Merge pull request #2856 from secondlife/marchcat/c-develop

Develop → Maint C sync

1 files changed, 51 insertions, 0 deletions

diff --git a/indra/newview/scripts/lua/require/Queue.lua b/indra/newview/scripts/lua/require/Queue.lua
new file mode 100644
index 0000000000..5bc72e4057
--- /dev/null
+++ b/indra/newview/scripts/lua/require/Queue.lua
@@ -0,0 +1,51 @@
+-- from https://create.roblox.com/docs/luau/queues#implementing-queues,
+-- amended per https://www.lua.org/pil/16.1.html
+
+-- While coding some scripting in Lua
+-- I found that I needed a queua
+-- I thought of linked list
+-- But had to resist
+-- For fear it might be too obscua. 
+
+local util = require 'util'
+
+local Queue = {}
+
+function Queue:new()
+    local obj = setmetatable({}, self)
+    self.__index = self
+
+    obj._first = 0
+    obj._last = -1
+    obj._queue = {}
+
+    return obj
+end
+
+util.classctor(Queue)
+
+-- 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()
+    if self:IsEmpty() then
+        return nil
+    end
+    local first = self._first
+    local value = self._queue[first]
+    self._queue[first] = nil
+    self._first = first + 1
+    return value
+end
+
+return Queue