1 files changed, 69 insertions, 0 deletions
diff --git a/indra/newview/scripts/lua/require/util.lua b/indra/newview/scripts/lua/require/util.lua
new file mode 100644
index 0000000000..bfbfc8637c
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+++ b/indra/newview/scripts/lua/require/util.lua
@@ -0,0 +1,69 @@
+-- utility functions, in alpha order
+
+local util = {}
+
+-- Allow MyClass(ctor args...) equivalent to MyClass:new(ctor args...)
+-- Usage:
+-- local MyClass = {}
+-- function MyClass:new(...)
+--     ...
+-- end
+-- ...
+-- util.classctor(MyClass)
+-- or if your constructor is named something other than MyClass:new(), e.g.
+-- MyClass:construct():
+-- util.classctor(MyClass, MyClass.construct)
+-- return MyClass
+function util.classctor(class, ctor)
+    -- get the metatable for the passed class
+    local mt = getmetatable(class)
+    if mt == nil then
+        -- if it doesn't already have a metatable, then create one
+        mt = {}
+        setmetatable(class, mt)
+    end
+    -- now that class has a metatable, set its __call method to the specified
+    -- constructor method (class.new if not specified)
+    mt.__call = ctor or class.new
+end
+
+-- check if array-like table contains certain value
+function util.contains(t, v)
+    return table.find(t, v) ~= nil
+end
+
+-- reliable count of the number of entries in table t
+-- (since #t is unreliable)
+function util.count(t)
+    local count = 0
+    for _ in pairs(t) do
+        count += 1
+    end
+    return count
+end
+
+-- cheap test whether table t is empty
+function util.empty(t)
+    return not next(t)
+end
+
+-- recursive table equality
+function util.equal(t1, t2)
+    if not (type(t1) == 'table' and type(t2) == 'table') then
+        return t1 == t2
+    end
+    -- both t1 and t2 are tables: get modifiable copy of t2
+    local temp = table.clone(t2)
+    for k, v in pairs(t1) do
+        -- if any key in t1 doesn't have same value in t2, not equal
+        if not util.equal(v, temp[k]) then
+            return false
+        end
+        -- temp[k] == t1[k], delete temp[k]
+        temp[k] = nil
+    end
+    -- All keys in t1 have equal values in t2; t2 == t1 if there are no extra keys in t2
+    return util.empty(temp)
+end
+
+return util