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//
// Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/json
//
#ifndef BOOST_JSON_OBJECT_HPP
#define BOOST_JSON_OBJECT_HPP
#include <boost/json/detail/config.hpp>
#include <boost/json/kind.hpp>
#include <boost/json/pilfer.hpp>
#include <boost/json/storage_ptr.hpp>
#include <boost/json/string_view.hpp>
#include <boost/json/detail/object.hpp>
#include <boost/json/detail/value.hpp>
#include <cstdlib>
#include <initializer_list>
#include <iterator>
#include <type_traits>
#include <utility>
BOOST_JSON_NS_BEGIN
class value;
class value_ref;
class key_value_pair;
/** A dynamically sized associative container of JSON key/value pairs.
This is an associative container whose elements
are key/value pairs with unique keys.
\n
The elements are stored contiguously; iterators are
ordinary pointers, allowing random access pointer
arithmetic for retrieving elements.
In addition, the container maintains an internal
index to speed up find operations, reducing the
average complexity for most lookups and insertions.
\n
Reallocations are usually costly operations in terms of
performance, as elements are copied and the internal
index must be rebuilt. The @ref reserve function can
be used to eliminate reallocations if the number of
elements is known beforehand.
@par Allocators
All elements stored in the container, and their
children if any, will use the same memory resource that
was used to construct the container.
@par Thread Safety
Non-const member functions may not be called
concurrently with any other member functions.
@par Satisfies
<a href="https://en.cppreference.com/w/cpp/named_req/ContiguousContainer"><em>ContiguousContainer</em></a>,
<a href="https://en.cppreference.com/w/cpp/named_req/ReversibleContainer"><em>ReversibleContainer</em></a>, and
<a href="https://en.cppreference.com/w/cpp/named_req/SequenceContainer"><em>SequenceContainer</em></a>.
*/
class object
{
struct table;
class revert_construct;
class revert_insert;
friend class value;
friend class object_test;
using access = detail::access;
using index_t = std::uint32_t;
static index_t constexpr null_index_ =
std::uint32_t(-1);
storage_ptr sp_; // must come first
kind k_ = kind::object; // must come second
table* t_;
BOOST_JSON_DECL
static table empty_;
template<class T>
using is_inputit = typename std::enable_if<
std::is_constructible<key_value_pair,
typename std::iterator_traits<T>::value_type
>::value>::type;
BOOST_JSON_DECL
explicit
object(detail::unchecked_object&& uo);
public:
/** The type of _Allocator_ returned by @ref get_allocator
This type is a @ref polymorphic_allocator.
*/
#ifdef BOOST_JSON_DOCS
// VFALCO doc toolchain renders this incorrectly
using allocator_type = __see_below__;
#else
using allocator_type = polymorphic_allocator<value>;
#endif
/** The type of keys.
The function @ref string::max_size returns the
maximum allowed size of strings used as keys.
*/
using key_type = string_view;
/// The type of mapped values
using mapped_type = value;
/// The element type
using value_type = key_value_pair;
/// The type used to represent unsigned integers
using size_type = std::size_t;
/// The type used to represent signed integers
using difference_type = std::ptrdiff_t;
/// A reference to an element
using reference = value_type&;
/// A const reference to an element
using const_reference = value_type const&;
/// A pointer to an element
using pointer = value_type*;
/// A const pointer to an element
using const_pointer = value_type const*;
/// A random access iterator to an element
using iterator = value_type*;
/// A const random access iterator to an element
using const_iterator = value_type const*;
/// A reverse random access iterator to an element
using reverse_iterator =
std::reverse_iterator<iterator>;
/// A const reverse random access iterator to an element
using const_reverse_iterator =
std::reverse_iterator<const_iterator>;
//------------------------------------------------------
/** Destructor.
The destructor for each element is called if needed,
any used memory is deallocated, and shared ownership
of the @ref memory_resource is released.
@par Complexity
Constant, or linear in @ref size().
@par Exception Safety
No-throw guarantee.
*/
BOOST_JSON_DECL
~object() noexcept;
//------------------------------------------------------
/** Default constructor.
