# RLE Compression Options Schema

## Purpose

Zod schema for the per-call `CompressionOptions` accepted by `compressRle` / `decompressRle`. The RLE codec is byte-only and exposes a single tuning knob (`level`) — this schema validates that knob at the boundary so untrusted input can be normalized before reaching the codec.

## Features

- `rleCompressionOptionsSchema` — strict, single optional field
- `level` is a non-negative integer; the codec ignores values outside its supported range
- `as unknown as z.ZodType<T>` cast for the EOPT mismatch

## Usage: Basic Example

```ts
import { compressRle, rleCompressionOptionsSchema } from "@suaveplan/bitpacker-compressed";

const opts = rleCompressionOptionsSchema.parse({ level: 1 });
const compressed = compressRle(new Uint8Array([0, 0, 0, 0, 1, 2]), opts);
```

## Usage: Advanced Example

```ts
import {
    compressRle,
    decompressRle,
    rleCompressionOptionsSchema,
} from "@suaveplan/bitpacker-compressed";

function safeRoundTrip(data: Uint8Array, rawOpts: unknown) {
    const opts = rleCompressionOptionsSchema.parse(rawOpts);
    const compressed = compressRle(data, opts);
    const decompressed = decompressRle(compressed);
    return decompressed;
}
```

## API Reference

### `rleCompressionOptionsSchema: z.ZodType<CompressionOptions>`

Strict schema. `level` is an optional non-negative integer. Throws `ZodError` on negative or non-integer values, or on unknown keys.

## Implementation Notes

- **Why a one-field schema.** Even a single-field bundle benefits from boundary validation: a `{ level: "9" }` (string instead of number) would otherwise reach the codec and produce undefined behaviour. Refusing it at parse time keeps the codec's contract simple.
- **Codec ignores out-of-range levels.** The schema enforces non-negative integer; the codec itself ignores values outside `[0, 9]`. The schema is the boundary; the codec is the implementation.