Intel Threading Building Blocks

Parallel Iteration

The types const_range_type and range_type model the Range Concept and provide methods to access the bounds of the range, as shown in Table 5-5. The types differ only in that the bounds for a const_range_type are of type const_iterator, whereas the bounds for a range_type are of type iterator.

Use the range types in conjunction with parallel_for, parallel_reduce, and parallel_scan to iterate over pairs in a concurrent_hash_map.

Table 5-5. Concept for concurrent_hash_map range R

Pseudosignature	Semantics
R::iterator R::begin() const	First item in range
R::iterator R::end() const	One past last item in range

const_range_type range( size_t grainsize ) const

Effects: constructs a const_range_type representing all keys in the table. The grainsize parameter is in units of hash table slots. Each slot typically has only one key-value pair.

Returns: a const_range_type object for the table.

range_type range( size_t grainsize )

Returns: like const_range_type, but returns a range_type object for the table.