Vector3D in a google dense_hash_map

output

$g++ vector_map.cpp -o vector_test && ./vector_test
Vector with x: 645 y: 413 z: 958 has value: 1312704908
Vector with x: 496 y: 358 z: 749 has value: 1988979514
Vector with x: 223 y: 868 z: 203 has value: 141221503
Vector with x: 345 y: 350 z: 869 has value: 1678149073
Vector with x: 565 y: 366 z: 722 has value: 1934444366
Vector with x: 934 y: 419 z: 619 has value: 560261625
Vector with x: 426 y: 92 z: 351 has value: 427818382
Vector with x: 24 y: 263 z: 407 has value: 760253072
...
...
...
Vector with x: 124 y: 98 z: 792 has value: 1145850991
Vector with x: 907 y: 710 z: 889 has value: 765247744
Vector with x: 779 y: 248 z: 943 has value: 976951297
Vector with x: 917 y: 929 z: 736 has value: 112463024
Found vector with x: 744 y: 492 z: 624 value: 1436855325
Found vector with x: 587 y: 110 z: 825 value: 24739836
Found vector with x: 707 y: 356 z: 243 value: 1515119730
Found vector with x: 610 y: 194 z: 331 value: 19997493
Found vector with x: 693 y: 59 z: 907 value: 502595634
Found vector with x: 57 y: 128 z: 923 value: 100460565
Found vector with x: 15 y: 512 z: 879 value: 248460847
Found vector with x: 256 y: 434 z: 859 value: 313975801
Found vector with x: 388 y: 42 z: 542 value: 473907356
Found vector with x: 409 y: 822 z: 963 value: 100666490

vector_map.cpp

#include <cstdlib>
#include <iostream>
#include <google/dense_hash_map>

using google::dense_hash_map; 
using namespace std;

struct Vector3D{
  uint32_t x;
  uint32_t y;
  uint32_t z;

  Vector3D(const uint32_t x,const uint32_t y,const uint32_t z):
  x(x),y(y),z(z)
  {}

  Vector3D():
  x(0),y(0),z(0)
  {}
};

typedef struct{
  inline size_t operator() (const Vector3D& v) const {
    return (v.x*73856093)^(v.y*19349663)^(v.z*83492791);
  }
} Vector3DHash;

typedef struct{
  inline bool operator() (const Vector3D& lhs, const Vector3D &rhs) const { 
    return (lhs.x==rhs.x)&&(lhs.y==rhs.y)&&(lhs.z==rhs.z);
  }
} Vector3DEq;

typedef dense_hash_map<Vector3D,uint32_t,Vector3DHash,Vector3DEq> vector_map_t;

int main(int argc, char** argv) {
  const uint32_t MAX_DISTANCE = 1000;
  const size_t LOOP_COUNT = 100000;
  vector_map_t vectors;
  
  // This assumes a vector with x:0 y:0 z:0 will never exist
  // If this is not true use tr1/unordered_map !!!
  vectors.set_empty_key(Vector3D());
  
  // Fill with some random vectors and keys
  for(size_t i=0;i<LOOP_COUNT;i++){
    Vector3D v(rand()%MAX_DISTANCE+1,rand()%MAX_DISTANCE+1,rand()%MAX_DISTANCE+1);
    vectors[v]=rand();
  }
  
  // Display whole map
  for(vector_map_t::const_iterator it=vectors.begin(),ite=vectors.end();it!=ite;++it){
    cout << "Vector with x: " << it->first.x <<" y: " << it->first.y << " z: " << it->first.z << " has value: " << it->second << endl;
  }
  
  // Do some random lookups
  for(size_t i=0;i<LOOP_COUNT;i++){
    Vector3D v(rand()%MAX_DISTANCE+1,rand()%MAX_DISTANCE+1,rand()%MAX_DISTANCE+1);
    vector_map_t::const_iterator it=vectors.find(v);
    if (it!=vectors.end()){
      cout << "Found vector with x: " << it->first.x <<" y: " << it->first.y << " z: " << it->first.z << " value: " << it->second << endl;
    }
  }
  return 0;
}