250 lines
13 KiB
C
250 lines
13 KiB
C
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// Crude implementation of JSON value object and parser.
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//
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// VERSION 0.1
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//
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// LICENSE
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// This software is dual-licensed to the public domain and under the following
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// license: you are granted a perpetual, irrevocable license to copy, modify,
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// publish, and distribute this file as you see fit.
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//
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// CREDITS
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// Written by Michal Cichon
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# ifndef __CRUDE_JSON_H__
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# define __CRUDE_JSON_H__
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# pragma once
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# include <type_traits>
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# include <string>
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# include <vector>
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# include <map>
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# include <cstddef>
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# include <algorithm>
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# include <sstream>
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# ifndef CRUDE_ASSERT
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# include <cassert>
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# define CRUDE_ASSERT(expr) assert(expr)
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# endif
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# ifndef CRUDE_JSON_IO
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# define CRUDE_JSON_IO 1
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# endif
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namespace crude_json {
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struct value;
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using string = std::string;
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using object = std::map<string, value>;
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using array = std::vector<value>;
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using number = double;
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using boolean = bool;
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using null = std::nullptr_t;
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enum class type_t
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{
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null,
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object,
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array,
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string,
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boolean,
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number,
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discarded
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};
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struct value
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{
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value(type_t type = type_t::null): m_Type(construct(m_Storage, type)) {}
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value(value&& other);
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value(const value& other);
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value( null) : m_Type(construct(m_Storage, null())) {}
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value( object&& v): m_Type(construct(m_Storage, std::move(v))) {}
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value(const object& v): m_Type(construct(m_Storage, v)) {}
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value( array&& v): m_Type(construct(m_Storage, std::move(v))) {}
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value(const array& v): m_Type(construct(m_Storage, v)) {}
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value( string&& v): m_Type(construct(m_Storage, std::move(v))) {}
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value(const string& v): m_Type(construct(m_Storage, v)) {}
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value(const char* v): m_Type(construct(m_Storage, v)) {}
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value( boolean v): m_Type(construct(m_Storage, v)) {}
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value( number v): m_Type(construct(m_Storage, v)) {}
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~value() { destruct(m_Storage, m_Type); }
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value& operator=(value&& other) { if (this != &other) { value(std::move(other)).swap(*this); } return *this; }
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value& operator=(const value& other) { if (this != &other) { value( other).swap(*this); } return *this; }
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value& operator=( null) { auto other = value( ); swap(other); return *this; }
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value& operator=( object&& v) { auto other = value(std::move(v)); swap(other); return *this; }
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value& operator=(const object& v) { auto other = value( v); swap(other); return *this; }
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value& operator=( array&& v) { auto other = value(std::move(v)); swap(other); return *this; }
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value& operator=(const array& v) { auto other = value( v); swap(other); return *this; }
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value& operator=( string&& v) { auto other = value(std::move(v)); swap(other); return *this; }
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value& operator=(const string& v) { auto other = value( v); swap(other); return *this; }
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value& operator=(const char* v) { auto other = value( v); swap(other); return *this; }
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value& operator=( boolean v) { auto other = value( v); swap(other); return *this; }
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value& operator=( number v) { auto other = value( v); swap(other); return *this; }
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type_t type() const { return m_Type; }
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operator type_t() const { return m_Type; }
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value& operator[](size_t index);
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const value& operator[](size_t index) const;
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value& operator[](const string& key);
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const value& operator[](const string& key) const;
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bool contains(const string& key) const;
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void push_back(const value& value);
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void push_back(value&& value);
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size_t erase(const string& key);
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bool is_primitive() const { return is_string() || is_number() || is_boolean() || is_null(); }
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bool is_structured() const { return is_object() || is_array(); }
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bool is_null() const { return m_Type == type_t::null; }
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bool is_object() const { return m_Type == type_t::object; }
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bool is_array() const { return m_Type == type_t::array; }
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bool is_string() const { return m_Type == type_t::string; }
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bool is_boolean() const { return m_Type == type_t::boolean; }
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bool is_number() const { return m_Type == type_t::number; }
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bool is_discarded() const { return m_Type == type_t::discarded; }
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template <typename T> const T& get() const;
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template <typename T> T& get();
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template <typename T> const T* get_ptr() const;
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template <typename T> T* get_ptr();
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string dump(const int indent = -1, const char indent_char = ' ') const;
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void swap(value& other);
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inline friend void swap(value& lhs, value& rhs) { lhs.swap(rhs); }
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// Returns discarded value for invalid inputs.
