@pr4j3sh/bitter/src/pieces.js

bittorrent client

const parser = require("./parser");

module.exports = class {
  constructor(torrent) {
    function buildPiecesArray() {
      const nPieces = torrent.info.pieces.length / 20;
      const arr = new Array(nPieces).fill(null);
      return arr.map((_, i) =>
        new Array(parser.blocksPerPiece(torrent, i)).fill(false),
      );
    }

    this._requested = buildPiecesArray();
    this._received = buildPiecesArray();
  }

  addRequested(pieceBlock) {
    const blockIndex = pieceBlock.begin / parser.BLOCK_LEN;
    this._requested[pieceBlock.index][blockIndex] = true;
  }

  addReceived(pieceBlock) {
    const blockIndex = pieceBlock.begin / parser.BLOCK_LEN;
    this._received[pieceBlock.index][blockIndex] = true;
  }

  needed(pieceBlock) {
    if (this._requested.every((blocks) => blocks.every((i) => i))) {
      this._requested = this._received.map((blocks) => blocks.slice());
    }
    const blockIndex = pieceBlock.begin / parser.BLOCK_LEN;
    return !this._requested[pieceBlock.index][blockIndex];
  }

  isDone() {
    return this._received.every((blocks) => blocks.every((i) => i));
  }

  printPercentDone() {
    const downloaded = this._received.reduce((totalBlocks, blocks) => {
      return blocks.filter((i) => i).length + totalBlocks;
    }, 0);
    const total = this._received.reduce((totalBlocks, blocks) => {
      return blocks.length + totalBlocks;
    }, 0);

    const percent = Math.floor((downloaded / total) * 100);

    process.stdout.write("[/] downloading: " + percent + "%\r");
  }
};