The constructed object is empty with zero
capacity, using the default memory resource.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
object() noexcept
: t_(&empty_)
{
}
/** Constructor.
The constructed object is empty with zero
capacity, using the specified memory resource.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
@param sp A pointer to the @ref memory_resource
to use. The container will acquire shared
ownership of the memory resource.
*/
explicit
object(storage_ptr sp) noexcept
: sp_(std::move(sp))
, t_(&empty_)
{
}
/** Constructor.
The constructed object is empty with capacity
equal to the specified minimum capacity,
using the specified memory resource.
@par Complexity
Constant.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param min_capacity The minimum number
of elements for which capacity is guaranteed
without a subsequent reallocation.
@param sp A pointer to the @ref memory_resource
to use. The container will acquire shared
ownership of the memory resource.
*/
BOOST_JSON_DECL
object(
std::size_t min_capacity,
storage_ptr sp = {});
/** Constructor.
The object is constructed with the elements
in the range `{first, last)`, preserving order,
using the specified memory resource.
If there are elements with duplicate keys; that
is, if multiple elements in the range have keys
that compare equal, only the first equivalent
element will be inserted.
@par Constraints
@code
std::is_constructible_v<
key_value_pair,
std::iterator_traits<InputIt>::value_type>
@endcode
@par Complexity
Linear in `std::distance(first, last)`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param first An input iterator pointing to the
first element to insert, or pointing to the end
of the range.
@param last An input iterator pointing to the end
of the range.
@param min_capacity The minimum number
of elements for which capacity is guaranteed
without a subsequent reallocation.
Upon construction, @ref capacity() will be greater
than or equal to this number.
@param sp A pointer to the @ref memory_resource
to use. The container will acquire shared
ownership of the memory resource.
@tparam InputIt a type satisfying the requirements
of __InputIterator__.
*/
template<
class InputIt
#ifndef BOOST_JSON_DOCS
,class = is_inputit<InputIt>
#endif
>
object(
InputIt first,
InputIt last,
std::size_t min_capacity = 0,
storage_ptr sp = {})
: sp_(std::move(sp))
, t_(&empty_)
{
construct(
first, last,
min_capacity,
typename std::iterator_traits<
InputIt>::iterator_category{});
}
/** Move constructor.
The object is constructed by acquiring ownership of
the contents of `other` and shared ownership
of `other`'s memory resource.
@note
After construction, the moved-from object behaves
as if newly constructed with its current memory resource.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
@param other The object to move.
*/
BOOST_JSON_DECL
object(object&& other) noexcept;
/** Move constructor.
The object is constructed with the contents of
`other` by move semantics, using the specified
memory resource:
@li If `*other.storage() == *sp`, ownership of
the underlying memory is transferred in constant
time, with no possibility of exceptions.
After construction, the moved-from object behaves
as if newly constructed with its current storage
pointer.
@li If `*other.storage() != *sp`, an
element-wise copy is performed, which may throw.
In this case, the moved-from object is not
changed.
@par Complexity
Constant or linear in `other.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param other The object to move.
@param sp A pointer to the @ref memory_resource
to use. The container will acquire shared
ownership of the memory resource.
*/
BOOST_JSON_DECL
object(
object&& other,
storage_ptr sp);
/** Pilfer constructor.
The object is constructed by acquiring ownership
of the contents of `other` using pilfer semantics.
This is more efficient than move construction, when
it is known that the moved-from object will be
immediately destroyed afterwards.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
@param other The value to pilfer. After pilfer
construction, `other` is not in a usable state
and may only be destroyed.
@see @ref pilfer,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0308r0.html">
Valueless Variants Considered Harmful</a>
*/
object(pilfered<object> other) noexcept
: sp_(std::move(other.get().sp_))
, t_(detail::exchange(
other.get().t_, &empty_))
{
}
/** Copy constructor.
The object is constructed with a copy of the
contents of `other`, using `other`'s memory resource.
@par Complexity
Linear in `other.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param other The object to copy.
