Class hashtable

Overview

Class hashtable is a polymorphic implementation of a generic hashtable.

Interface

Constructor

• template <typename ktype, typename vtype> hashtable <ktype, vtype> :: hashtable()

  builds an hashtable with vtype as value type and ktype as key type.

Destructor

• template <typename ktype, typename vtype> hashtable <ktype, vtype> :: ~hashtable()

  destroys the hashtable.

Methods

• void add(const ktype & key, const vtype & value)

  adds an element to the hashtable.

• void remove(const ktype & key)

  removes the element with the givent key from the hashtable.

• template <typename lambda> void each(const lambda & function) const

  given a lambda function that takes an argument of the same type of vtype, executes the lambda function to each element of the hashtable.

Operators

• const vtype & operator [] (const ktype & key)

  access the k-th element of the hashtable.

Private elements

Private methods

• size_t slot(const ktype & key) const

  Returns the corresponding index of the object with the given key.

• void realloc(const size_t & alloc)

  Allocates a new array of the given size an moves the elements of the hashtable to this new array. Called when it’s necessary to allocate more memory.

Private static methods

• template <typename type, typename std :: enable_if <sizeof(type) == 4> :: type * = nullptr> static size_t hash(const type & item)

  Standard hashing method for an hashtable with key type of size 4.

• template <typename type, typename std :: enable_if <sizeof(type) == 8> :: type * = nullptr> static size_t hash(const type &);

  Standard hashing method for an hashtable with key type of size 8.