-- | Benchmarking utilities. For example, functions for generating
-- random strings.
module Util.String where
import System.Random (mkStdGen, randomRs)
-- | Generate a number of fixed length strings where the content of
-- the strings are letters in ascending order.
asc :: Int -- ^ Length of each string
-> Int -- ^ Number of strings
-> [String]
asc strlen num = take num $ iterate (snd . inc) $ replicate strlen 'a'
where inc [] = (True, [])
inc (c:cs) = case inc cs of (True, cs') | c == 'z' -> (True, 'a' : cs')
| otherwise -> (False, succ c : cs')
(False, cs') -> (False, c : cs')
-- | Generate a number of fixed length strings where the content of
-- the strings are letters in random order.
rnd :: Int -- ^ Length of each string
-> Int -- ^ Number of strings
-> [String]
rnd strlen num = take num $ split $ randomRs ('a', 'z') $ mkStdGen 1234
where
split cs = case splitAt strlen cs of (str, cs') -> str : split cs'
-- | Generate a number of fixed length strings where the content of
-- the strings are letters in random order, different from rnd
rnd' :: Int -- ^ Length of each string
-> Int -- ^ Number of strings
-> [String]
rnd' strlen num = take num $ split $ randomRs ('a', 'z') $ mkStdGen 5678
where
split cs = case splitAt strlen cs of (str, cs') -> str : split cs'