root / src / Ganeti / Utils.hs @ 3e02cd3c
History | View | Annotate | Download (12.7 kB)
1 | 525bfb36 | Iustin Pop | {-| Utility functions. -} |
---|---|---|---|
2 | e4f08c46 | Iustin Pop | |
3 | e2fa2baf | Iustin Pop | {- |
4 | e2fa2baf | Iustin Pop | |
5 | a7f0953a | Iustin Pop | Copyright (C) 2009, 2010, 2011, 2012, 2013 Google Inc. |
6 | e2fa2baf | Iustin Pop | |
7 | e2fa2baf | Iustin Pop | This program is free software; you can redistribute it and/or modify |
8 | e2fa2baf | Iustin Pop | it under the terms of the GNU General Public License as published by |
9 | e2fa2baf | Iustin Pop | the Free Software Foundation; either version 2 of the License, or |
10 | e2fa2baf | Iustin Pop | (at your option) any later version. |
11 | e2fa2baf | Iustin Pop | |
12 | e2fa2baf | Iustin Pop | This program is distributed in the hope that it will be useful, but |
13 | e2fa2baf | Iustin Pop | WITHOUT ANY WARRANTY; without even the implied warranty of |
14 | e2fa2baf | Iustin Pop | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
15 | e2fa2baf | Iustin Pop | General Public License for more details. |
16 | e2fa2baf | Iustin Pop | |
17 | e2fa2baf | Iustin Pop | You should have received a copy of the GNU General Public License |
18 | e2fa2baf | Iustin Pop | along with this program; if not, write to the Free Software |
19 | e2fa2baf | Iustin Pop | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
20 | e2fa2baf | Iustin Pop | 02110-1301, USA. |
21 | e2fa2baf | Iustin Pop | |
22 | e2fa2baf | Iustin Pop | -} |
23 | e2fa2baf | Iustin Pop | |
24 | 26d62e4c | Iustin Pop | module Ganeti.Utils |
25 | ebf38064 | Iustin Pop | ( debug |
26 | ebf38064 | Iustin Pop | , debugFn |
27 | ebf38064 | Iustin Pop | , debugXy |
28 | ebf38064 | Iustin Pop | , sepSplit |
29 | ebf38064 | Iustin Pop | , stdDev |
30 | ebf38064 | Iustin Pop | , if' |
31 | ebf38064 | Iustin Pop | , select |
32 | ebf38064 | Iustin Pop | , applyIf |
33 | ebf38064 | Iustin Pop | , commaJoin |
34 | 79eef90b | Agata Murawska | , ensureQuoted |
35 | ebf38064 | Iustin Pop | , tryRead |
36 | ebf38064 | Iustin Pop | , formatTable |
37 | c3024b7e | René Nussbaumer | , printTable |
38 | ebf38064 | Iustin Pop | , parseUnit |
39 | 19e310cc | René Nussbaumer | , plural |
40 | 04edfc99 | Iustin Pop | , niceSort |
41 | 04edfc99 | Iustin Pop | , niceSortKey |
42 | 88a10df5 | Iustin Pop | , exitIfBad |
43 | 88a10df5 | Iustin Pop | , exitErr |
44 | 88a10df5 | Iustin Pop | , exitWhen |
45 | 88a10df5 | Iustin Pop | , exitUnless |
46 | 256e28c4 | Iustin Pop | , rStripSpace |
47 | 80a0546b | Michele Tartara | , newUUID |
48 | ace37e24 | Michele Tartara | , getCurrentTime |
49 | a6e054a8 | Iustin Pop | , getCurrentTimeUSec |
50 | b6aeda4a | Dato Simó | , clockTimeToString |
51 | b009f682 | Dato Simó | , chompPrefix |
52 | 9fb621af | Yiannis Tsiouris | , wrap |
53 | 9fb621af | Yiannis Tsiouris | , trim |
54 | 72747d91 | Iustin Pop | , defaultHead |
55 | 72747d91 | Iustin Pop | , exitIfEmpty |
56 | ebf38064 | Iustin Pop | ) where |
57 | e4f08c46 | Iustin Pop | |
