Function plug_holes

src/mem.c:119–157

#endif /* RT_USING_MEMTRACE */

static void plug_holes(struct rt_small_mem *m, struct rt_small_mem_item *mem)
{
    struct rt_small_mem_item *nmem;
    struct rt_small_mem_item *pmem;

    RT_ASSERT((rt_uint8_t *)mem >= m->heap_ptr);
    RT_ASSERT((rt_uint8_t *)mem < (rt_uint8_t *)m->heap_end);

    /* plug hole forward */
    nmem = (struct rt_small_mem_item *)&m->heap_ptr[mem->next];
    if (mem != nmem && !MEM_ISUSED(nmem) &&
        (rt_uint8_t *)nmem != (rt_uint8_t *)m->heap_end)
    {
        /* if mem->next is unused and not end of m->heap_ptr,
         * combine mem and mem->next
         */
        if (m->lfree == nmem)
        {
            m->lfree = mem;
        }
        nmem->pool_ptr = 0;
        mem->next = nmem->next;
        ((struct rt_small_mem_item *)&m->heap_ptr[nmem->next])->prev = (rt_uint8_t *)mem - m->heap_ptr;
    }

    /* plug hole backward */
    pmem = (struct rt_small_mem_item *)&m->heap_ptr[mem->prev];
    if (pmem != mem && !MEM_ISUSED(pmem))
    {
        /* if mem->prev is unused, combine mem and mem->prev */
        if (m->lfree == mem)
        {
            m->lfree = pmem;
        }
        mem->pool_ptr = 0;
        pmem->next = mem->next;
        ((struct rt_small_mem_item *)&m->heap_ptr[mem->next])->prev = (rt_uint8_t *)pmem - m->heap_ptr;
    }
}

/**
 * @brief This function will initialize small memory management algorithm.