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45 lines
1.3 KiB
TypeScript
45 lines
1.3 KiB
TypeScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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import { DEFAULT_BUFFER_SIZE } from "./_constants.ts";
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import { writeAll } from "./write_all.ts";
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import type { Reader, Writer } from "./types.ts";
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/**
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* Copies from `src` to `dst` until either EOF (`null`) is read from `src` or
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* an error occurs. It resolves to the number of bytes copied or rejects with
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* the first error encountered while copying.
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*
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* @example Usage
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* ```ts no-eval
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* import { copy } from "@std/io/copy";
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*
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* const source = await Deno.open("my_file.txt");
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* const bytesCopied1 = await copy(source, Deno.stdout);
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* const destination = await Deno.create("my_file_2.txt");
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* const bytesCopied2 = await copy(source, destination);
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* ```
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*
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* @param src The source to copy from
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* @param dst The destination to copy to
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* @param options Can be used to tune size of the buffer. Default size is 32kB
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* @returns Number of bytes copied
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*/
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export async function copy(
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src: Reader,
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dst: Writer,
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options?: {
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bufSize?: number;
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},
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): Promise<number> {
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let n = 0;
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const b = new Uint8Array(options?.bufSize ?? DEFAULT_BUFFER_SIZE);
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while (true) {
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const result = await src.read(b);
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if (result === null) break;
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await writeAll(dst, b.subarray(0, result));
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n += result;
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}
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return n;
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}
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