usaa24/cv6/a_station.c

#include "a_station.h"
#include <stdlib.h>
#include <string.h>

struct station* create_station()
{
   struct station* station = (struct station*)calloc(1,sizeof(struct station));
   station->tracks = (struct car**)calloc(STATION_SIZE, sizeof(struct car*));
   station->track_count = STATION_SIZE;
   return station;
}

void destroy_station(struct station* station)
{
    if (station == NULL) 
    {
        return;
    }

    for (int i = 0; i < station->track_count; i++)
    {
        struct car* this = station->tracks[i];
        while (this != NULL)
        {
            struct car* temp = this;
            this = this->next;
            free(temp); 
        }
    }

    free(station->tracks);
    free(station);
}

int select_track(struct station* station, const char* target)
{
    //DJB2 hash
    unsigned int hash = 5381;
    int c;

    while ((c = *target++))
    {
        hash = hash * 33 + c;
    }
    
    return hash % station->track_count;
}

void add_target_capacity(struct station* station, const char* target, int capacity) 
{
    int stIndex = select_track(station, target);
    struct car* start = station->tracks[stIndex];
    
    struct car* this = start;
    while (this != NULL)
    {
        
        if (strcmp(this->value, target) == 0)
        {
            this->capacity += capacity;
            return;
        }
        this = this->next;
    }

    
    struct car* nCar = (struct car*)malloc(sizeof(struct car));
    if (nCar == NULL)
    {
        return;
    }
    
    strncpy(nCar->value, target, TARGET_SIZE - 1);
    nCar->value[TARGET_SIZE - 1] = '\0';
    nCar->capacity = capacity;
    nCar->next = start;

    station->tracks[stIndex] = nCar;
}


int get_target_capacity(struct station* station,const char* target)
{
    int indTr = select_track(station, target) % station->track_count;
    struct car* this = station->tracks[indTr];

    while (this != NULL)
    {
        if (strcmp(this->value, target) == 0)
        {
            return this->capacity;
        }
        this = this->next;
    }

    return 0;
}

int count_targets(struct station* station)
{
    int count = 0;

    for (int i = 0; i < station->track_count; i++)
    {
        struct car* current = station->tracks[i];
        
        while (current != NULL)
        {
            count++;
            current = current->next;
        }
    }

    return count;
}

int count_capacity(struct station* station)
{
    int res = 0;

    for (int i = 0; i < station->track_count; i++)
    {
        struct car* current = station->tracks[i];
        
        while (current != NULL)
        {
            res += current->capacity;
            current = current->next;
        }
    }

    return res;
}