58 | 256e28c4 | Iustin Pop | import Data.Char (toUpper, isAlphaNum, isDigit, isSpace) |
59 | 04edfc99 | Iustin Pop | import Data.Function (on) |
60 | 29ac5975 | Iustin Pop | import Data.List |
61 | e4f08c46 | Iustin Pop | |
62 | e4f08c46 | Iustin Pop | import Debug.Trace |
63 | e4f08c46 | Iustin Pop | |
64 | 88a10df5 | Iustin Pop | import Ganeti.BasicTypes |
65 | 80a0546b | Michele Tartara | import qualified Ganeti.Constants as C |
66 | 88a10df5 | Iustin Pop | import System.IO |
67 | 88a10df5 | Iustin Pop | import System.Exit |
68 | b6aeda4a | Dato Simó | import System.Time |
69 | 88a10df5 | Iustin Pop | |
70 | 9188aeef | Iustin Pop | -- * Debug functions |
71 | 9188aeef | Iustin Pop | |
72 | e4f08c46 | Iustin Pop | -- | To be used only for debugging, breaks referential integrity. |
73 | e4f08c46 | Iustin Pop | debug :: Show a => a -> a |
74 | e4f08c46 | Iustin Pop | debug x = trace (show x) x |
75 | e4f08c46 | Iustin Pop | |
76 | 525bfb36 | Iustin Pop | -- | Displays a modified form of the second parameter before returning |
77 | 525bfb36 | Iustin Pop | -- it. |
78 | adc5c176 | Iustin Pop | debugFn :: Show b => (a -> b) -> a -> a |
79 | adc5c176 | Iustin Pop | debugFn fn x = debug (fn x) `seq` x |
80 | adc5c176 | Iustin Pop | |
81 | 525bfb36 | Iustin Pop | -- | Show the first parameter before returning the second one. |
82 | adc5c176 | Iustin Pop | debugXy :: Show a => a -> b -> b |
83 | 05ff7a00 | Agata Murawska | debugXy = seq . debug |
84 | adc5c176 | Iustin Pop | |
85 | 525bfb36 | Iustin Pop | -- * Miscellaneous |
86 | 1b7cf8ca | Iustin Pop | |
87 | 61bbbed7 | Agata Murawska | -- | Apply the function if condition holds, otherwise use default value. |
88 | 61bbbed7 | Agata Murawska | applyIf :: Bool -> (a -> a) -> a -> a |
89 | 61bbbed7 | Agata Murawska | applyIf b f x = if b then f x else x |
90 | 61bbbed7 | Agata Murawska | |
91 | e4f08c46 | Iustin Pop | -- | Comma-join a string list. |
92 | e4f08c46 | Iustin Pop | commaJoin :: [String] -> String |
93 | e4f08c46 | Iustin Pop | commaJoin = intercalate "," |
94 | e4f08c46 | Iustin Pop | |
95 | 748d5d50 | Iustin Pop | -- | Split a list on a separator and return an array. |
96 | 748d5d50 | Iustin Pop | sepSplit :: Eq a => a -> [a] -> [[a]] |
97 | e4f08c46 | Iustin Pop | sepSplit sep s |
98 | ebf38064 | Iustin Pop | | null s = [] |
99 | ebf38064 | Iustin Pop | | null xs = [x] |
100 | ebf38064 | Iustin Pop | | null ys = [x,[]] |
101 | ebf38064 | Iustin Pop | | otherwise = x:sepSplit sep ys |
102 | ebf38064 | Iustin Pop | where (x, xs) = break (== sep) s |
103 | ebf38064 | Iustin Pop | ys = drop 1 xs |
104 | e4f08c46 | Iustin Pop | |
105 | 19e310cc | René Nussbaumer | -- | Simple pluralize helper |
106 | 19e310cc | René Nussbaumer | plural :: Int -> String -> String -> String |
107 | 19e310cc | René Nussbaumer | plural 1 s _ = s |
108 | 19e310cc | René Nussbaumer | plural _ _ p = p |
109 | 19e310cc | René Nussbaumer | |
110 | 79eef90b | Agata Murawska | -- | Ensure a value is quoted if needed. |
111 | 79eef90b | Agata Murawska | ensureQuoted :: String -> String |
