chunkedseq_7.cpp

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#include <iostream>
#include <string>
#include <assert.h>

#include "chunkedseq.hpp"

template <class Chunkedseq, class UnaryPredicate>
void pcopy_if(typename Chunkedseq::iterator first,
              typename Chunkedseq::iterator last,
              Chunkedseq& destination,
              const UnaryPredicate& pred) {
  using iterator = typename Chunkedseq::iterator;
  using value_type = typename Chunkedseq::value_type;
  using ptr = typename Chunkedseq::const_pointer;
  
  const long cutoff = 8192;
  
  long sz = last.size() - first.size();
  
  if (sz <= cutoff) {
    
    // compute result in a sequential fashion
    Chunkedseq::for_each_segment(first, last, [&] (ptr lo, ptr hi) {
      for (ptr p = lo; p < hi; p++) {
        value_type v = *p;
        if (pred(v))
          destination.push_back(v);
      }
    });
    
  } else {
    
    // select split position to be the median
    iterator mid = first + (sz/2);
    
    Chunkedseq destination2;
    
    // recurse on subproblems
    // calls can execute in parallel
    pcopy_if(first, mid,  destination,  pred);
    pcopy_if(mid,   last, destination2, pred);
    
    destination.concat(destination2);
  }
}

int main(int argc, const char * argv[]) {
  
  const int chunk_size = 2;
  using mydeque_type = pasl::data::chunkedseq::bootstrapped::deque<int, chunk_size>;
  
  mydeque_type mydeque = { 0, 1, 2, 3, 4, 5 };
  mydeque_type mydeque2;
  
  pcopy_if(mydeque.begin(), mydeque.end(), mydeque2, [] (int i) { return i%2==0; });
  
  std::cout << "mydeque2 contains:";
  auto p = mydeque2.begin();
  while (p != mydeque2.end())
    std::cout << " " << *p++;
  std::cout << std::endl;
  
  return 0;
  
}
//! [pcopy_if_example]