Function rt_malloc_align

src/kservice.c:1012–1049

* @brief This function allocates a memory block, which address is aligned to the * specified alignment size. * * @param size is the allocated memory block size. * * @param align is the alignment size. * * @return The memory block address was returned successfully, otherwise it was * returned empty RT_NULL. */

 *         returned empty RT_NULL.
 */
rt_weak void *rt_malloc_align(rt_size_t size, rt_size_t align)
{
    void *ptr = RT_NULL;
    void *align_ptr = RT_NULL;
    int uintptr_size = 0;
    rt_size_t align_size = 0;

    /* sizeof pointer */
    uintptr_size = sizeof(void*);
    uintptr_size -= 1;

    /* align the alignment size to uintptr size byte */
    align = ((align + uintptr_size) & ~uintptr_size);

    /* get total aligned size */
    align_size = ((size + uintptr_size) & ~uintptr_size) + align;
    /* allocate memory block from heap */
    ptr = rt_malloc(align_size);
    if (ptr != RT_NULL)
    {
        /* the allocated memory block is aligned */
        if (((rt_uintptr_t)ptr & (align - 1)) == 0)
        {
            align_ptr = (void *)((rt_uintptr_t)ptr + align);
        }
        else
        {
            align_ptr = (void *)(((rt_uintptr_t)ptr + (align - 1)) & ~(align - 1));
        }

        /* set the pointer before alignment pointer to the real pointer */
        *((rt_uintptr_t *)((rt_uintptr_t)align_ptr - sizeof(void *))) = (rt_uintptr_t)ptr;

        ptr = align_ptr;
    }

    return ptr;
}
RTM_EXPORT(rt_malloc_align);

/**