Booleanize u64 objects.

src/circuit/boolean.rs

@@ -234,6 +234,36 @@ impl AllocatedBit {
     }
 }
 
+pub fn u64_into_allocated_bits_be<E: Engine, CS: ConstraintSystem<E>>(
+    mut cs: CS,
+    value: Option<u64>
+) -> Result<Vec<AllocatedBit>, SynthesisError>
+{
+    let values = match value {
+        Some(ref value) => {
+            let mut tmp = Vec::with_capacity(64);
+
+            for i in (0..64).rev() {
+                tmp.push(Some(*value >> i & 1 == 1));
+            }
+
+            tmp
+        },
+        None => {
+            vec![None; 64]
+        }
+    };
+
+    let bits = values.into_iter().enumerate().map(|(i, b)| {
+        AllocatedBit::alloc(
+            cs.namespace(|| format!("bit {}", i)),
+            b
+        )
+    }).collect::<Result<Vec<_>, SynthesisError>>()?;
+
+    Ok(bits)
+}
+
 pub fn field_into_allocated_bits_be<E: Engine, CS: ConstraintSystem<E>, F: PrimeField>(
     mut cs: CS,
     value: Option<F>
@@ -553,7 +583,8 @@ mod test {
     use super::{
         AllocatedBit,
         Boolean,
-        field_into_allocated_bits_be
+        field_into_allocated_bits_be,
+        u64_into_allocated_bits_be
     };
 
     #[test]
@@ -1175,6 +1206,27 @@ mod test {
         }
     }
 
+    #[test]
+    fn test_u64_into_allocated_bits_be() {
+        let mut cs = TestConstraintSystem::<Bls12>::new();
+
+        let bits = u64_into_allocated_bits_be(&mut cs, Some(17234652694787248421)).unwrap();
+
+        assert!(cs.is_satisfied());
+
+        assert_eq!(bits.len(), 64);
+
+        assert_eq!(bits[0].value.unwrap(), true);
+        assert_eq!(bits[1].value.unwrap(), true);
+        assert_eq!(bits[2].value.unwrap(), true);
+        assert_eq!(bits[3].value.unwrap(), false);
+        assert_eq!(bits[4].value.unwrap(), true);
+        assert_eq!(bits[5].value.unwrap(), true);
+        assert_eq!(bits[20].value.unwrap(), true);
+        assert_eq!(bits[21].value.unwrap(), false);
+        assert_eq!(bits[22].value.unwrap(), false);
+    }
+
     #[test]
     fn test_field_into_allocated_bits_be() {
         let mut cs = TestConstraintSystem::<Bls12>::new();