sfl::static_vector

March 16, 2026 · View on GitHub

Table of Contents

Summary
Template Parameters
Public Member Types
Public Data Members
- static_capacity
Public Member Functions
- (constructor)
- (destructor)
- assign
- assign_range
- operator=
- begin, cbegin
- end, cend
- rbegin, crbegin
- rend, crend
- nth
- index_of
- empty
- full
- size
- max_size
- capacity
- available
- at
- operator[]
- front
- back
- data
- clear
- emplace
- insert
- insert_range
- emplace_back
- push_back
- append_range
- pop_back
- erase
- resize
- swap
Non-member Functions
- operator==
- operator!=
- operator<
- operator>
- operator<=
- operator>=
- swap
- erase
- erase_if

Summary

Defined in header sfl/static_vector.hpp:

namespace sfl
{
    template < typename T, std::size_t N >
    class static_vector;
}

sfl::static_vector is a sequence container similar to std::vector, but with a fixed maximum capacity defined at compile time and backed entirely by statically allocated storage. This container internally holds a statically allocated array of size N and stores elements in this array, which avoids dynamic memory allocation and deallocation. This container never uses dynamic memory management. The number of elements in the static vector cannot be greater than N. Attempting to insert more than N elements into this container results in undefined behavior. This design provides a compact and cache-friendly representation optimized for use cases where the maximum size is known in advance. It is also well-suited for bare-metal embedded development where predictable memory usage and no dynamic allocation are critical.

sfl::static_vector is not specialized for bool.

sfl::static_vector meets the requirements of Container, ReversibleContainer, ContiguousContainer and SequenceContainer.

sfl::static_vector can be used in C++20 constant expressions.

Note: Support for C++20 constant expressions is not fully mature in the major compilers (GCC, Clang, MSVC), so the following limitations apply:

The data() member function cannot be used in constant expressions.
On GCC, it is not possible to declare constexpr objects of static_vector. Clang and MSVC allow this, so this is a compiler-specific limitation (possibly a bug).

Template Parameters

```
typename T
```
The type of the elements.
```
std::size_t N
```
Size of the internal statically allocated array, i.e. the maximal number of elements that this container can contain.

Public Member Types

Member Type	Definition
`value_type`	`T`
`size_type`	Unsigned integer type
`difference_type`	Signed integer type
`reference`	`value_type&`
`const_reference`	`const value_type&`
`pointer`	Pointer to `value_type`
`const_pointer`	Pointer to `const value_type`
`iterator`	LegacyRandomAccessIterator and LegacyContiguousIterator to `value_type`
`const_iterator`	LegacyRandomAccessIterator and LegacyContiguousIterator to `const value_type`
`reverse_iterator`	`std::reverse_iterator<iterator>`
`const_reverse_iterator`	`std::reverse_iterator<const_iterator>`

Public Data Members

static_capacity

static constexpr size_type static_capacity = N;

Public Member Functions

(constructor)

```
static_vector() noexcept;
```
Effects: Constructs an empty container.

Complexity: Constant.
```
static_vector(size_type n);
```
Preconditions: n <= capacity()

Effects: Constructs the container with n value-initialized elements.

Complexity: Linear in n.
```
static_vector(size_type n, sfl::default_init_t);
```
Preconditions: n <= capacity()

Effects: Constructs the container with n default-initialized elements.

Complexity: Linear in n.
```
static_vector(size_type n, const T& value);
```
Preconditions: n <= capacity()

Effects: Constructs the container with n copies of elements with value value.

Complexity: Linear in n.
```
template <typename InputIt>
static_vector(InputIt first, InputIt last);
```
Preconditions: std::distance(first, last) <= capacity()

Effects: Constructs the container with the contents of the range [first, last).

Note: This overload participates in overload resolution only if InputIt satisfies requirements of LegacyInputIterator.

