gmx::ArrayRef< T > Class Template Reference

#include <gromacs/utility/arrayref.h>

Description

template<typename T>
class gmx::ArrayRef< T >

STL-like interface to a C array of T (or part of a std container of T).

Template Parameters

T	Value type of elements.

This class provides an interface similar to std::vector<T, A>, with the following main differences:

• This class does not have its own storage. Instead, it references an existing array of values (either a C-style array or part of an existing std::vector<T, A> or std::array<T>).
• It is only possible to modify the values themselves through ArrayRef; it is not possible to add or remove values.
• Copying objects of this type is cheap, and the copies behave identically to the original object: the copy references the same set of values.

This class is useful for writing wrappers that expose a view of the internal data stored as a single vector/array, which can be a whole or part of the underlying storage.

Methods in this class do not throw, except where indicated.

Note that due to a Doxygen limitation, the constructor that takes a C array whose size is known at compile time does not appear in the documentation.

To refer to const data of type T, ArrayRef<const T> is used. For both const and non-const std::vector and std::array an ArrayRef view can be created. Attempting to create a non-const ArrayRef of a const vector/array will result in a compiler error in the respective constructor.

For SIMD types there is template specialization available (e.g. ArrayRef<SimdReal>) in gromacs/simd/simd_memory.h which should have the same functionality as much as possible.

Todo:

This class is not complete. There are likely also methods missing (not required for current usage).

Public Types
typedef T	value_type
	Type of values stored in the reference.
typedef index	size_type
	Type for representing size of the reference.
typedef ptrdiff_t	difference_type
	Type for representing difference between two indices.
typedef const T &	const_reference
	Const reference to an element.
typedef const T *	const_pointer
	Const pointer to an element.
typedef const T *	const_iterator
	Const iterator type to an element.
typedef T &	reference
	Reference to an element.
typedef T *	pointer
	Pointer to an element.
typedef T *	iterator
	Iterator type to an element.
typedef std::reverse_iterator < iterator >	reverse_iterator
	Standard reverse iterator.
typedef std::reverse_iterator < const_iterator >	const_reverse_iterator
	Standard reverse iterator.

Public Member Functions
	ArrayRef ()
	Constructs an empty reference.
	ArrayRef (const EmptyArrayRef &)
	Constructs an empty reference. More...
template<typename U , typename = typename std::enable_if< std::is_convertible<typename std::remove_reference<U>::type::pointer, pointer>::value>::type>
	ArrayRef (U &&o)
	Constructs a reference to a container or reference. More...
	ArrayRef (pointer begin, pointer end)
	Constructs a reference to a particular range. More...
ArrayRef	subArray (size_type start, size_type count) const
	Returns a reference to part of the memory.
iterator	begin () const
	Returns an iterator to the beginning of the reference.
iterator	end () const
	Returns an iterator to the end of the reference.
reverse_iterator	rbegin () const
	Returns an iterator to the reverse beginning of the reference.
reverse_iterator	rend () const
	Returns an iterator to the reverse end of the reference.
size_type	size () const
	Returns the size of the reference.
size_type	capacity () const
	Identical to size().
bool	empty () const
	Whether the reference refers to no memory.
reference	operator[] (size_type n) const
	Access an element.
reference	at (size_type n) const
	Access an element (throws on out-of-range error).
reference	front () const
	Returns the first element.
reference	back () const
	Returns the first element.
pointer	data () const
	Returns a raw pointer to the contents of the array.
void	swap (ArrayRef< T > &other)
	Swaps referenced memory with the other object. More...

Related Functions
(Note that these are not member functions.)
template<typename T >
ArrayRef< T >	arrayRefFromArray (T *begin, size_t size)
template<typename T >
ArrayRef< const T >	constArrayRefFromArray (const T *begin, size_t size)

Constructor & Destructor Documentation

template<typename T>

gmx::ArrayRef< T >::ArrayRef ( const EmptyArrayRef< T > &  )

inline

Constructs an empty reference.

This is provided for convenience, such that EmptyArrayRef can be used to initialize any ArrayRef, without specifying the template type. It is not explicit to enable that usage.

template<typename T>

template<typename U , typename = typename std::enable_if< std::is_convertible<typename std::remove_reference<U>::type::pointer, pointer>::value>::type>

gmx::ArrayRef< T >::ArrayRef ( U &&  o )

inline

Constructs a reference to a container or reference.

Parameters

[in]

o

container to reference.

Can be used to create a reference to a whole vector, std::array or an ArrayRef. The destination has to have a convertible pointer type (identical besides const or base class).

Passed container must remain valid and not be reallocated for the lifetime of this object.

This constructor is not explicit to allow directly passing a container to a method that takes ArrayRef.

template<typename T>

gmx::ArrayRef< T >::ArrayRef ( pointer  begin, pointer  end  )

inline

Constructs a reference to a particular range.

Parameters

[in]	begin	Pointer to the beginning of a range.
[in]	end	Pointer to the end of a range.

Passed pointers must remain valid for the lifetime of this object.

Member Function Documentation

template<typename T>

void gmx::ArrayRef< T >::swap ( ArrayRef< T > &  other )

inline

Swaps referenced memory with the other object.

The actual memory areas are not modified, only the references are swapped.

Friends And Related Function Documentation

template<typename T >

ArrayRef< T > arrayRefFromArray ( T *  begin, size_t  size  )

related

template<typename T >

ArrayRef< const T > constArrayRefFromArray ( const T *  begin, size_t  size  )

related

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The documentation for this class was generated from the following files:

• src/gromacs/commandline/cmdlinehelpwriter.h
• src/gromacs/utility/arrayref.h