112 | 79eef90b | Agata Murawska | ensureQuoted v = if not (all (\c -> isAlphaNum c || c == '.') v) |
113 | 79eef90b | Agata Murawska | then '\'':v ++ "'" |
114 | 79eef90b | Agata Murawska | else v |
115 | 79eef90b | Agata Murawska | |
116 | 9188aeef | Iustin Pop | -- * Mathematical functions |
117 | 9188aeef | Iustin Pop | |
118 | 185297fa | Iustin Pop | -- Simple and slow statistical functions, please replace with better |
119 | 185297fa | Iustin Pop | -- versions |
120 | e4f08c46 | Iustin Pop | |
121 | 525bfb36 | Iustin Pop | -- | Standard deviation function. |
122 | 4715711d | Iustin Pop | stdDev :: [Double] -> Double |
123 | 4715711d | Iustin Pop | stdDev lst = |
124 | 7570569e | Iustin Pop | -- first, calculate the list length and sum lst in a single step, |
125 | 7570569e | Iustin Pop | -- for performance reasons |
126 | 7570569e | Iustin Pop | let (ll', sx) = foldl' (\(rl, rs) e -> |
127 | 7570569e | Iustin Pop | let rl' = rl + 1 |
128 | 7570569e | Iustin Pop | rs' = rs + e |
129 | 7570569e | Iustin Pop | in rl' `seq` rs' `seq` (rl', rs')) (0::Int, 0) lst |
130 | 7570569e | Iustin Pop | ll = fromIntegral ll'::Double |
131 | 7570569e | Iustin Pop | mv = sx / ll |
132 | 7570569e | Iustin Pop | av = foldl' (\accu em -> let d = em - mv in accu + d * d) 0.0 lst |
133 | 4715711d | Iustin Pop | in sqrt (av / ll) -- stddev |
134 | dd4c56ed | Iustin Pop | |
135 | bfe6c954 | Guido Trotter | -- * Logical functions |
136 | bfe6c954 | Guido Trotter | |
137 | bfe6c954 | Guido Trotter | -- Avoid syntactic sugar and enhance readability. These functions are proposed |
138 | bfe6c954 | Guido Trotter | -- by some for inclusion in the Prelude, and at the moment they are present |
139 | bfe6c954 | Guido Trotter | -- (with various definitions) in the utility-ht package. Some rationale and |
140 | bfe6c954 | Guido Trotter | -- discussion is available at <http://www.haskell.org/haskellwiki/If-then-else> |
141 | bfe6c954 | Guido Trotter | |
142 | bfe6c954 | Guido Trotter | -- | \"if\" as a function, rather than as syntactic sugar. |
143 | bfe6c954 | Guido Trotter | if' :: Bool -- ^ condition |
144 | bfe6c954 | Guido Trotter | -> a -- ^ \"then\" result |
145 | bfe6c954 | Guido Trotter | -> a -- ^ \"else\" result |
146 | bfe6c954 | Guido Trotter | -> a -- ^ \"then\" or "else" result depending on the condition |
147 | bfe6c954 | Guido Trotter | if' True x _ = x |
148 | bfe6c954 | Guido Trotter | if' _ _ y = y |
149 | bfe6c954 | Guido Trotter | |
150 | 5b763470 | Iustin Pop | -- * Parsing utility functions |
151 | 5b763470 | Iustin Pop | |
152 | 525bfb36 | Iustin Pop | -- | Parse results from readsPrec. |
153 | 5b763470 | Iustin Pop | parseChoices :: (Monad m, Read a) => String -> String -> [(a, String)] -> m a |
154 | 5b763470 | Iustin Pop | parseChoices _ _ ((v, ""):[]) = return v |
155 | 5b763470 | Iustin Pop | parseChoices name s ((_, e):[]) = |
156 | 5b763470 | Iustin Pop | fail $ name ++ ": leftover characters when parsing '" |
157 | 5b763470 | Iustin Pop | ++ s ++ "': '" ++ e ++ "'" |
158 | 5b763470 | Iustin Pop | parseChoices name s _ = fail $ name ++ ": cannot parse string '" ++ s ++ "'" |
