[#BloombergLP-bslalg-DequeIterator-0d]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslalg.adoc[bslalg]::DequeIterator
:relfileprefix: ../../
:mrdocs:

Implementation of a deque iterator, parameterized by the `VALUE_TYPE`, for a deque with the parameterized `BLOCK_LENGTH`, and suitable for use by the `bslstl::RandomAccessIterator` adapter. Note that `BLOCK_LENGTH` is the number of items of `VALUE_TYPE` within a block, not the size of a block in bytes.

== Synopsis

Declared in `<bslalg_dequeiterator.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class VALUE_TYPE,
    int BLOCK_LENGTH>
class DequeIterator;
----

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslalg/DequeIterator-0d/2constructor-04.adoc[`DequeIterator`]         [.small]#[constructor]#
| Constructors
| xref:BloombergLP/bslalg/DequeIterator-0d/blockBegin.adoc[`blockBegin`] 
| Return the address of the first element in the block pointed to by this iterator.
| xref:BloombergLP/bslalg/DequeIterator-0d/blockEnd.adoc[`blockEnd`] 
| Return the address of (one‐past) the last element in the block pointed to by this iterator.
| xref:BloombergLP/bslalg/DequeIterator-0d/blockPtr-02.adoc[`blockPtr`] 
| Return the address of the block pointer pointed to by this iterator.
| xref:BloombergLP/bslalg/DequeIterator-0d/nextBlock.adoc[`nextBlock`] 
| Set this iterator to point to the first element of the next block.
| xref:BloombergLP/bslalg/DequeIterator-0d/offsetInBlock.adoc[`offsetInBlock`] 
| Return the offset of the element pointed to by this iterator, from the beginning of the block containing it.
| xref:BloombergLP/bslalg/DequeIterator-0d/operator_star.adoc[`operator*`] 
| Return a reference to the parameterized `VALUE_TYPE` object pointed to by this iterator. Note that this value is modifiable if `VALUE_TYPE` is modifiable, and non‐modifiable if it is not.
| xref:BloombergLP/bslalg/DequeIterator-0d/operator_plus.adoc[`operator+`] 
| Return an iterator pointing the element at the specified `offset` after this iterator.
| xref:BloombergLP/bslalg/DequeIterator-0d/operator_inc.adoc[`operator++`] 
| Increment this iterator to point to the next element in the corresponding deque (i.e., the element following the current one in the same block or, if the current element is the last one in the block, the first element in the next block).
| xref:BloombergLP/bslalg/DequeIterator-0d/operator_plus_eq.adoc[`operator+=`] 
| Advance this iterator by the specified `offset`.
| xref:BloombergLP/bslalg/DequeIterator-0d/operator_minus-06.adoc[`operator‐`] 
| Subtraction operators
| xref:BloombergLP/bslalg/DequeIterator-0d/operator_dec.adoc[`operator‐‐`] 
| Decrement this iterator to point to the previous element in the corresponding deque (i.e., the element preceding the current one in the same block or, if the current element is the first one in the block, the last element in the previous block).
| xref:BloombergLP/bslalg/DequeIterator-0d/operator_minus_eq.adoc[`operator‐=`] 
| Move this iterator backward by the specified `offset`.
| xref:BloombergLP/bslalg/DequeIterator-0d/previousBlock.adoc[`previousBlock`] 
| Set this iterator to point to the first (not the last) element of the previous block.
| xref:BloombergLP/bslalg/DequeIterator-0d/remainingInBlock.adoc[`remainingInBlock`] 
| Return the number of elements in the block pointed to by this iterator, until the end of this block, starting at (and including) the element pointed to by this iterator.
| xref:BloombergLP/bslalg/DequeIterator-0d/setBlock.adoc[`setBlock`] 
| Set this iterator to point to the first element of the block pointed to by the specified `blockPtrPtr`.
| xref:BloombergLP/bslalg/DequeIterator-0d/valuePtr.adoc[`valuePtr`] 
| Return the address of the parameterized `VALUE_TYPE` object pointed to by this iterator.
| xref:BloombergLP/bslalg/DequeIterator-0d/valuePtrDecrement.adoc[`valuePtrDecrement`] 
| Decrement this iterator to point to the next element in the block of the corresponding deque. The behavior is undefined unless this iterator is pointed to a valid position of the deque. Note that this method is used only for optimization purposes in `bslstl_Deque`, and clients of this package should not use this directly.
| xref:BloombergLP/bslalg/DequeIterator-0d/valuePtrIncrement.adoc[`valuePtrIncrement`] 
| Increment this iterator to point to the next element in the block of the corresponding deque. The behavior is undefined unless this iterator is pointed to a valid position of the deque. Note that this method is used only for optimization purposes in `bslstl_Deque`, and clients of this package should not use this directly.
|===


== Specializations

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslalg/DequeIterator-01.adoc[`DequeIterator<VALUE_TYPE, 1>`] 
| This partial specialization of `DequeIterator` for the case when there is a single element per block uses simpler storage and a simpler implementation. The contract for all functions is the same, and so not repeated.
|===


== Friends

[cols="1,4"]
|===
| Name| Description
| `xref:BloombergLP/bslalg/operator_3way-0aa.adoc[BloombergLP::bslalg::operator<=>]`
| Perform a three‐way comparison between the specified `lhs` and `rhs` iterators. The behavior is undefined unless `lhs` and `rhs` are iterators over the same deque.
| `xref:BloombergLP/bslalg/operator_eq-02.adoc[BloombergLP::bslalg::operator==]`
| Return `true` if the specified `lhs` iterator points to the same element in the same block as the specified `rhs` iterator, and `false` otherwise. The behavior is undefined unless `lhs` and `rhs` are iterators over the same deque. Note that this friend is a regular functon, not a function template, so there is no way to declare it outside the class in order to provide the definition.
|===


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