*/
object(
object const& other)
: object(other, other.sp_)
{
}
/** Copy constructor.
The object is constructed with a copy of the
contents of `other`, using the specified memory resource.
@par Complexity
Linear in `other.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param other The object to copy.
@param sp A pointer to the @ref memory_resource
to use. The container will acquire shared
ownership of the memory resource.
*/
BOOST_JSON_DECL
object(
object const& other,
storage_ptr sp);
/** Construct from initializer-list.
The object is constructed with a copy of the values
in the initializer-list in order, using the
specified memory resource.
If there are elements with duplicate keys; that
is, if multiple elements in the range have keys
that compare equal, only the first equivalent
element will be inserted.
@par Complexity
Linear in `init.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param init The initializer list to insert.
@param sp A pointer to the @ref memory_resource
to use. The container will acquire shared
ownership of the memory resource.
*/
object(
std::initializer_list<
std::pair<string_view, value_ref>> init,
storage_ptr sp = {})
: object(init, 0, std::move(sp))
{
}
/** Construct from initializer-list.
Storage for at least `min_capacity` elements is
reserved, and then
the object is constructed with a copy of the values
in the initializer-list in order, using the
specified memory resource.
If there are elements with duplicate keys; that
is, if multiple elements in the range have keys
that compare equal, only the first equivalent
element will be inserted.
@par Complexity
Linear in `init.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param init The initializer list to insert.
@param min_capacity The minimum number
of elements for which capacity is guaranteed
without a subsequent reallocation.
Upon construction, @ref capacity() will be greater
than or equal to this number.
@param sp A pointer to the @ref memory_resource
to use. The container will acquire shared
ownership of the memory resource.
*/
BOOST_JSON_DECL
object(
std::initializer_list<
std::pair<string_view, value_ref>> init,
std::size_t min_capacity,
storage_ptr sp = {});
//------------------------------------------------------
//
// Assignment
//
//------------------------------------------------------
/** Copy assignment.
The contents of the object are replaced with an
element-wise copy of `other`.
@par Complexity
Linear in @ref size() plus `other.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param other The object to copy.
*/
BOOST_JSON_DECL
object&
operator=(object const& other);
/** Move assignment.
The contents of the object are replaced with the
contents of `other` using move semantics:
@li If `*other.storage() == *sp`, ownership of
the underlying memory is transferred in constant
time, with no possibility of exceptions.
After assignment, the moved-from object behaves
as if newly constructed with its current storage
pointer.
@li If `*other.storage() != *sp`, an
element-wise copy is performed, which may throw.
In this case, the moved-from object is not
changed.
@par Complexity
Constant or linear in @ref size() plus `other.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param other The object to move.
*/
BOOST_JSON_DECL
object&
operator=(object&& other);
/** Assignment.
Replaces the contents with the contents of an
initializer list.
@par Complexity
Linear in @ref size() plus
average case linear in `init.size()`,
worst case quadratic in `init.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param init The initializer list to copy.
*/
BOOST_JSON_DECL
object&
operator=(std::initializer_list<
std::pair<string_view, value_ref>> init);
//------------------------------------------------------
/** Return the associated @ref memory_resource
This returns the @ref memory_resource used by
the container.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
storage_ptr const&
storage() const noexcept
{
return sp_;
}
/** Return the associated @ref memory_resource
This function returns an instance of
@ref polymorphic_allocator constructed from the
associated @ref memory_resource.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
allocator_type
get_allocator() const noexcept
{
return sp_.get();
}
//------------------------------------------------------
//
// Iterators
//
//------------------------------------------------------
/** Return an iterator to the first element.
If the container is empty, @ref end() is returned.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
iterator
begin() noexcept;
/** Return a const iterator to the first element.
If the container is empty, @ref end() is returned.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
const_iterator
begin() const noexcept;
/** Return a const iterator to the first element.
If the container is empty, @ref cend() is returned.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
const_iterator
cbegin() const noexcept;
/** Return an iterator to the element following the last element.
The element acts as a placeholder; attempting
to access it results in undefined behavior.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
iterator
end() noexcept;
/** Return a const iterator to the element following the last element.
