Ignore planet, use our own crc32.

crc32.rkt

@@ -1,6 +1,17 @@
 #lang racket
 
-(require (planet untyped/unlib/crc))
+; -- Taken from unlib/crc, under LGPL
+; http://planet.racket-lang.org/display.ss?package=unlib.plt&owner=untyped
+
+(define (crc32 data)
+  (bitwise-xor
+   (for/fold ([accum #xFFFFFFFF])
+     ([byte  (in-bytes data)])
+     (for/fold ([accum (bitwise-xor accum byte)])
+       ([num (in-range 0 8)])
+       (bitwise-xor (quotient accum 2)
+                    (* #xEDB88320 (bitwise-and accum 1)))))
+   #xFFFFFFFF))
 
 (define (string->crc32 s)
   (crc32 (string->bytes/utf-8 s)))
@@ -12,6 +23,7 @@
   (number->hex-string (string->crc32 s)))
 
 (provide/contract
+ [crc32 (-> bytes? natural-number/c)]
  [string->crc32 (-> string? natural-number/c)]
  [number->hex-string (-> number? any/c)]
  [string->crc32/hex (-> string? any/c)])