diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright Author name here (c) 2017
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
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+[![Hackage](https://img.shields.io/hackage/v/stm-extras.svg)](https://hackage.haskell.org/package/stm-extras)
+[![Build Status](https://secure.travis-ci.org/louispan/stm-extras.png?branch=master)](http://travis-ci.org/louispan/stm-extras)
+
+Extra STM functions
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
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+import Distribution.Simple
+main = defaultMain
diff --git a/src/Control/Concurrent/STM/TMVar/Extras.hs b/src/Control/Concurrent/STM/TMVar/Extras.hs
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--- /dev/null
+++ b/src/Control/Concurrent/STM/TMVar/Extras.hs
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+module Control.Concurrent.STM.TMVar.Extras where
+
+import Control.Concurrent.STM
+import Control.Concurrent.STM.TMVar
+
+-- | Non-blocking swap of TMVar irreguardless if it previously contained a value or not.
+-- Returns what was in the TMVar (if exists)
+forceSwapTMVar :: TMVar a -> a -> STM (Maybe a)
+forceSwapTMVar v a = (Just <$> swapTMVar v a) `orElse` (const Nothing <$> putTMVar v a)
+
+-- | Block until TMVar is empty.
+-- The argument a is used to try to put into TMVar, but is taken out again in the same
+-- transaction
+waitTillEmptyTMVar :: TMVar a -> a -> STM ()
+waitTillEmptyTMVar v a = putTMVar v a >> takeTMVar v >> pure ()
+
+-- | Block until TMVar is full.
+waitTillFullTMVar :: TMVar a -> STM ()
+waitTillFullTMVar v = takeTMVar v >>= putTMVar v
diff --git a/stm-extras.cabal b/stm-extras.cabal
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--- /dev/null
+++ b/stm-extras.cabal
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+name:                stm-extras
+version:             0.1.0.0
+synopsis:            Extra STM functions
+description:         Please see README.md
+homepage:            https://github.com/louispan/stm-extras#readme
+license:             BSD3
+license-file:        LICENSE
+author:              Louis Pan
+maintainer:          louis@pan.me
+copyright:           2017 Louis Pan
+category:            Concurrency
+build-type:          Simple
+extra-source-files:  README.md
+cabal-version:       >=1.10
+tested-with:         GHC == 7.10.3, GHC == 8.0.1
+
+library
+  hs-source-dirs:      src
+  exposed-modules:     Control.Concurrent.STM.TMVar.Extras
+  build-depends:       base < 6
+                     , stm >= 2.4 && < 3
+  ghc-options:         -Wall
+  default-language:    Haskell2010
+
+source-repository head
+  type:     git
+  location: https://github.com/louispan/stm-extras