159 | 5b763470 | Iustin Pop | |
160 | 5b763470 | Iustin Pop | -- | Safe 'read' function returning data encapsulated in a Result. |
161 | 5b763470 | Iustin Pop | tryRead :: (Monad m, Read a) => String -> String -> m a |
162 | 5b763470 | Iustin Pop | tryRead name s = parseChoices name s $ reads s |
163 | c5f7412e | Iustin Pop | |
164 | 525bfb36 | Iustin Pop | -- | Format a table of strings to maintain consistent length. |
165 | c5f7412e | Iustin Pop | formatTable :: [[String]] -> [Bool] -> [[String]] |
166 | c5f7412e | Iustin Pop | formatTable vals numpos = |
167 | c5f7412e | Iustin Pop | let vtrans = transpose vals -- transpose, so that we work on rows |
168 | c5f7412e | Iustin Pop | -- rather than columns |
169 | c5f7412e | Iustin Pop | mlens = map (maximum . map length) vtrans |
170 | c5f7412e | Iustin Pop | expnd = map (\(flds, isnum, ml) -> |
171 | c5f7412e | Iustin Pop | map (\val -> |
172 | c5f7412e | Iustin Pop | let delta = ml - length val |
173 | c5f7412e | Iustin Pop | filler = replicate delta ' ' |
174 | c5f7412e | Iustin Pop | in if delta > 0 |
175 | c5f7412e | Iustin Pop | then if isnum |
176 | c5f7412e | Iustin Pop | then filler ++ val |
177 | c5f7412e | Iustin Pop | else val ++ filler |
178 | c5f7412e | Iustin Pop | else val |
179 | c5f7412e | Iustin Pop | ) flds |
180 | c5f7412e | Iustin Pop | ) (zip3 vtrans numpos mlens) |
181 | c5f7412e | Iustin Pop | in transpose expnd |
182 | 9b9da389 | Iustin Pop | |
183 | c3024b7e | René Nussbaumer | -- | Constructs a printable table from given header and rows |
184 | c3024b7e | René Nussbaumer | printTable :: String -> [String] -> [[String]] -> [Bool] -> String |
185 | c3024b7e | René Nussbaumer | printTable lp header rows isnum = |
186 | 2cdaf225 | Iustin Pop | unlines . map ((++) lp . (:) ' ' . unwords) $ |
187 | c3024b7e | René Nussbaumer | formatTable (header:rows) isnum |
188 | c3024b7e | René Nussbaumer | |
189 | 1cdcf8f3 | Iustin Pop | -- | Converts a unit (e.g. m or GB) into a scaling factor. |
190 | 1cdcf8f3 | Iustin Pop | parseUnitValue :: (Monad m) => String -> m Rational |
191 | 1cdcf8f3 | Iustin Pop | parseUnitValue unit |
192 | 1cdcf8f3 | Iustin Pop | -- binary conversions first |
193 | 1cdcf8f3 | Iustin Pop | | null unit = return 1 |
194 | 1cdcf8f3 | Iustin Pop | | unit == "m" || upper == "MIB" = return 1 |
195 | 1cdcf8f3 | Iustin Pop | | unit == "g" || upper == "GIB" = return kbBinary |
196 | 1cdcf8f3 | Iustin Pop | | unit == "t" || upper == "TIB" = return $ kbBinary * kbBinary |
197 | 1cdcf8f3 | Iustin Pop | -- SI conversions |
198 | 1cdcf8f3 | Iustin Pop | | unit == "M" || upper == "MB" = return mbFactor |
199 | 1cdcf8f3 | Iustin Pop | | unit == "G" || upper == "GB" = return $ mbFactor * kbDecimal |
200 | 1cdcf8f3 | Iustin Pop | | unit == "T" || upper == "TB" = return $ mbFactor * kbDecimal * kbDecimal |
201 | 1cdcf8f3 | Iustin Pop | | otherwise = fail $ "Unknown unit '" ++ unit ++ "'" |
202 | 1cdcf8f3 | Iustin Pop | where upper = map toUpper unit |
203 | 5850e990 | Iustin Pop | kbBinary = 1024 :: Rational |
