GC

#include <stdlib.h>
#include <stdio.h>

struct list_items
{
    struct list_items *next;
    int *data;
    int size;
};

struct list_ptrs
{
    struct list_ptrs *next;
    struct list_items *items;
};

static struct list_ptrs *spl = NULL;

int *alloc_continue(int n)
{
    printf("alloc_continue(%d)\n", n);
    struct list_ptrs *ptr = spl;
    struct list_items *item = malloc(sizeof(struct list_items));
    item->next = ptr->items;
    item->data = malloc(sizeof(int)*n);
    item->size = n;
    ptr->items = item;
    return item->data;
}


int *alloc_begin(int n)
{
    printf("alloc_begin(%d)\n", n);
    struct list_ptrs *ptr = malloc(sizeof(struct list_ptrs));
    ptr->next = spl;
    ptr->items = NULL;
    spl = ptr;
    return alloc_continue(n);
}

void print_spl()
{
    int l = 0;
    struct list_ptrs *ptr = spl;
    while(ptr)
    {
        printf("%d: ", l);
        struct list_items *item = ptr->items;
        while(item)
        {
            printf("%p[%d] ", item->data, item->size);
            item = item->next;
        }
        printf("\n");
        ptr = ptr->next;
        l++;
    }
}

void free_block()
{
    struct list_ptrs *ptr = spl;
    if(!ptr)
        return;
    struct list_items *item = ptr->items;
    spl = ptr->next;
    free(ptr);
    printf("Delete: ");
    while(item)
    {
        printf("[%d] ", item->size);
        free(item->data);
        struct list_items *item_tmp = item;
        item = item->next;
        free(item_tmp);
    }
    printf("\n");
}

void foo()
{
    int *a1 = alloc_begin(1);
    int *a2 = alloc_continue(2);
    int *a3 = alloc_continue(3);
    {
        int *a4 = alloc_begin(4);
        int *a5 = alloc_continue(5);
        print_spl();
        free_block();
    }
    free_block();
}

int main()
{
    foo();
    return 0;
}