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Module

std/io/limited_reader.ts

Deno standard library
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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * A `LimitedReader` reads from `reader` but limits the amount of data returned to just `limit` bytes. * Each call to `read` updates `limit` to reflect the new amount remaining. * `read` returns `null` when `limit` <= `0` or * when the underlying `reader` returns `null`. */import type { Reader } from "../types.d.ts";
/** * @deprecated (will be removed after 1.0.0) Use Web Streams instead. */export class LimitedReader implements Reader { constructor(public reader: Reader, public limit: number) {}
async read(p: Uint8Array): Promise<number | null> { if (this.limit <= 0) { return null; }
if (p.length > this.limit) { p = p.subarray(0, this.limit); } const n = await this.reader.read(p); if (n === null) { return null; }
this.limit -= n; return n; }}