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/* Animal class implementation */
#define MAX_NAME_LEN 10
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "animal_priv.h"
struct animal * animal_new() {
return (struct animal *)malloc(sizeof(struct animal));
}
/*
* By passing the custom sound function to the constructor, we prevent the need to expose the
* Animal's private interface to the sub-class
*
* This is an attempt to get as much abstraction as possible of a C program.
* The sub-class has no business in understanding the inner functionality of the parent class,
* so, this is an attempt to hide the animal implementation as much as possible from the sub-class.
*/
void animal_ctor(struct animal *animal,
void (*sound_fn)(void))
{
animal->name = malloc(MAX_NAME_LEN * sizeof(char));
if (sound_fn)
animal->make_sound = sound_fn;
else
animal->make_sound = NULL;
}
void animal_dtor(struct animal *animal)
{
free(animal->name);
}
void animal_get_name(struct animal *animal, char *name)
{
strncpy(name, animal->name, MAX_NAME_LEN);
}
void animal_set_name(struct animal *animal, const char *name)
{
if (strlen(name) >= MAX_NAME_LEN)
strncpy(animal->name, "\0", 1);
else
strncpy(animal->name, name, MAX_NAME_LEN);
}
/*
* To be able to access the object specific implementation of make_sound(),
* this function should somehow access the function pointer to the
* object-specific implementation.
*
* This could be done in two ways:
* - By having the Animal object embedded within the sub-class, so both
* the Animal object and the Sub-Class object will share the same address
* in memory, or:
* - We add an 'ops' field in the Animal object, which should be populated
* by the sub-class.
*
* In both ways, there is no way to really hide the Animal implementation from
* the sub-class, as in one way or another, we'll need to have access to the
* Animal class fields, so we can override the functions.
*/
void animal_sound(struct animal *animal)
{
if (animal->make_sound)
animal->make_sound();
}
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