Trash Stacks

Trash Stacks — maintain a stack of unused allocated memory chunks.

Synopsis


#include <glib.h>


            GTrashStack;
void        g_trash_stack_push              (GTrashStack **stack_p,
                                             gpointer data_p);
gpointer    g_trash_stack_pop               (GTrashStack **stack_p);
gpointer    g_trash_stack_peek              (GTrashStack **stack_p);
guint       g_trash_stack_height            (GTrashStack **stack_p);

Description

A GTrashStack is an efficient way to keep a stack of unused allocated memory chunks. Each memory chunk is required to be large enough to hold a gpointer. This allows the stack to be maintained without any space overhead, since the stack pointers can be stored inside the memory chunks.

There is no function to create a GTrashStack. A NULL GTrashStack* is a perfectly valid empty stack.

Details

GTrashStack

typedef struct {
  GTrashStack *next;
} GTrashStack;

Each piece of memory that is pushed onto the stack is cast to a GTrashStack*.

GTrashStack *next; pointer to the previous element of the stack, gets stored in the first sizeof (gpointer) bytes of the element.

g_trash_stack_push ()

void        g_trash_stack_push              (GTrashStack **stack_p,
                                             gpointer data_p);

Pushes a piece of memory onto a GTrashStack.

stack_p : a pointer to a GTrashStack.
data_p : the piece of memory to push on the stack.

g_trash_stack_pop ()

gpointer    g_trash_stack_pop               (GTrashStack **stack_p);

Pops a piece of memory off a GTrashStack.

stack_p : a pointer to a GTrashStack.
Returns : the element at the top of the stack.

g_trash_stack_peek ()

gpointer    g_trash_stack_peek              (GTrashStack **stack_p);

Returns the element at the top of a GTrashStack which may be NULL.

stack_p : a pointer to a GTrashStack.
Returns : the element at the top of the stack.

g_trash_stack_height ()

guint       g_trash_stack_height            (GTrashStack **stack_p);

Returns the height of a GTrashStack. Note that execution of this function is of O(N) complexity where N denotes the number of items on the stack.

stack_p : a pointer to a GTrashStack.
Returns : the height of the stack.