# normalizeSource

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_(no submodules)_
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## Purpose

Converts the four shapes accepted as a packer source — `Uint8Array`, `Blob`, `ReadableStream<Uint8Array>`, `AsyncIterable<Uint8Array>` — into a single uniform `AsyncIterable<Uint8Array>` so downstream pipelines (compressor, AEAD encrypt-stream, chunk chopper) can iterate without branching on input type. Buffered sources are sliced to `chunkSize` boundaries; already-streaming sources preserve their inbound chunk boundaries.

## Features

- Accepts buffered: `Uint8Array`, `Blob`.
- Accepts streaming: `ReadableStream<Uint8Array>`, `AsyncIterable<Uint8Array>`.
- Single unified output: `AsyncIterable<Uint8Array>`.
- Releases `ReadableStream` reader lock in `finally` to prevent leaks on early termination.
- Rejects unsupported inputs with `PackerError(PACKER.INVALID_SOURCE)`.

## Usage: Basic Example

```ts
import { normalizeSource } from "@suaveplan/packer/streaming";

const source = new Uint8Array([1, 2, 3, 4, 5]);
for await (const chunk of normalizeSource(source, 2)) {
    console.log(chunk); // Uint8Array(2)[1,2], (2)[3,4], (1)[5]
}
```

## Usage: Advanced Example

```ts
import { normalizeSource } from "@suaveplan/packer/streaming";
import { open } from "node:fs/promises";

const fh = await open("/large/file.bin");
const stream = fh.readableWebStream() as ReadableStream<Uint8Array>;

let totalBytes = 0;
for await (const chunk of normalizeSource(stream, 64 * 1024)) {
    totalBytes += chunk.byteLength;
    // pass chunk through next stage of the pipeline
}
await fh.close();
```

## API Reference

`normalizeSource(source: PackSource, chunkSize: number): AsyncIterable<Uint8Array>`

- **`source`** — `Uint8Array | Blob | ReadableStream<Uint8Array> | AsyncIterable<Uint8Array>`. The input bytes.
- **`chunkSize`** — positive integer. Slice boundary for buffered inputs. Ignored for streaming inputs (their boundaries pass through unchanged).
- **Returns** — `AsyncIterable<Uint8Array>`.
- **Throws** — `PackerError(PACKER.INVALID_SOURCE)` if `source` is none of the supported types.

## Implementation Notes

`Uint8Array.subarray` is used for buffered slicing (zero-copy view, not a copy). `Blob` paths recurse through `Blob.stream()`, which itself yields the streaming branch. The `Symbol.asyncIterator in source` check precedes the `getReader` branch because modern `ReadableStream` instances satisfy both protocols and async iteration is the simpler path. The reader-based fallback exists for environments where `ReadableStream` lacks async-iteration support; the `try/finally` ensures the lock is released even when the consumer aborts mid-stream.