C1-Linux_SYS_Prog-AS-/Iterative_macros/dll.c

/*
 * =====================================================================================
 *
 *       Filename:  dll.c
 *
 *    Description:  
 *
 *        Version:  1.0
 *        Created:  05/02/24 08:04:39 PM IST
 *       Revision:  none
 *       Compiler:  gcc
 *
 *         Author:  YOUR NAME (), 
 *   Organization:  
 *
 * =====================================================================================
 */

#include "dll.h"
#include <memory.h>
#include <stdlib.h>

/* Public Function Implementation to create and return
 * new empty doubly linked list*/

dll_t *
get_new_dll(){

    dll_t *dll = calloc(1, sizeof(dll_t));
    dll->head = NULL;
    dll->key_match = NULL;
    return dll;
}

void
register_key_match_callback(dll_t *dll, 
                             int (*key_match)(void *, void *)){

    dll->key_match = key_match;
}

void
register_comparison_callback(dll_t *dll,
                            int (*comparison_cb)(void *, void *)){

    dll->comparison_fn = comparison_cb;
}

/*Generic Search function*/
void *
dll_search_by_key (dll_t *dll, void *key){

    if(!dll || !dll->head) return NULL;

    dll_node_t *head = dll->head;

    while(head){
        if(dll->key_match(head->data, key) == 0)
            return (void *)head->data;
        head = head->right;
    }
    return NULL;
}

/*Return 0 - on success
 *       -1 on Failure*/
int
dll_priority_insert_data (dll_t *dll, void *data){

    if(!dll)
        return -1;

    /*if DLL is empty*/
    if(!dll->head){
        add_data_to_dll(dll, data);
        return 0;
    }

    dll_node_t *data_node = calloc(1, sizeof(dll_node_t));
    data_node->data = data;
    data_node->left = NULL;
    data_node->right = NULL;

    /* if there is only one node in DLL*/
    if(dll->head && !dll->head->right){
        if(dll->comparison_fn(dll->head->data, data) == -1){
            dll->head->right = data_node;
            data_node->left = dll->head;
        }
        else{
            dll->head->left = data_node;
            data_node->right = dll->head;
            dll->head = data_node;
        }
        return 0;
    }

    /*if More than one node in DLL*/
    if(dll->comparison_fn(data, dll->head->data) == -1){
        data_node->right = dll->head;
        dll->head->left = data_node;
        dll->head = data_node;
        return 0;
    }

    dll_node_t *prev = NULL,
               *curr = NULL;

    curr = dll->head;

    while(curr){
        if(dll->comparison_fn(data, curr->data) != -1){
            prev = curr;
            curr = curr->right;
            continue;
        }

        prev->right = data_node;
        data_node->left = prev;
        data_node->right = curr;
        curr->left = data_node;
        return 0;
    }

    /*Add in the end*/
    prev->right = data_node;
    data_node->left = prev;
    return 0;
}

/* Public Function Implementation to add a new application
 *  * data to DLL */
int
add_data_to_dll (dll_t *dll, void *app_data){

    if(!dll || !app_data) return -1;
    
    dll_node_t *dll_new_node = calloc(1, sizeof(dll_node_t));
    dll_new_node->left = NULL;
    dll_new_node->right = NULL;
    dll_new_node->data = app_data;

    /*Now add this to the front of DLL*/
    if(!dll->head){
        dll->head = dll_new_node;
        return 0;
    }

    dll_node_t *first_node = dll->head;
    dll_new_node->right = first_node;
    first_node->left = dll_new_node;
    dll->head = dll_new_node;
    return 0;
}