1 files changed, 61 insertions, 0 deletions
diff --git a/src/Queue.js b/src/Queue.js
new file mode 100644
index 0000000..621c887
--- /dev/null
+++ b/src/Queue.js
@@ -0,0 +1,61 @@
+SVG.Queue = SVG.invent({
+  create: function () {
+    this._first = null
+    this._last = null
+  },
+
+  extend: {
+    push: function (value) {
+      // An item stores an id and the provided value
+      var item = value.next ? value : { value: value, next: null, prev: null }
+
+      // Deal with the queue being empty or populated
+      if (this._last) {
+        item.prev = this._last
+        this._last.next = item
+        this._last = item
+      } else {
+        this._last = item
+        this._first = item
+      }
+
+      // Update the length and return the current item
+      return item
+    },
+
+    shift: function () {
+      // Check if we have a value
+      var remove = this._first
+      if (!remove) return null
+
+      // If we do, remove it and relink things
+      this._first = remove.next
+      if (this._first) this._first.prev = null
+      this._last = this._first ? this._last : null
+      return remove.value
+    },
+
+    // Shows us the first item in the list
+    first: function () {
+      return this._first && this._first.value
+    },
+
+    // Shows us the last item in the list
+    last: function () {
+      return this._last && this._last.value
+    },
+
+    // Removes the item that was returned from the push
+    remove: function (item) {
+      // Relink the previous item
+      if (item.prev) item.prev.next = item.next
+      if (item.next) item.next.prev = item.prev
+      if (item === this._last) this._last = item.prev
+      if (item === this._first) this._first = item.next
+
+      // Invalidate item
+      item.prev = null
+      item.next = null
+    }
+  }
+})