struct_manipulation.js

/*
typedef struct {
	char *name;
	int age;
}person;

// Returns new person with name "test => name" and age equals age
person * create_person(char *name, int age) {
	person * p = (person*)malloc(sizeof(person));
	p->name = (char*)malloc(sizeof(char) * 250);
	sprintf(p->name, "test => %s", name);
	p->age = age;

	return p;
}

// Will write struct information into output.txt file
void print_person(person *p) {
	FILE *fp;
	fp = fopen("output.txt", "w");
  	fprintf(fp, "Name is %s\n", p->name);
  	fprintf(fp, "Age is %d\n", p->age);
	fclose(fp);
}
*/

// Interpreting struct 
const _create_person = new NativeFunction(Module.getExportByName(null
, 'create_person'), 'pointer', ['pointer', 'int']);
conse 

const p1 = _create_person(Memory.allocUtf8String("John"), 24);

const retName = p1.readPointer()
const retAge = p1.add(Process.pointerSize)
console.log(retName.readCString())  // test => John
console.log(retAge.readInt())       // 24



// Creating struct variable
const _print_person = new NativeFunction(Module.getExportByName(null, 'print_person'), 'void', ['pointer']);

const new_person = Memory.alloc(50); // need to alloc real size, this is way too much but fuck it
const name = Memory.allocUtf8String("erhad");
const age = 30;

/* since the first property inside the struct is char*, by accessing the struct
object we are accessing the pointer inside of it*/
new_person.writePointer(name); 

/* inside the memory, age comes after the char *name, so we need to add write 
our int to <struct object> + pointerSize */
new_person.add(Process.pointerSize).writeInt(age);

_print_person(new_person); // will call the function which will save the output to output.txt

/* If we take a look at output.txt we would see following
$ cat output.txt
Name is erhad
Age is 30

*/