147 lines
3.3 KiB
C
147 lines
3.3 KiB
C
#include "a_station.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/**
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* Vytvori prazdnu stanicu.
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* Alokuje pole smernikov tracks a inicializuje ich na NULL.
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*/
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struct station* create_station() {
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struct station* s = malloc(sizeof(struct station));
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if (!s) return NULL;
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s->track_count = STATION_SIZE;
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s->tracks = calloc(s->track_count, sizeof(struct car*)); // všetky položky na NULL
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if (!s->tracks) {
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free(s);
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return NULL;
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}
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return s;
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}
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/**
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* Uvolni pamat celej databazy (vratane vsetkych spojkovych zoznamov).
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*/
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void destroy_station(struct station* s) {
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if (!s) return;
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for (int i = 0; i < s->track_count; i++) {
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struct car* current = s->tracks[i];
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while (current) {
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struct car* next = current->next;
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free(current);
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current = next;
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}
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}
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free(s->tracks);
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free(s);
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}
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/**
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* Jednoducha hash funkcia pre rozdelenie zaznamov do trati.
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* Pouziva variant DJB2 hash algoritmu.
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*/
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int select_track(struct station* s, const char* target) {
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if (!s || !target) return 0;
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unsigned long hash = 5381;
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int c;
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while ((c = *target++))
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hash = ((hash << 5) + hash) + c; // hash * 33 + c
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return (int)(hash % s->track_count);
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}
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/**
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* Prida alebo aktualizuje zaznam pre danu cielovu stanicu.
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*/
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void add_target_capacity(struct station* s, const char* target, int capacity) {
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if (!s || !target || capacity <= 0) return;
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int index = select_track(s, target);
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struct car* current = s->tracks[index];
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struct car* prev = NULL;
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// Skontroluj, ci uz existuje
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while (current) {
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if (strcmp(current->value, target) == 0) {
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current->capacity += capacity;
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return;
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}
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prev = current;
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current = current->next;
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}
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// Ak neexistuje, vytvor novy zaznam
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struct car* new_car = malloc(sizeof(struct car));
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if (!new_car) return;
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strncpy(new_car->value, target, TARGET_SIZE - 1);
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new_car->value[TARGET_SIZE - 1] = '\0';
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new_car->capacity = capacity;
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new_car->next = NULL;
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if (prev)
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prev->next = new_car;
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else
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s->tracks[index] = new_car;
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}
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/**
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* Ziska kapacitu pre danu stanicu.
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*/
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int get_target_capacity(struct station* s, const char* target) {
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if (!s || !target) return 0;
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int index = select_track(s, target);
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struct car* current = s->tracks[index];
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while (current) {
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if (strcmp(current->value, target) == 0)
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return current->capacity;
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current = current->next;
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}
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return 0;
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}
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/**
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* Spocita pocet cielovych stanic (vsetky uzly vo vsetkych tratiach).
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*/
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int count_targets(struct station* s) {
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if (!s) return 0;
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int count = 0;
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for (int i = 0; i < s->track_count; i++) {
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struct car* current = s->tracks[i];
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while (current) {
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count++;
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current = current->next;
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}
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}
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return count;
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}
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/**
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* Spocita celkovu kapacitu vsetkych zaznamov.
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*/
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int count_capacity(struct station* s) {
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if (!s) return 0;
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int sum = 0;
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for (int i = 0; i < s->track_count; i++) {
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struct car* current = s->tracks[i];
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while (current) {
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sum += current->capacity;
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current = current->next;
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}
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}
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return sum;
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}
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