Revision bbd8efd2 Ganeti/HTools/PeerMap.hs

b/Ganeti/HTools/PeerMap.hs
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-- | Add or update (via a custom function) an element.
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addWith :: (Elem -> Elem -> Elem) -> Key -> Elem -> PeerMap -> PeerMap
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addWith fn k v lst =
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    let r = lookup k lst
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    in
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      case r of
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        Nothing -> insertBy pmCompare (k, v) lst
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        Just o -> insertBy pmCompare (k, fn o v) (remove k lst)
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    case lookup k lst of
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      Nothing -> insertBy pmCompare (k, v) lst
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      Just o -> insertBy pmCompare (k, fn o v) (remove k lst)
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-- | Create a PeerMap from an association list, with possible duplicates


  		





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accumArray :: (Elem -> Elem -> Elem) -- ^ function used to merge the elements


  		





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              -> [(Key, Elem)]       -- ^ source data


  		





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              -> PeerMap             -- ^ results


  		





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accumArray fn lst =


  		





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    case lst of


  		





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      [] -> empty


  		





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      (k, v):xs -> addWith fn k v $ accumArray fn xs


  		





  
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accumArray _  [] = empty


  		





  
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accumArray fn ((k, v):xs) = addWith fn k v $ accumArray fn xs


  		





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-- * Basic operations


  		





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  ......




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-- | Remove an element from a peermap


  		





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remove :: Key -> PeerMap -> PeerMap


  		





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remove k c = case c of


  		





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               [] -> []


  		





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               (x@(x', _)):xs -> if k == x' then xs


  		





  
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remove _ [] = []


  		





  
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remove k ((x@(x', _)):xs) = if k == x'


  		





  
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                            then xs


  		





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                            else x:remove k xs


  		





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-- | Find the maximum element.


  		





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-- Since this is a sorted list, we just get the value at the head of


  		





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-- the list, or zero for a null list


  		





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maxElem :: PeerMap -> Elem


  		





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maxElem c = if null c then 0 else snd . head $ c


  		





  
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maxElem (x:_) = snd x


  		





  
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maxElem _ = 0


  		












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