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ssh-buffer.js (3877B)

      1 // Copyright 2015 Joyent, Inc.
      2 
      3 module.exports = SSHBuffer;
      4 
      5 var assert = require('assert-plus');
      6 var Buffer = require('safer-buffer').Buffer;
      7 
      8 function SSHBuffer(opts) {
      9 	assert.object(opts, 'options');
     10 	if (opts.buffer !== undefined)
     11 		assert.buffer(opts.buffer, 'options.buffer');
     12 
     13 	this._size = opts.buffer ? opts.buffer.length : 1024;
     14 	this._buffer = opts.buffer || Buffer.alloc(this._size);
     15 	this._offset = 0;
     16 }
     17 
     18 SSHBuffer.prototype.toBuffer = function () {
     19 	return (this._buffer.slice(0, this._offset));
     20 };
     21 
     22 SSHBuffer.prototype.atEnd = function () {
     23 	return (this._offset >= this._buffer.length);
     24 };
     25 
     26 SSHBuffer.prototype.remainder = function () {
     27 	return (this._buffer.slice(this._offset));
     28 };
     29 
     30 SSHBuffer.prototype.skip = function (n) {
     31 	this._offset += n;
     32 };
     33 
     34 SSHBuffer.prototype.expand = function () {
     35 	this._size *= 2;
     36 	var buf = Buffer.alloc(this._size);
     37 	this._buffer.copy(buf, 0);
     38 	this._buffer = buf;
     39 };
     40 
     41 SSHBuffer.prototype.readPart = function () {
     42 	return ({data: this.readBuffer()});
     43 };
     44 
     45 SSHBuffer.prototype.readBuffer = function () {
     46 	var len = this._buffer.readUInt32BE(this._offset);
     47 	this._offset += 4;
     48 	assert.ok(this._offset + len <= this._buffer.length,
     49 	    'length out of bounds at +0x' + this._offset.toString(16) +
     50 	    ' (data truncated?)');
     51 	var buf = this._buffer.slice(this._offset, this._offset + len);
     52 	this._offset += len;
     53 	return (buf);
     54 };
     55 
     56 SSHBuffer.prototype.readString = function () {
     57 	return (this.readBuffer().toString());
     58 };
     59 
     60 SSHBuffer.prototype.readCString = function () {
     61 	var offset = this._offset;
     62 	while (offset < this._buffer.length &&
     63 	    this._buffer[offset] !== 0x00)
     64 		offset++;
     65 	assert.ok(offset < this._buffer.length, 'c string does not terminate');
     66 	var str = this._buffer.slice(this._offset, offset).toString();
     67 	this._offset = offset + 1;
     68 	return (str);
     69 };
     70 
     71 SSHBuffer.prototype.readInt = function () {
     72 	var v = this._buffer.readUInt32BE(this._offset);
     73 	this._offset += 4;
     74 	return (v);
     75 };
     76 
     77 SSHBuffer.prototype.readInt64 = function () {
     78 	assert.ok(this._offset + 8 < this._buffer.length,
     79 	    'buffer not long enough to read Int64');
     80 	var v = this._buffer.slice(this._offset, this._offset + 8);
     81 	this._offset += 8;
     82 	return (v);
     83 };
     84 
     85 SSHBuffer.prototype.readChar = function () {
     86 	var v = this._buffer[this._offset++];
     87 	return (v);
     88 };
     89 
     90 SSHBuffer.prototype.writeBuffer = function (buf) {
     91 	while (this._offset + 4 + buf.length > this._size)
     92 		this.expand();
     93 	this._buffer.writeUInt32BE(buf.length, this._offset);
     94 	this._offset += 4;
     95 	buf.copy(this._buffer, this._offset);
     96 	this._offset += buf.length;
     97 };
     98 
     99 SSHBuffer.prototype.writeString = function (str) {
    100 	this.writeBuffer(Buffer.from(str, 'utf8'));
    101 };
    102 
    103 SSHBuffer.prototype.writeCString = function (str) {
    104 	while (this._offset + 1 + str.length > this._size)
    105 		this.expand();
    106 	this._buffer.write(str, this._offset);
    107 	this._offset += str.length;
    108 	this._buffer[this._offset++] = 0;
    109 };
    110 
    111 SSHBuffer.prototype.writeInt = function (v) {
    112 	while (this._offset + 4 > this._size)
    113 		this.expand();
    114 	this._buffer.writeUInt32BE(v, this._offset);
    115 	this._offset += 4;
    116 };
    117 
    118 SSHBuffer.prototype.writeInt64 = function (v) {
    119 	assert.buffer(v, 'value');
    120 	if (v.length > 8) {
    121 		var lead = v.slice(0, v.length - 8);
    122 		for (var i = 0; i < lead.length; ++i) {
    123 			assert.strictEqual(lead[i], 0,
    124 			    'must fit in 64 bits of precision');
    125 		}
    126 		v = v.slice(v.length - 8, v.length);
    127 	}
    128 	while (this._offset + 8 > this._size)
    129 		this.expand();
    130 	v.copy(this._buffer, this._offset);
    131 	this._offset += 8;
    132 };
    133 
    134 SSHBuffer.prototype.writeChar = function (v) {
    135 	while (this._offset + 1 > this._size)
    136 		this.expand();
    137 	this._buffer[this._offset++] = v;
    138 };
    139 
    140 SSHBuffer.prototype.writePart = function (p) {
    141 	this.writeBuffer(p.data);
    142 };
    143 
    144 SSHBuffer.prototype.write = function (buf) {
    145 	while (this._offset + buf.length > this._size)
    146 		this.expand();
    147 	buf.copy(this._buffer, this._offset);
    148 	this._offset += buf.length;
    149 };