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42 lines
1.1 KiB
TypeScript
42 lines
1.1 KiB
TypeScript
// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
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type Reader = Deno.Reader;
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import { encode } from "../strings/mod.ts";
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/** Reader utility for strings */
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export class StringReader implements Reader {
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private offs = 0;
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private buf = new Uint8Array(encode(this.s));
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constructor(private readonly s: string) {}
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async read(p: Uint8Array): Promise<number | Deno.EOF> {
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const n = Math.min(p.byteLength, this.buf.byteLength - this.offs);
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p.set(this.buf.slice(this.offs, this.offs + n));
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this.offs += n;
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if (n === 0) {
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return Deno.EOF;
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}
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return n;
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}
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}
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/** Reader utility for combining multiple readers */
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export class MultiReader implements Reader {
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private readonly readers: Reader[];
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private currentIndex = 0;
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constructor(...readers: Reader[]) {
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this.readers = readers;
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}
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async read(p: Uint8Array): Promise<number | Deno.EOF> {
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const r = this.readers[this.currentIndex];
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if (!r) return Deno.EOF;
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const result = await r.read(p);
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if (result === Deno.EOF) {
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this.currentIndex++;
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return 0;
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}
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return result;
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}
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}
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