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131 lines
3.0 KiB
131 lines
3.0 KiB
'use strict'; |
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const { EMPTY_BUFFER } = require('./constants'); |
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const FastBuffer = Buffer[Symbol.species]; |
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/** |
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* Merges an array of buffers into a new buffer. |
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* |
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* @param {Buffer[]} list The array of buffers to concat |
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* @param {Number} totalLength The total length of buffers in the list |
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* @return {Buffer} The resulting buffer |
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* @public |
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*/ |
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function concat(list, totalLength) { |
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if (list.length === 0) return EMPTY_BUFFER; |
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if (list.length === 1) return list[0]; |
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const target = Buffer.allocUnsafe(totalLength); |
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let offset = 0; |
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for (let i = 0; i < list.length; i++) { |
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const buf = list[i]; |
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target.set(buf, offset); |
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offset += buf.length; |
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} |
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if (offset < totalLength) { |
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return new FastBuffer(target.buffer, target.byteOffset, offset); |
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} |
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return target; |
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} |
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/** |
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* Masks a buffer using the given mask. |
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* |
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* @param {Buffer} source The buffer to mask |
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* @param {Buffer} mask The mask to use |
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* @param {Buffer} output The buffer where to store the result |
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* @param {Number} offset The offset at which to start writing |
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* @param {Number} length The number of bytes to mask. |
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* @public |
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*/ |
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function _mask(source, mask, output, offset, length) { |
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for (let i = 0; i < length; i++) { |
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output[offset + i] = source[i] ^ mask[i & 3]; |
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} |
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} |
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/** |
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* Unmasks a buffer using the given mask. |
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* |
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* @param {Buffer} buffer The buffer to unmask |
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* @param {Buffer} mask The mask to use |
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* @public |
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*/ |
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function _unmask(buffer, mask) { |
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for (let i = 0; i < buffer.length; i++) { |
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buffer[i] ^= mask[i & 3]; |
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} |
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} |
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/** |
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* Converts a buffer to an `ArrayBuffer`. |
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* |
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* @param {Buffer} buf The buffer to convert |
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* @return {ArrayBuffer} Converted buffer |
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* @public |
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*/ |
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function toArrayBuffer(buf) { |
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if (buf.length === buf.buffer.byteLength) { |
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return buf.buffer; |
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} |
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return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.length); |
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} |
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/** |
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* Converts `data` to a `Buffer`. |
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* |
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* @param {*} data The data to convert |
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* @return {Buffer} The buffer |
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* @throws {TypeError} |
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* @public |
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*/ |
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function toBuffer(data) { |
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toBuffer.readOnly = true; |
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if (Buffer.isBuffer(data)) return data; |
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let buf; |
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if (data instanceof ArrayBuffer) { |
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buf = new FastBuffer(data); |
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} else if (ArrayBuffer.isView(data)) { |
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buf = new FastBuffer(data.buffer, data.byteOffset, data.byteLength); |
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} else { |
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buf = Buffer.from(data); |
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toBuffer.readOnly = false; |
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} |
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return buf; |
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} |
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module.exports = { |
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concat, |
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mask: _mask, |
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toArrayBuffer, |
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toBuffer, |
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unmask: _unmask |
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}; |
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/* istanbul ignore else */ |
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if (!process.env.WS_NO_BUFFER_UTIL) { |
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try { |
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const bufferUtil = require('bufferutil'); |
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module.exports.mask = function (source, mask, output, offset, length) { |
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if (length < 48) _mask(source, mask, output, offset, length); |
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else bufferUtil.mask(source, mask, output, offset, length); |
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}; |
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module.exports.unmask = function (buffer, mask) { |
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if (buffer.length < 32) _unmask(buffer, mask); |
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else bufferUtil.unmask(buffer, mask); |
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}; |
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} catch (e) { |
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// Continue regardless of the error. |
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} |
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}
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