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static value parse(const string& data);
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# if CRUDE_JSON_IO
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static std::pair<value, bool> load(const string& path);
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bool save(const string& path, const int indent = -1, const char indent_char = ' ') const;
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# endif
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private:
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struct parser;
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// VS2015: std::max() is not constexpr yet.
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# define CRUDE_MAX2(a, b) ((a) < (b) ? (b) : (a))
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# define CRUDE_MAX3(a, b, c) CRUDE_MAX2(CRUDE_MAX2(a, b), c)
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# define CRUDE_MAX4(a, b, c, d) CRUDE_MAX2(CRUDE_MAX3(a, b, c), d)
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# define CRUDE_MAX5(a, b, c, d, e) CRUDE_MAX2(CRUDE_MAX4(a, b, c, d), e)
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enum
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{
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max_size = CRUDE_MAX5( sizeof(string), sizeof(object), sizeof(array), sizeof(number), sizeof(boolean)),
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max_align = CRUDE_MAX5(alignof(string), alignof(object), alignof(array), alignof(number), alignof(boolean))
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};
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# undef CRUDE_MAX5
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# undef CRUDE_MAX4
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# undef CRUDE_MAX3
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# undef CRUDE_MAX2
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using storage_t = std::aligned_storage<max_size, max_align>::type;
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static object* object_ptr( storage_t& storage) { return reinterpret_cast< object*>(&storage); }
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static const object* object_ptr(const storage_t& storage) { return reinterpret_cast<const object*>(&storage); }
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static array* array_ptr( storage_t& storage) { return reinterpret_cast< array*>(&storage); }
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static const array* array_ptr(const storage_t& storage) { return reinterpret_cast<const array*>(&storage); }
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static string* string_ptr( storage_t& storage) { return reinterpret_cast< string*>(&storage); }
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static const string* string_ptr(const storage_t& storage) { return reinterpret_cast<const string*>(&storage); }
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static boolean* boolean_ptr( storage_t& storage) { return reinterpret_cast< boolean*>(&storage); }
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static const boolean* boolean_ptr(const storage_t& storage) { return reinterpret_cast<const boolean*>(&storage); }
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static number* number_ptr( storage_t& storage) { return reinterpret_cast< number*>(&storage); }
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static const number* number_ptr(const storage_t& storage) { return reinterpret_cast<const number*>(&storage); }
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static type_t construct(storage_t& storage, type_t type)
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{
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switch (type)
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{
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case type_t::object: new (&storage) object(); break;
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case type_t::array: new (&storage) array(); break;
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case type_t::string: new (&storage) string(); break;
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case type_t::boolean: new (&storage) boolean(); break;
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case type_t::number: new (&storage) number(); break;
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default: break;
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}
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return type;
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}
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static type_t construct(storage_t& storage, null) { (void)storage; return type_t::null; }
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static type_t construct(storage_t& storage, object&& value) { new (&storage) object(std::forward<object>(value)); return type_t::object; }
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static type_t construct(storage_t& storage, const object& value) { new (&storage) object(value); return type_t::object; }
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static type_t construct(storage_t& storage, array&& value) { new (&storage) array(std::forward<array>(value)); return type_t::array; }
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static type_t construct(storage_t& storage, const array& value) { new (&storage) array(value); return type_t::array; }
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static type_t construct(storage_t& storage, string&& value) { new (&storage) string(std::forward<string>(value)); return type_t::string; }
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static type_t construct(storage_t& storage, const string& value) { new (&storage) string(value); return type_t::string; }
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static type_t construct(storage_t& storage, const char* value) { new (&storage) string(value); return type_t::string; }
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static type_t construct(storage_t& storage, boolean value) { new (&storage) boolean(value); return type_t::boolean; }
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static type_t construct(storage_t& storage, number value) { new (&storage) number(value); return type_t::number; }
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static void destruct(storage_t& storage, type_t type)
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{
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switch (type)
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{
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case type_t::object: object_ptr(storage)->~object(); break;
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case type_t::array: array_ptr(storage)->~array(); break;
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case type_t::string: string_ptr(storage)->~string(); break;
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default: break;
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}
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}
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struct dump_context_t
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{
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std::ostringstream out;
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const int indent = -1;
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const char indent_char = ' ';
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// VS2015: Aggregate initialization isn't a thing yet.