Complexity: Linear in std::distance(first, last).
```
static_vector(std::initializer_list<T> ilist);
```
Preconditions: ilist.size() <= capacity()

Effects: Constructs the container with the contents of the initializer list ilist.

Complexity: Linear in ilist.size().
```
static_vector(const static_vector& other);
```
Effects: Copy constructor. Constructs the container with the copy of the contents of other.

Complexity: Linear in size.
```
static_vector(static_vector&& other);
```
Effects: Move constructor. Constructs the container with the contents of other using move semantics.

other is not guaranteed to be empty after the move.

other is in a valid but unspecified state after the move.

Complexity: Linear in size.
```
template <typename Range>
static_vector(sfl::from_range_t, Range&& range);
```
Preconditions: Number of elements in range must be <= capacity().

Effects: Constructs the container with the contents of range.

Note: It is available in C++11. In C++20 are used proper C++20 range concepts.

(destructor)

```
~static_vector();
```
Effects: Destructs the container. The destructors of the elements are called and the used storage is deallocated.

Complexity: Linear in size.

assign

```
void assign(size_type n, const T& value);
```
Preconditions: n <= capacity()

Effects: Replaces the contents of the container with n copies of value value.

Complexity: Linear in size.
```
template <typename InputIt>
void assign(InputIt first, InputIt last);
```
Preconditions: std::distance(first, last) <= capacity()

Effects: Replaces the contents of the container with the contents of the range [first, last).

Note: This overload participates in overload resolution only if InputIt satisfies requirements of LegacyInputIterator.

Note: The behavior is undefined if either first or last is an iterator into *this.

Complexity: Linear in size.
```
void assign(std::initializer_list<T> ilist);
```
Preconditions: ilist.size() <= capacity()

Effects: Replaces the contents of the container with the contents of the initializer list ilist.

Complexity: Linear in size.

assign_range

```
template <typename Range>
void assign_range(Range&& range);
```
Preconditions: Number of elements in range must be <= capacity().

Effects: Replaces the contents of the container with the contents of range.

Note: It is available in C++11. In C++20 are used proper C++20 range concepts.

operator=

```
static_vector& operator=(const static_vector& other);
```
Effects: Copy assignment operator. Replaces the contents with a copy of the contents of other.

Returns: *this().

Complexity: Linear in size.
```
static_vector& operator=(static_vector&& other);
```
Effects: Move assignment operator. Replaces the contents with those of other using move semantics.

other is not guaranteed to be empty after the move.

other is in a valid but unspecified state after the move.

Returns: *this().

Complexity: Linear in size.
```
static_vector& operator=(std::initializer_list<T> ilist);
```
Preconditions: ilist.size() <= capacity()

Effects: Replaces the contents with those identified by initializer list ilist.

Returns: *this().

Complexity: Linear in size.

begin, cbegin

```
iterator begin() noexcept;
```
```
const_iterator begin() const noexcept;
```
```
const_iterator cbegin() const noexcept;
```
Effects: Returns an iterator to the first element of the container. If the container is empty, the returned iterator will be equal to end().

Complexity: Constant.

end, cend

```
iterator end() noexcept;
```
```
const_iterator end() const noexcept;
```
```
const_iterator cend() const noexcept;
```
Effects: Returns an iterator to the element following the last element of the container. This element acts as a placeholder; attempting to access it results in undefined behavior.

Complexity: Constant.

rbegin, crbegin

```
reverse_iterator rbegin() noexcept;
```

const_reverse_iterator rbegin() const noexcept;

```
const_reverse_iterator crbegin() const noexcept;
```
Effects: Returns a reverse iterator to the first element of the reversed container. It corresponds to the last element of the non-reversed container. If the container is empty, the returned iterator is equal to rend().

Complexity: Constant.

rend, crend

```
reverse_iterator rend() noexcept;
```

const_reverse_iterator rend() const noexcept;

```
const_reverse_iterator crend() const noexcept;
```
Effects: Returns a reverse iterator to the element following the last element of the reversed container. It corresponds to the element preceding the first element of the non-reversed container. This element acts as a placeholder, attempting to access it results in undefined behavior.

