foop

C Framework for Object-Orientated Programming

• Normal C Code

struct User user;

user_init(&user);

user_setName(&user, "John");
user_setAge(&user, 37);
user_print(&user, 37);

user_free(&user);

• With foop

struct User *user = new(User);

$(user)->setName("John");
$(user)->setAge(37);
$(user)->print();

delete(user);

Features

• Standardised utility libraries such as foop-string.
• Almost non-existent CPU overhead; requires a single extra pointer for a method call.
• Requires only slightly more memory, used for storing reference to the class in an instance and pointers to function methods.
• Very small codebase with large compatibility.

Documentation

class_t

Structure for a class definition.

Members

• void (*constructor)() - pointer to a function that constructs the object pointed to at _this. Can be NULL.
• void (*destructor)() - pointer to a function that destructs the object pointed to at _this. Can be NULL.
• size_t size - size of the object (instance) structure in bytes.

void UserConstructor() {
	struct User *this = _this;

	strcpy(this->name, "Monty"):
	this->age = 16;
}

void UserDestructor() {
	printf("Deleting User!\n");
}

const class_t _User = {
	&UserConstructor,
	&UserDestructor,
	sizeof(struct User)
};

const class_t *User = &_User;

void *new(const class_t *class)

Returns a pointer to the new object (instance) of the passed class.

• Allocates memory for the object structure + reference to original class
• Call the class constructor
• Returns the object

struct User *user = new(User);

void delete(void *object)

Deletes the passed object pointer.

• Calls the class destructor
• Frees memory allocated to object structure + reference to class

delete(user);

const class_t *instanceOf(void *object)

Returns a pointer to the original class used to create the object (instance).

instanceOf(user) == User; // true
instanceOf(user) == AnotherClass; // false;

void foop_reconstruct(void *object)

Destructs the object and creates a new one in it's place.

• Calls the class destructor
• Zeros out associated memory
• Calls the class constructor

void *_this

Pointer to the object about to be acted upon.

struct User {
	int age;
	void (*birthday)();
}

void UserBirthday() {
	User *this = _this;

	user->age++;
}

void UserConstructor() {
	User *this = _this;

	user->age = 20;
	usser->birthday = &UserBirthday;
}

const class_t _User {
	&UserConstructor,
	NULL, // no destructor needed
	sizeof(struct User)
}

const class_t *User = &_User;

int main() {
	struct User *user = new(User);

	user->age; // 20
	$(user)->birthday();
	user->age; // 21
}

$(void *object)

Sets _this to the object and returns the object casted to the type it was passed as.