zakero::messagepack::Map Struct Reference

A Key/Value collection of Objects. More...

Public Member Functions
const Object &	at (const Object &) const noexcept
	Get the value of a key. More...
Object &	at (Object &) noexcept
	Get the value of a key. More...
void	clear () noexcept
	Remove the contents of the Map. More...
void	erase (const Object &) noexcept
	Erase a key/value pair. More...
bool	keyExists (const Object &) const noexcept
	Check if a key exists. More...
std::error_code	set (const Object &, const Object &) noexcept
	Set a key/value pair. More...
std::error_code	set (Object &, Object &) noexcept
	Set a key/value pair. More...
size_t	size () const noexcept
	Get the size of the Map. More...

Detailed Description

The MessagePack specification allows any Object to be the "key" of a map.
As interesting as it would be to having a Map as the key to another Map, programmatically, it is not practical. This implementation limits the types of the "keys" to include all MessagePack types except Array, Binary, Ext, and Map.

The Map uses several std::map's to hold the "values". While it is possible to directly access these std::map's, it is recommended to use Map's methods since they ensure the uniqueness of the key and other checks.

Objects can be tested to find out if they are Map by using Object::isMap() and converted into a Map with Object::asMap(). A Map can not be converted into an Object. However, an Object can be constructed using a Map.

Member Function Documentation

at() [1/2]

const Object & zakero::messagepack::Map::at ( const Object &  key ) const

noexcept

The value associated with the provided key will be returned. If the key does not exist, then a reference to the key will be returned.

Example

zakero::messagepack::Map map;
 
map.set(Object{uint64_t(42)}, Object{std::string("The Answer"});
 
const zakero::messagepack::Object key = Object{true};
const zakero::messagepack::Object& object = map.at({true});
 
if(&object == &key)
{
        // key not found
}

Returns

The value.

Parameters

key

The key

at() [2/2]

Object & zakero::messagepack::Map::at ( Object &  key )

noexcept

The value associated with the provided key will be returned. If the key does not exist, then a reference to the key will be returned.
Checking if the key exists (keyExists()) is more reliable than using this error handling.

Example

zakero::messagepack::Map map;
 
map.set(Object{uint64_t(42)}, Object{std::string("The Answer"});
zakero::messagepack::Object& thing = map.at({uint64_t(42)});
 
zakero::messagepack::Object key = Object{true};
zakero::messagepack::Object& object = map.at(key);
 
if(&object == &key)
{
        // key not found
}

Returns

The value.

Parameters

key

The key

clear()

void zakero::messagepack::Map::clear ( )

inlinenoexcept

All of the key/value pairs will be removed.

erase()

void zakero::messagepack::Map::erase ( const Object &  key )

noexcept

If the specified key exists, the key and matching value will be removed frame the Map.

Example

zakero::messagepack::Map map;
 
// What is true?
map.set({true}, {uint64_t(123456)});
 
// Truth can not be defined...
map.erase({true});

Parameters

key

The key

keyExists()

bool zakero::messagepack::Map::keyExists ( const Object &  key ) const

noexcept

Search the Map and return true if the key exists. If the key was not found, return false.

Example

zakero::messagepack::Map map;
 
map.set(Object{}, Object{});
if(map.keyExists(Object{}))
{
        // In the Key of Null
}

Return values

true	The key exists.
false	The key does not exist.

Parameters

key	The key Object

set() [1/2]

std::error_code zakero::messagepack::Map::set ( const Object &  key, const Object &  value  )

noexcept

The provided key / value pair will be added to the Map. If the key already exists, its value will be replaced with value.

Example

zakero::messagepack::Map map;
 
map.set({std::string("Error Code")}   , {uint64_t(42)});
map.set({std::string("Error Message")}, {std::string("All the errors!")});

Returns

An error code.

Parameters

key	The key
value	The value

set() [2/2]

std::error_code zakero::messagepack::Map::set ( Object &  key, Object &  value  )

noexcept

The provided key / value pair will be added to the Map. If the key already exists, its value will be replaced with value.

Example

zakero::messagepack::Map map;
 
map.set({std::string("Error Code")}   , {uint64_t(42)});
map.set({std::string("Error Message")}, {std::string("All the errors!")});

Returns

An error code.

Parameters

key	The key
value	The value

size()

size_t zakero::messagepack::Map::size ( ) const

inlinenoexcept

Returns

The number of key/value pairs.

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The documentation for this struct was generated from the following file:

• Zakero_MessagePack.h