ParseFastack explained & tests

kcp2k/Assets/Tests/Editor/KcpTests.cs

@@ -159,6 +159,7 @@ void Output(byte[] data, int len) {}
  Assert.That(kcp.snd_buf[2], Is.EqualTo(three));
  }
 
+ // test with empty buffer
  [Test]
  public void ParseUna_Empty()
  {
@@ -172,6 +173,7 @@ void Output(byte[] data, int len) {}
  Assert.That(kcp.snd_buf.Count, Is.EqualTo(0));
  }
 
+ // test where no elements should be removed
  [Test]
  public void ParseUna_None()
  {
@@ -196,6 +198,7 @@ void Output(byte[] data, int len) {}
  Assert.That(kcp.snd_buf[2], Is.EqualTo(three));
  }
 
+ // test where some elements should be removed
  [Test]
  public void ParseUna_Some()
  {
@@ -219,6 +222,7 @@ void Output(byte[] data, int len) {}
  Assert.That(kcp.snd_buf[1], Is.EqualTo(three));
  }
 
+ // test where all elements should be removed
  [Test]
  public void ParseUna_All()
  {
@@ -240,6 +244,111 @@ void Output(byte[] data, int len) {}
  Assert.That(kcp.snd_buf.Count, Is.EqualTo(0));
  }
 
+ // test with no elements in send buffer
+ [Test]
+ public void ParseFastack_Empty()
+ {
+ void Output(byte[] data, int len) {}
+
+ // setup KCP
+ Kcp kcp = new Kcp(0, Output);
+
+ kcp.snd_una = 1; // == sn to ensure <= is checked
+ kcp.snd_nxt = 2; // sn + 1 to ensure < is checked
+
+ kcp.ParseFastack(1, 0);
+ Assert.That(kcp.snd_buf.Count, Is.EqualTo(0));
+ }
+
+ // test where no elements should be counted
+ [Test]
+ public void ParseFastAck_None()
+ {
+ void Output(byte[] data, int len) {}
+
+ // setup KCP
+ Kcp kcp = new Kcp(0, Output);
+
+ // insert three segments into send buffer
+ Segment one = new Segment{sn=2};
+ kcp.snd_buf.Add(one);
+ Segment two = new Segment{sn=3};
+ kcp.snd_buf.Add(two);
+ Segment three = new Segment{sn=4};
+ kcp.snd_buf.Add(three);
+
+ // sn needs to be between snd_una and snd_nxt
+ kcp.snd_una = 1; // == sn to ensure <= is checked
+ kcp.snd_nxt = 2; // sn + 1 to ensure < is checked
+
+ // only segments with seg.sn < sn should have their fastack incremented
+ // in this case, none
+ kcp.ParseFastack(1, 0);
+ Assert.That(kcp.snd_buf.Count, Is.EqualTo(3));
+ Assert.That(kcp.snd_buf[0].fastack, Is.EqualTo(0));
+ Assert.That(kcp.snd_buf[1].fastack, Is.EqualTo(0));
+ Assert.That(kcp.snd_buf[2].fastack, Is.EqualTo(0));
+ }
+
+ // test where some elements should be counted
+ [Test]
+ public void ParseFastAck_Some()
+ {
+ void Output(byte[] data, int len) {}
+
+ // setup KCP
+ Kcp kcp = new Kcp(0, Output);
+
+ // insert three segments into send buffer
+ Segment one = new Segment{sn=2};
+ kcp.snd_buf.Add(one);
+ Segment two = new Segment{sn=3};
+ kcp.snd_buf.Add(two);
+ Segment three = new Segment{sn=4};
+ kcp.snd_buf.Add(three);
+
+ // sn needs to be between snd_una and snd_nxt
+ kcp.snd_una = 3; // == sn to ensure <= is checked
+ kcp.snd_nxt = 4; // sn + 1 to ensure < is checked
+
+ // only segments with seg.sn < sn should have their fastack incremented
+ kcp.ParseFastack(3, 0);
+ Assert.That(kcp.snd_buf.Count, Is.EqualTo(3));
+ Assert.That(kcp.snd_buf[0].fastack, Is.EqualTo(1));
+ Assert.That(kcp.snd_buf[1].fastack, Is.EqualTo(0));
+ Assert.That(kcp.snd_buf[2].fastack, Is.EqualTo(0));
+ }
+
+ // test where all elements should be counted
+ [Test]
+ public void ParseFastAck_All()
+ {
+ void Output(byte[] data, int len) {}
+
+ // setup KCP
+ Kcp kcp = new Kcp(0, Output);
+
+ // insert three segments into send buffer
+ Segment one = new Segment{sn=2};
+ kcp.snd_buf.Add(one);
+ Segment two = new Segment{sn=3};
+ kcp.snd_buf.Add(two);
+ Segment three = new Segment{sn=4};
+ kcp.snd_buf.Add(three);
+
+ // sn needs to be between snd_una and snd_nxt
+ kcp.snd_una = 5; // == sn to ensure <= is checked
+ kcp.snd_nxt = 6; // sn + 1 to ensure < is checked
+
+ // only segments with seg.sn < sn should have their fastack incremented
+ // in this case, all
+ kcp.ParseFastack(5, 0);
+ Assert.That(kcp.snd_buf.Count, Is.EqualTo(3));
+ Assert.That(kcp.snd_buf[0].fastack, Is.EqualTo(1));
+ Assert.That(kcp.snd_buf[1].fastack, Is.EqualTo(1));
+ Assert.That(kcp.snd_buf[2].fastack, Is.EqualTo(1));
+ }
+
  // peek without any messages in the receive queue
  [Test]
  public void PeekSize_Empty()

kcp2k/Assets/kcp2k/kcp/Kcp.cs

@@ -410,8 +410,10 @@ internal void ParseUna(uint una)
  }
 
  // ikcp_parse_fastack
- void ParseFastack(uint sn, uint ts) // serial number, timestamp
+ internal void ParseFastack(uint sn, uint ts) // serial number, timestamp
  {
+ // sn needs to be between snd_una and snd_nxt
+ // if !(snd_una <= sn && sn < snd_nxt) return;
  if (Utils.TimeDiff(sn, snd_una) < 0)
  return;