204 | 5850e990 | Iustin Pop | kbDecimal = 1000 :: Rational |
205 | 1cdcf8f3 | Iustin Pop | decToBin = kbDecimal / kbBinary -- factor for 1K conversion |
206 | 1cdcf8f3 | Iustin Pop | mbFactor = decToBin * decToBin -- twice the factor for just 1K |
207 | 1cdcf8f3 | Iustin Pop | |
208 | 1cb92fac | Iustin Pop | -- | Tries to extract number and scale from the given string. |
209 | 1cb92fac | Iustin Pop | -- |
210 | 1cb92fac | Iustin Pop | -- Input must be in the format NUMBER+ SPACE* [UNIT]. If no unit is |
211 | 1cb92fac | Iustin Pop | -- specified, it defaults to MiB. Return value is always an integral |
212 | 1cb92fac | Iustin Pop | -- value in MiB. |
213 | 1cb92fac | Iustin Pop | parseUnit :: (Monad m, Integral a, Read a) => String -> m a |
214 | 1cb92fac | Iustin Pop | parseUnit str = |
215 | ebf38064 | Iustin Pop | -- TODO: enhance this by splitting the unit parsing code out and |
216 | ebf38064 | Iustin Pop | -- accepting floating-point numbers |
217 | 1cdcf8f3 | Iustin Pop | case (reads str::[(Int, String)]) of |
218 | ebf38064 | Iustin Pop | [(v, suffix)] -> |
219 | ebf38064 | Iustin Pop | let unit = dropWhile (== ' ') suffix |
220 | 1cdcf8f3 | Iustin Pop | in do |
221 | 1cdcf8f3 | Iustin Pop | scaling <- parseUnitValue unit |
222 | 1cdcf8f3 | Iustin Pop | return $ truncate (fromIntegral v * scaling) |
223 | ebf38064 | Iustin Pop | _ -> fail $ "Can't parse string '" ++ str ++ "'" |
224 | 88a10df5 | Iustin Pop | |
225 | 88a10df5 | Iustin Pop | -- | Unwraps a 'Result', exiting the program if it is a 'Bad' value, |
226 | 88a10df5 | Iustin Pop | -- otherwise returning the actual contained value. |
227 | 88a10df5 | Iustin Pop | exitIfBad :: String -> Result a -> IO a |
228 | 707cd3d7 | Helga Velroyen | exitIfBad msg (Bad s) = exitErr (msg ++ ": " ++ s) |
229 | 88a10df5 | Iustin Pop | exitIfBad _ (Ok v) = return v |
230 | 88a10df5 | Iustin Pop | |
231 | 88a10df5 | Iustin Pop | -- | Exits immediately with an error message. |
232 | 88a10df5 | Iustin Pop | exitErr :: String -> IO a |
233 | 88a10df5 | Iustin Pop | exitErr errmsg = do |
234 | 707cd3d7 | Helga Velroyen | hPutStrLn stderr $ "Error: " ++ errmsg |
235 | 88a10df5 | Iustin Pop | exitWith (ExitFailure 1) |
236 | 88a10df5 | Iustin Pop | |
237 | 88a10df5 | Iustin Pop | -- | Exits with an error message if the given boolean condition if true. |
238 | 88a10df5 | Iustin Pop | exitWhen :: Bool -> String -> IO () |
239 | 88a10df5 | Iustin Pop | exitWhen True msg = exitErr msg |
240 | 88a10df5 | Iustin Pop | exitWhen False _ = return () |
241 | 88a10df5 | Iustin Pop | |
242 | 88a10df5 | Iustin Pop | -- | Exits with an error message /unless/ the given boolean condition |
243 | 88a10df5 | Iustin Pop | -- if true, the opposite of 'exitWhen'. |
244 | 88a10df5 | Iustin Pop | exitUnless :: Bool -> String -> IO () |
245 | 88a10df5 | Iustin Pop | exitUnless cond = exitWhen (not cond) |
246 | 04edfc99 | Iustin Pop | |
247 | 04edfc99 | Iustin Pop | -- | Helper for 'niceSort'. Computes the key element for a given string. |
248 | 04edfc99 | Iustin Pop | extractKey :: [Either Integer String] -- ^ Current (partial) key, reversed |