Complexity: Constant.

nth

```
iterator nth(size_type pos) noexcept;
```
```
const_iterator nth(size_type pos) const noexcept;
```
Preconditions: pos <= size()

Effects: Returns an iterator to the element at position pos.

If pos == size(), the returned iterator is equal to end().

Complexity: Constant.

index_of

```
size_type index_of(const_iterator pos) const noexcept;
```
Preconditions: cbegin() <= pos && pos <= cend()

Effects: Returns position of the element pointed by iterator pos, i.e. std::distance(begin(), pos).

If pos == end(), the returned value is equal to size().

Complexity: Constant.

empty

```
bool empty() const noexcept;
```
Effects: Returns true if the container has no elements, i.e. whether begin() == end().

Complexity: Constant.

full

```
bool full() const noexcept;
```
Effects: Returns true if the container is full, i.e. whether size() == capacity().

Complexity: Constant.

size

```
size_type size() const noexcept;
```
Effects: Returns the number of elements in the container, i.e. std::distance(begin(), end()).

Complexity: Constant.

max_size

```
static constexpr size_type max_size() const noexcept;
```
Effects: Returns the maximum number of elements the container is able to hold, i.e. N.

Complexity: Constant.

capacity

```
static constexpr size_type capacity() const noexcept;
```
Effects: Returns the maximum number of elements the container is able to hold, i.e. N.

Complexity: Constant.

available

```
size_type available() const noexcept;
```
Effects: Returns the number of elements that can be inserted into the container, i.e. capacity() - size().

Complexity: Constant.

at

```
reference at(size_type pos);
```
```
const_reference at(size_type pos) const;
```
Effects: Returns a reference to the element at specified location pos, with bounds checking.

Complexity: Constant.

Exceptions: std::out_of_range if pos >= size().

operator[]

reference operator[](size_type pos) noexcept;

```
const_reference operator[](size_type pos) const noexcept;
```
Preconditions: pos < size()

Effects: Returns a reference to the element at specified location pos. No bounds checking is performed.

Note: This operator never inserts a new element into the container.

Complexity: Constant.

front

```
reference front() noexcept;
```
```
const_reference front() const noexcept;
```
Preconditions: !empty()

Effects: Returns a reference to the first element in the container.

Complexity: Constant.

back

```
reference back() noexcept;
```
```
const_reference back() const noexcept;
```
Preconditions: !empty()

Effects: Returns a reference to the last element in the container.

Complexity: Constant.

data

```
T* data() noexcept;
```
```
const T* data() const noexcept;
```
Effects: Returns pointer to the underlying array serving as element storage. The pointer is such that range [data(), data() + size()) is always a valid range, even if the container is empty. data() is not dereferenceable if the container is empty.

Complexity: Constant.

clear

```
void clear() noexcept;
```
Effects: Erases all elements from the container. After this call, size() returns zero.

Complexity: Linear in size().

emplace

```
template <typename... Args>
iterator emplace(const_iterator pos, Args&&... args);
```
Preconditions:
1. !full()
2. cbegin() <= pos && pos <= cend()
Effects: Inserts a new element into the container at position pos.

New element is constructed as value_type(std::forward<Args>(args)...).

args... may directly or indirectly refer to a value in the container.

Returns: Iterator to the inserted element.

Complexity: Constant plus linear in std::distance(pos, end()).

insert

```
iterator insert(const_iterator pos, const T& value);
```
Preconditions:
1. !full()
2. cbegin() <= pos && pos <= cend()
Effects: Inserts copy of value at position pos.

Returns: Iterator to the inserted element.

Complexity: Constant plus linear in std::distance(pos, end()).
```
iterator insert(const_iterator pos, T&& value);
```
Preconditions:
1. !full()
2. cbegin() <= pos && pos <= cend()
Effects: Inserts value using move semantics at position pos.

