Function shrinkMapping

src/e9patch/e9mapping.cpp:611–642

* Shrink a mapping (if possible). */

 * Shrink a mapping (if possible).
 */
static void shrinkMapping(Mapping *mapping0, size_t granularity)
{
    if (mapping0->size == granularity)
        return;

    intptr_t lb = INTPTR_MAX, ub = INTPTR_MIN;
    for (auto mapping = mapping0; mapping != nullptr;
        mapping = mapping->merged)
    {
        lb = std::min(lb, mapping->lb);
        ub = std::max(ub, mapping->ub);
    }

    lb = lb - lb % granularity;
    if (ub % granularity != 0)
    {
        ub += granularity;
        ub = ub - ub % granularity;
    }
    size_t size = ub - lb;
    if (size >= mapping0->size)
        return;

    for (auto mapping = mapping0; mapping != nullptr;
        mapping = mapping->merged)
    {
        mapping->base += lb;
        mapping->size  = size;
        mapping->lb   -= lb;
        mapping->ub   -= lb;
    }
}

/*
 * Optimize the given set of mappings.