The element acts as a placeholder; attempting
to access it results in undefined behavior.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
const_iterator
end() const noexcept;
/** Return a const iterator to the element following the last element.
The element acts as a placeholder; attempting
to access it results in undefined behavior.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
const_iterator
cend() const noexcept;
/** Return a reverse iterator to the first element of the reversed container.
The pointed-to element corresponds to the
last element of the non-reversed container.
If the container is empty, @ref rend() is returned.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
reverse_iterator
rbegin() noexcept;
/** Return a const reverse iterator to the first element of the reversed container.
The pointed-to element corresponds to the
last element of the non-reversed container.
If the container is empty, @ref rend() is returned.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
const_reverse_iterator
rbegin() const noexcept;
/** Return a const reverse iterator to the first element of the reversed container.
The pointed-to element corresponds to the
last element of the non-reversed container.
If the container is empty, @ref crend() is returned.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
const_reverse_iterator
crbegin() const noexcept;
/** Return a reverse iterator to the element following the last element of the reversed container.
The pointed-to element corresponds to the element
preceding the first element of the non-reversed container.
This element acts as a placeholder, attempting
to access it results in undefined behavior.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
reverse_iterator
rend() noexcept;
/** Return a const reverse iterator to the element following the last element of the reversed container.
The pointed-to element corresponds to the element
preceding the first element of the non-reversed container.
This element acts as a placeholder, attempting
to access it results in undefined behavior.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
const_reverse_iterator
rend() const noexcept;
/** Return a const reverse iterator to the element following the last element of the reversed container.
The pointed-to element corresponds to the element
preceding the first element of the non-reversed container.
This element acts as a placeholder, attempting
to access it results in undefined behavior.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
const_reverse_iterator
crend() const noexcept;
//------------------------------------------------------
//
// Capacity
//
//------------------------------------------------------
/** Return whether there are no elements.
Returns `true` if there are no elements in
the container, i.e. @ref size() returns 0.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
bool
empty() const noexcept;
/** Return the number of elements.
This returns the number of elements in the container.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
std::size_t
size() const noexcept;
/** Return the maximum number of elements any object can hold
The maximum is an implementation-defined number dependent
on system or library implementation. This value is a
theoretical limit; at runtime, the actual maximum size
may be less due to resource limits.
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
static
constexpr
std::size_t
max_size() noexcept;
/** Return the number of elements that can be held in currently allocated memory
This number may be larger than the value returned
by @ref size().
@par Complexity
Constant.
@par Exception Safety
No-throw guarantee.
*/
inline
std::size_t
capacity() const noexcept;
/** Increase the capacity to at least a certain amount.
This increases the @ref capacity() to a value
that is greater than or equal to `new_capacity`.
If `new_capacity > capacity()`, new memory is
allocated. Otherwise, the call has no effect.
The number of elements and therefore the
@ref size() of the container is not changed.
\n
If new memory is allocated, all iterators
including any past-the-end iterators, and all
references to the elements are invalidated.
Otherwise, no iterators or references are
invalidated.
@par Complexity
Constant or average case linear in
@ref size(), worst case quadratic.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param new_capacity The new minimum capacity.
@throw std::length_error `new_capacity > max_size()`
*/
void
reserve(std::size_t new_capacity)
{
if(new_capacity <= capacity())
return;
rehash(new_capacity);
}
//------------------------------------------------------
//
// Modifiers
//
//------------------------------------------------------
/** Erase all elements.
Erases all elements from the container without
changing the capacity.
After this call, @ref size() returns zero.
All references, pointers, and iterators are
invalidated.
@par Complexity
Linear in @ref size().
@par Exception Safety
No-throw guarantee.
*/
BOOST_JSON_DECL
void
clear() noexcept;
/** Insert elements.
Inserts `p`, from which @ref value_type must
be constructible.
@par Constraints
@code
std::is_constructible_v<value_type, P>
@endcode
@par Complexity
Average case amortized constant,
worst case linear in @ref size().
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param p The value to insert.
