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json/include/nlohmann/detail/output/fancy_serializer.hpp

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#pragma once
#include <algorithm> // reverse, remove, fill, find, none_of
#include <array> // array
#include <cassert> // assert
#include <ciso646> // and, or
#include <clocale> // localeconv, lconv
#include <cmath> // labs, isfinite, isnan, signbit
#include <cstddef> // size_t, ptrdiff_t
#include <cstdint> // uint8_t
#include <cstdio> // snprintf
#include <limits> // numeric_limits
#include <string> // string
#include <type_traits> // is_same
#include <map>
#include <sstream>
#include <nlohmann/detail/exceptions.hpp>
#include <nlohmann/detail/conversions/to_chars.hpp>
#include <nlohmann/detail/macro_scope.hpp>
#include <nlohmann/detail/meta.hpp>
#include <nlohmann/detail/output/output_adapters.hpp>
#include <nlohmann/detail/value_t.hpp>
#include <nlohmann/detail/output/primitive_serializer.hpp>
#include <nlohmann/detail/json_pointer.hpp>
namespace nlohmann
{
struct fancy_serializer_style
{
unsigned int indent_step = 4;
char indent_char = ' ';
unsigned int depth_limit = std::numeric_limits<unsigned>::max();
unsigned int strings_maximum_length = 0;
bool space_after_colon = false;
bool space_after_comma = false;
bool multiline = false;
void set_old_multiline()
{
space_after_colon = space_after_comma = multiline = true;
}
};
template<typename BasicJsonType>
class basic_fancy_serializer_stylizer
{
public:
using string_t = typename BasicJsonType::string_t;
basic_fancy_serializer_stylizer(fancy_serializer_style const& ds)
: default_style(ds)
{}
basic_fancy_serializer_stylizer() = default;
public:
const fancy_serializer_style& get_default_style() const
{
return default_style;
}
fancy_serializer_style& get_default_style()
{
return default_style;
}
const fancy_serializer_style* get_new_style_or_active(
const string_t& j,
const fancy_serializer_style* active_style) const
{
auto iter = key_styles.find(j);
return iter == key_styles.end() ? active_style : &iter->second;
}
fancy_serializer_style& get_or_insert_style(const string_t& j)
{
return key_styles[j];
}
private:
fancy_serializer_style default_style;
std::map<string_t, fancy_serializer_style> key_styles;
};
namespace detail
{
///////////////////
// serialization //
///////////////////
template<typename BasicJsonType>
class fancy_serializer
{
using stylizer_t = basic_fancy_serializer_stylizer<BasicJsonType>;
using primitive_serializer_t = primitive_serializer<BasicJsonType>;
using string_t = typename BasicJsonType::string_t;
using number_float_t = typename BasicJsonType::number_float_t;
using number_integer_t = typename BasicJsonType::number_integer_t;
using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
using json_pointer_t = json_pointer<BasicJsonType>;
static constexpr uint8_t UTF8_ACCEPT = 0;
static constexpr uint8_t UTF8_REJECT = 1;
public:
/*!
@param[in] s output stream to serialize to
@param[in] ichar indentation character to use
*/
fancy_serializer(output_adapter_t<char> s,
const stylizer_t& st)
: o(std::move(s)), stylizer(st),
indent_string(512, st.get_default_style().indent_char)
{}
// delete because of pointer members
fancy_serializer(const fancy_serializer&) = delete;
fancy_serializer& operator=(const fancy_serializer&) = delete;
void dump(const BasicJsonType& val, const bool ensure_ascii)
{
dump(val, ensure_ascii, 0, &stylizer.get_default_style(), json_pointer_t());
}
private:
/*!
@brief internal implementation of the serialization function
This function is called by the public member function dump and organizes
the serialization internally. The indentation level is propagated as
additional parameter. In case of arrays and objects, the function is
called recursively.
