libcruft-util/json/tree.hpp

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/*
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* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
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* http://www.apache.org/licenses/LICENSE-2.0
*
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* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Copyright 2010-2018 Danny Robson <danny@nerdcruft.net>
*/
#ifndef __UTIL_JSON_TREE_HPP
#define __UTIL_JSON_TREE_HPP
#include "flat.hpp"
#include "fwd.hpp"
#include "../iterator.hpp"
#include "../view.hpp"
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#include <iosfwd>
#include <map>
#include <memory>
#include <string>
#include <vector>
#include <experimental/filesystem>
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///////////////////////////////////////////////////////////////////////////////
namespace json::tree {
enum type_t {
OBJECT,
ARRAY,
STRING,
NUMBER,
BOOLEAN,
NONE
};
/// Parse an encoded form of JSON into a tree structure
template <typename T>
std::unique_ptr<node>
parse (const util::view<T> &data);
std::unique_ptr<node>
parse (const std::experimental::filesystem::path &);
extern void write (const json::tree::node&, std::ostream&);
/// Abstract base for all JSON values
class node {
public:
node (const node&) = delete;
virtual ~node () { ; }
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virtual std::unique_ptr<node> clone (void) const = 0;
virtual const object& as_object (void) const&;
virtual const array& as_array (void) const&;
virtual const string& as_string (void) const&;
virtual const number& as_number (void) const&;
virtual const boolean& as_boolean (void) const&;
virtual const null& as_null (void) const&;
virtual object& as_object (void)&;
virtual array& as_array (void)&;
virtual string& as_string (void)&;
virtual number& as_number (void)&;
virtual boolean& as_boolean (void)&;
virtual null& as_null (void)&;
// we don't provide operators for conversion due to ambiguities
// introduced when using indexing operators with pointer
// arguments.
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virtual bool as_bool (void) const;
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virtual float as_float (void) const;
virtual double as_double (void) const;
virtual intmax_t as_sint (void) const;
virtual uintmax_t as_uint (void) const;
virtual const char* as_chars (void) const&;
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template <typename T>
T as (void) const;
virtual bool is_object (void) const { return false; }
virtual bool is_array (void) const { return false; }
virtual bool is_string (void) const { return false; }
virtual bool is_number (void) const { return false; }
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virtual bool is_integer (void) const { return false; }
virtual bool is_boolean (void) const { return false; }
virtual bool is_null (void) const { return false; }
virtual type_t type (void) const = 0;
virtual bool operator==(const node &rhs) const = 0;
virtual bool operator!=(const node &rhs) const;
virtual bool operator==(const object &) const { return false; }
virtual bool operator==(const array &) const { return false; }
virtual bool operator==(const string &) const { return false; }
virtual bool operator==(const number &) const { return false; }
virtual bool operator==(const boolean &) const { return false; }
virtual bool operator==(const null &) const { return false; }
virtual bool operator==(const char *rhs) const;
virtual bool operator!=(const char *rhs) const { return !(*this == rhs); }
virtual node& operator[] (const std::string&)&;
virtual node& operator[] (size_t)&;
virtual const node& operator[] (const std::string&) const&;
virtual const node& operator[] (size_t) const&;
virtual std::ostream& write (std::ostream &os) const = 0;
protected:
node () = default;
};
/// Represents a JSON object, and contains its children.
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class object final : public node {
private:
using value_store = std::map<std::string, std::unique_ptr<node>>;
public:
typedef value_store::iterator iterator;
typedef value_store::const_iterator const_iterator;
public:
virtual ~object ();
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virtual std::unique_ptr<node> clone (void) const override;
virtual const object& as_object (void) const& override { return *this; }
virtual object& as_object (void) & override { return *this; }
virtual bool is_object (void) const override { return true; }
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virtual type_t type (void) const override { return OBJECT; }
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virtual bool operator==(const object &rhs) const override;
virtual bool operator==(const node &rhs) const override
{ return rhs == *this; }
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virtual void insert (const std::string &key, std::unique_ptr<node>&& value);
virtual const node& operator[] (const std::string &key) const& override;
virtual node& operator[] (const std::string &key)& override;
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virtual bool has (const std::string&) const;
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virtual const_iterator find (const std::string&) const;
virtual const_iterator begin (void) const;
virtual const_iterator end (void) const;
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virtual const_iterator cbegin (void) const { return begin (); }
virtual const_iterator cend (void) const { return end (); }
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virtual size_t size (void) const;
virtual void clear (void);
virtual void erase (const std::string &key);
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virtual std::ostream& write (std::ostream &os) const override;
private:
value_store m_values;
};
/// Represents a JSON array, and contains its children.
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class array final : public node {
protected:
typedef std::vector<std::unique_ptr<node>>::iterator pointer_array_iterator;
typedef std::vector<std::unique_ptr<node>>::const_iterator const_pointer_array_iterator;
public:
typedef referencing_iterator<pointer_array_iterator> iterator;
typedef referencing_iterator<const_pointer_array_iterator> const_iterator;
protected:
std::vector<std::unique_ptr<node>> m_values;
public:
virtual ~array();
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virtual std::unique_ptr<node> clone (void) const override;
virtual const array& as_array (void) const& override { return *this; }
virtual array& as_array (void) & override { return *this; }
virtual bool is_array (void) const override { return true; }
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virtual type_t type (void) const override { return ARRAY; }
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virtual bool operator==(const array &rhs) const override;
virtual bool operator==(const node &rhs) const override;
virtual size_t size (void) const;
virtual node& operator[] (size_t idx)& override;
virtual const node& operator[] (size_t idx) const& override;
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virtual iterator begin (void);
virtual iterator end (void);
virtual const_iterator begin (void) const;
virtual const_iterator end (void) const;
virtual const_iterator cbegin (void) const;
virtual const_iterator cend (void) const;
virtual void insert (std::unique_ptr<json::tree::node> &&_value);
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virtual std::ostream& write (std::ostream &os) const override;
};
/// Represents a JSON string literal.
