text: // Copyright 2015 Joyent, Inc.
  
  module.exports = SSHBuffer;
  
  var assert = require('assert-plus');
  
  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 || (new Buffer(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 = new Buffer(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(new Buffer(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;
  };
  