1 | 'use strict';
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2 |
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3 | var bufferUtil = require('../util/buffer');
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4 | var assert = require('assert');
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5 |
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6 | var BufferWriter = function BufferWriter(obj) {
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7 | if (!(this instanceof BufferWriter))
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8 | return new BufferWriter(obj);
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9 | this.bufLen = 0;
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10 | if (obj)
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11 | this.set(obj);
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12 | else
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13 | this.bufs = [];
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14 | };
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15 |
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16 | BufferWriter.prototype.set = function(obj) {
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17 | this.bufs = obj.bufs || this.bufs || [];
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18 | this.bufLen = this.bufs.reduce(function(prev, buf){ return prev + buf.length; }, 0);
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19 | return this;
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20 | };
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21 |
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22 | BufferWriter.prototype.toBuffer = function() {
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23 | return this.concat();
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24 | };
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25 |
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26 | BufferWriter.prototype.concat = function() {
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27 | return Buffer.concat(this.bufs, this.bufLen);
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28 | };
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29 |
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30 | BufferWriter.prototype.write = function(buf) {
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31 | assert(bufferUtil.isBuffer(buf));
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32 | this.bufs.push(buf);
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33 | this.bufLen += buf.length;
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34 | return this;
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35 | };
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36 |
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37 | BufferWriter.prototype.writeReverse = function(buf) {
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38 | assert(bufferUtil.isBuffer(buf));
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39 | this.bufs.push(bufferUtil.reverse(buf));
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40 | this.bufLen += buf.length;
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41 | return this;
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42 | };
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43 |
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44 | BufferWriter.prototype.writeUInt8 = function(n) {
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45 | var buf = Buffer.alloc(1);
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46 | buf.writeUInt8(n, 0);
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47 | this.write(buf);
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48 | return this;
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49 | };
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50 |
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51 | BufferWriter.prototype.writeUInt16BE = function(n) {
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52 | var buf = Buffer.alloc(2);
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53 | buf.writeUInt16BE(n, 0);
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54 | this.write(buf);
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55 | return this;
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56 | };
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57 |
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58 | BufferWriter.prototype.writeUInt16LE = function(n) {
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59 | var buf = Buffer.alloc(2);
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60 | buf.writeUInt16LE(n, 0);
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61 | this.write(buf);
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62 | return this;
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63 | };
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64 |
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65 | BufferWriter.prototype.writeUInt32BE = function(n) {
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66 | var buf = Buffer.alloc(4);
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67 | buf.writeUInt32BE(n, 0);
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68 | this.write(buf);
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69 | return this;
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70 | };
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71 |
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72 | BufferWriter.prototype.writeInt32LE = function(n) {
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73 | var buf = Buffer.alloc(4);
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74 | buf.writeInt32LE(n, 0);
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75 | this.write(buf);
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76 | return this;
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77 | };
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78 |
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79 | BufferWriter.prototype.writeUInt32LE = function(n) {
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80 | var buf = Buffer.alloc(4);
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81 | buf.writeUInt32LE(n, 0);
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82 | this.write(buf);
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83 | return this;
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84 | };
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85 |
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86 | BufferWriter.prototype.writeUInt64BEBN = function(bn) {
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87 | var buf = bn.toBuffer({size: 8});
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88 | this.write(buf);
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89 | return this;
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90 | };
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91 |
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92 | BufferWriter.prototype.writeUInt64LEBN = function(bn) {
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93 | var buf = bn.toBuffer({size: 8});
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94 | this.writeReverse(buf);
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95 | return this;
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96 | };
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97 |
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98 | BufferWriter.prototype.writeVarintNum = function(n) {
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99 | var buf = BufferWriter.varintBufNum(n);
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100 | this.write(buf);
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101 | return this;
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102 | };
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103 |
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104 | BufferWriter.prototype.writeVarintBN = function(bn) {
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105 | var buf = BufferWriter.varintBufBN(bn);
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106 | this.write(buf);
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107 | return this;
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108 | };
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109 |
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110 | BufferWriter.varintBufNum = function(n) {
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111 | var buf = undefined;
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112 | if (n < 253) {
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113 | buf = Buffer.alloc(1);
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114 | buf.writeUInt8(n, 0);
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115 | } else if (n < 0x10000) {
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116 | buf = Buffer.alloc(1 + 2);
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117 | buf.writeUInt8(253, 0);
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118 | buf.writeUInt16LE(n, 1);
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119 | } else if (n < 0x100000000) {
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120 | buf = Buffer.alloc(1 + 4);
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121 | buf.writeUInt8(254, 0);
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122 | buf.writeUInt32LE(n, 1);
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123 | } else {
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124 | buf = Buffer.alloc(1 + 8);
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125 | buf.writeUInt8(255, 0);
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126 | buf.writeInt32LE(n & -1, 1);
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127 | buf.writeUInt32LE(Math.floor(n / 0x100000000), 5);
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128 | }
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129 | return buf;
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130 | };
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131 |
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132 | BufferWriter.varintBufBN = function(bn) {
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133 | var buf = undefined;
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134 | var n = bn.toNumber();
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135 | if (n < 253) {
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136 | buf = Buffer.alloc(1);
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137 | buf.writeUInt8(n, 0);
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138 | } else if (n < 0x10000) {
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139 | buf = Buffer.alloc(1 + 2);
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140 | buf.writeUInt8(253, 0);
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141 | buf.writeUInt16LE(n, 1);
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142 | } else if (n < 0x100000000) {
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143 | buf = Buffer.alloc(1 + 4);
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144 | buf.writeUInt8(254, 0);
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145 | buf.writeUInt32LE(n, 1);
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146 | } else {
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147 | var bw = new BufferWriter();
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148 | bw.writeUInt8(255);
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149 | bw.writeUInt64LEBN(bn);
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150 | var buf = bw.concat();
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151 | }
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152 | return buf;
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153 | };
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154 |
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155 | module.exports = BufferWriter;
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