Returns: Iterator to the inserted element.

Complexity: Constant plus linear in std::distance(pos, end()).
```
iterator insert(const_iterator pos, size_type n, const T& value);
```
Preconditions:
1. n <= available()
2. cbegin() <= pos && pos <= cend()
Effects: Inserts n copies of value before position pos.

Returns: Iterator to the first element inserted, or pos if n == 0.

Complexity: Linear in n plus linear in std::distance(pos, end()).
```
template <typename InputIt>
iterator insert(const_iterator pos, InputIt first, InputIt last);
```
Preconditions:
1. std::distance(first, last) <= available()
2. cbegin() <= pos && pos <= cend()
Effects: Inserts elements from the range [first, last) before position pos.

Note: This overload participates in overload resolution only if InputIt satisfies requirements of LegacyInputIterator.

Returns: Iterator to the first element inserted, or pos if first == last.

Complexity: Linear in std::distance(first, last) plus linear in std::distance(pos, end()).
```
iterator insert(const_iterator pos, std::initializer_list<T> ilist);
```
Preconditions:
1. ilist.size() <= available()
2. cbegin() <= pos && pos <= cend()
Effects: Inserts elements from initializer list ilist before position pos.

Returns: Iterator to the first element inserted, or pos if ilist is empty.

Complexity: Linear in ilist.size() plus linear in std::distance(pos, end()).

insert_range

```
template <typename Range>
iterator insert_range(const_iterator pos, Range&& range);
```
Preconditions: Number of elements in range must be <= available().

Effects: Inserts elements from range before position pos. Elements are inserted in non-reversing order.

range must not overlap with the container. Otherwise, the behavior is undefined.

Returns: Iterator to the first element inserted, or pos if range is empty.

Note: It is available in C++11. In C++20 are used proper C++20 range concepts.

emplace_back

```
template <typename... Args>
reference emplace_back(Args&&... args);
```
Preconditions: !full()

Effects: Inserts a new element at the end of container.

New element is constructed as value_type(std::forward<Args>(args)...).

Returns: Reference to the inserted element.

Complexity: Constant.

push_back

```
void push_back(const T& value);
```
Preconditions: !full()

Effects: Inserts copy of value at the end of container.

Complexity: Constant.
```
void push_back(T&& value);
```
Preconditions: !full()

Effects: Inserts value using move semantics at the end of container.

Complexity: Constant.

append_range

```
template <typename Range>
void append_range(Range&& range);
```
Preconditions: Number of elements in range must be <= available().

Effects: Inserts elements from range before end(). Elements are inserted in non-reversing order.

Note: It is available in C++11. In C++20 are used proper C++20 range concepts.

pop_back

```
void pop_back();
```
Preconditions: !empty()

Effects: Removes the last element of the container.

Complexity: Constant.

erase

```
iterator erase(const_iterator pos);
```
Preconditions: cbegin() <= pos && pos < cend()

Effects: Removes the element at pos.

Returns: Iterator following the last removed element.

If pos refers to the last element, then the end() iterator is returned.
```
iterator erase(const_iterator first, const_iterator last);
```
Preconditions: cbegin() <= first && first <= last && last <= cend()

Effects: Removes the elements in the range [first, last).

Returns: Iterator following the last removed element.

If last == end() prior to removal, then the updated end() iterator is returned.

