1 files changed, 58 insertions, 0 deletions
diff --git a/vendor/crypto-bigint/src/uint/split.rs b/vendor/crypto-bigint/src/uint/split.rs
new file mode 100644
index 000000000..ecff9d6d8
--- /dev/null
+++ b/vendor/crypto-bigint/src/uint/split.rs
@@ -0,0 +1,58 @@
+// TODO(tarcieri): use `const_evaluatable_checked` when stable to make generic around bits.
+macro_rules! impl_split {
+    ($(($name:ident, $bits:expr)),+) => {
+        $(
+            impl $name {
+                /// Split this number in half, returning its high and low components
+                /// respectively.
+                pub const fn split(&self) -> (UInt<{nlimbs!($bits) / 2}>, UInt<{nlimbs!($bits) / 2}>) {
+                    let mut lo = [Limb::ZERO; nlimbs!($bits) / 2];
+                    let mut hi = [Limb::ZERO; nlimbs!($bits) / 2];
+                    let mut i = 0;
+                    let mut j = 0;
+
+                    while j < (nlimbs!($bits) / 2) {
+                        lo[j] = self.limbs[i];
+                        i += 1;
+                        j += 1;
+                    }
+
+                    j = 0;
+                    while j < (nlimbs!($bits) / 2) {
+                        hi[j] = self.limbs[i];
+                        i += 1;
+                        j += 1;
+                    }
+
+                    (UInt { limbs: hi }, UInt { limbs: lo })
+                }
+            }
+
+            impl Split for $name {
+                type Output = UInt<{nlimbs!($bits) / 2}>;
+
+                fn split(&self) -> (Self::Output, Self::Output) {
+                    self.split()
+                }
+            }
+
+            impl From<$name> for (UInt<{nlimbs!($bits) / 2}>, UInt<{nlimbs!($bits) / 2}>) {
+                fn from(num: $name) -> (UInt<{nlimbs!($bits) / 2}>, UInt<{nlimbs!($bits) / 2}>) {
+                    num.split()
+                }
+            }
+        )+
+     };
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{U128, U64};
+
+    #[test]
+    fn split() {
+        let (hi, lo) = U128::from_be_hex("00112233445566778899aabbccddeeff").split();
+        assert_eq!(hi, U64::from_u64(0x0011223344556677));
+        assert_eq!(lo, U64::from_u64(0x8899aabbccddeeff));
+    }
+}