249 | 04edfc99 | Iustin Pop | -> String -- ^ Remaining string |
250 | 04edfc99 | Iustin Pop | -> ([Either Integer String], String) |
251 | 04edfc99 | Iustin Pop | extractKey ek [] = (reverse ek, []) |
252 | 04edfc99 | Iustin Pop | extractKey ek xs@(x:_) = |
253 | 04edfc99 | Iustin Pop | let (span_fn, conv_fn) = if isDigit x |
254 | 04edfc99 | Iustin Pop | then (isDigit, Left . read) |
255 | 04edfc99 | Iustin Pop | else (not . isDigit, Right) |
256 | 04edfc99 | Iustin Pop | (k, rest) = span span_fn xs |
257 | 04edfc99 | Iustin Pop | in extractKey (conv_fn k:ek) rest |
258 | 04edfc99 | Iustin Pop | |
259 | 04edfc99 | Iustin Pop | {-| Sort a list of strings based on digit and non-digit groupings. |
260 | 04edfc99 | Iustin Pop | |
261 | 04edfc99 | Iustin Pop | Given a list of names @['a1', 'a10', 'a11', 'a2']@ this function |
262 | 04edfc99 | Iustin Pop | will sort the list in the logical order @['a1', 'a2', 'a10', 'a11']@. |
263 | 04edfc99 | Iustin Pop | |
264 | 04edfc99 | Iustin Pop | The sort algorithm breaks each name in groups of either only-digits or |
265 | 04edfc99 | Iustin Pop | no-digits, and sorts based on each group. |
266 | 04edfc99 | Iustin Pop | |
267 | 04edfc99 | Iustin Pop | Internally, this is not implemented via regexes (like the Python |
268 | 04edfc99 | Iustin Pop | version), but via actual splitting of the string in sequences of |
269 | 04edfc99 | Iustin Pop | either digits or everything else, and converting the digit sequences |
270 | 04edfc99 | Iustin Pop | in /Left Integer/ and the non-digit ones in /Right String/, at which |
271 | 04edfc99 | Iustin Pop | point sorting becomes trivial due to the built-in 'Either' ordering; |
272 | 04edfc99 | Iustin Pop | we only need one extra step of dropping the key at the end. |
273 | 04edfc99 | Iustin Pop | |
274 | 04edfc99 | Iustin Pop | -} |
275 | 04edfc99 | Iustin Pop | niceSort :: [String] -> [String] |
276 | a7f0953a | Iustin Pop | niceSort = niceSortKey id |
277 | 04edfc99 | Iustin Pop | |
278 | 04edfc99 | Iustin Pop | -- | Key-version of 'niceSort'. We use 'sortBy' and @compare `on` fst@ |
279 | 04edfc99 | Iustin Pop | -- since we don't want to add an ordering constraint on the /a/ type, |
280 | 04edfc99 | Iustin Pop | -- hence the need to only compare the first element of the /(key, a)/ |
281 | 04edfc99 | Iustin Pop | -- tuple. |
282 | 04edfc99 | Iustin Pop | niceSortKey :: (a -> String) -> [a] -> [a] |
283 | 04edfc99 | Iustin Pop | niceSortKey keyfn = |
284 | 04edfc99 | Iustin Pop | map snd . sortBy (compare `on` fst) . |
285 | 04edfc99 | Iustin Pop | map (\s -> (fst . extractKey [] $ keyfn s, s)) |
286 | 256e28c4 | Iustin Pop | |
287 | 256e28c4 | Iustin Pop | -- | Strip space characthers (including newline). As this is |
288 | 256e28c4 | Iustin Pop | -- expensive, should only be run on small strings. |
289 | 256e28c4 | Iustin Pop | rStripSpace :: String -> String |
290 | 256e28c4 | Iustin Pop | rStripSpace = reverse . dropWhile isSpace . reverse |
291 | 80a0546b | Michele Tartara | |
