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470 lines
10 KiB
Markdown
470 lines
10 KiB
Markdown
---
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title: iterator
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---
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{{< callout type="info">}}
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Header: `iterator.h`
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Since: `TBC`
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{{< /callout >}}
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A set of templates to more easily determine the properties of iterator types.
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## Input iterators
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```cpp
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is_input_iterator<T>::value
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```
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**Description**
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Is `T` an input iterator?
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---
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```cpp
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is_input_iterator_concept<T>::value
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```
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**Description**
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Can `T` be used as an input iterator?
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## Output iterators
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```cpp
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is_output_iterator<T>::value
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```
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**Description**
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Is `T` an output iterator?
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---
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```cpp
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is_output_iterator_concept<T>::value
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```
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**Description**
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Can `T` be used as an output iterator?
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## Forward iterators
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```cpp
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is_forward_iterator<T>::value
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```
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**Description**
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Is `T` a forward iterator?
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---
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```cpp
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is_forward_iterator_concept<T>::value
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```
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**Description**
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Can `T` be used as an forward iterator?
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## Bidirectional iterators
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```cpp
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is_bidirectional_iterator<T>::value
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```
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**Description**
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Is `T` a bidirectional iterator?
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---
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```cpp
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is_bidirectional_iterator_concept<T>::value
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```
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**Description**
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Can `T` be used as a bidirectional iterator?
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## Random iterators
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```cpp
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is_random_iterator<T>::value
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```
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**Description**
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Is `T` a random iterator?
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```cpp
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is_random_iterator_concept<T>::value
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```
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**Description**
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Can `T` be used as a random iterator?
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## Iterator tags
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```cpp
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struct input_iterator_tag
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struct output_iterator_tag
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struct forward_iterator_tag
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struct bidirectional_iterator_tag
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struct random_access_iterator_tag
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```
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## Iterator traits
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```cpp
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template <typename TIterator>
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struct iterator_traits
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```
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**Defined types**
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```cpp
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iterator_category
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value_type
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difference_type
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pointer
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reference
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```
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## advance
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```cpp
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template <typename TIterator, typename TDistance>
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ETL_CONSTEXPR17 void advance(TIterator& itr, TDistance n)
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```
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## prev
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```cpp
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template<typename TIterator>
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ETL_CONSTEXPR17 TIterator prev(TIterator itr,
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typename etl::iterator_traits<TIterator>::difference_type n = 1)
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```
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## next
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```cpp
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template<typename TIterator>
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ETL_CONSTEXPR17 TIterator next(TIterator itr,
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typename etl::iterator_traits<TIterator>::difference_type n = 1)
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```
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## distance
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```cpp
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template<typename TIterator>
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ETL_CONSTEXPR17 typename std::iterator_traits<TIterator>::difference_type
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distance(TIterator first, TIterator last)
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```
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## iterator
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A base class provided to simplify definitions of the required types for iterators.
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https://en.cppreference.com/w/cpp/iterator/iterator
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```cpp
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template <typename TCategory,
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typename T,
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typename TDistance = ptrdiff_t,
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typename TPointer = T* ,
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typename TReference = T&>
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struct iterator
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```
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**Defined types**
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```cpp
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value_type
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difference_type
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pointer
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reference
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iterator_category
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```
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## reverse_iterator
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An iterator adaptor that reverses the direction of a given iterator
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```cpp
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template <typename TIterator>
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class reverse_iterator
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```
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**Defined types**
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```cpp
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iterator_category
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value_type
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iterator_type
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difference_type
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pointer
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reference
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```
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## move_iterator
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An iterator adaptor that converts the value returned by the underlying iterator into an rvalue.
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C++11 or above.
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```cpp
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template <typename TIterator>
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class move_iterator
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```
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**Defined types**
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```cpp
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iterator_category
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value_type
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iterator_type
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difference_type
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pointer
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reference
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```
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## back_insert_iterator
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Inserts using `push_back`.
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```cpp
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template <typename TContainer>
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class back_insert_iterator
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```
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---
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```cpp
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template <typename TContainer>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::back_insert_iterator<TContainer> back_inserter(TContainer& container)
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```
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## front_insert_iterator
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Inserts using `push_front`.
