didier amyot
0d627c9051
The class was already implemented in "https://deno.land/std@0.144.0/streams/conversion.ts". So, I litterally lost 1 day of work! I hate myself.
42 lines
1.0 KiB
TypeScript
42 lines
1.0 KiB
TypeScript
// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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import { assert } from "../_util/asserts.ts";
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import type { Reader, Writer } from "../types.d.ts";
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const DEFAULT_BUFFER_SIZE = 32 * 1024;
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/**
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* Copy N size at the most. If read size is lesser than N, then returns nread
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* @param r Reader
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* @param dest Writer
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* @param size Read size
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*/
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export async function copyN(
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r: Reader,
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dest: Writer,
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size: number,
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): Promise<number> {
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let bytesRead = 0;
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let buf = new Uint8Array(DEFAULT_BUFFER_SIZE);
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while (bytesRead < size) {
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if (size - bytesRead < DEFAULT_BUFFER_SIZE) {
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buf = new Uint8Array(size - bytesRead);
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}
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const result = await r.read(buf);
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const nread = result ?? 0;
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bytesRead += nread;
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if (nread > 0) {
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let n = 0;
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while (n < nread) {
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n += await dest.write(buf.slice(n, nread));
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}
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assert(n === nread, "could not write");
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}
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if (result === null) {
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break;
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}
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}
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return bytesRead;
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}
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