c-hooks/hooks.h

#define HOOKS

#ifndef LINKED_LIST
#include "linkedList.h"
#endif

struct hook {
  LISTEL *start;
  int insertDirection;
};

struct hookFunction {
  void (*function)();
};

typedef struct hook HOOK;
typedef struct hookFunction HOOKFUNC;

HOOK * initializeHook(int direction)
{
  HOOK * theReturn = malloc(sizeof(HOOK));
  theReturn->insertDirection = direction;
  return theReturn;
}

void runHook(HOOK * hook) {
  if (hook != NULL) {
    LISTEL * head = hook->start;
    while (head != NULL) {
      ((HOOKFUNC*)(head->data))->function();
      head = head->next;
    }
  }
}

void addToHook(HOOK * hook, void (*function)()) {
  if (hook == NULL) hook = initializeHook(1);
  HOOKFUNC *hookFunction = malloc(sizeof(HOOKFUNC));
  hookFunction->function = function;
  if (hook->start == NULL)
    {
      LISTEL *element = malloc(sizeof(LISTEL));
      element->data = (void*) hookFunction;
      hook->start = element;
    }
  else if (hook->insertDirection == 0)
    {
      LISTEL *newHead = insertBefore((void*) hookFunction, hook->start);
      hook->start = newHead;
    }
  else
    {
      LISTEL *addAfter = hook->start;
      while (addAfter->next != NULL)
        addAfter = addAfter->next;
      insertAfter((void*) hookFunction, addAfter);
    }
}