Function malloc_fix_invariant

examples/stdlib.c:1827–1843

* Fix the interval-tree invariant (RB-tree augmentation). */

 * Fix the interval-tree invariant (RB-tree augmentation).
 */
static void malloc_fix_invariant(struct malloc_pool_s *pool, uint32_t n)
{
    if (n == MA_NIL)
        return;
    uint32_t l = MA_LEFT(pool, n), r = MA_RIGHT(pool, n);
    uint32_t llb = (l != MA_NIL? MA_LB(pool, l): MA_POOL_UB(pool));
    intptr_t rub = (r != MA_NIL? MA_UB(pool, r): MA_POOL_LB(pool));
    MA_LB(pool, n) = MA_MIN(llb, n);
    MA_UB(pool, n) = MA_MAX(rub, n + MA_SIZE(pool, n));
    uint32_t lgap = (l != MA_NIL? MA_GAP(pool, l): 0);
    uint32_t rgap = (r != MA_NIL? MA_GAP(pool, r): 0);
    uint32_t gap  = MA_MAX(lgap, rgap);
    gap = MA_MAX(gap, (uint32_t)(l != MA_NIL?  n - MA_UB(pool, l): 0));
    gap = MA_MAX(gap, (uint32_t)(r != MA_NIL?
        MA_LB(pool, r) - (n + MA_SIZE(pool, n)): 0));
    MA_GAP(pool, n) = gap;
}

static void malloc_rotate_left(struct malloc_pool_s *pool, uint32_t n)
{