X-Git-Url: https://git.ralfj.de/rust-101.git/blobdiff_plain/63b086dfbd9a5e90700f595c2e6ef7ee10522559..e2374eed1c3ae8d0063138ea011e86bbd42473ab:/src/part08.rs?ds=sidebyside

diff --git a/src/part08.rs b/src/part08.rs
new file mode 100644
index 0000000..558bd62
--- /dev/null
+++ b/src/part08.rs
@@ -0,0 +1,79 @@
+use std::cmp;
+use std::ops;
+use std::fmt;
+use part05::BigInt;
+
+impl PartialEq for BigInt {
+    fn eq(&self, other: &BigInt) -> bool {
+        debug_assert!(self.test_invariant() && other.test_invariant());
+        self.data == other.data
+    }
+}
+
+fn call_eq() {
+    let b1 = BigInt::new(13);
+    let b2 = BigInt::new(37);
+    println!("b1 == b1: {} ; b1 == b2: {}; b1 != b2: {}", b1 == b1, b1 == b2, b1 != b2);
+}
+
+
+impl fmt::Debug for BigInt {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.data.fmt(f)
+    }
+}
+
+
+
+impl BigInt {
+    pub fn inc(&mut self, mut by: u64) {
+        panic!("Not yet implemented.");
+    }
+}
+
+
+#[test]
+fn test_inc() {
+    let mut b = BigInt::new(1337);
+    b.inc(1337);
+    assert!(b == BigInt::new(1337 + 1337));
+
+    b = BigInt::new(0);
+    assert_eq!(b, BigInt::from_vec(vec![0]));
+    b.inc(1 << 63);
+    assert_eq!(b, BigInt::from_vec(vec![1 << 63]));
+    b.inc(1 << 63);
+    assert_eq!(b, BigInt::from_vec(vec![0, 1]));
+    b.inc(1 << 63);
+    assert_eq!(b, BigInt::from_vec(vec![1 << 63, 1]));
+    b.inc(1 << 63);
+    assert_eq!(b, BigInt::from_vec(vec![0, 2]));
+}
+
+
+// Add with carry, returning the sum and the carry
+fn overflowing_add(a: u64, b: u64, carry: bool) -> (u64, bool) {
+    let sum = u64::wrapping_add(a, b);
+    if sum >= a {
+        panic!("First addition did not overflow. Not implemented.");
+    } else {
+        panic!("First addition *did* overflow. Not implemented.");
+    }
+}
+
+/*#[test]*/
+fn test_overflowing_add() {
+    assert_eq!(overflowing_add(10, 100, false), (110, false));
+    assert_eq!(overflowing_add(10, 100, true), (111, false));
+    assert_eq!(overflowing_add(1 << 63, 1 << 63, false), (0, true));
+    assert_eq!(overflowing_add(1 << 63, 1 << 63, true), (1, true));
+    assert_eq!(overflowing_add(1 << 63, (1 << 63) -1 , true), (0, true));
+}
+
+impl ops::Add for BigInt {
+    type Output = BigInt;
+    fn add(self, rhs: BigInt) -> Self::Output {
+        let mut result_vec:Vec<u64> = Vec::with_capacity(cmp::max(self.data.len(), rhs.data.len()));
+        panic!("Not yet implemented.");
+    }
+}