work.suroh.tk/node_modules/ws/lib/buffer-util.js

73 lines
1.9 KiB
JavaScript

'use strict';
/**
* 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) {
const target = Buffer.allocUnsafe(totalLength);
var offset = 0;
for (var i = 0; i < list.length; i++) {
const buf = list[i];
buf.copy(target, offset);
offset += buf.length;
}
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 (var 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 (var i = 0; i < length; i++) {
buffer[i] ^= mask[i & 3];
}
}
try {
const bufferUtil = require('bufferutil');
const bu = bufferUtil.BufferUtil || bufferUtil;
module.exports = {
mask(source, mask, output, offset, length) {
if (length < 48) _mask(source, mask, output, offset, length);
else bu.mask(source, mask, output, offset, length);
},
unmask(buffer, mask) {
if (buffer.length < 32) _unmask(buffer, mask);
else bu.unmask(buffer, mask);
},
concat
};
} catch (e) /* istanbul ignore next */ {
module.exports = { concat, mask: _mask, unmask: _unmask };
}