123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146 |
- 'use strict';
-
- const { EMPTY_BUFFER } = require('./constants');
-
- /**
- * Merges an array of buffers into a new buffer.
- *
- * @param {Buffer[]} list The array of buffers to concat
- * @param {Number} totalLength The total length of buffers in the list
- * @return {Buffer} The resulting buffer
- * @public
- */
- function concat(list, totalLength) {
- if (list.length === 0) return EMPTY_BUFFER;
- if (list.length === 1) return list[0];
-
- const target = Buffer.allocUnsafe(totalLength);
- let offset = 0;
-
- for (let i = 0; i < list.length; i++) {
- const buf = list[i];
- target.set(buf, offset);
- offset += buf.length;
- }
-
- if (offset < totalLength) return target.slice(0, offset);
-
- return target;
- }
-
- /**
- * Masks a buffer using the given mask.
- *
- * @param {Buffer} source The buffer to mask
- * @param {Buffer} mask The mask to use
- * @param {Buffer} output The buffer where to store the result
- * @param {Number} offset The offset at which to start writing
- * @param {Number} length The number of bytes to mask.
- * @public
- */
- function _mask(source, mask, output, offset, length) {
- for (let i = 0; i < length; i++) {
- output[offset + i] = source[i] ^ mask[i & 3];
- }
- }
-
- /**
- * Unmasks a buffer using the given mask.
- *
- * @param {Buffer} buffer The buffer to unmask
- * @param {Buffer} mask The mask to use
- * @public
- */
- function _unmask(buffer, mask) {
- // Required until https://github.com/nodejs/node/issues/9006 is resolved.
- const length = buffer.length;
- for (let i = 0; i < length; i++) {
- buffer[i] ^= mask[i & 3];
- }
- }
-
- /**
- * Converts a buffer to an `ArrayBuffer`.
- *
- * @param {Buffer} buf The buffer to convert
- * @return {ArrayBuffer} Converted buffer
- * @public
- */
- function toArrayBuffer(buf) {
- if (buf.byteLength === buf.buffer.byteLength) {
- return buf.buffer;
- }
-
- return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
- }
-
- /**
- * Converts `data` to a `Buffer`.
- *
- * @param {*} data The data to convert
- * @return {Buffer} The buffer
- * @throws {TypeError}
- * @public
- */
- function toBuffer(data) {
- toBuffer.readOnly = true;
-
- if (Buffer.isBuffer(data)) return data;
-
- let buf;
-
- if (data instanceof ArrayBuffer) {
- buf = Buffer.from(data);
- } else if (ArrayBuffer.isView(data)) {
- buf = viewToBuffer(data);
- } else {
- buf = Buffer.from(data);
- toBuffer.readOnly = false;
- }
-
- return buf;
- }
-
- /**
- * Converts an `ArrayBuffer` view into a buffer.
- *
- * @param {(DataView|TypedArray)} view The view to convert
- * @return {Buffer} Converted view
- * @private
- */
- function viewToBuffer(view) {
- const buf = Buffer.from(view.buffer);
-
- if (view.byteLength !== view.buffer.byteLength) {
- return buf.slice(view.byteOffset, view.byteOffset + view.byteLength);
- }
-
- return buf;
- }
-
- try {
- const bufferUtil = require('bufferutil');
- const bu = bufferUtil.BufferUtil || bufferUtil;
-
- module.exports = {
- concat,
- mask(source, mask, output, offset, length) {
- if (length < 48) _mask(source, mask, output, offset, length);
- else bu.mask(source, mask, output, offset, length);
- },
- toArrayBuffer,
- toBuffer,
- unmask(buffer, mask) {
- if (buffer.length < 32) _unmask(buffer, mask);
- else bu.unmask(buffer, mask);
- }
- };
- } catch (e) /* istanbul ignore next */ {
- module.exports = {
- concat,
- mask: _mask,
- toArrayBuffer,
- toBuffer,
- unmask: _unmask
- };
- }
|