TP 9 exo2: Better handling of special cases in list_delete()

[TD_C.git] / TP_9 / exo2 / clist.c

#include <stdlib.h>

#include "clist.h"

link_t* list_new(int value) {
    link_t* link_new;	
    link_new = malloc(sizeof(link_t));
    link_new->value = value;
    link_new->next = NULL;
    return link_new;
}

link_t* list_append(link_t* head, int value) {

    if (head == NULL) { 
        return head = list_new(value);
    } else {
        link_t* head_first = head;
        while (head->next != NULL) {
    	    head = head->next; 
        }
        head->next = list_new(value);
        return head_first;
    }
}

link_t* list_prepend(link_t* head, int value) {
    link_t* first_link = list_new(value);
    
    first_link->next = head;
    return first_link;
}

link_t* list_insert(link_t* head, unsigned index, int value) {

    if (index == 0) {
        return list_prepend(head, value);  
    } else if (index == list_count(head)) {
        return list_append(head, value);
    } else {
        link_t* link_insrt = list_new(value);  
        link_t* head_first = head;
        link_t* head_next = NULL;
        for (unsigned i = 0; i < index-1; i++) {
            head = head->next;
        }
        head_next = head->next;
        head->next = link_insrt;
        head = link_insrt;
        head->next = head_next; 
        return head_first;
    }
}

link_t* list_delete(link_t* head, unsigned index) {
    link_t* head_prev = NULL;
    link_t* head_next = NULL;
    link_t* head_ret = NULL;
   
    if (head == NULL) {
        return NULL;
    } else if (index == 0) {
        head_next = head->next;
        free(head);
        head = head_next;
        head_ret = head;
    } else {
        link_t* head_first = head;
        for (unsigned i = 0; i < index-1; i++) {
            head = head->next;
        }
        head_prev = head;
        head = head->next;
        head_next = head->next;
        free(head);
        head = head_prev;
        head->next = head_next;
        head_ret = head_first;
    }
    if (head_ret != NULL) {
        return head_ret;
    } else {
        return NULL;
    }
}

unsigned list_count(link_t* head) {
    int count = 0;
    
    while (head != NULL) {
        ++count;
        head = head->next;
    } 
    return count;
}

void list_set(link_t* head, unsigned index, int value) {
    unsigned count = 0;

    while (head != NULL && count < index) {
        ++count;
        head = head->next;
    }
    if (head != NULL) { head->value = value; }
}

int list_get(link_t* head, unsigned index) {
    unsigned count = 0;    

    while (head != NULL && count < index) {
        ++count;
        head = head->next; 
    }
    if (head != NULL) { 
        return head->value;
    } else {
        return -1;
    }
}

void list_clear(link_t* head) {
    link_t* next_link = NULL;

    while (head != NULL) {
        next_link = head->next;
        free(head);
        head = next_link;
    }
}