text: // Copyright 2015 Joyent, Inc.
  
  module.exports = SSHBuffer;
  
  var assert = require('assert-plus-plus');
  var Buffer = require('safe-buffer').Buffer;
  
  function SSHBuffer(opts) {
  	assert.object(opts, 'options');
  	if (opts.buffer !== undefined)
  		assert.buffer(opts.buffer, 'options.buffer');
  
  	this._size = opts.buffer ? opts.buffer.length : 1024;
  	this._buffer = opts.buffer || Buffer.alloc(this._size);
  	this._offset = 0;
  }
  
  SSHBuffer.prototype.toBuffer = function () {
  	return (this._buffer.slice(0, this._offset));
  };
  
  SSHBuffer.prototype.atEnd = function () {
  	return (this._offset >= this._buffer.length);
  };
  
  SSHBuffer.prototype.remainder = function () {
  	return (this._buffer.slice(this._offset));
  };
  
  SSHBuffer.prototype.skip = function (n) {
  	this._offset += n;
  };
  
  SSHBuffer.prototype.expand = function () {
  	this._size *= 2;
  	var buf = Buffer.alloc(this._size);
  	this._buffer.copy(buf, 0);
  	this._buffer = buf;
  };
  
  SSHBuffer.prototype.readPart = function () {
  	return ({data: this.readBuffer()});
  };
  
  SSHBuffer.prototype.readBuffer = function () {
  	var len = this._buffer.readUInt32BE(this._offset);
  	this._offset += 4;
  	assert.ok(this._offset + len <= this._buffer.length,
  	    'length out of bounds at +0x' + this._offset.toString(16) +
  	    ' (data truncated?)');
  	var buf = this._buffer.slice(this._offset, this._offset + len);
  	this._offset += len;
  	return (buf);
  };
  
  SSHBuffer.prototype.readString = function () {
  	return (this.readBuffer().toString());
  };
  
  SSHBuffer.prototype.readCString = function () {
  	var offset = this._offset;
  	while (offset < this._buffer.length &&
  	    this._buffer[offset] !== 0x00)
  		offset++;
  	assert.ok(offset < this._buffer.length, 'c string does not terminate');
  	var str = this._buffer.slice(this._offset, offset).toString();
  	this._offset = offset + 1;
  	return (str);
  };
  
  SSHBuffer.prototype.readInt = function () {
  	var v = this._buffer.readUInt32BE(this._offset);
  	this._offset += 4;
  	return (v);
  };
  
  SSHBuffer.prototype.readInt64 = function () {
  	assert.ok(this._offset + 8 < this._buffer.length,
  	    'buffer not long enough to read Int64');
  	var v = this._buffer.slice(this._offset, this._offset + 8);
  	this._offset += 8;
  	return (v);
  };
  
  SSHBuffer.prototype.readChar = function () {
  	var v = this._buffer[this._offset++];
  	return (v);
  };
  
  SSHBuffer.prototype.writeBuffer = function (buf) {
  	while (this._offset + 4 + buf.length > this._size)
  		this.expand();
  	this._buffer.writeUInt32BE(buf.length, this._offset);
  	this._offset += 4;
  	buf.copy(this._buffer, this._offset);
  	this._offset += buf.length;
  };
  
  SSHBuffer.prototype.writeString = function (str) {
  	this.writeBuffer(Buffer.from(str, 'utf8'));
  };
  
  SSHBuffer.prototype.writeCString = function (str) {
  	while (this._offset + 1 + str.length > this._size)
  		this.expand();
  	this._buffer.write(str, this._offset);
  	this._offset += str.length;
  	this._buffer[this._offset++] = 0;
  };
  
  SSHBuffer.prototype.writeInt = function (v) {
  	while (this._offset + 4 > this._size)
  		this.expand();
  	this._buffer.writeUInt32BE(v, this._offset);
  	this._offset += 4;
  };
  
  SSHBuffer.prototype.writeInt64 = function (v) {
  	assert.buffer(v, 'value');
  	if (v.length > 8) {
  		var lead = v.slice(0, v.length - 8);
  		for (var i = 0; i < lead.length; ++i) {
  			assert.strictEqual(lead[i], 0,
  			    'must fit in 64 bits of precision');
  		}
  		v = v.slice(v.length - 8, v.length);
  	}
  	while (this._offset + 8 > this._size)
  		this.expand();
  	v.copy(this._buffer, this._offset);
  	this._offset += 8;
  };
  
  SSHBuffer.prototype.writeChar = function (v) {
  	while (this._offset + 1 > this._size)
  		this.expand();
  	this._buffer[this._offset++] = v;
  };
  
  SSHBuffer.prototype.writePart = function (p) {
  	this.writeBuffer(p.data);
  };
  
  SSHBuffer.prototype.write = function (buf) {
  	while (this._offset + buf.length > this._size)
  		this.expand();
  	buf.copy(this._buffer, this._offset);
  	this._offset += buf.length;
  };
  