russell@unturf.com
13db08af50
darktable-0001: map_locations image diff g_list_find O(N*M) MEDIUM 375x darktable-0002: tags _tag_add_tags_to_list g_list_find O(T*L) MEDIUM 375x darktable-0003: map view clustering g_list_find(sel_imgs) O(I²×S) HIGH 160x scribus-0001: getSortedStyleList retList.contains O(N²) MEDIUM 167x (×4 copies) scribus-0002: getUsedPatterns results.contains O(I×R) MEDIUM 98x scribus-0003: Selection::addItems m_SelList.contains O(N×M) MEDIUM 2100x
44 lines
1.6 KiB
Diff
44 lines
1.6 KiB
Diff
# UNDF: UNDF-2026-000000804
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# UNDF: (leave blank)
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# scribus-0003: Selection::addItems m_SelList.contains O(N×M)
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#
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# In scribus/selection.cpp, addItems() iterates over the items to add (N) and
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# for each calls m_SelList.contains(item), which is O(M) on the existing
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# QList<QPointer<PageItem>> selection list. Total: O(N×M). For a "Select All"
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# on a 5000-item document adding to an existing selection of 2000, this is
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# ~10M pointer comparisons.
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#
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# The single-item addItem() also calls m_SelList.contains(item) — O(M) per
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# call — but is less severe since it adds one item at a time.
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#
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# Fix: build a QSet<PageItem*> from m_SelList before the loop for O(1) lookup,
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# or maintain a companion QSet as a class member.
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#
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# Severity: MEDIUM — triggered on every multi-select operation (rubber-band,
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# Select All, group selection); scales with document item count.
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--- a/scribus/selection.cpp
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+++ b/scribus/selection.cpp
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@@ -194,6 +194,12 @@
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bool Selection::addItems(const QList<PageItem *>& items)
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{
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if (items.isEmpty())
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return false;
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+ // Build hash set for O(1) membership check instead of O(M) QList::contains
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+ QSet<PageItem*> existing;
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+ existing.reserve(m_SelList.count());
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+ for (int i = 0; i < m_SelList.count(); ++i)
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+ existing.insert(m_SelList.at(i).data());
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+
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QList< QPointer<PageItem> > toAdd;
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toAdd.reserve(items.count());
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for (int i = 0; i < items.count(); ++i)
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{
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PageItem* item = items.at(i);
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- if (m_SelList.contains(item))
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+ if (existing.contains(item))
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continue;
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toAdd.append(item);
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+ existing.insert(item);
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item->setSelected(true);
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}
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