292 | 80a0546b | Michele Tartara | -- | Returns a random UUID. |
293 | 80a0546b | Michele Tartara | -- This is a Linux-specific method as it uses the /proc filesystem. |
294 | 80a0546b | Michele Tartara | newUUID :: IO String |
295 | 80a0546b | Michele Tartara | newUUID = do |
296 | 80a0546b | Michele Tartara | contents <- readFile C.randomUuidFile |
297 | 37dfcacb | Iustin Pop | return $! rStripSpace $ take 128 contents |
298 | b6aeda4a | Dato Simó | |
299 | a6e054a8 | Iustin Pop | -- | Returns the current time as an 'Integer' representing the number |
300 | a6e054a8 | Iustin Pop | -- of seconds from the Unix epoch. |
301 | ace37e24 | Michele Tartara | getCurrentTime :: IO Integer |
302 | ace37e24 | Michele Tartara | getCurrentTime = do |
303 | ace37e24 | Michele Tartara | TOD ctime _ <- getClockTime |
304 | ace37e24 | Michele Tartara | return ctime |
305 | ace37e24 | Michele Tartara | |
306 | a6e054a8 | Iustin Pop | -- | Returns the current time as an 'Integer' representing the number |
307 | a6e054a8 | Iustin Pop | -- of microseconds from the Unix epoch (hence the need for 'Integer'). |
308 | a6e054a8 | Iustin Pop | getCurrentTimeUSec :: IO Integer |
309 | a6e054a8 | Iustin Pop | getCurrentTimeUSec = do |
310 | a6e054a8 | Iustin Pop | TOD ctime pico <- getClockTime |
311 | a6e054a8 | Iustin Pop | -- pico: 10^-12, micro: 10^-6, so we have to shift seconds left and |
312 | a6e054a8 | Iustin Pop | -- picoseconds right |
313 | a6e054a8 | Iustin Pop | return $ ctime * 1000000 + pico `div` 1000000 |
314 | a6e054a8 | Iustin Pop | |
315 | b6aeda4a | Dato Simó | -- | Convert a ClockTime into a (seconds-only) timestamp. |
316 | b6aeda4a | Dato Simó | clockTimeToString :: ClockTime -> String |
317 | b6aeda4a | Dato Simó | clockTimeToString (TOD t _) = show t |
318 | b009f682 | Dato Simó | |
319 | b009f682 | Dato Simó | {-| Strip a prefix from a string, allowing the last character of the prefix |
320 | b009f682 | Dato Simó | (which is assumed to be a separator) to be absent from the string if the string |
321 | b009f682 | Dato Simó | terminates there. |
322 | b009f682 | Dato Simó | |
323 | 0e42ef67 | Michele Tartara | \>>> chompPrefix \"foo:bar:\" \"a:b:c\" |
324 | b009f682 | Dato Simó | Nothing |
325 | b009f682 | Dato Simó | |
326 | 0e42ef67 | Michele Tartara | \>>> chompPrefix \"foo:bar:\" \"foo:bar:baz\" |
327 | 0e42ef67 | Michele Tartara | Just \"baz\" |
328 | b009f682 | Dato Simó | |
329 | 0e42ef67 | Michele Tartara | \>>> chompPrefix \"foo:bar:\" \"foo:bar:\" |
330 | 0e42ef67 | Michele Tartara | Just \"\" |
331 | b009f682 | Dato Simó | |
332 | 0e42ef67 | Michele Tartara | \>>> chompPrefix \"foo:bar:\" \"foo:bar\" |
333 | 0e42ef67 | Michele Tartara | Just \"\" |
334 | b009f682 | Dato Simó | |
335 | 0e42ef67 | Michele Tartara | \>>> chompPrefix \"foo:bar:\" \"foo:barbaz\" |
336 | b009f682 | Dato Simó | Nothing |
337 | b009f682 | Dato Simó | -} |
338 | b009f682 | Dato Simó | chompPrefix :: String -> String -> Maybe String |
339 | b009f682 | Dato Simó | chompPrefix pfx str = |
340 | b009f682 | Dato Simó | if pfx `isPrefixOf` str || str == init pfx |
