copy_stream.cpp

/* core tpie configurations and initializations */
#include <tpie/tpie.h>
#include <tpie/file_stream.h>
#include <string>
#include <ctime>

using std::cerr;
using std::endl;


/* a basic struct storing a 3D segment */
struct segment_t {
  double x1, y1, x2, y2;
  float z1, z2;
};

struct segmentstr_t {
  char* str1;
};
struct segmentstr_t make_segment(int x){
  struct segmentstr_t s;
  s.str1 = (char*)malloc(sizeof(char)*10);
  strcpy(s.str1,"Hello");
  return s;
}



/* make a dummy segment with given x1,y1, but
 * setting other coordinates to 0 */
struct segment_t make_segment(double x1, double y1){
  struct segment_t s;
  s.x1=x1; s.y1=y1;
  s.x2=s.y2=s.z1=s.z2=0.f;
  return s;
}

/* print x1, y1 coords of segment */
void print_item(const struct segment_t& item){
  printf("(%6.2f %6.2f)", item.x1, item.y1);
}

void print_item(const struct segmentstr_t& item){
  printf("%s", item.str1);
}


/* write n segment items to tpie::file_stream with given
 * output file name fname. Overwrites any previous file */
void writestream(const std::string& fname, size_t n){

  tpie::file_stream<struct segmentstr_t> out;
  out.open(fname, tpie::open::write_only);
  for(size_t i=0; i<n; i++){
    struct segmentstr_t item = make_segment(i);
    //print_item(item); printf("\n");
    out.write(item);
  }
}

/* Read all segments from a tpie::file_stream with
 * file name given by fname and prints results */
void readstream(const std::string& fname){

  tpie::file_stream<struct segmentstr_t> in;
  in.open(fname, tpie::open::read_only);
  printf("size of stream: %6ld\n\n", in.size());
  while (in.can_read()) {
    segmentstr_t item = in.read();
    //print_item(item); printf("\n");
  }
}

/* copy infile name to outfile name. Assumes infile
 * is a valid tpie::file_stream and overwrites outfile
 */
void copystream(const std::string & infile,
    const std::string & outfile) {
  tpie::file_stream<struct segmentstr_t> in;
  tpie::file_stream<struct segmentstr_t> out;

  in.open(infile);
  out.open(outfile, tpie::open::write_only);
  while (in.can_read()) {
     segmentstr_t item = in.read();
     out.write(item);
   }
 }


 /* core subsystems needed for using file_streams */
 #define SUBSYS tpie::MEMORY_MANAGER | tpie::STREAMS


 int main(int /*argc*/, char ** /*argv*/) {
   size_t memory_limit_mb = 10000;



   /* start up TPIE subsystems, set memory limit */
   tpie::tpie_init(SUBSYS);
   tpie::get_memory_manager().set_limit(memory_limit_mb*1024*1024);

   std::string a = "test.in";
   std::string b = "test.out";
   //cerr << "Writing " << a << endl;
   clock_t begin = clock();
   writestream(a, 70000000);
   clock_t end = clock();
   //cerr << "Copying  " << a << " to " << b << endl;
   copystream(a, b);
   //cerr << "Reading  " << b << endl;
   readstream(b);

   double elapsed_secs = double(end - begin) / CLOCKS_PER_SEC;
   cerr << elapsed_secs << endl;
   /* wrap up */
   tpie::tpie_finish(SUBSYS);
   return EXIT_SUCCESS;
 }