1 | 'use strict';
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2 |
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3 | const { EMPTY_BUFFER } = require('./constants');
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4 |
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5 |
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6 |
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7 |
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8 |
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9 |
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10 |
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11 |
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12 |
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13 | function concat(list, totalLength) {
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14 | if (list.length === 0) return EMPTY_BUFFER;
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15 | if (list.length === 1) return list[0];
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16 |
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17 | const target = Buffer.allocUnsafe(totalLength);
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18 | let offset = 0;
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19 |
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20 | for (let i = 0; i < list.length; i++) {
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21 | const buf = list[i];
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22 | target.set(buf, offset);
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23 | offset += buf.length;
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24 | }
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25 |
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26 | if (offset < totalLength) return target.slice(0, offset);
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27 |
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28 | return target;
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29 | }
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30 |
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31 |
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32 |
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33 |
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34 |
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35 |
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36 |
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37 |
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38 |
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39 |
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40 |
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41 | function _mask(source, mask, output, offset, length) {
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42 | for (let i = 0; i < length; i++) {
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43 | output[offset + i] = source[i] ^ mask[i & 3];
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44 | }
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45 | }
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46 |
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47 |
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48 |
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49 |
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50 |
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51 |
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52 |
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53 |
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54 | function _unmask(buffer, mask) {
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55 |
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56 | const length = buffer.length;
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57 | for (let i = 0; i < length; i++) {
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58 | buffer[i] ^= mask[i & 3];
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59 | }
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60 | }
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61 |
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62 |
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63 |
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64 |
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65 |
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66 |
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67 |
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68 |
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69 | function toArrayBuffer(buf) {
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70 | if (buf.byteLength === buf.buffer.byteLength) {
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71 | return buf.buffer;
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72 | }
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73 |
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74 | return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
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75 | }
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76 |
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77 |
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78 |
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79 |
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80 |
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81 |
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82 |
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83 |
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84 |
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85 | function toBuffer(data) {
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86 | toBuffer.readOnly = true;
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87 |
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88 | if (Buffer.isBuffer(data)) return data;
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89 |
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90 | let buf;
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91 |
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92 | if (data instanceof ArrayBuffer) {
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93 | buf = Buffer.from(data);
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94 | } else if (ArrayBuffer.isView(data)) {
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95 | buf = Buffer.from(data.buffer, data.byteOffset, data.byteLength);
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96 | } else {
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97 | buf = Buffer.from(data);
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98 | toBuffer.readOnly = false;
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99 | }
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100 |
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101 | return buf;
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102 | }
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103 |
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104 | try {
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105 | const bufferUtil = require('bufferutil');
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106 | const bu = bufferUtil.BufferUtil || bufferUtil;
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107 |
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108 | module.exports = {
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109 | concat,
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110 | mask(source, mask, output, offset, length) {
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111 | if (length < 48) _mask(source, mask, output, offset, length);
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112 | else bu.mask(source, mask, output, offset, length);
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113 | },
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114 | toArrayBuffer,
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115 | toBuffer,
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116 | unmask(buffer, mask) {
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117 | if (buffer.length < 32) _unmask(buffer, mask);
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118 | else bu.unmask(buffer, mask);
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119 | }
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120 | };
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121 | } catch (e) {
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122 | module.exports = {
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123 | concat,
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124 | mask: _mask,
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125 | toArrayBuffer,
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126 | toBuffer,
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127 | unmask: _unmask
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128 | };
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129 | }
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