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std/io/_iotest.ts

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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// Ported to Deno from// Copyright 2009 The Go Authors. All rights reserved.// Use of this source code is governed by a BSD-style// license that can be found in the LICENSE file.import type { Reader } from "./types.d.ts";
/** OneByteReader returns a Reader that implements * each non-empty Read by reading one byte from r. */export class OneByteReader implements Reader { constructor(readonly r: Reader) {}
read(p: Uint8Array): Promise<number | null> { if (p.byteLength === 0) { return Promise.resolve(0); } if (!(p instanceof Uint8Array)) { throw Error("expected Uint8Array"); } return Promise.resolve(this.r.read(p.subarray(0, 1))); }}
/** HalfReader returns a Reader that implements Read * by reading half as many requested bytes from r. */export class HalfReader implements Reader { constructor(readonly r: Reader) {}
read(p: Uint8Array): Promise<number | null> { if (!(p instanceof Uint8Array)) { throw Error("expected Uint8Array"); } const half = Math.floor((p.byteLength + 1) / 2); return Promise.resolve(this.r.read(p.subarray(0, half))); }}
/** TimeoutReader returns `Deno.errors.TimedOut` on the second read * with no data. Subsequent calls to read succeed. */export class TimeoutReader implements Reader { count = 0; constructor(readonly r: Reader) {}
read(p: Uint8Array): Promise<number | null> { this.count++; if (this.count === 2) { throw new Deno.errors.TimedOut(); } return Promise.resolve(this.r.read(p)); }}