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class string final : public node {
protected:
std::string m_value;
public:
template <typename T>
string (T first, T last): m_value (first, last) { ; }
explicit string (const std::string &_value): m_value (_value) { ; }
explicit string (const char *_value): m_value (_value) { ; }
string (const char *_first, const char *_last): m_value (_first, _last) { ; }
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virtual std::unique_ptr<node> clone (void) const override;
virtual const string& as_string (void) const& override { return *this; }
virtual string& as_string (void) & override { return *this; }
virtual bool is_string (void) const override { return true; }
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virtual type_t type (void) const override { return STRING; }
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virtual bool operator==(const char *rhs) const override;
virtual bool operator==(const string &rhs) const override;
virtual bool operator==(const std::string &rhs) const;
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virtual bool operator==(const node &rhs) const override
{ return rhs == *this; }
virtual bool operator!= (const std::string &rhs) const { return !(*this == rhs); }
virtual size_t size (void) const { return m_value.size (); }
operator const std::string&(void) const { return m_value; }
const std::string& native (void) const { return m_value; }
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virtual std::ostream& write (std::ostream &os) const override;
};
/// Represents a JSON integer/float literal.
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class number final : public node {
public:
enum repr_t {
REAL,
SINT,
UINT
};
using real_t = double;
using sint_t = intmax_t;
using uint_t = uintmax_t;
explicit number (real_t _value): m_repr (REAL) { m_value.r = _value; }
explicit number (sint_t _value): m_repr (SINT) { m_value.s = _value; }
explicit number (uint_t _value): m_repr (UINT) { m_value.u = _value; }
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virtual std::unique_ptr<node> clone (void) const override;
virtual const number& as_number (void) const& override { return *this; }
virtual number& as_number (void) & override { return *this; }
virtual bool is_number (void) const override { return true; }
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virtual bool is_integer (void) const override { return repr () == UINT || repr () == SINT; }
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virtual type_t type (void) const override { return NUMBER; }
virtual repr_t repr (void) const { return m_repr; }
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virtual bool operator==(const number &rhs) const override;
virtual bool operator==(const node &rhs) const override
{ return rhs == *this; }
operator real_t (void) const;
operator sint_t (void) const;
operator uint_t (void) const;
real_t real (void) const;
sint_t sint (void) const;
uint_t uint (void) const;
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virtual std::ostream& write (std::ostream &os) const override;
private:
union {
real_t r;
sint_t s;
uint_t u;
} m_value;
repr_t m_repr;
};
/// Represents a JSON boolean literal.
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class boolean final : public node {
protected:
bool m_value;
public:
explicit boolean (bool _value): m_value (_value) { ; }
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virtual std::unique_ptr<node> clone (void) const override;
virtual const boolean& as_boolean (void) const& override { return *this; }
virtual boolean& as_boolean (void) & override { return *this; }
virtual bool is_boolean (void) const override { return true; }
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virtual type_t type (void) const override { return BOOLEAN; }
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virtual bool operator==(const boolean &rhs) const override;
virtual bool operator==(const node &rhs) const override
{ return rhs == *this; }
operator bool (void) const { return m_value; }
bool native (void) const { return m_value; }
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virtual std::ostream& write (std::ostream &os) const override;
};
/// Represents a JSON null value.
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class null final : public node {
public:
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virtual type_t type (void) const override { return NONE; }
virtual std::unique_ptr<node> clone (void) const override;
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virtual bool operator==(const null&) const override { return true; }
virtual bool operator==(const node &rhs) const override
{ return rhs == *this; }
virtual const null& as_null (void) const& override { return *this; }
virtual null& as_null (void) & override { return *this; }
virtual bool is_null (void) const override { return true; }
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virtual std::ostream& write (std::ostream &os) const override;
};
std::ostream&
operator <<(std::ostream &os, const json::tree::node &n);
// Instantiate this template for the type you wish to output. We use a
// helper class here to avoid partial template specialisation of a
// function (eg, for templated types).
template <typename T, typename ...Args>
struct io {
static std::unique_ptr<json::tree::node>
serialise (const T&, Args &&...args);
static T
deserialise (const json::tree::node&, Args &&...args);
};
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}
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///////////////////////////////////////////////////////////////////////////////
template <typename T, class ...Args>
std::unique_ptr<json::tree::node>
to_json (const T &t, Args&&... args)
{
return json::tree::io<T,Args...>::serialise (
t, std::forward<Args>(args)...
);
}
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///////////////////////////////////////////////////////////////////////////////
template <typename T, class ...Args>
T
from_json (const json::tree::node &n, Args&&... args)
{
return json::tree::io<T,Args...>::deserialise (
n, std::forward<Args>(args)...
);
}
//-----------------------------------------------------------------------------
template <typename T, class ...Args>
T
from_json (const std::experimental::filesystem::path &src, Args &&...args)
{
return from_json<T,Args...> (
*json::tree::parse (src),
std::forward<Args> (args)...
);
}
#endif