/home/mesh/mesh/include/trash_stack.h

/*************************************************************************
    This file is part of MESH.

    MESH is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    MESH is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with MESH.  If not, see <http://www.gnu.org/licenses/>.
**************************************************************************/
#ifndef __trash_stack
#define __trash_stack

#include <glib.h>
#include <string.h>

typedef struct trash_stack_list {
    struct trash_stack_list *next;
} trash_stack_list;

typedef struct {
    unsigned item_size;
    trash_stack_list *free_list;
    unsigned next_index;
    GSList *buffers;
} trash_stack;

trash_stack *mesh_create_trash_stack(unsigned item_size);

void mesh_destroy_trash_stack(trash_stack *stack);

gpointer mesh_trash_stack_alloc_slow(trash_stack *stack);

inline static
gpointer mesh_trash_stack_alloc(trash_stack *stack) {
    
    // anything on the list?
    if(stack->free_list) {
        trash_stack_list *item = stack->free_list;
        stack->free_list = item->next;
        return item;
    }

    // darn. fall back to plan B.
    return mesh_trash_stack_alloc_slow(stack);
}

inline static 
gpointer mesh_trash_stack_alloc0(trash_stack *stack) {
    gpointer *item = mesh_trash_stack_alloc(stack);
    memset(item, 0, stack->item_size);
    return item;
}

inline static
void mesh_trash_stack_free(trash_stack *stack, gpointer item) {
    // put at the head of the free list
    trash_stack_list *head = item;
    head->next = stack->free_list;
    stack->free_list = head;
}

#endif