starting working on faster buffer writer

test/unit/writer-tests.js

@@ -1,57 +1,121 @@
 require(__dirname + "/test-helper");
 
-
-BufferList.prototype.compare = function(expected) {
-  var buf = this.join();
-  assert.equalBuffers(buf, expected);
+var ElasticBuffer = function(size) {
+  this.size = size || 1024;
+  this.buffer = new Buffer(this.size);
+  this.offset = 0;
 };
 
-test('adds int16', function() {
-  new BufferList().addInt16(5).compare([0, 5]);
-});
+var p = ElasticBuffer.prototype;
 
-test('adds two int16s', function() {
-  new BufferList().addInt16(5).addInt16(3).compare([0,5,0,3]);
-});
+p._remaining = function() {
+  return this.buffer.length - this.offset;
+}
 
-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]);
-});
+p._resize = function() {
+  var oldBuffer = this.buffer;
+  this.buffer = Buffer(oldBuffer.length + this.size);
+  oldBuffer.copy(this.buffer);
+}
 
-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]);
-});
+//resizes internal buffer if not enough size left
+p._ensure = function(size) {
+  if(this._remaining() < size) {
+    this._resize()
+  }
+}
 
-test('computes length', function() {
-  var buf = new BufferList().join(true);
-  assert.equalBuffers(buf, [0,0,0,4]);
-});
+p.addInt32 = function(num) {
+  this._ensure(4)
+  this.buffer[this.offset++] = (num >>> 24 & 0xFF)
+  this.buffer[this.offset++] = (num >>> 16 & 0xFF)
+  this.buffer[this.offset++] = (num >>>  8 & 0xFF)
+  this.buffer[this.offset++] = (num >>>  0 & 0xFF)
+  return this;
+}
 
-test('appends character', function() {
-  var buf = new BufferList().join(false,'!');
-  assert.equalBuffers(buf,[33]);
-});
+p.addInt16 = function(num) {
+  this._ensure(2)
+  this.buffer[this.offset++] = (num >>>  8 & 0xFF)
+  this.buffer[this.offset++] = (num >>>  0 & 0xFF)
+  return this;
+}
 
-test('appends char and length', function() {
-  var buf = new BufferList().join(true,'!');
-  assert.equalBuffers(buf,[33,0,0,0,4]);
-});
+p.addCString = function(string) {
+  var string = string || "";
+  var len = Buffer.byteLength(string) + 1;
+  this._ensure(len);
+  
+}
 
-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]);
-});
+p.join = function() {
+  return this.buffer.slice(0, this.offset)
+}
 
-test('concats', function() {
-  var buf1 = new BufferList().addInt32(8).join(false,'!');
-  var buf2 = new BufferList().addInt16(1).join();
-  var result = BufferList.concat(buf1, buf2);
-  assert.equalBuffers(result, [33, 0, 0, 0, 8, 0, 1]);
-});
+test('adding int32', function() {
+  var testAddingInt32 = function(int, expectedBuffer) {
+    test('writes ' + int, function() {
+      var subject = new ElasticBuffer();
+      var result = subject.addInt32(int).join();
+      assert.equalBuffers(result, expectedBuffer);
+    })
+  }
+
+  testAddingInt32(0, [0, 0, 0, 0]);
+  testAddingInt32(1, [0, 0, 0, 1]);
+  testAddingInt32(256, [0, 0, 1, 0]);
+  test('writes largest int32', function() {
+    //todo need to find largest int32 when I have internet access
+    return false;
+  })
+
+  test('writing multiple int32s', function() {
+    var subject = new ElasticBuffer();
+    var result = subject.addInt32(1).addInt32(10).addInt32(0).join();
+    assert.equalBuffers(result, [0, 0, 0, 1, 0, 0, 0, 0x0a, 0, 0, 0, 0]);
+  })
+
+  test('having to resize the buffer', function() {
+    test('after resize correct result returned', function() {
+      var subject = new ElasticBuffer(10);
+      subject.addInt32(1).addInt32(1).addInt32(1)
+      assert.equalBuffers(subject.join(), [0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1])
+    })
+  })
+})
+
+test('int16', function() {
+  test('writes 0', function() {
+    var subject = new ElasticBuffer();
+    var result = subject.addInt16(0).join();
+    assert.equalBuffers(result, [0,0]);
+  })
+
+  test('writes 400', function() {
+    var subject = new ElasticBuffer();
+    var result = subject.addInt16(400).join();
+    assert.equalBuffers(result, [1, 0x90])
+  })
+
+  test('writes many', function() {
+    var subject = new ElasticBuffer();
+    var result = subject.addInt16(0).addInt16(1).addInt16(2).join();
+    assert.equalBuffers(result, [0, 0, 0, 1, 0, 2])
+  })
+
+  test('resizes if internal buffer fills up', function() {
+    var subject = new ElasticBuffer(3);
+    var result = subject.addInt16(2).addInt16(3).join();
+    assert.equalBuffers(result, [0, 2, 0, 3])
+  })
+
+})
+
+test('cString', function() {
+  test('writes empty cstring', function() {
+    var subject = new ElasticBuffer();
+    var result = subject.addCString().join();
+    assert.equalBuffers(result, [0])
+  })
+
+})