- strings and object keys are escaped using `escape_string()`
- integer numbers are converted implicitly via `operator<<`
- floating-point numbers are converted to a string using `"%g"` format
@param[in] val value to serialize
@param[in] pretty_print whether the output shall be pretty-printed
@param[in] depth the current recursive depth
*/
void dump(const BasicJsonType& val,
const bool ensure_ascii,
const unsigned int depth,
const fancy_serializer_style* active_style,
const json_pointer_t& context)
{
if (context.cbegin() != context.cend())
{
active_style = stylizer.get_new_style_or_active(*context.crbegin(), active_style);
}
switch (val.m_type)
{
case value_t::object:
{
dump_object(val, ensure_ascii, depth, active_style, context);
return;
}
case value_t::array:
{
dump_array(val, ensure_ascii, depth, active_style, context);
return;
}
case value_t::string:
{
dump_string(*val.m_value.string, ensure_ascii, active_style);
return;
}
case value_t::boolean:
{
if (val.m_value.boolean)
{
o->write_characters("true", 4);
}
else
{
o->write_characters("false", 5);
}
return;
}
case value_t::number_integer:
{
prim_serializer.dump_integer(*o, val.m_value.number_integer);
return;
}
case value_t::number_unsigned:
{
prim_serializer.dump_integer(*o, val.m_value.number_unsigned);
return;
}
case value_t::number_float:
{
prim_serializer.dump_float(*o, val.m_value.number_float);
return;
}
case value_t::discarded:
{
o->write_characters("<discarded>", 11);
return;
}
case value_t::null:
{
o->write_characters("null", 4);
return;
}
}
}
private:
template <typename Iterator>
void dump_object_key_value(
Iterator i, bool ensure_ascii, unsigned int depth,
const fancy_serializer_style* active_style,
const json_pointer_t& context)
{
const auto new_indent = (depth + 1) * active_style->indent_step * active_style->multiline;
const int newline_len = active_style->space_after_colon;
o->write_characters(indent_string.c_str(), new_indent);
o->write_character('\"');
prim_serializer.dump_escaped(*o, i->first, ensure_ascii);
o->write_characters("\": ", 2 + newline_len);
dump(i->second, ensure_ascii, depth + 1, active_style, context.appended(i->first));
}
void dump_object(const BasicJsonType& val,
bool ensure_ascii,
unsigned int depth,
const fancy_serializer_style* active_style,
const json_pointer_t& context)
{
if (val.m_value.object->empty())
{
o->write_characters("{}", 2);
return;
}
else if (depth >= active_style->depth_limit)
{
o->write_characters("{...}", 5);
return;
}
// variable to hold indentation for recursive calls
const auto old_indent = depth * active_style->indent_step * active_style->multiline;
const auto new_indent = (depth + 1) * active_style->indent_step * active_style->multiline;
if (JSON_UNLIKELY(indent_string.size() < new_indent))
{
indent_string.resize(indent_string.size() * 2, active_style->indent_char);
}
const int newline_len = (active_style->multiline ? 1 : 0);
o->write_characters("{\n", 1 + newline_len);
// first n-1 elements
auto i = val.m_value.object->cbegin();
for (std::size_t cnt = 0; cnt < val.m_value.object->size() - 1; ++cnt, ++i)
{
dump_object_key_value(i, ensure_ascii, depth, active_style, context);
o->write_characters(",\n", 1 + newline_len);
}
// last element
assert(i != val.m_value.object->cend());
assert(std::next(i) == val.m_value.object->cend());
dump_object_key_value(i, ensure_ascii, depth, active_style, context);
o->write_characters("\n", newline_len);
o->write_characters(indent_string.c_str(), old_indent);
o->write_character('}');
}
void dump_array(const BasicJsonType& val,
bool ensure_ascii,
unsigned int depth,
const fancy_serializer_style* active_style,
const json_pointer_t& context)
{
if (val.m_value.array->empty())
{
o->write_characters("[]", 2);
return;
}
else if (depth >= active_style->depth_limit)
