Merge pull request #910 from secondlife/lua-queue

Add Queue.lua from roblox.com documentation.

1 files changed, 40 insertions, 0 deletions

diff --git a/indra/newview/scripts/lua/Queue.lua b/indra/newview/scripts/lua/Queue.lua
new file mode 100644
index 0000000000..e178ad9969
--- /dev/null
+++ b/indra/newview/scripts/lua/Queue.lua
@@ -0,0 +1,40 @@
+-- from https://create.roblox.com/docs/luau/queues#implementing-queues
+
+local Queue = {}
+Queue.__index = Queue
+
+function Queue.new()
+	local self = setmetatable({}, Queue)
+
+	self._first = 0
+	self._last = -1
+	self._queue = {}
+
+	return self
+end
+
+-- Check if the queue is empty
+function Queue:IsEmpty()
+	return self._first > self._last
+end
+
+-- Add a value to the queue
+function Queue:Enqueue(value)
+	local last = self._last + 1
+	self._last = last
+	self._queue[last] = value
+end
+
+-- Remove a value from the queue
+function Queue:Dequeue()
+	local first = self._first
+	if self:IsEmpty() then
+		return nil
+	end
+	local value = self._queue[first]
+	self._queue[first] = nil
+	self._first = first + 1
+	return value
+end
+
+return Queue