uber/h3

Inline _isBaseCellPentagon

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#984 opened on Mar 9, 2025

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help wanted

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Description

This is a follow-up for https://github.com/uber/h3/pull/968

As discussed in https://github.com/uber/h3/pull/968, it would be nice to inline _isBaseCellPentagon for use in isValidCell (and potentially other spots in the code base).

I couldn't get this working in https://github.com/uber/h3/pull/968 after trying a mixture of inline and extern, so making this ticket to follow up and revisit.

Some notes:

  • maybe benchmark the array of structs vs stuct of arrays in baseCellData

Contributor guide

Research direction
Examine the current isBaseCellPentagon function and its usage in isValidCell. Study the baseCellData struct layout and try inlining with different combinations of inline and extern. Benchmark the array of structs vs struct of arrays approach to measure performance impact.
Tech stack
c
Domain
backendapi
Issue type
Refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C programmingunderstanding of H3 base cell data structuresbenchmarking
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60