inline T read_single_value(const buffer &buffer,
size_t index,
command_queue &queue)
{
BOOST_ASSERT(index < buffer.size() / sizeof(T));
BOOST_ASSERT(buffer.get_context() == queue.get_context());
T value;
queue.enqueue_read_buffer(buffer,
sizeof(T) * index,
sizeof(T),
&value);
return value;
}
inline HostIterator copy_to_host(DeviceIterator first,
DeviceIterator last,
HostIterator result,
command_queue &queue)
{
typedef typename
std::iterator_traits<DeviceIterator>::value_type
value_type;
size_t count = iterator_range_size(first, last);
if(count == 0){
return result;
}
const buffer &buffer = first.get_buffer();
size_t offset = first.get_index();
queue.enqueue_read_buffer(buffer,
offset * sizeof(value_type),
count * sizeof(value_type),
::boost::addressof(*result));
return iterator_plus_distance(result, count);
}