Data commit

Task/Binary-digits/Icon/binary-digits.icon

@@ -0,0 +1,23 @@
+procedure main()
+every i := 5 | 50 | 255 | 1285 | 9000 do
+  write(i," = ",binary(i))
+end
+
+procedure binary(n)                      #: return bitstring for integer n
+static CT, cm, cb
+initial {
+   CT := table()                         # cache table for results
+   cm := 2 ^ (cb := 4)                   # (tunable) cache modulus & pad bits
+   }
+
+b := ""                                  # build reversed bit string
+while n > 0 do {                         # use cached result ...
+   if not (b ||:= \CT[1(i := n % cm, n /:= cm) ]) then {
+      CT[j := i] := ""                   # ...or start new cache entry
+      while j > 0 do
+         CT[i] ||:=  "01"[ 1(1+j % 2, j /:= 2 )]
+      b ||:= CT[i] := left(CT[i],cb,"0") # finish cache with padding
+      }
+   }
+return reverse(trim(b,"0"))              # nothing extraneous
+end