Add support for scaling numbers by primitive types.

src/signed/scale.rs

@@ -0,0 +1,121 @@
+macro_rules! scale_impls
+{
+    ($base: ident, $big: ident) => {
+        scale_impls!($base, $big, u8);
+        scale_impls!($base, $big, u16);
+        scale_impls!($base, $big, u32);
+        scale_impls!($base, $big, u64);
+        scale_impls!($base, $big, usize);
+
+        scale_impls!($base, $big, scaled i8);
+        scale_impls!($base, $big, scaled i16);
+        scale_impls!($base, $big, scaled i32);
+        scale_impls!($base, $big, scaled i64);
+        scale_impls!($base, $big, scaled isize);
+    };
+    ($base: ident, $big: ident, $prim: ident) => {
+        impl Mul<$prim> for $base {
+            type Output = $big;
+
+            fn mul(self, factor: $prim) -> $big {
+                &self * factor
+            }
+        }
+
+        impl<'a> Mul<$prim> for &'a $base {
+            type Output = $big;
+
+            fn mul(self, factor: $prim) -> $big {
+                let mut res = $big::zero();
+                scale(&mut res.value.value, &self.value.value, factor as u64);
+                res.negative = self.negative && !res.value.is_zero();
+                res
+            }
+        }
+
+        impl Mul<$base> for $prim {
+            type Output = $big;
+
+            fn mul(self, rhs: $base) -> $big {
+                rhs.mul(self)
+            }
+        }
+
+        impl<'a> Mul<&'a $base> for $prim {
+            type Output = $big;
+
+            fn mul(self, rhs: &$base) -> $big {
+                rhs.mul(self)
+            }
+        }
+    };
+    ($base: ident, $big: ident, scaled $prim: ident) => {
+        impl Mul<$prim> for $base {
+            type Output = $big;
+
+            fn mul(self, factor: $prim) -> $big {
+                &self * factor
+            }
+        }
+
+        impl<'a> Mul<$prim> for &'a $base {
+            type Output = $big;
+
+            fn mul(self, factor: $prim) -> $big {
+                let mut res = $big::zero();
+                scale(&mut res.value.value, &self.value.value, factor.abs() as u64);
+                res.negative = (self.negative ^ (factor < 0)) && !res.value.is_zero();
+                res
+            }
+        }
+
+        impl Mul<$base> for $prim {
+            type Output = $big;
+
+            fn mul(self, rhs: $base) -> $big {
+                rhs.mul(self)
+            }
+        }
+
+        impl<'a> Mul<&'a $base> for $prim {
+            type Output = $big;
+
+            fn mul(self, rhs: &$base) -> $big {
+                rhs.mul(self)
+            }
+        }
+    };
+}
+
+#[cfg(test)]
+macro_rules! generate_sigscale_tests
+{
+    ($name: ident, $uname: ident, $lname: ident, $big: ident, $ubig: ident) => {
+        #[test]
+        fn $lname() {
+            generate_sigscale_tests!(body $name, $uname, $lname, $big, $ubig);
+        }
+    };
+    (ignore $name: ident, $uname:ident, $lname: ident, $big: ident, $ubig: ident) => {
+        #[test]
+        #[ignore]
+        fn $lname() {
+            generate_sigscale_tests!(body $name, $uname, $lname, $big, $ubig);
+        }
+    };
+    (body $name: ident, $uname: ident, $lname: ident, $big: ident, $ubig: ident) => {
+        let fname = build_test_path("sigscale", stringify!($name));
+        run_test(fname.to_string(), 3, |case| {
+            let (nega, abytes) = case.get("a").unwrap();
+            let (negb, bbytes) = case.get("b").unwrap();
+            let (negc, cbytes) = case.get("c").unwrap();
+
+            let a    = $name::new(*nega, $uname::from_bytes(abytes));
+            let bbig = $name::new(*negb, $uname::from_bytes(bbytes));
+            let c    = $big::new(*negc, $ubig::from_bytes(cbytes));
+            let b    = i64::from(&bbig);
+            let res = &a * b;
+            assert_eq!(c, res);
+        });
+    };
+}