// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license. const { Buffer, mkdir, open } = Deno; type File = Deno.File; type Reader = Deno.Reader; import { encode } from "../strings/mod.ts"; import * as path from "../fs/path.ts"; // `off` is the offset into `dst` where it will at which to begin writing values // from `src`. // Returns the number of bytes copied. export function copyBytes(dst: Uint8Array, src: Uint8Array, off = 0): number { off = Math.max(0, Math.min(off, dst.byteLength)); const r = dst.byteLength - off; if (src.byteLength > r) { src = src.subarray(0, r); } dst.set(src, off); return src.byteLength; } export function charCode(s: string): number { return s.charCodeAt(0); } export function stringsReader(s: string): Reader { return new Buffer(encode(s).buffer); } /** Create or open a temporal file at specified directory with prefix and postfix */ export async function tempFile( dir: string, opts: { prefix?: string; postfix?: string; } = { prefix: "", postfix: "" } ): Promise<{ file: File; filepath: string }> { const r = Math.floor(Math.random() * 1000000); const filepath = path.resolve( `${dir}/${opts.prefix || ""}${r}${opts.postfix || ""}` ); await mkdir(path.dirname(filepath), true); const file = await open(filepath, "a"); return { file, filepath }; }