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Module

std/bytes/copy.ts

The Deno Standard Library
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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Copy bytes from the source array to the destination array and returns the * number of bytes copied. * * If the source array is larger than what the `dst` array can hold, only the * amount of bytes that fit in the `dst` array are copied. * * @param src Source array to copy from. * @param dst Destination array to copy to. * @param offset Offset in the destination array to start copying to. Defaults * to 0. * @returns Number of bytes copied. * * @example Basic usage * ```ts * import { copy } from "https://deno.land/std@$STD_VERSION/bytes/copy.ts"; * * const src = new Uint8Array([9, 8, 7]); * const dst = new Uint8Array([0, 1, 2, 3, 4, 5]); * * copy(src, dst); // 3 * dst; // Uint8Array(6) [9, 8, 7, 3, 4, 5] * ``` * * @example Copy with offset * ```ts * import { copy } from "https://deno.land/std@$STD_VERSION/bytes/copy.ts"; * * const src = new Uint8Array([1, 1, 1, 1]); * const dst = new Uint8Array([0, 0, 0, 0]); * * copy(src, dst, 1); // 3 * dst; // Uint8Array(4) [0, 1, 1, 1] * ``` * Defining an offset will start copying at the specified index in the * destination array. */export function copy(src: Uint8Array, dst: Uint8Array, offset = 0): number { offset = Math.max(0, Math.min(offset, dst.byteLength)); const dstBytesAvailable = dst.byteLength - offset; if (src.byteLength > dstBytesAvailable) { src = src.subarray(0, dstBytesAvailable); } dst.set(src, offset); return src.byteLength;}