raw_storage_iterator

Overview

The output iterator raw_storage_iterator makes it possible for standard algorithms to store results in uninitialized memory.

Details

Regular iterators operate on a certain type of objects, which have already been constructed. A raw_storage_iterator wraps one of these regular iterators into a special output iterator which constructs objects at the location being pointed before being written.

Whenever the algorithm writes an object of type T to the dereferenced iterator, the object is copy-constructed into the location in the uninitialized storage pointed to by the iterator. 

Syntax

The syntax is as below. 

template< class OutputIterator,
          class T>
class raw_storage_iterator;

Name	Description
OutputIterator	Underlying iterator type.
T	Type of objects to be constructed on each element location.

Members

 It defines following types.

member type	definition
iterator_category	output_iterator_tag
value_type	void
difference_type	void
pointer	void
reference	void

Operation

An raw_storage_iterator as an output iterator supports operators *, ++, and =. 

 Functionality

Constructors

Name	Description
raw_storage_iterator( OutputIt  it)	Initializes the iterator to point to the same value as it points.

Overloaded operators

Name	Description
raw_storage_iterator & operator*()	Does nothing. Returns a reference to the object.
raw_storage_iterator & operator++() raw_storage_iterator & operator++(int)	Advances the iterator. Pre-increment. Returns the updated iterator. Post-increment. Returns the old value of the iterator.
raw_storage_iterator & operator= (const T& value)	Constructs a new object of type T at the location pointed by the iterator and initializes its value to a copy of the argument used as right-hand side of the operator. Example: string numbers[] = {"one", "two", "three", "four"}; size_t sz = sizeof(numbers); char *buf = new char[sizeof(string)*sz]; string *sbuf = reinterpret_cast<string*>(buf); auto last = copy(begin(numbers), end(numbers), raw_storage_iterator<string*, string>(sbuf)); //prints one two three four for (auto itr = sbuf; itr != sbuf+sz; ++itr) cout << *itr << " "; for (auto itr = sbuf; itr != sbuf+sz; ++itr) itr->~string(); delete[] buf;