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C++26 introduces std::hive container combining pointer stability with cache locality
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C++26 introduces std::hive, a new container that provides stable pointers and iterators through insertions and erasures while maintaining cache locality via multiple memory blocks and a run-length-encoded skipfield.
This container resolves the traditional trade-off between pointer stability and cache performance that forces developers to choose between std::list and std::vector. It is particularly useful for systems managing numerous entities with cross-references, such as game engines or connection pools, where pointer invalidation causes bugs or complexity.
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std::hive uses multiple memory blocks so that insertions and erasures never reallocate existing elements, keeping pointers and iterators valid.
A run-length-encoded skipfield allows iterators to jump over erased elements in O(1) amortized time, avoiding the branch misprediction of boolean flags.
The container reuses erased slots for new insertions and allows runtime tuning of block capacities via std::hive_limits, block_capacity_limits(), and reshape().
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