node-postgres/test/writer-tests.js

require(__dirname + "/test-helper");

var BufferList = function() {
  this.buffers = [];
};

BufferList.prototype.add = function(buffer, front) {
  this.buffers[front ? "unshift" : "push"](buffer);
  return this;
};

BufferList.prototype.addInt16 = function(val, front) {
  return this.add(Buffer([(val >>> 8),(val >>> 0)]),front);
};

BufferList.prototype.getByteLength = function(initial) {
  return this.buffers.reduce(function(previous, current){
    return previous + current.length;
  },initial || 0);
};

BufferList.prototype.addInt32 = function(val, first) {
  return this.add(Buffer([
    (val >>> 24),
    (val >>> 16),
    (val >>> 8),
    (val >>> 0)
  ]),first);
};

BufferList.prototype.addCString = function(val) {
  return this.add(Buffer(val + '\0','utf8'));
};

BufferList.prototype.join = function(appendLength, char) {
  var length = this.getByteLength();
  if(appendLength) {
    this.addInt32(length+4, true);
    return this.join(false, char);
  }
  if(char) {
    this.buffers.unshift(Buffer(char,'utf8'));
    length++;
  }
  var result = Buffer(length);
  var index = 0;
  this.buffers.forEach(function(buffer) {
    buffer.copy(result, index, 0);
    index += buffer.length;
  });
  return result;
};

assert.equalBuffers = function(actual, expected) {
  if(actual.length != expected.length) {
    console.log(actual);
    console.log(expected);
    assert.equal(actual.length, expected.length);
  }
  for(var i = 0; i < actual.length; i++) {
    if(actual[i] != expected[i]) {
      console.log(actual);
      console.log(expected);
    }
    assert.equal(actual[i],expected[i]);
  }
}

BufferList.prototype.compare = function(expected) {
  var buf = this.join();
  assert.equalBuffers(buf, expected);
};

test('adds int16', function() {
  new BufferList().addInt16(5).compare([0, 5]);
});

test('adds two int16s', function() {
  new BufferList().addInt16(5).addInt16(3).compare([0,5,0,3]);
});

test('adds int32', function() {
  new BufferList().addInt32(1).compare([0,0,0,1]);
  new BufferList().addInt32(1).addInt32(3).compare([0,0,0,1,0,0,0,3]);
});

test('adds CStrings', function() {
  new BufferList().addCString('').compare([0]);
  new BufferList().addCString('!!').compare([33,33,0]);
  new BufferList().addCString('!').addCString('!').compare([33,0,33,0]);
});

test('computes length', function() {
  var buf = new BufferList().join(true);
  assert.equalBuffers(buf, [0,0,0,4]);
});

test('appends character', function() {
  var buf = new BufferList().join(false,'!');
  assert.equalBuffers(buf,[33]);
});

test('appends char and length', function() {
  var buf = new BufferList().join(true,'!');
  assert.equalBuffers(buf,[33,0,0,0,4]);
});

test('does complicated buffer', function() {
  var buf = new BufferList()
    .addInt32(1)
    .addInt16(2)
    .addCString('!')
    .join(true,'!');
  assert.equalBuffers(buf, [33, 0, 0, 0, 0x0c, 0, 0, 0, 1, 0, 2, 33, 0]);
});