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dump_context_t(const int indent, const char indent_char)
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: indent(indent)
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, indent_char(indent_char)
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{
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}
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void write_indent(int level);
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void write_separator();
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void write_newline();
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};
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void dump(dump_context_t& context, int level) const;
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storage_t m_Storage;
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type_t m_Type;
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};
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template <> inline const object& value::get<object>() const { CRUDE_ASSERT(m_Type == type_t::object); return *object_ptr(m_Storage); }
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template <> inline const array& value::get<array>() const { CRUDE_ASSERT(m_Type == type_t::array); return *array_ptr(m_Storage); }
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template <> inline const string& value::get<string>() const { CRUDE_ASSERT(m_Type == type_t::string); return *string_ptr(m_Storage); }
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template <> inline const boolean& value::get<boolean>() const { CRUDE_ASSERT(m_Type == type_t::boolean); return *boolean_ptr(m_Storage); }
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template <> inline const number& value::get<number>() const { CRUDE_ASSERT(m_Type == type_t::number); return *number_ptr(m_Storage); }
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template <> inline object& value::get<object>() { CRUDE_ASSERT(m_Type == type_t::object); return *object_ptr(m_Storage); }
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template <> inline array& value::get<array>() { CRUDE_ASSERT(m_Type == type_t::array); return *array_ptr(m_Storage); }
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template <> inline string& value::get<string>() { CRUDE_ASSERT(m_Type == type_t::string); return *string_ptr(m_Storage); }
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template <> inline boolean& value::get<boolean>() { CRUDE_ASSERT(m_Type == type_t::boolean); return *boolean_ptr(m_Storage); }
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template <> inline number& value::get<number>() { CRUDE_ASSERT(m_Type == type_t::number); return *number_ptr(m_Storage); }
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template <> inline const object* value::get_ptr<object>() const { if (m_Type == type_t::object) return object_ptr(m_Storage); else return nullptr; }
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template <> inline const array* value::get_ptr<array>() const { if (m_Type == type_t::array) return array_ptr(m_Storage); else return nullptr; }
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template <> inline const string* value::get_ptr<string>() const { if (m_Type == type_t::string) return string_ptr(m_Storage); else return nullptr; }
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template <> inline const boolean* value::get_ptr<boolean>() const { if (m_Type == type_t::boolean) return boolean_ptr(m_Storage); else return nullptr; }
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template <> inline const number* value::get_ptr<number>() const { if (m_Type == type_t::number) return number_ptr(m_Storage); else return nullptr; }
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template <> inline object* value::get_ptr<object>() { if (m_Type == type_t::object) return object_ptr(m_Storage); else return nullptr; }
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template <> inline array* value::get_ptr<array>() { if (m_Type == type_t::array) return array_ptr(m_Storage); else return nullptr; }
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template <> inline string* value::get_ptr<string>() { if (m_Type == type_t::string) return string_ptr(m_Storage); else return nullptr; }
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template <> inline boolean* value::get_ptr<boolean>() { if (m_Type == type_t::boolean) return boolean_ptr(m_Storage); else return nullptr; }
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template <> inline number* value::get_ptr<number>() { if (m_Type == type_t::number) return number_ptr(m_Storage); else return nullptr; }
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} // namespace crude_json
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# endif // __CRUDE_JSON_H__
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