Nothrow: Substitutes for standard C++ containers and memory resources, with pluggable pointer storage policies#272
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…r comparisons. 1. Emplace — true in-place construction - Added a Node(parent, std::in_place_t, Args&&...) constructor and AllocateNode. Emplace to construct the value_type directly in allocated node memory - Emplace now allocates the node first, constructs in-place, then searches the tree; destroys the node if a duplicate key is found - Eliminates the intermediate stack temporary + move that the old implementation used 2. clear() — no freed-pointer comparisons - Replaced the previous-tracking traversal (which compared freed addresses — UB per [basic.stc]/4) with a descend-to-leaf approach - Each iteration descends left/right until hitting a leaf, nulls the parent's link, then destroys the leaf and backs up to the parent - All pointer comparisons are against live objects only
…o container algorithm without UB. Add combined benchmark.
- Shared insert-position search (FindInsertPosition) - Consolidated key comparison (CompareKey) used in insert/find - Added specialized 2-arg Emplace(...) overloads to avoid pre-construct-and-destroy on duplicates - RebalanceFrom(..., stop_on_stable_height) early-exit for insert flows
… final equality check, and reused that for insert-position search (removing extra compare/branch work). I also added a std::greater<int> regression test in score/shm/map_test.cpp.
…plus OrAbort variants), with std-like neighbor checks and fallback. Sorted fast path via maintained leftmost_/rightmost_ and boundary-aware insertion checks, used in Create(range) and Clone() with rolling hint. Udated score/shm/BENCHMARK.md with the full latest suite results from the current codebase.
…hrow with pointer box renames. Move score/shm/ to score/nothrow/ to reflect that these containers and memory resources are nothrow std-container substitutes, not shared-memory-specific. Rename pointer storage types to reflect their role as encoding boxes: - OffsetPtr -> OffsetBox - NullableOffsetPtr -> NullableOffsetBox - DirectPtr -> RawBox (serves as both Ptr and NullablePtr) - ShmPointerPolicy -> OffsetBoxPolicy - ShmDirectPointerPolicy -> RawBoxPolicy - offset_ptr.h -> pointer_box.h Update all include paths, header guards, namespaces, BUILD targets, documentation, and example code. Add reverse iterators (rbegin/rend/crbegin/crend), ordered lookup methods (count, lower_bound, upper_bound, equal_range), iterator-based erase overloads (const_iterator and range), and equality operators. Fix GetOrInsertDefault to use Emplace instead of constructing an intermediate value_type, avoiding an unnecessary key copy. All new members follow the naming conventions from score/shm/README.md: non-allocating operations use standard snake_case spelling.
Updated the benchmark analysis section to clarify the overhead cause and corrected terminology from 'OffsetBox' to 'OffsetPtr'. Signed-off-by: MichaelSteffens17 <michael.steffens@vector.com>
…ffsetBox. Signed-off-by: MichaelSteffens17 <michael.steffens@vector.com>
Signed-off-by: MichaelSteffens17 <michael.steffens@vector.com>
Signed-off-by: MichaelSteffens17 <michael.steffens@vector.com>
Signed-off-by: MichaelSteffens17 <michael.steffens@vector.com>
…irly to NoBoundsCheck timings. Add boost::interprocess container and completed score::memory::shared::Map benchmarks.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
…e remaining bare OS macro check in upstream google_benchmark.
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The created documentation from the pull request is available at: docu-html |
limdor
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Jun 17, 2026
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Yes, sorry, will remove that.
Mit freundlichen Grüßen
Michael
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Subject: Re: [eclipse-score/baselibs] Nothrow: Substitutes for standard C++ containers and memory resources, with pluggable pointer storage policies (PR #272)
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On map.tar.gz<#272 (comment)>:
What is this zip file? Accidentally checked in?
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Provision a Map's node storage directly from an external buffer, bypassing the templated allocator the same way Vector::CreateWithBuffer does. The map manages an internal free-list pool over the buffer: nodes are carved on insert and recycled on erase, bounding the map to a fixed node count. All pool state is position-independent -- the cell base is stored through the pointer policy (offset-encoded by default) and the free-list head/capacity are indices -- so a buffer-backed map with OffsetSlotPolicy is relocatable and can be both read and mutated across processes mapping the same segment, without the vtable, raw buffer pointer, and process-local upstream singleton that a polymorphic MemoryResource would drag along. - map.h: PoolCell union + CreateWithBuffer(), uses_buffer(), cell_size(), cell_alignment(), required_bytes(); pool-routed AllocateNode/DestroyNode; move ctor/assignment extended to carry pool state. - map_test.cpp: tests for empty/insert/find, capacity bound, freed-cell reuse, move, and OrAbort-on-exhaustion death test. - bounded_containers.h: convert the shared-memory example bundle to the allocator-free buffer API. - README.md: document the cross-process map mutation capability. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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The child now inserts new keys into the parent's map, exercising node allocation from the shared free-list pool across processes (not just in-place value updates). The parent observes the grown map (size 3 -> 5) after remapping the segment, confirming pooled allocation is position-independent. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A buffer not aligned to cell_alignment() would misalign the pooled nodes. That is a caller precondition violation, so trap it with std::abort() like the map's other contract checks rather than returning an error. Add a death test. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Reflect the child's new insertion step: the README now describes node allocation from the shared free-list pool across processes (map grows 3 -> 5), not just in-place value updates. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Part of #167