{
o->write_characters("[...]", 5);
return;
}
// variable to hold indentation for recursive calls
const auto old_indent = depth * active_style->indent_step * active_style->multiline;;
const auto new_indent = (depth + 1) * active_style->indent_step * active_style->multiline;;
if (JSON_UNLIKELY(indent_string.size() < new_indent))
{
indent_string.resize(indent_string.size() * 2, active_style->indent_char);
}
const int newline_len = (active_style->multiline ? 1 : 0);
using pair = std::pair<const char*, int>;
auto comma_string =
active_style->multiline ? pair(",\n", 2) :
active_style->space_after_comma ? pair(", ", 2) :
pair(",", 1);
o->write_characters("[\n", 1 + newline_len);
// first n-1 elements
for (auto i = val.m_value.array->cbegin();
i != val.m_value.array->cend() - 1; ++i)
{
o->write_characters(indent_string.c_str(), new_indent);
dump(*i, ensure_ascii, depth + 1, active_style,
context.appended(i - val.m_value.array->cbegin()));
o->write_characters(comma_string.first, comma_string.second);
}
// last element
assert(not val.m_value.array->empty());
o->write_characters(indent_string.c_str(), new_indent);
dump(val.m_value.array->back(), ensure_ascii, depth + 1, active_style,
context.appended(val.m_value.array->size()));
o->write_characters("\n", newline_len);
o->write_characters(indent_string.c_str(), old_indent);
o->write_character(']');
}
void dump_string(const string_t& str, bool ensure_ascii,
const fancy_serializer_style* active_style)
{
o->write_character('\"');
if (active_style->strings_maximum_length == 0)
{
prim_serializer.dump_escaped(*o, str, ensure_ascii);
}
else
{
std::stringstream ss;
nlohmann::detail::output_adapter<char> o_string(ss);
nlohmann::detail::output_adapter_t<char> oo_string = o_string;
prim_serializer.dump_escaped(*oo_string, str, ensure_ascii);
std::string full_str = ss.str();
if (full_str.size() <= active_style->strings_maximum_length)
{
o->write_characters(full_str.c_str(), full_str.size());
}
else
{
const unsigned start_len = [](unsigned int maxl)
{
if (maxl <= 3)
{
// There is only room for the ellipsis,
// no characters from the string
return 0u;
}
else if (maxl <= 5)
{
// With four allowed characters, we add in the
// first from the string. With five, we add in
// the *last* instead, so still just one at
// the start.
return 1u;
}
else
{
// We subtract three for the ellipsis
// and one for the last character.
return maxl - 4;
}
}(active_style->strings_maximum_length);
const unsigned end_len =
active_style->strings_maximum_length >= 5 ? 1 : 0;
const unsigned ellipsis_length =
active_style->strings_maximum_length >= 3
? 3
: active_style->strings_maximum_length;
o->write_characters(full_str.c_str(), start_len);
o->write_characters("...", ellipsis_length);
o->write_characters(full_str.c_str() + str.size() - end_len, end_len);
}
}
o->write_character('\"');
}
private:
/// the output of the fancy_serializer
output_adapter_t<char> o = nullptr;
/// Used for serializing "base" objects. Strings are sort of
/// counted in this, but not completely.
primitive_serializer_t prim_serializer;
/// the indentation string
string_t indent_string;
/// Output style
const stylizer_t stylizer;
};
}
template<typename BasicJsonType>
std::ostream& fancy_dump(std::ostream& o, const BasicJsonType& j,
basic_fancy_serializer_stylizer<BasicJsonType> const& stylizer)
{
// do the actual serialization
detail::fancy_serializer<BasicJsonType> s(detail::output_adapter<char>(o), stylizer);
s.dump(j, false);
return o;
}
template<typename BasicJsonType>
std::ostream& fancy_dump(std::ostream& o, const BasicJsonType& j,
fancy_serializer_style style)
{
basic_fancy_serializer_stylizer<BasicJsonType> stylizer(style);
return fancy_dump(o, j, stylizer);
}
}
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