +5891,9 @@ class basic_json
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// reset width to 0 for subsequent calls to this stream
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o.width(0);
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// fix locale problems
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const auto old_locale = o.imbue(std::locale::classic());
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// set precision
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// 6, 15 or 16 digits of precision allows round-trip IEEE 754
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// string->float->string, string->double->string or string->long
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// double->string; to be safe, we read this value from
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// std::numeric_limits<number_float_t>::digits10
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const auto old_precision = o.precision(std::numeric_limits<double>::digits10);
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// do the actual serialization
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j.dump(o, pretty_print, static_cast<unsigned int>(indentation));
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// reset locale and precision
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o.imbue(old_locale);
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o.precision(old_precision);
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return o;
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}
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@ -6419,6 +6394,146 @@ class basic_json
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return result;
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}
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/*!
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@brief locale-independent serialization for built-in arithmetic types
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*/
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struct numtostr
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{
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public:
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template<typename T>
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numtostr(T value)
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{
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x_write(value, std::is_integral<T>());
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}
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operator const char*() const
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{
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return m_buf.data();
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}
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const char* c_str() const
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{
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return m_buf.data();
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}
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private:
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static constexpr size_t s_capacity = 30;
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std::array<char, s_capacity + 2> m_buf{};
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template<typename T>
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void x_write(T x, std::true_type)
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{
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const bool is_neg = x < 0;
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size_t i = 0;
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while(x and i < s_capacity)
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{
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m_buf[i++] = '0' + abs(x % 10);
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x /= 10;
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}
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if(i == s_capacity)
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{
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std::runtime_error(
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"Number is unexpectedly long: "
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+ std::to_string(x));
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}
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if(i == 0)
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{
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m_buf[i++] = '0';
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}
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if(is_neg)
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{
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m_buf[i++] = '-';
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}
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std::reverse(m_buf.begin(), m_buf.begin() + i);
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}
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template<typename T>
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void x_write(T x, std::false_type)
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{
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if (x == 0)
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{
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std::strcpy(m_buf.data(),
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std::signbit(x) ? "-0.0" : "0.0");
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return;
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}
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static constexpr auto d =
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std::numeric_limits<number_float_t>::digits10+1;
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// I'm not sure why we need that +1 above, if at all,
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// but without it there's a unit-test that fails
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// that asserts precision of the output
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static_assert(d == 6 or d == 15 or d == 16 or d == 17, "");
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static constexpr auto fmt = d == 6 ? "%.6g"
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: d == 15 ? "%.15g"
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: d == 16 ? "%.16g"
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: d == 17 ? "%.17g"
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: "%.18g";
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snprintf(m_buf.data(), m_buf.size(), fmt, x);
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const std::locale loc;
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// erase thousands separator
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{
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const char sep =
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std::use_facet< std::numpunct<char> >(
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loc).thousands_sep();
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auto end = std::remove(m_buf.begin(),
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m_buf.end(),
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sep);
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std::fill(end, m_buf.end(), '\0');
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}
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// convert decimal point to '.'
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{
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const char decimal_point =
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std::use_facet< std::numpunct<char> >(
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loc).decimal_point();
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for(auto& c : m_buf)
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{
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if(decimal_point == '.') {
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break;
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}
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if(c == decimal_point)
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{
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c = '.';
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break;
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}
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}
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}
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// determine if need to apperd ".0"
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auto data_end = m_buf.begin() + strlen(m_buf.data());
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const bool value_is_int_like =
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std::find_if(m_buf.begin(), data_end,
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[](const char c)
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{ return (c >= '0' and c <= '9')
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or c == '-'; })
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== data_end;
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assert(data_end + 2 < m_buf.end());
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if(value_is_int_like)
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{
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strcat(m_buf.data(), ".0");
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}
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}
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};
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/*!
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@brief internal implementation of the serialization function
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@ -6538,27 +6653,19 @@ class basic_json
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case value_t::number_integer:
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{
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o << m_value.number_integer;
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o << numtostr(m_value.number_integer).c_str();
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return;
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}
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case value_t::number_unsigned:
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{
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o << m_value.number_unsigned;
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o << numtostr(m_value.number_unsigned).c_str();
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return;
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}
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case value_t::number_float:
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{
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if (m_value.number_float == 0)
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{
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// special case for zero to get "0.0"/"-0.0"
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o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
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}
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else
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{
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o << m_value.number_float;
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}
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o << numtostr(m_value.number_float).c_str();
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return;
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}
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@ -2180,14 +2180,6 @@ class basic_json
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string_t dump(const int indent = -1) const
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{
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std::stringstream ss;
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// fix locale problems
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ss.imbue(std::locale::classic());
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// 6, 15 or 16 digits of precision allows round-trip IEEE 754
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// string->float->string, string->double->string or string->long
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// double->string; to be safe, we read this value from
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// std::numeric_limits<number_float_t>::digits10
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ss.precision(std::numeric_limits<double>::digits10);
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if (indent >= 0)
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{
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@ -5878,10 +5870,6 @@ class basic_json
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`std::setw(4)` on @a o sets the indentation level to `4` and the
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serialization result is the same as calling `dump(4)`.
