Notes

#include <stdlib.h>
#include <stdio.h>
#include <math.h>

#include "gps.h"


struct poi* create_poi(double latitude, double longitude, enum type type, char* description)
{
if(latitude == 0) return NULL;
if(longitude == 0) return NULL;
if(description == NULL || description[0] == '') return NULL;

struct poi* poi = (struct poi *) calloc(1, sizeof(struct poi));
poi->latitude = latitude;
poi->longitude = longitude;
poi->description = description;
poi->type = type;
return poi;
}


struct entry* append_poi(struct entry* first, struct poi* poi)
{
if(poi == NULL) return first;
if(first == NULL)
{
struct entry* new = (struct entry*)calloc(1, sizeof(struct entry));
new->poi = poi;
new->next = NULL;
return new;
}
struct entry* new = (struct entry*)calloc(1, sizeof(struct entry));
struct entry* act = first;
while(act->next != NULL)
{
act = act->next;
}
act->next = new;
new->poi = poi;
new->next = NULL;
return first;
}


double get_distance_between(struct poi* poi1, struct poi* poi2)
{
if(poi1 ==NULL|| poi2==NULL) return -1;


double x = (to_radians(poi2->longitude) - to_radians(poi1->longitude)) * cos((to_radians(poi1->latitude) + to_radians(poi2->latitude))/2.0);
double y = (to_radians(poi2->latitude) - to_radians(poi1->latitude));
return (sqrt(x*x +y*y) * EARTH_RADIUS);
}


struct poi* find_closest(struct entry* first, double latitude, double longitude, enum type type)
{
if(first == NULL || first->poi ==NULL)
{return NULL;}
struct poi* closest = (struct poi*) calloc(1, sizeof(struct poi));
return closest;
}


struct entry* search_nearby(struct entry* first, double latitude, double longitude, int radius)
{
if(first == NULL || first->poi ==NULL) return NULL;
struct entry* nearby = (struct entry*) calloc(1, sizeof(struct entry));
return nearby;
}


double to_degrees(double radians)
{
double degrees = radians * (180/PI);
return degrees;
}


double to_radians(double degrees)
{
double radians = ((degrees * PI) / 180);
return radians;
}