spb/admin-ka

1'use strict';23const { EMPTY_BUFFER } = require('./constants');45const FastBuffer = Buffer[Symbol.species];67/**8 * Merges an array of buffers into a new buffer.9 *10 * @param {Buffer[]} list The array of buffers to concat11 * @param {Number} totalLength The total length of buffers in the list12 * @return {Buffer} The resulting buffer13 * @public14 */15function concat(list, totalLength) {16  if (list.length === 0) return EMPTY_BUFFER;17  if (list.length === 1) return list[0];1819  const target = Buffer.allocUnsafe(totalLength);20  let offset = 0;2122  for (let i = 0; i < list.length; i++) {23    const buf = list[i];24    target.set(buf, offset);25    offset += buf.length;26  }2728  if (offset < totalLength) {29    return new FastBuffer(target.buffer, target.byteOffset, offset);30  }3132  return target;33}3435/**36 * Masks a buffer using the given mask.37 *38 * @param {Buffer} source The buffer to mask39 * @param {Buffer} mask The mask to use40 * @param {Buffer} output The buffer where to store the result41 * @param {Number} offset The offset at which to start writing42 * @param {Number} length The number of bytes to mask.43 * @public44 */45function _mask(source, mask, output, offset, length) {46  for (let i = 0; i < length; i++) {47    output[offset + i] = source[i] ^ mask[i & 3];48  }49}5051/**52 * Unmasks a buffer using the given mask.53 *54 * @param {Buffer} buffer The buffer to unmask55 * @param {Buffer} mask The mask to use56 * @public57 */58function _unmask(buffer, mask) {59  for (let i = 0; i < buffer.length; i++) {60    buffer[i] ^= mask[i & 3];61  }62}6364/**65 * Converts a buffer to an `ArrayBuffer`.66 *67 * @param {Buffer} buf The buffer to convert68 * @return {ArrayBuffer} Converted buffer69 * @public70 */71function toArrayBuffer(buf) {72  if (buf.length === buf.buffer.byteLength) {73    return buf.buffer;74  }7576  return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.length);77}7879/**80 * Converts `data` to a `Buffer`.81 *82 * @param {*} data The data to convert83 * @return {Buffer} The buffer84 * @throws {TypeError}85 * @public86 */87function toBuffer(data) {88  toBuffer.readOnly = true;8990  if (Buffer.isBuffer(data)) return data;9192  let buf;9394  if (data instanceof ArrayBuffer) {95    buf = new FastBuffer(data);96  } else if (ArrayBuffer.isView(data)) {97    buf = new FastBuffer(data.buffer, data.byteOffset, data.byteLength);98  } else {99    buf = Buffer.from(data);100    toBuffer.readOnly = false;101  }102103  return buf;104}105106module.exports = {107  concat,108  mask: _mask,109  toArrayBuffer,110  toBuffer,111  unmask: _unmask112};113114/* istanbul ignore else  */115if (!process.env.WS_NO_BUFFER_UTIL) {116  try {117    const bufferUtil = require('bufferutil');118119    module.exports.mask = function (source, mask, output, offset, length) {120      if (length < 48) _mask(source, mask, output, offset, length);121      else bufferUtil.mask(source, mask, output, offset, length);122    };123124    module.exports.unmask = function (buffer, mask) {125      if (buffer.length < 32) _unmask(buffer, mask);126      else bufferUtil.unmask(buffer, mask);127    };128  } catch (e) {129    // Continue regardless of the error.130  }131}132