Tweak kcp_parse_ack

src/kcp.rs

@@ -309,30 +309,23 @@ impl<W: Write> KCP<W> {
  }
 
  fn parse_ack(&mut self, sn: u32) {
- if timediff(sn, self.snd_una) < 0 || timediff(sn, self.snd_nxt) >= 0 {
+ if sn < self.snd_una || sn >= self.snd_nxt {
  return;
  }
- let mut index: usize = 0;
- let mut rm = false;
- for (i, seg) in self.snd_buf.iter().enumerate() {
- if sn == seg.sn {
- index = i;
- rm = true;
+ for i in 0..self.snd_buf.len() {
+ if sn == self.snd_buf[i].sn {
+ self.snd_buf.remove(i);
+ break;
+ } else if sn < self.snd_buf[i].sn {
  break;
  }
- if timediff(sn, seg.sn) < 0 {
- return;
- }
- }
- if rm {
- self.snd_buf.remove(index);
  }
  }
 
  fn parse_una(&mut self, una: u32) {
  let mut index: usize = 0;
  for seg in &self.snd_buf {
- if timediff(una, seg.sn) > 0 {
+ if una > seg.sn {
  index += 1;
  } else {
  break;
@@ -345,11 +338,11 @@ impl<W: Write> KCP<W> {
  }
 
  fn parse_fastack(&mut self, sn: u32) {
- if timediff(sn, self.snd_una) < 0 || timediff(sn, self.snd_nxt) >= 0 {
+ if sn < self.snd_una || sn >= self.snd_nxt {
  return;
  }
  for seg in &mut self.snd_buf {
- if timediff(sn, seg.sn) < 0 {
+ if sn < seg.sn {
  break;
  } else if sn != seg.sn {
  seg.fastack += 1;
@@ -359,20 +352,18 @@ impl<W: Write> KCP<W> {
 
  fn parse_data(&mut self, newseg: Segment) {
  let sn = newseg.sn;
- let mut repeat = false;
-
- if timediff(sn, self.rcv_nxt + self.rcv_wnd) >= 0 || timediff(sn, self.rcv_nxt) < 0 {
+ if sn >= self.rcv_nxt + self.rcv_wnd || sn < self.rcv_nxt {
  // ikcp_segment_delete(kcp, newseg);
  return;
  }
 
+ let mut repeat = false;
  let mut index: usize = self.rcv_buf.len();
  for seg in self.rcv_buf.iter().rev() {
- if seg.sn == sn {
+ if sn == seg.sn {
  repeat = true;
  break;
- }
- if timediff(sn, seg.sn) > 0 {
+ } else if sn > seg.sn {
  break;
  }
  index -= 1;
@@ -385,6 +376,7 @@ impl<W: Write> KCP<W> {
  }
 
  index = 0;
+ // move available data from rcv_buf -> rcv_queue
  for seg in &self.rcv_buf {
  if seg.sn == self.rcv_nxt && self.rcv_queue.len() < self.rcv_wnd as usize {
  self.rcv_nxt += 1;
@@ -444,24 +436,24 @@ impl<W: Write> KCP<W> {
  self.parse_una(una);
  self.shrink_buf();
  if cmd == KCP_CMD_ACK {
- let diff = timediff(self.current, ts);
- if diff >= 0 {
- self.update_ack(diff as u32);
+ let rtt = timediff(self.current, ts);
+ if rtt >= 0 {
+ self.update_ack(rtt as u32);
  }
  self.parse_ack(sn);
  self.shrink_buf();
  if !flag {
  flag = true;
  maxack = sn;
  } else {
- if timediff(sn, maxack) > 0 {
+ if sn > maxack {
  maxack = sn;
  }
  }
  } else if cmd == KCP_CMD_PUSH {
- if timediff(sn, self.rcv_nxt + self.rcv_wnd) < 0 {
+ if sn < self.rcv_nxt + self.rcv_wnd {
  self.acklist.push((sn, ts));
- if timediff(sn, self.rcv_nxt) >= 0 {
+ if sn >= self.rcv_nxt {
  let mut seg = Segment::new(len);
  seg.conv = conv;
  seg.cmd = cmd;
@@ -470,14 +462,13 @@ impl<W: Write> KCP<W> {
  seg.ts = ts;
  seg.sn = sn;
  seg.una = una;
-
- if len > 0 {
- seg.data.extend_from_slice(&data[p..p + len]);
- }
+ seg.data.extend_from_slice(&data[p..p + len]);
  self.parse_data(seg);
  }
  }
  } else if cmd == KCP_CMD_WASK {
+ // ready to send back KCP_CMD_WINS in `flush`
+ // tell remote my window size
  self.probe |= KCP_ASK_TELL;
  } else if cmd == KCP_CMD_WINS {
  // do nothing
@@ -492,7 +483,7 @@ impl<W: Write> KCP<W> {
  self.parse_fastack(maxack);
  }
 
- if timediff(self.snd_una, old_una) > 0 {
+ if self.snd_una > old_una {
  if self.cwnd < self.rmt_wnd {
  let mss = self.mss;
  if self.cwnd < self.ssthresh {
@@ -525,7 +516,7 @@ impl<W: Write> KCP<W> {
  }
 
  fn flush(&mut self) {
- // 'ikcp_update' haven't been called.
+ // `update` haven't been called.
  if !self.updated {
  return;
  }
@@ -538,11 +529,8 @@ impl<W: Write> KCP<W> {
 
  seg.conv = self.conv;
  seg.cmd = KCP_CMD_ACK;
- seg.frg = 0;
  seg.wnd = self.wnd_unused();
  seg.una = self.rcv_nxt;
- seg.sn = 0;
- seg.ts = 0;
 
  // flush acknowledges
  for ack in &self.acklist {
@@ -609,7 +597,7 @@ impl<W: Write> KCP<W> {
  }
 
  // move data from snd_queue to snd_buf
- while timediff(self.snd_nxt, self.snd_una + cwnd) < 0 {
+ while self.snd_nxt < self.snd_una + cwnd {
  if let Some(mut newseg) = self.snd_queue.pop_front() {
  newseg.conv = self.conv;
  newseg.cmd = KCP_CMD_PUSH;
@@ -724,6 +712,9 @@ impl<W: Write> KCP<W> {
  }
  }
 
+ // update state (call it repeatedly, every 10ms-100ms), or you can ask
+ // `check` when to call it again (without `input`/`send` calling).
+ // `current` - current timestamp in millisec.
  pub fn update(&mut self, current: u32) {
  self.current = current;
  if !self.updated {