Move ethcore files back into root.

util/src/vector.rs

@@ -0,0 +1,85 @@
+//! vector util functions
+
+use std::ptr;
+
+pub trait InsertSlice<T> {
+    fn insert_slice(&mut self, index: usize, elements: &[T]);
+}
+
+/// based on `insert` function implementation from standard library
+impl<T> InsertSlice<T> for Vec<T> {
+    fn insert_slice(&mut self, index: usize, elements: &[T]) {
+        let e_len = elements.len();
+        if e_len == 0 {
+            return;
+        }
+
+        let len = self.len();
+        assert!(index <= len);
+
+        // space for the new element
+        self.reserve(e_len);
+
+        unsafe {
+            {
+                let p = self.as_mut_ptr().offset(index as isize);
+                let ep = elements.as_ptr().offset(0);
+                // shift everything by e_len, to make space
+                ptr::copy(p, p.offset(e_len as isize), len - index);
+                // write new element
+                ptr::copy(ep, p, e_len); 
+            }
+            self.set_len(len + e_len);
+        }
+    }
+}
+
+/// Returns len of prefix shared with elem
+/// 
+/// ```rust
+///	extern crate ethcore_util as util;
+///	use util::vector::SharedPrefix;
+///	
+///	fn main () {
+///		let a = vec![1,2,3,3,5];
+///		let b = vec![1,2,3];
+///		assert_eq!(a.shared_prefix_len(&b), 3);
+///	}
+/// ```
+pub trait SharedPrefix <T> {
+	fn shared_prefix_len(&self, elem: &[T]) -> usize;
+}
+
+impl <T> SharedPrefix<T> for Vec<T> where T: Eq {
+	fn shared_prefix_len(&self, elem: &[T]) -> usize {
+		use std::cmp;
+		let len = cmp::min(self.len(), elem.len());
+		(0..len).take_while(|&i| self[i] == elem[i]).count()
+	}
+}
+
+#[cfg(test)]
+mod test {
+	use vector::SharedPrefix;
+
+	#[test]
+	fn test_shared_prefix() {
+		let a = vec![1,2,3,4,5,6];
+		let b = vec![4,2,3,4,5,6];
+		assert_eq!(a.shared_prefix_len(&b), 0);
+	}
+
+	#[test]
+	fn test_shared_prefix2() {
+		let a = vec![1,2,3,3,5];
+		let b = vec![1,2,3];
+		assert_eq!(a.shared_prefix_len(&b), 3);
+	}
+	
+	#[test]
+	fn test_shared_prefix3() {
+		let a = vec![1,2,3,4,5,6];
+		let b = vec![1,2,3,4,5,6];
+		assert_eq!(a.shared_prefix_len(&b), 6);
+	}
+}