Sync

Task/Variable-length-quantity/Haskell/variable-length-quantity-1.hs

@@ -0,0 +1,10 @@
+import Numeric
+
+to = flip showOct ""
+
+from = fst . head . readOct
+
+main = do
+	fancy 2097152
+	fancy 2097151
+		where fancy i = putStrLn $ to i ++ " <-> " ++ show (from $ to i)

Task/Variable-length-quantity/Haskell/variable-length-quantity-2.hs

@@ -0,0 +1,11 @@
+base = 8
+
+to 0 = []
+to i = to (div i base) ++ [mod i base]
+
+from = foldl1 (\x y -> x*base + y)
+
+main = do
+	fancy 2097152
+	fancy 2097151
+		where fancy i = putStrLn $ concatMap show (to i) ++ " <-> " ++ show (from $ to i)

Task/Variable-length-quantity/Racket/variable-length-quantity.rkt

@@ -0,0 +1,15 @@
+#lang racket
+
+(define (try n)
+  (printf "Original number: ~s (0x~x)\n" n n)
+  (define 4octets (integer->integer-bytes n 4 #f))
+  (printf "Octets: ~a (byte-string: ~s)\n"
+          (string-join (map (λ(o) (~r o #:base 16))
+                            (bytes->list 4octets))
+                       ":")
+          4octets)
+  (define m (integer-bytes->integer 4octets #f))
+  (printf "Back to a number: ~s (~a)\n"
+          m (if (= m n) "OK" "BAD")))
+
+(for-each try '(#x200000 #x1fffff))