@throw std::length_error key is too long.
@throw std::length_error @ref size() >= max_size().
@return A pair where `first` is an iterator
to the existing or inserted element, and `second`
is `true` if the insertion took place or `false` if
the assignment took place.
*/
template<class P
#ifndef BOOST_JSON_DOCS
,class = typename std::enable_if<
std::is_constructible<key_value_pair,
P, storage_ptr>::value>::type
#endif
>
std::pair<iterator, bool>
insert(P&& p);
/** Insert elements.
The elements in the range `{first, last)` whose
keys are unique are inserted one at a time, in order.
If there are elements with duplicate keys; that
is, if multiple elements in the range have keys
that compare equal, only the first equivalent
element will be inserted.
@par Precondition
`first` and `last` are not iterators into `*this`.
@par Constraints
@code
std::is_constructible_v<value_type, std::iterator_traits<InputIt>::value_type>
@endcode
@par Complexity
Linear in `std::distance(first, last)`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param first An input iterator pointing to the first
element to insert, or pointing to the end of the range.
@param last An input iterator pointing to the end
of the range.
@tparam InputIt a type satisfying the requirements
of __InputIterator__.
*/
template<
class InputIt
#ifndef BOOST_JSON_DOCS
,class = is_inputit<InputIt>
#endif
>
void
insert(InputIt first, InputIt last)
{
insert(first, last, typename
std::iterator_traits<InputIt
>::iterator_category{});
}
/** Insert elements.
The elements in the initializer list whose
keys are unique are inserted one at a time, in order.
If there are elements with duplicate keys; that
is, if multiple elements in the range have keys
that compare equal, only the first equivalent
element will be inserted.
@par Complexity
Linear in `init.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param init The initializer list to insert
*/
BOOST_JSON_DECL
void
insert(std::initializer_list<
std::pair<string_view, value_ref>> init);
/** Insert an element or assign to the current element if the key already exists.
If the key equivalent to `key` already exists in the
container. assigns `std::forward<M>(obj)` to the
`mapped type` corresponding to the key. Otherwise,
inserts the new value at the end as if by insert,
constructing it from
`value_type(key, std::forward<M>(obj))`.
If the insertion occurs and results in a rehashing
of the container, all iterators are invalidated.
Otherwise, iterators are not affected.
References are not invalidated.
Rehashing occurs only if the new number of elements
is greater than @ref capacity().
@par Complexity
Amortized constant on average, worst case linear in @ref size().
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@return A `std::pair` where `first` is an iterator
to the existing or inserted element, and `second`
is `true` if the insertion took place or `false` if
the assignment took place.
@param key The key used for lookup and insertion
@param m The value to insert or assign
@throw std::length_error if key is too long
*/
template<class M>
std::pair<iterator, bool>
insert_or_assign(
string_view key, M&& m);
/** Construct an element in-place.
Inserts a new element into the container constructed
in-place with the given argument if there is no
element with the key in the container.
The element is inserted after all the existing
elements.
If the insertion occurs and results in a rehashing
of the container, all iterators are invalidated.
Otherwise, iterators are not affected.
References are not invalidated.
Rehashing occurs only if the new number of elements
is greater than @ref capacity().
@par Complexity
Amortized constant on average, worst case linear in @ref size().
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@return A `std::pair` where `first` is an iterator
to the existing or inserted element, and `second`
is `true` if the insertion took place or `false` if
the assignment took place.
@param key The key used for lookup and insertion
@param arg The argument used to construct the value.
This will be passed as `std::forward<Arg>(arg)` to
the @ref value constructor.
@throw std::length_error if key is too long
*/
template<class Arg>
std::pair<iterator, bool>
emplace(string_view key, Arg&& arg);
/** Erase an element
Remove the element pointed to by `pos`, which must
be valid and dereferenceable. Thus the @ref end()
iterator (which is valid but cannot be dereferenced)
cannot be used as a value for `pos`.
References and iterators to the erased element are
invalidated. Other iterators and references are not
invalidated.
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
No-throw guarantee.
@return An iterator following the last removed element.