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@note During serializaion, the locale and the precision of the output
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stream @a o are changed. The original values are restored when the
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function returns.
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@param[in,out] o stream to serialize to
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@param[in] j JSON value to serialize
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@ -5903,22 +5891,9 @@ class basic_json
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// reset width to 0 for subsequent calls to this stream
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o.width(0);
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// fix locale problems
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const auto old_locale = o.imbue(std::locale::classic());
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// set precision
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// 6, 15 or 16 digits of precision allows round-trip IEEE 754
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// string->float->string, string->double->string or string->long
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// double->string; to be safe, we read this value from
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// std::numeric_limits<number_float_t>::digits10
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const auto old_precision = o.precision(std::numeric_limits<double>::digits10);
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// do the actual serialization
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j.dump(o, pretty_print, static_cast<unsigned int>(indentation));
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// reset locale and precision
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o.imbue(old_locale);
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o.precision(old_precision);
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return o;
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}
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@ -6419,6 +6394,146 @@ class basic_json
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return result;
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}
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/*!
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@brief locale-independent serialization for built-in arithmetic types
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*/
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struct numtostr
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{
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public:
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template<typename T>
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numtostr(T value)
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{
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x_write(value, std::is_integral<T>());
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}
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operator const char*() const
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{
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return m_buf.data();
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}
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const char* c_str() const
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{
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return m_buf.data();
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}
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private:
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static constexpr size_t s_capacity = 30;
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std::array<char, s_capacity + 2> m_buf{};
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template<typename T>
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void x_write(T x, std::true_type)
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{
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const bool is_neg = x < 0;
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size_t i = 0;
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while(x and i < s_capacity)
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{
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m_buf[i++] = '0' + abs(x % 10);
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x /= 10;
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}
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if(i == s_capacity)
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{
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std::runtime_error(
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"Number is unexpectedly long: "
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+ std::to_string(x));
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}
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if(i == 0)
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{
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m_buf[i++] = '0';
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}
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if(is_neg)
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{
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m_buf[i++] = '-';
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}
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std::reverse(m_buf.begin(), m_buf.begin() + i);
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}
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template<typename T>
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void x_write(T x, std::false_type)
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{
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if (x == 0)
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{
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std::strcpy(m_buf.data(),
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std::signbit(x) ? "-0.0" : "0.0");
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return;
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}
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static constexpr auto d =
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std::numeric_limits<number_float_t>::digits10+1;
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// I'm not sure why we need that +1 above, if at all,
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// but without it there's a unit-test that fails
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// that asserts precision of the output
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static_assert(d == 6 or d == 15 or d == 16 or d == 17, "");
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static constexpr auto fmt = d == 6 ? "%.6g"
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: d == 15 ? "%.15g"
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: d == 16 ? "%.16g"
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: d == 17 ? "%.17g"
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: "%.18g";
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snprintf(m_buf.data(), m_buf.size(), fmt, x);
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const std::locale loc;
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// erase thousands separator
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{
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const char sep =
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std::use_facet< std::numpunct<char> >(
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loc).thousands_sep();
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auto end = std::remove(m_buf.begin(),
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m_buf.end(),
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sep);
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std::fill(end, m_buf.end(), '\0');
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}
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// convert decimal point to '.'
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{
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const char decimal_point =
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std::use_facet< std::numpunct<char> >(
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loc).decimal_point();
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for(auto& c : m_buf)
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{
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if(decimal_point == '.') {
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break;
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}
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if(c == decimal_point)
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{
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c = '.';
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break;
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}
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}
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}
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// determine if need to apperd ".0"
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auto data_end = m_buf.begin() + strlen(m_buf.data());
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const bool value_is_int_like =
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std::find_if(m_buf.begin(), data_end,
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[](const char c)
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{ return (c >= '0' and c <= '9')
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or c == '-'; })
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== data_end;
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assert(data_end + 2 < m_buf.end());
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if(value_is_int_like)
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{
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strcat(m_buf.data(), ".0");
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}
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}
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};
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/*!
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@brief internal implementation of the serialization function
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@ -6538,27 +6653,19 @@ class basic_json
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case value_t::number_integer:
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{
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o << m_value.number_integer;
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o << numtostr(m_value.number_integer).c_str();
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return;
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}
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case value_t::number_unsigned:
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{
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o << m_value.number_unsigned;
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o << numtostr(m_value.number_unsigned).c_str();
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return;
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}
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case value_t::number_float:
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{
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if (m_value.number_float == 0)
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{
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// special case for zero to get "0.0"/"-0.0"
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o << (std::signbit(m_value.number_float) ? "-0.0" : "0.0");
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}
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else
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{
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o << m_value.number_float;
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}
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o << numtostr(m_value.number_float).c_str();
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return;
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}
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