341 | b009f682 | Dato Simó | then Just $ drop (length pfx) str |
342 | b009f682 | Dato Simó | else Nothing |
343 | 9fb621af | Yiannis Tsiouris | |
344 | 9fb621af | Yiannis Tsiouris | -- | Breaks a string in lines with length \<= maxWidth. |
345 | 9fb621af | Yiannis Tsiouris | -- |
346 | 9fb621af | Yiannis Tsiouris | -- NOTE: The split is OK if: |
347 | 9fb621af | Yiannis Tsiouris | -- |
348 | 9fb621af | Yiannis Tsiouris | -- * It doesn't break a word, i.e. the next line begins with space |
349 | 9fb621af | Yiannis Tsiouris | -- (@isSpace . head $ rest@) or the current line ends with space |
350 | 9fb621af | Yiannis Tsiouris | -- (@null revExtra@); |
351 | 9fb621af | Yiannis Tsiouris | -- |
352 | 9fb621af | Yiannis Tsiouris | -- * It breaks a very big word that doesn't fit anyway (@null revLine@). |
353 | 9fb621af | Yiannis Tsiouris | wrap :: Int -- ^ maxWidth |
354 | 9fb621af | Yiannis Tsiouris | -> String -- ^ string that needs wrapping |
355 | 9fb621af | Yiannis Tsiouris | -> [String] -- ^ string \"broken\" in lines |
356 | 9fb621af | Yiannis Tsiouris | wrap maxWidth = filter (not . null) . map trim . wrap0 |
357 | 9fb621af | Yiannis Tsiouris | where wrap0 :: String -> [String] |
358 | 9fb621af | Yiannis Tsiouris | wrap0 text |
359 | 9fb621af | Yiannis Tsiouris | | length text <= maxWidth = [text] |
360 | 9fb621af | Yiannis Tsiouris | | isSplitOK = line : wrap0 rest |
361 | 9fb621af | Yiannis Tsiouris | | otherwise = line' : wrap0 rest' |
362 | 9fb621af | Yiannis Tsiouris | where (line, rest) = splitAt maxWidth text |
363 | 9fb621af | Yiannis Tsiouris | (revExtra, revLine) = break isSpace . reverse $ line |
364 | 9fb621af | Yiannis Tsiouris | (line', rest') = (reverse revLine, reverse revExtra ++ rest) |
365 | 9fb621af | Yiannis Tsiouris | isSplitOK = |
366 | 9fb621af | Yiannis Tsiouris | null revLine || null revExtra || startsWithSpace rest |
367 | 9fb621af | Yiannis Tsiouris | startsWithSpace (x:_) = isSpace x |
368 | 9fb621af | Yiannis Tsiouris | startsWithSpace _ = False |
369 | 9fb621af | Yiannis Tsiouris | |
370 | 9fb621af | Yiannis Tsiouris | -- | Removes surrounding whitespace. Should only be used in small |
371 | 9fb621af | Yiannis Tsiouris | -- strings. |
372 | 9fb621af | Yiannis Tsiouris | trim :: String -> String |
373 | 9fb621af | Yiannis Tsiouris | trim = reverse . dropWhile isSpace . reverse . dropWhile isSpace |
374 | 72747d91 | Iustin Pop | |
375 | 72747d91 | Iustin Pop | -- | A safer head version, with a default value. |
376 | 72747d91 | Iustin Pop | defaultHead :: a -> [a] -> a |
377 | 72747d91 | Iustin Pop | defaultHead def [] = def |
378 | 72747d91 | Iustin Pop | defaultHead _ (x:_) = x |
379 | 72747d91 | Iustin Pop | |
380 | 72747d91 | Iustin Pop | -- | A 'head' version in the I/O monad, for validating parameters |
381 | 72747d91 | Iustin Pop | -- without which we cannot continue. |
382 | 72747d91 | Iustin Pop | exitIfEmpty :: String -> [a] -> IO a |
383 | 72747d91 | Iustin Pop | exitIfEmpty _ (x:_) = return x |
384 | 72747d91 | Iustin Pop | exitIfEmpty s [] = exitErr s |