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```cpp
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template <typename TContainer>
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class front_insert_iterator
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```
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---
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```cpp
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template <typename TContainer>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::front_insert_iterator<TContainer> front_inserter(TContainer& container)
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```
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## push_insert_iterator
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Inserts using `push`.
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```cpp
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template <typename TContainer>
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class push_insert_iterator
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```
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---
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```cpp
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template <typename TContainer>
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ETL_NODISCARD
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ETL_CONSTEXPR14
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etl::push_insert_iterator<TContainer> push_inserter(TContainer& container)
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```
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## begin
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::iterator begin(TContainer& container)
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Get the 'begin' iterator of `container`.
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```
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::const_iterator begin(const TContainer& container)
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```
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Get the `begin` `const_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::const_iterator cbegin(const TContainer& container)
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```
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Get the `begin` `const_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR TValue* begin(TValue(&data)[Array_Size])
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```
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Get the `begin` `pointer` for an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR const TValue* begin(const TValue(&data)[Array_Size])
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```
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Get the `begin` `const pointer` for an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR const TValue* cbegin(const TValue(&data)[Array_Size])
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```
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Get the `begin` `const pointer` for an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::reverse_iterator rbegin(TContainer& container)
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```
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Get the `begin` `reverse_iterator` of `container`.
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Enabled if ETL_NOT_USING_STL or ETL_CPP14_NOT_SUPPORTED.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::const_reverse_iterator rbegin(const TContainer& container)
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```
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Get the `begin` `const_reverse_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::const_reverse_iterator crbegin(const TContainer& container)
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```
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Get the `begin`' `const_reverse_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_OR_STD::reverse_iterator<TValue*> rbegin(TValue(&data)[Array_Size])
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```
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Get the `begin` `reverse_iterator` for an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR ETL_OR_STD::reverse_iterator<const TValue*> crbegin(const TValue(&data)[Array_Size])
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```
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Get the `begin` `const_reverse_iterator` for an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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## end
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::iterator end(TContainer& container)
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```
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Get the `end` iterator of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::const_iterator end(const TContainer& container)
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```
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Get the `end` `const_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::const_iterator cend(const TContainer& container)
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```
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Get the `end` `const_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR TValue* end(TValue(&data)[Array_Size])
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```
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Get the `end` `pointer` for an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR const TValue* end(const TValue(&data)[Array_Size])
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```
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Get the `end` `const pointer` of an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR const TValue* cend(const TValue(&data)[Array_Size])
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```
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Get the `end` `const pointer` of an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP11_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::reverse_iterator rend(TContainer& container)
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```
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Get the `end` `reverse_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::const_reverse_iterator rend(TContainer& container)
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```
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Get the `end` `const_reverse_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::const_reverse_iterator crend(const TContainer& container)
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```
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Get the `end` `const_reverse_iterator` of `container`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR ETL_OR_STD::reverse_iterator<TValue*> rend(TValue(&data)[Array_Size])
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```
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Get the `end` `reverse_iterator` for an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR ETL_OR_STD::reverse_iterator<const TValue*> crend(const TValue(&data)[Array_Size])
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```
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Get the `end` `const_reverse_iterator` for an array.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP14_NOT_SUPPORTED`.
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## size
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```cpp
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template <typename TContainer>
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ETL_CONSTEXPR typename TContainer::size_type size(const TContainer& container)
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```
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Get the size of a container.
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Expects the container to have defined `size_type`.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP17_NOT_SUPPORTED`.
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---
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```cpp
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template <typename TValue, size_t Array_Size>
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ETL_CONSTEXPR size_t size(TValue(&)[Array_Size])
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```
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Get the size of an array in elements at run time, or compile time if C++11 or above.
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP17_NOT_SUPPORTED`.
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---
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```cpp
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template <typename T, size_t Array_Size>
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char(&array_size(T(&array)[Array_Size]))[Array_Size];
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```
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Get the size of an array in elements at compile time for C++03
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Usage:- `sizeof(array_size(array))`
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Enabled if `ETL_NOT_USING_STL` or `ETL_CPP17_NOT_SUPPORTED`.
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---
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`ETL_ARRAY_SIZE(a)` calls `sizeof(etl::array_size(a))`
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