@param pos An iterator pointing to the element to be
removed.
*/
BOOST_JSON_DECL
iterator
erase(const_iterator pos) noexcept;
/** Erase an element
Remove the element which matches `key`, if it exists.
References and iterators to the erased element are
invalidated. Other iterators and references are not
invalidated.
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
No-throw guarantee.
@return The number of elements removed, which will
be either 0 or 1.
@param key The key to match.
*/
BOOST_JSON_DECL
std::size_t
erase(string_view key) noexcept;
/** Swap two objects.
Exchanges the contents of this object with another
object. Ownership of the respective @ref memory_resource
objects is not transferred.
@li If `*other.storage() == *this->storage()`,
ownership of the underlying memory is swapped in
constant time, with no possibility of exceptions.
All iterators and references remain valid.
@li If `*other.storage() != *this->storage()`,
the contents are logically swapped by making copies,
which can throw. In this case all iterators and
references are invalidated.
@par Complexity
Constant or linear in @ref size() plus `other.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param other The object to swap with.
If `this == &other`, this function call has no effect.
*/
BOOST_JSON_DECL
void
swap(object& other);
/** Swap two objects.
Exchanges the contents of the object `lhs` with
another object `rhs`. Ownership of the respective
@ref memory_resource objects is not transferred.
@li If `*lhs.storage() == *rhs.storage()`,
ownership of the underlying memory is swapped in
constant time, with no possibility of exceptions.
All iterators and references remain valid.
@li If `*lhs.storage() != *rhs.storage()`,
the contents are logically swapped by making a copy,
which can throw. In this case all iterators and
references are invalidated.
@par Effects
@code
lhs.swap( rhs );
@endcode
@par Complexity
Constant or linear in `lhs.size() + rhs.size()`.
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@param lhs The object to exchange.
@param rhs The object to exchange.
If `&lhs == &rhs`, this function call has no effect.
@see @ref object::swap
*/
friend
void
swap(object& lhs, object& rhs)
{
lhs.swap(rhs);
}
//------------------------------------------------------
//
// Lookup
//
//------------------------------------------------------
/** Access the specified element, with bounds checking.
Returns a reference to the mapped value of the element
that matches `key`, otherwise throws.
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
Strong guarantee.
@return A reference to the mapped value.
@param key The key of the element to find.
@throw std::out_of_range if no such element exists.
*/
inline
value&
at(string_view key);
/** Access the specified element, with bounds checking.
Returns a constant reference to the mapped value of
the element that matches `key`, otherwise throws.
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
Strong guarantee.
@return A reference to the mapped value.
@param key The key of the element to find.
@throw std::out_of_range if no such element exists.
*/
inline
value const&
at(string_view key) const;
/** Access or insert the specified element
Returns a reference to the value that is mapped
to a key equivalent to key, performing an insertion
of a null value if such key does not already exist.
\n
If an insertion occurs and results in a rehashing of
the container, all iterators are invalidated. Otherwise
iterators are not affected. References are not
invalidated. Rehashing occurs only if the new
number of elements is greater than @ref capacity().
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
Strong guarantee.
Calls to `memory_resource::allocate` may throw.
@return A reference to the mapped value.
@param key The key of the element to find.
*/
BOOST_JSON_DECL
value&
operator[](string_view key);
/** Count the number of elements with a specific key
This function returns the count of the number of
elements match `key`. The only possible return values
are 0 and 1.
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
No-throw guarantee.
@param key The key of the element to find.
*/
BOOST_JSON_DECL
std::size_t
count(string_view key) const noexcept;
/** Find an element with a specific key
This function returns an iterator to the element
matching `key` if it exists, otherwise returns
@ref end().
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
No-throw guarantee.
@param key The key of the element to find.
*/
BOOST_JSON_DECL
iterator
find(string_view key) noexcept;
/** Find an element with a specific key
This function returns a constant iterator to
the element matching `key` if it exists,
otherwise returns @ref end().
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
No-throw guarantee.
@param key The key of the element to find.
