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construct/include/ircd/json/array.h

222 lines
5.5 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_JSON_ARRAY_H
namespace ircd::json
{
struct array;
bool empty(const array &);
bool operator!(const array &);
size_t size(const array &);
string_view stringify(mutable_buffer &buf, const string_view *const &begin, const string_view *const &end);
string_view stringify(mutable_buffer &buf, const std::string *const &begin, const std::string *const &end);
size_t serialized(const string_view *const &begin, const string_view *const &end);
size_t serialized(const std::string *const &begin, const std::string *const &end);
}
/// Lightweight interface to a JSON array string.
///
/// This object accepts queries with numerical indexing. The same parsing
/// approach is used in ircd::json::object and that is important to note here:
/// iterating this array by incrementing your own numerical index and making
/// calls into this object is NOT efficient. Simply put, do not do something
/// like `for(int x=0; x<array.count(); x++) array.at(x)` as that will parse
/// the array from the beginning on every single increment. Instead, use the
/// provided iterator object.
///
struct ircd::json::array
:string_view
{
struct const_iterator;
using value_type = const string_view;
using pointer = value_type *;
using reference = value_type &;
using iterator = const_iterator;
using size_type = size_t;
using difference_type = ptrdiff_t;
static const uint max_recursion_depth;
const_iterator end() const;
const_iterator begin() const;
const_iterator find(size_t i) const;
bool empty() const;
size_t count() const;
size_t size() const;
template<class T> T at(const size_t &i) const;
string_view at(const size_t &i) const;
string_view operator[](const size_t &i) const;
explicit operator std::string() const;
using string_view::string_view;
template<class it> static string_view stringify(mutable_buffer &, const it &b, const it &e);
friend string_view stringify(mutable_buffer &, const array &);
friend std::ostream &operator<<(std::ostream &, const array &);
};
struct ircd::json::array::const_iterator
{
using value_type = const string_view;
using pointer = value_type *;
using reference = value_type &;
using iterator = const_iterator;
using size_type = size_t;
using difference_type = ptrdiff_t;
using iterator_category = std::forward_iterator_tag;
protected:
friend class array;
const char *start;
const char *stop;
string_view state;
const_iterator(const char *const &start, const char *const &stop)
:start{start}
,stop{stop}
{}
public:
value_type *operator->() const { return &state; }
value_type &operator*() const { return *operator->(); }
const_iterator &operator++();
friend bool operator==(const const_iterator &, const const_iterator &);
friend bool operator!=(const const_iterator &, const const_iterator &);
friend bool operator<=(const const_iterator &, const const_iterator &);
friend bool operator>=(const const_iterator &, const const_iterator &);
friend bool operator<(const const_iterator &, const const_iterator &);
friend bool operator>(const const_iterator &, const const_iterator &);
};
inline ircd::string_view
ircd::json::array::operator[](const size_t &i)
const
{
const auto it(find(i));
return it != end()? *it : string_view{};
}
template<class T>
T
ircd::json::array::at(const size_t &i)
const try
{
return lex_cast<T>(at(i));
}
catch(const bad_lex_cast &e)
{
throw type_error("indice %zu must cast to type %s", i, typeid(T).name());
}
inline ircd::string_view
ircd::json::array::at(const size_t &i)
const
{
const auto it(find(i));
return likely(it != end())? *it : throw not_found("indice %zu", i);
}
inline ircd::json::array::const_iterator
ircd::json::array::find(size_t i)
const
{
auto it(begin());
for(; it != end() && i; ++it, i--);
return it;
}
inline size_t
ircd::json::size(const array &array)
{
return array.size();
}
inline size_t
ircd::json::array::size()
const
{
return count();
}
inline size_t
ircd::json::array::count()
const
{
return std::distance(begin(), end());
}
inline bool
ircd::json::operator!(const array &array)
{
return empty(array);
}
inline bool
ircd::json::empty(const array &array)
{
return array.empty();
}
inline bool
ircd::json::array::empty()
const
{
const string_view &sv{*this};
assert(sv.size() > 2 || (sv.empty() || sv == empty_array));
return sv.size() <= 2;
}
inline bool
ircd::json::operator==(const array::const_iterator &a, const array::const_iterator &b)
{
return a.start == b.start;
}
inline bool
ircd::json::operator!=(const array::const_iterator &a, const array::const_iterator &b)
{
return a.start != b.start;
}
inline bool
ircd::json::operator<=(const array::const_iterator &a, const array::const_iterator &b)
{
return a.start <= b.start;
}
inline bool
ircd::json::operator>=(const array::const_iterator &a, const array::const_iterator &b)
{
return a.start >= b.start;
}
inline bool
ircd::json::operator<(const array::const_iterator &a, const array::const_iterator &b)
{
return a.start < b.start;
}
inline bool
ircd::json::operator>(const array::const_iterator &a, const array::const_iterator &b)
{
return a.start > b.start;
}