Zroar
Serialized Roaring Bitmaps in Zig
Details
- External ID
- 49393285
- Source
- HN
- Company
- —
- Product
- rovar
- Website domain
- github.com
- Launched
- Aug. 21, 2026
- Cohort
- —
- Upvotes
- 6
- Upvotes percentile
- 0.3125
- Tags
- —
- Fetched at
- Sept. 10, 2026, 5:32 a.m.
- Updated at
- Sept. 10, 2026, 5:32 a.m.
Description
zroar is a ground-up implementation of Roaring Bitmaps data structure in Zig. zroar stores both the keys and (array, bitmap) containers in a single flat byte buffer, making the in-memory representation equal to the on-disk or over-the-network representation, eliminating the serialization/deserialization step entirely.The design was originally aimed at systems which keep their posting lists on disk, but zroar performs faster than CRoaring even for purely in-memory ops, due to CPU cache locality.Against CRoaring 5.0's benchmarking suite (ported to Zig), zroar is faster in 339 out of 360 tests, being 2x-9x faster (geometric mean), and up to 600x faster on serialize/deserialize.zroar avoids complex mechanism (like adaptive radix trees), uses Zig native SIMD ops and is simpler. The main logic is written in ~2000 lines of code, while CRoaring's 64-bit bitmap codebase is over 17000 LOC.Not yet: By choice, zroar doesn't support run containers, and is 64-bit only.There are more details in the GitHub README. Try it out! I'd love feedback on the API and design. zroar is a Zig-based successor to my other project, sroar in Go, which showed a similar boost. So, I think this design should show performance gains in any language.
Enrichment
- Theme
- lightweight and on-device AI runtimes
- Vertical
- Horizontal
- Function
- Data infrastructure
- Audience
- Developer
- AI stance
- Not AI
- Project type
- Hobby / open-source project
- Normalized one-liner
- bitmap serialization library in zig
- Manually corrected
- False
Could you build this?
No Implementing a zero-copy, highly optimized serialized Roaring Bitmap data structure in Zig requires expert systems programming and rigorous mathematical bit-manipulation engineering.
What it would actually take: Requires an implementation of the Roaring Bitmap specification in Zig with custom memory layout guarantees ensuring in-memory buffers match serialization formats without deserialization overhead. The core complexity lies in SIMD-accelerated bitwise operations (AND, OR, XOR), differential run-length encoding, cache-line-aware memory alignment, and zero-allocation iterator semantics. This demands deep systems software optimization expertise and intricate knowledge of binary low-level data structures.
Discussion
No comments on this launch.
Competitors
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Attention rank: #41 of 54 (itself plus its competitors, highest first — normalized so YC and Product Hunt are compared fairly).
Launched 293 days after the earliest competitor.
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- CodeDiff · hn · 2026-09-29 · 6 upvotes · similarity 0.38
- zkGolf · hn · 2026-07-02 · 69 upvotes · similarity 0.37
- Glyd · github · 2026-09-19 · 164 upvotes · similarity 0.37
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