If [first, last) is an empty range, then last is returned.

resize

```
void resize(size_type n);
```
Preconditions: n <= capacity()

Effects: Resizes the container to contain n elements.
1. If the n > size(), additional elements are inserted at the end of container. Additional elements are value-initialized.
2. If the n < size(), the last size() - n elements are removed.
Complexity: Linear in difference between size() and n.
```
void resize(size_type n, sfl::default_init_t);
```
Preconditions: n <= capacity()

Effects: Resizes the container to contain n elements.
1. If the n > size(), additional elements are inserted at the end of container. Additional elements are default-initialized.
2. If the n < size(), the last size() - n elements are removed.
Complexity: Linear in difference between size() and n.
```
void resize(size_type n, const T& value);
```
Preconditions: n <= capacity()

Effects: Resizes the container to contain n elements.
1. If the n > size(), additional copies of value are inserted at the end of container.
2. If the n < size(), the last size() - n elements are removed.
Complexity: Linear in difference between size() and n.

swap

```
void swap(static_vector& other);
```
Effects: Exchanges the contents of the container with those of other.

Complexity: Linear in size.

Non-member Functions

operator==

```
template <typename T, std::size_t N>
bool operator==
(
    const static_vector<T, N>& x,
    const static_vector<T, N>& y
);
```
Effects: Checks if the contents of x and y are equal.

The contents of x and y are equal if the following conditions hold:
- x.size() == y.size()
- Each element in x compares equal with the element in y at the same position.
Returns: true if the contents of the x and y are equal, false otherwise.

Complexity: Constant if x and y are of different size, otherwise linear in the size of the container.

operator!=

```
template <typename T, std::size_t N>
bool operator!=
(
    const static_vector<T, N>& x,
    const static_vector<T, N>& y
);
```
Effects: Checks if the contents of x and y are equal.

For details see operator==.

Returns: true if the contents of the x and y are not equal, false otherwise.

Complexity: Constant if x and y are of different size, otherwise linear in the size of the container.

operator<

```
template <typename T, std::size_t N>
bool operator<
(
    const static_vector<T, N>& x,
    const static_vector<T, N>& y
);
```
Effects: Compares the contents of x and y lexicographically. The comparison is performed by a function std::lexicographical_compare.

Returns: true if the contents of the x are lexicographically less than the contents of y, false otherwise.

Complexity: Linear in the size of the container.

operator>

```
template <typename T, std::size_t N>
bool operator>
(
    const static_vector<T, N>& x,
    const static_vector<T, N>& y
);
```
Effects: Compares the contents of x and y lexicographically. The comparison is performed by a function std::lexicographical_compare.

Returns: true if the contents of the x are lexicographically greater than the contents of y, false otherwise.

Complexity: Linear in the size of the container.

operator<=

```
template <typename T, std::size_t N>
bool operator<=
(
    const static_vector<T, N>& x,
    const static_vector<T, N>& y
);
```
Effects: Compares the contents of x and y lexicographically. The comparison is performed by a function std::lexicographical_compare.

Returns: true if the contents of the x are lexicographically less than or equal to the contents of y, false otherwise.

Complexity: Linear in the size of the container.

operator>=

```
template <typename T, std::size_t N>
bool operator>=
(
    const static_vector<T, N>& x,
    const static_vector<T, N>& y
);
```
Effects: Compares the contents of x and y lexicographically. The comparison is performed by a function std::lexicographical_compare.

Returns: true if the contents of the x are lexicographically greater than or equal to the contents of y, false otherwise.

Complexity: Linear in the size of the container.

swap

template <typename T, std::size_t N>
void swap
(
    static_vector<T, N>& x,
    static_vector<T, N>& y
);

Effects: Swaps the contents of x and y. Calls x.swap(y).

erase

template <typename T, std::size_t N, typename U>
typename static_vector<T, N>::size_type
    erase(static_vector<T, N>& c, const U& value);

Effects: Erases all elements that compare equal to value from the container.

Returns: The number of erased elements.

Complexity: Linear.

erase_if

```
template <typename T, std::size_t N, typename Predicate>
typename static_vector<T, N>::size_type
    erase_if(static_vector<T, N>& c, Predicate pred);
```
Effects: Erases all elements that satisfy the predicate pred from the container.

pred is unary predicate which returns true if the element should be removed.

Returns: The number of erased elements.

Complexity: Linear.

End of document.