inline void merge_sort_by_key_on_cpu(KeyIterator keys_first,
KeyIterator keys_last,
ValueIterator values_first,
Compare compare,
command_queue &queue)
{
typedef typename std::iterator_traits<KeyIterator>::value_type key_type;
typedef typename std::iterator_traits<ValueIterator>::value_type value_type;
size_t count = iterator_range_size(keys_first, keys_last);
if(count < 2){
return;
}
// for small input size only insertion sort is performed
else if(count <= 512){
block_insertion_sort(keys_first, values_first, compare,
count, count, true, queue);
return;
}
const context &context = queue.get_context();
const device &device = queue.get_device();
// loading parameters
std::string cache_key =
std::string("__boost_merge_sort_by_key_on_cpu_") + type_name<value_type>()
+ "_with_" + type_name<key_type>();
boost::shared_ptr<parameter_cache> parameters =
detail::parameter_cache::get_global_cache(device);
const size_t block_size =
parameters->get(cache_key, "insertion_sort_by_key_block_size", 64);
block_insertion_sort(keys_first, values_first, compare,
count, block_size, true, queue);
// temporary buffer for merge results
vector<value_type> values_temp(count, context);
vector<key_type> keys_temp(count, context);
bool result_in_temporary_buffer = false;
for(size_t i = block_size; i < count; i *= 2){
result_in_temporary_buffer = !result_in_temporary_buffer;
if(result_in_temporary_buffer) {
merge_blocks(keys_first, values_first,
keys_temp.begin(), values_temp.begin(),
compare, count, i, true, queue);
} else {
merge_blocks(keys_temp.begin(), values_temp.begin(),
keys_first, values_first,
compare, count, i, true, queue);
}
}
if(result_in_temporary_buffer) {
copy(keys_temp.begin(), keys_temp.end(), keys_first, queue);
copy(values_temp.begin(), values_temp.end(), values_first, queue);
}
}
virtual bool onEvent(uint64_t time, const stdsrc::CVariantTree& props)
{
size_t size = props.get_bags().size();
std::vector<const stdsrc::uchar_t*> names(size), values(size);
std::vector<stdsrc::ustring> values_temp(size);
names.reserve(size);
values.reserve(size);
size_t i = 0;
for (const auto& pair : props.get_bags())
{
const stdsrc::CVariantTree& prop = pair.second;
const stdsrc::CVariant& name = prop.get_variant(stdsrc::bagname::Name);
names[i] = name.is_empty() ? nullptr : name.get<stdsrc::ustring>().c_str();
const stdsrc::CVariant& value = prop.get_variant(stdsrc::bagname::Value);
values[i] = value.is_empty() ? nullptr : value.as_str(values_temp[i]).c_str();
++i;
}
return m_receive(m_receiver, time, (uint16_t)size, size ? &names[0] : nullptr, size ? &values[0] : nullptr, m_reader.getProgress());
}