notes/science/nlp/stack.txt

// foma.h

/** User stack */
struct stack_entry {
  int number;
  struct apply_handle *ah;
  struct apply_med_handle *amedh;
  struct fsm *fsm;
  struct stack_entry *next;
  struct stack_entry *previous;    
};

// stack.c

extern int quiet_mode;

struct stack_entry *main_stack;

int stack_size() {
  int i;
  struct stack_entry *stack_ptr;
  for (i=0, stack_ptr = main_stack; stack_ptr->next != NULL; i++)
    stack_ptr = stack_ptr->next;
  return i;
}

int stack_init() {
  main_stack = xxmalloc(sizeof(struct stack_entry));
  main_stack->number = -1;
  main_stack->fsm = NULL;
  main_stack->next = NULL;
  main_stack->previous = NULL;
  return 1;
}

int stack_add(struct fsm *fsm) {
  int i;
  struct stack_entry *stack_ptr, *stack_ptr_previous;
  stack_ptr_previous = NULL;

  fsm_count(fsm);
  if (strcmp(fsm->name,"") == 0) 
      sprintf(fsm->name, "%X",rand());
  for (i=0, stack_ptr = main_stack; stack_ptr->number != -1; i++) {
    stack_ptr_previous = stack_ptr;
    stack_ptr = stack_ptr->next;
  }
  stack_ptr->next = xxmalloc(sizeof(struct stack_entry));
  stack_ptr->fsm = fsm;
  stack_ptr->ah = NULL;
  stack_ptr->amedh = NULL;
  stack_ptr->number = i;
  stack_ptr->previous = stack_ptr_previous;
  (stack_ptr->next)->number = -1;
  (stack_ptr->next)->fsm = NULL;
  (stack_ptr->next)->next = NULL;
  (stack_ptr->next)->previous = stack_ptr;
  if (!quiet_mode)
      print_stats(fsm);
  return(stack_ptr->number);
}



struct apply_handle *stack_get_ah() {
    struct stack_entry *se;
    se = stack_find_top();
    if (se == NULL) {
	return(NULL);
    }
    if (se->ah == NULL) {
	se->ah = apply_init(se->fsm); // apply.c, !!!clb!!! simple data-race like a singleton
    }
    return(se->ah);
}

struct stack_entry *stack_find_top () {
  struct stack_entry *stack_ptr;
  if (main_stack->number == -1) {
    return NULL;
  }
  for (stack_ptr = main_stack; (stack_ptr->next)->number != -1; stack_ptr = stack_ptr->next);
  return(stack_ptr);
}