Rewrite against a newer cryptonum.

src/utils.rs

@@ -0,0 +1,41 @@
+use cryptonum::unsigned::*;
+use num::BigUint;
+
+pub trait TranslateNums {
+    fn from_num(x: BigUint) -> Self;
+    fn to_num(&self) -> BigUint;
+}
+
+macro_rules! from_biguint {
+    ($uname: ident, $size: expr) => {
+        impl TranslateNums for $uname {
+            fn from_num(x: BigUint) -> $uname {
+                let mut base_vec = x.to_bytes_be();
+                let target_bytes = $size / 8;
+
+                while target_bytes > base_vec.len() {
+                    base_vec.insert(0,0);
+                }
+
+                while base_vec.len() > target_bytes {
+                    base_vec.remove(0);
+                }
+
+                $uname::from_bytes(&base_vec)
+            }
+
+            fn to_num(&self) -> BigUint {
+                let bytes = self.to_bytes();
+                BigUint::from_bytes_be(&bytes)
+            }
+        }
+    };
+}
+
+from_biguint!(U512,   512);
+from_biguint!(U1024,  1024);
+from_biguint!(U2048,  2048);
+from_biguint!(U3072,  3072);
+from_biguint!(U4096,  4096);
+from_biguint!(U8192,  8192);
+from_biguint!(U15360, 15360);