*/
BOOST_JSON_DECL
const_iterator
find(string_view key) const noexcept;
/** Return `true` if the key is found
This function returns `true` if a key with the
specified string is found.
@par Effects
@code
return this->find(key) != this->end();
@endcode
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
No-throw guarantee.
@param key The key of the element to find.
@see @ref find
*/
BOOST_JSON_DECL
bool
contains(string_view key) const noexcept;
/** Return a pointer to the value if the key is found, or null
This function searches for a value with the given
key, and returns a pointer to it if found. Otherwise
it returns null.
@par Example
@code
if( auto p = obj.if_contains( "key" ) )
std::cout << *p;
@endcode
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
No-throw guarantee.
@param key The key of the element to find.
@see @ref find
*/
BOOST_JSON_DECL
value const*
if_contains(string_view key) const noexcept;
/** Return a pointer to the value if the key is found, or null
This function searches for a value with the given
key, and returns a pointer to it if found. Otherwise
it returns null.
@par Example
@code
if( auto p = obj.if_contains( "key" ) )
std::cout << *p;
@endcode
@par Complexity
Constant on average, worst case linear in @ref size().
@par Exception Safety
No-throw guarantee.
@param key The key of the element to find.
@see @ref find
*/
BOOST_JSON_DECL
value*
if_contains(string_view key) noexcept;
/** Return `true` if two objects are equal.
Objects are equal when their sizes are the same,
and when for each key in `lhs` there is a matching
key in `rhs` with the same value.
@par Complexity
Constant, or linear (worst case quadratic) in `lhs.size()`.
@par Exception Safety
No-throw guarantee.
*/
// inline friend speeds up overload resolution
friend
bool
operator==(
object const& lhs,
object const& rhs) noexcept
{
return lhs.equal(rhs);
}
/** Return `true` if two objects are not equal.
Objects are equal when their sizes are the same,
and when for each key in `lhs` there is a matching
key in `rhs` with the same value.
@par Complexity
Constant, or linear (worst case quadratic) in `lhs.size()`.
@par Exception Safety
No-throw guarantee.
*/
// inline friend speeds up overload resolution
friend
bool
operator!=(
object const& lhs,
object const& rhs) noexcept
{
return ! (lhs == rhs);
}
private:
#ifndef BOOST_JSON_DOCS
// VFALCO friending a detail function makes it public
template<class CharRange>
friend
std::pair<key_value_pair*, std::size_t>
detail::find_in_object(
object const& obj,
CharRange key) noexcept;
#endif
template<class InputIt>
void
construct(
InputIt first,
InputIt last,
std::size_t min_capacity,
std::input_iterator_tag);
template<class InputIt>
void
construct(
InputIt first,
InputIt last,
std::size_t min_capacity,
std::forward_iterator_tag);
template<class InputIt>
void
insert(
InputIt first,
InputIt last,
std::input_iterator_tag);
template<class InputIt>
void
insert(
InputIt first,
InputIt last,
std::forward_iterator_tag);
BOOST_JSON_DECL
std::pair<iterator, bool>
insert_impl(
pilfered<key_value_pair> p);
BOOST_JSON_DECL
key_value_pair*
insert_impl(
pilfered<key_value_pair> p,
std::size_t hash);
BOOST_JSON_DECL
void
rehash(std::size_t new_capacity);
BOOST_JSON_DECL
bool
equal(object const& other) const noexcept;
inline
std::size_t
growth(
std::size_t new_size) const;
inline
void
remove(
index_t& head,
key_value_pair& p) noexcept;
inline
void
destroy() noexcept;
inline
void
destroy(
key_value_pair* first,
key_value_pair* last) noexcept;
};
BOOST_JSON_NS_END
// std::hash specialization
#ifndef BOOST_JSON_DOCS
namespace std {
template <>
struct hash< ::boost::json::object > {
BOOST_JSON_DECL
std::size_t
operator()(::boost::json::object const& jo) const noexcept;
};
} // std
#endif
// Must be included here for this file to stand alone
#include <boost/json/value.hpp>
// includes are at the bottom of <boost/json/value.hpp>
#endif
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