New multitouch-compatible touch system.

lib/wire/seqqueue.js

@@ -1,25 +1,61 @@
-function SeqQueue() {
-  this.queue = []
-  this.seq = 0
+function SeqQueue(size, maxWaiting) {
+  this.lo = 0
+  this.size = size
+  this.maxWaiting = maxWaiting
+  this.waiting = 0
+  this.list = new Array(size)
+  this.locked = true
+}
+
+SeqQueue.prototype.start = function(seq) {
+  this.locked = false
+  this.lo = seq
+  this.maybeConsume()
+}
+
+SeqQueue.prototype.stop = function() {
+  this.locked = true
+  this.maybeConsume()
 }
 
 SeqQueue.prototype.push = function(seq, handler) {
-  this.queue[seq] = handler
-  this.maybeDequeue()
+  if (seq >= this.size) {
+    return
+  }
+
+  this.list[seq] = handler
+  this.waiting += 1
+  this.maybeConsume()
 }
 
-SeqQueue.prototype.done = function(seq, handler) {
-  this.queue[seq] = handler
-  this.maybeDequeue()
-}
+SeqQueue.prototype.maybeConsume = function() {
+  if (this.locked) {
+    return
+  }
 
-SeqQueue.prototype.maybeDequeue = function() {
-  var handler
+  while (this.waiting) {
+    // Did we reach the end of the loop? If so, start from the beginning.
+    if (this.lo === this.size) {
+      this.lo = 0
+    }
 
-  while ((handler = this.queue[this.seq])) {
-    this.queue[this.seq] = void 0
-    handler()
-    this.seq += 1
+    var handler = this.list[this.lo]
+    // Have we received it yet?
+    if (handler) {
+      this.list[this.lo] = void 0
+      handler()
+      this.lo += 1
+      this.waiting -= 1
+    }
+    // Are we too much behind? If so, just move on.
+    else if (this.waiting >= this.maxWaiting) {
+      this.lo += 1
+      this.waiting -= 1
+    }
+    // We don't have it yet, stop.
+    else {
+      break
+    }
   }
 }