nesemu/utils/linked_list.c

//
// Created by william on 1/16/24.
//

#include <stddef.h>
#include <malloc.h>
#include <stdlib.h>
#include <assert.h>
#include "linked_list.h"

LinkedList linked_list_init(bool circular) {
    LinkedList list;

    list.circular = circular;
    list.size = 0;
    list.head = NULL;
    list.end = NULL;
    list.current = NULL;

    return list;
}

void linked_list_add(LinkedList *list, void *data) {
    assert(list != NULL);

    LinkedListNode *node = malloc(sizeof(LinkedListNode));
    if (node == NULL) {
        perror("Failed to allocate memory for linked list node");
        exit(EXIT_FAILURE);
    }

    node->data = data;
    node->previous = list->end;

    if (list->head == NULL) {
        list->head = node;
        list->current = node;
    }

    if (list->end != NULL) {
        list->end->next = node;
    }

    if (list->circular) {
        node->next = list->head;
    } else {
        node->next = NULL;
    }

    list->end = node;
    list->size++;
}

LinkedListNode *linked_list_next(LinkedList *list) {
    assert(list != NULL);

    if (list->head == NULL) {
        return NULL;
    }

    LinkedListNode *next = list->current->next;
    list->current = next;
    return next;
}

void linked_list_cursor_reset(LinkedList *list) {
    assert(list != NULL);

    list->current = list->head;
}

LinkedListNode *linked_list_get_if(LinkedList *list, bool(*predicate)(void *, void *), void *userdata) {
    assert(list != NULL);
    assert(predicate != NULL);

    LinkedListNode *node = list->head;

    while (node != NULL) {
        if (predicate(node->data, userdata)) {
            return node;
        }

        node = node->next;
    }

    return NULL;
}

LinkedListNode *linked_list_get_near(LinkedList *list, int(*compute_distance)(void *, void *), void *userdata) {
    assert(list != NULL);
    assert(compute_distance != NULL);

    LinkedListNode *near_node = list->head;

//    int current_distance = compute_distance(near_node->data, userdata);
//    if (current_distance == 0) {
//        return near_node;
//    }

    int current_distance = 0x7fffffff;
    while (near_node->next != NULL && current_distance != 0) {
        int next_distance = compute_distance(near_node->next->data, userdata);
        if (next_distance > current_distance) {
            break;
        }

        near_node = near_node->next;
        current_distance = next_distance;
    }

    // After the loop, we have found the nearest node in the list, assuming there is only one point of convergence
    return near_node;
}

void linked_list_uninit(LinkedList *list) {
    assert(list != NULL);

    LinkedListNode *node = list->head;
    while (node != NULL) {
        LinkedListNode *current_node = node;
        node = node->next;

        free(current_node->data);
        free(current_node);

        if (node == list->head) {
            // The list may be circular, we don't want an infinite free loop
            break;
        }
    }
}