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import { copy, EventEmitter } from "../deps.ts";import GzipWriter from "./writer_gzip.ts";import GunzipWriter from "./writer_gunzip.ts";
export class GzipStream extends EventEmitter {  constructor() {    super();  }
  async compress(src: string, dest: string): Promise<void> {    // reader    const stat = await Deno.stat(src);    const size = stat.size;    const reader = await Deno.open(src, {      read: true,    });    // writer    const writer = new GzipWriter(dest, {      onceSize: size > 50 * 1024 * 1024 ? 1024 * 1024 : 512 * 1024,    });    await writer.setup(      src,      stat.mtime ? Math.round(stat.mtime.getTime() / 1000) : 0,    );    writer.on("bytesWritten", (bytesWritten: number) => {      const progress = (100 * bytesWritten / size).toFixed(2) + "%";      this.emit("progress", progress);    });
    /** 1: use Deno.copy */    await copy(reader, writer, {      bufSize: 1024 * 1024,    });
    /** 2: not use Deno.copy */    // let readed: number | null;    // const n = 16384; //16kb    // while (true) {    //   const p: Uint8Array = new Uint8Array(n);    //   readed = await reader.read(p);    //   if (readed === null) break;    //   if (readed < n) {    //     await writer.write(p.subarray(0, readed));    //     break;    //   } else {    //     await writer.write(p);    //   }    // }
    writer.close();    reader.close();  }
  async uncompress(src: string, dest: string): Promise<void> {    // reader    const size = (await Deno.stat(src)).size;    const reader = await Deno.open(src, {      read: true,    });    // writer    const writer = new GunzipWriter(dest, {      onceSize: size > 50 * 1024 * 1024 ? 1024 * 1024 : 512 * 1024,    });    await writer.setup();    writer.on("bytesWritten", (bytesWritten: number) => {      const progress = (100 * bytesWritten / size).toFixed(2) + "%";      this.emit("progress", progress);    });    // write    await copy(reader, writer, {      bufSize: 1024 * 1024,    });    // close    writer.close();    reader.close();  }}