Class template mapped_view

boost::compute::mapped_view — A mapped view of host memory.

Synopsis

// In header: <boost/compute/container/mapped_view.hpp>

template<typename T> 
class mapped_view {
public:
  // types
  typedef T                    value_type;     
  typedef size_t               size_type;      
  typedef ptrdiff_t            difference_type;
  typedef buffer_iterator< T > iterator;       
  typedef buffer_iterator< T > const_iterator; 

  // construct/copy/destruct
  mapped_view();
  mapped_view(T *, size_type, const context & = system::default_context());
  mapped_view(const T *, size_type, 
              const context & = system::default_context());
  mapped_view(const mapped_view< T > &);
  mapped_view< T > & operator=(const mapped_view< T > &);
  ~mapped_view();

  // public member functions
  iterator begin();
  const_iterator begin() const;
  const_iterator cbegin() const;
  iterator end();
  const_iterator end() const;
  const_iterator cend() const;
  size_type size() const;
  T * get_host_ptr();
  const T * get_host_ptr() const;
  void resize(size_type);
  bool empty() const;
  const buffer & get_buffer() const;
  void map(cl_map_flags, command_queue &);
  void map(command_queue &);
  void unmap(command_queue &);
};

Description

The mapped_view class simplifies mapping host-memory to a compute device. This allows for host-allocated memory to be used with the Boost.Compute algorithms.

The following example shows how to map a simple C-array containing data on the host to the device and run the reduce() algorithm to calculate the sum:

See Also:

buffer

`mapped_view` public construct/copy/destruct

```
mapped_view();
```
Creates a null mapped_view object.
```
mapped_view(T * host_ptr, size_type n, 
            const context & context = system::default_context());
```
Creates a mapped_view for host_ptr with n elements. After constructing a mapped_view the data is available for use by a compute device. Use the unmap() method to make the updated data available to the host.
```
mapped_view(const T * host_ptr, size_type n, 
            const context & context = system::default_context());
```
Creates a read-only mapped_view for host_ptr with n elements. After constructing a mapped_view the data is available for use by a compute device. Use the unmap() method to make the updated data available to the host.

mapped_view(const mapped_view< T > & other);

Creates a copy of other.

mapped_view< T > & operator=(const mapped_view< T > & other);

Copies the mapped buffer from other.

```
~mapped_view();
```
Destroys the mapped_view object.

`mapped_view` public member functions

```
iterator begin();
```
Returns an iterator to the first element in the mapped_view.
```
const_iterator begin() const;
```
Returns a const_iterator to the first element in the mapped_view.
```
const_iterator cbegin() const;
```
Returns a const_iterator to the first element in the mapped_view.
```
iterator end();
```
Returns an iterator to one past the last element in the mapped_view.
```
const_iterator end() const;
```
Returns a const_iterator to one past the last element in the mapped_view.
```
const_iterator cend() const;
```
Returns a const_iterator to one past the last element in the mapped_view.
```
size_type size() const;
```
Returns the number of elements in the mapped_view.
```
T * get_host_ptr();
```
Returns the host data pointer.
```
const T * get_host_ptr() const;
```
Returns the host data pointer.
```
void resize(size_type size);
```
Resizes the mapped_view to size elements.
```
bool empty() const;
```
Returns true if the mapped_view is empty.
```
const buffer & get_buffer() const;
```
Returns the mapped buffer.
```
void map(cl_map_flags flags, command_queue & queue);
```
Maps the buffer into the host address space.

See the documentation for clEnqueueMapBuffer() for more information.
```
void map(command_queue & queue);
```
Maps the buffer into the host address space for reading and writing.

Equivalent to:
```
map(CL_MAP_READ | CL_MAP_WRITE, queue);
```
```
void unmap(command_queue & queue);
```
Unmaps the buffer from the host address space.

See the documentation for clEnqueueUnmapMemObject() for more information.

Boost C++ Libraries

Class template mapped_view

Synopsis

Description

mapped_view public construct/copy/destruct

mapped_view public member functions

`mapped_view` public construct/copy/destruct

`mapped_view` public member functions