Template Class hash_t

Inheritance Relationships

Base Type

  • public std::unordered_map< key, value >

Class Documentation

template<typename key, typename value>
class hash_t : public std::unordered_map<key, value>

Thread-safe hash table wrapper around std::unordered_map.

It supports concurrent reads and synchronized writes.

Template Parameters:

  • key – Type of the hash-table key.

  • value – Type of the hash-table value.

Public Types

using shared_ptr = std::shared_ptr<hash_t<key, value>>

Shared pointer type.

using weak_ptr = std::weak_ptr<hash_t<key, value>>

Weak pointer type.

Public Functions

inline hash_t()

Default constructor.

inline hash_t(const std::pair<const key, value> &data_)

Constructor from a single pair

Parameters:

data_ – Initial key-value pair inserted at construction time.

inline hash_t(const hash_t<key, value> &other_)

Copy constructor

Parameters:

other_ – Source hash table copied while holding a read lock.

inline size_t size_() const

Get the size of the hash table

Returns:

Number of key-value entries currently stored.

inline bool contains_(const key &key_) const

Thread-safe check whether a key exists in the hash table.

Parameters:

key_ – Key tested for existence in the hash table.

Returns:

true when key_ exists, false otherwise.

inline value at_(const key &key_) const

Thread-safe access to a value by key.

Parameters:

key_ – Key whose associated value is retrieved.

Returns:

Copy of the value stored for key_.

inline void insert_(const std::pair<const key, value> &data_)

Thread-safe insertion of a key-value pair.

Parameters:

data_ – Key-value pair inserted into the hash table.

inline void try_emplace_(const key &key_, const value &value_)

Thread-safe emplacement of a key-value pair.

Parameters:

  • key_ – Key of the entry to insert or update in the hash table.

  • value_ – Value associated with key_ to insert or update.

inline void erase_(const key &key_)

Thread-safe erasure of a key-value pair by key.

Parameters:

key_ – Key of the entry to erase from the hash table.

inline void conditional_erase_(const key &key_)

Thread-safe conditional erasure of a key-value pair by key.

Parameters:

key_ – Key of the entry to conditionally erase from the hash table.

inline value *find_(const key &key_)

Find the value associated with a key in the hash table.

Parameters:

key_ – Key whose associated value is searched for.

Returns:

Pointer to the value if key_ exists, nullptr otherwise.

inline void lock_read() const

Lock the object for shared reading.

inline void unlock_read() const

Unlock the shared reading lock.

inline void lock() const

Lock the object for writing.

inline void unlock() const

Unlock the writing lock.

Public Static Functions

static inline hash_t<key, value>::shared_ptr make_shared()

Make shared pointer function

Returns:

Shared pointer owning a new empty thread-safe hash table.

Private Members

mutable std::shared_mutex _mutex

Mutex that is used to lock the dictionary for reading and writing.