Method performRealignment

src/controller.cpp:1388–1480

}

void RcxController::performRealignment(uint64_t structId, int targetAlign) {
    auto& tree = m_doc->tree;
    int rootIdx = tree.indexOfId(structId);
    if (rootIdx < 0) return;

    // Gather direct children sorted by offset
    QVector<int> kids = tree.childrenOf(structId);
    std::sort(kids.begin(), kids.end(), [&](int a, int b) {
        return tree.nodes[a].offset < tree.nodes[b].offset;
    });

    // Separate into real nodes (non-Padding) and padding nodes
    struct NodeInfo { uint64_t id; int offset; int size; };
    QVector<NodeInfo> realNodes;
    QVector<uint64_t> padIds;

    for (int ci : kids) {
        const Node& child = tree.nodes[ci];
        int sz = (child.kind == NodeKind::Struct || child.kind == NodeKind::Array)
            ? tree.structSpan(child.id) : child.byteSize();
        if (child.kind == NodeKind::Padding)
            padIds.append(child.id);
        else
            realNodes.append({child.id, child.offset, sz});
    }

    auto roundUp = [](int x, int align) -> int {
        return align <= 1 ? x : ((x + align - 1) / align) * align;
    };

    // Compute new offsets for real nodes
    struct OffChange { uint64_t id; int oldOff; int newOff; };
    QVector<OffChange> offChanges;
    int cursor = 0;
    for (auto& rn : realNodes) {
        int newOff = roundUp(cursor, targetAlign);
        if (newOff != rn.offset)
            offChanges.append({rn.id, rn.offset, newOff});
        rn.offset = newOff;  // update local copy for gap computation
        cursor = newOff + rn.size;
    }

    // Compute where padding is needed (gaps between consecutive nodes)
    struct PadInsert { int offset; int size; };
    QVector<PadInsert> padsNeeded;

    for (int i = 0; i < realNodes.size(); i++) {
        int gapStart = (i == 0) ? 0 : realNodes[i - 1].offset + realNodes[i - 1].size;
        int gapEnd = realNodes[i].offset;
        if (gapEnd > gapStart)
            padsNeeded.append({gapStart, gapEnd - gapStart});
    }

    // Check if anything actually changes
    if (offChanges.isEmpty() && padIds.isEmpty() && padsNeeded.isEmpty())
        return;

    // Apply as undoable macro