# `ExDataSketch.Backend.Pure`
[🔗](https://github.com/thanos/ex_data_sketch/blob/main/lib/ex_data_sketch/backend/pure.ex#L1)

Pure Elixir backend for ExDataSketch.

This module implements the `ExDataSketch.Backend` behaviour using only
Elixir/Erlang standard library functions. It is always available and
serves as the default backend.

## Implementation Notes

- All state is stored as Elixir binaries with documented layouts.
- Operations are pure: input binary in, new binary out. No side effects.
- Batch operations (`update_many`) decode the register/counter array to a
  tuple for O(1) access, fold over all items, then re-encode once to
  minimize binary copying.

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*Consult [api-reference.md](api-reference.md) for complete listing*