Added needle methods for slices

Author: kennytm

src/liballoc/slice.rs

@@ -92,6 +92,7 @@ use core::cmp::Ordering::{self, Less};
 use core::mem::{self, size_of};
 use core::ptr;
 use core::{u8, u16, u32};
+use core::needle::{ext, Needle, Searcher, Consumer};
 
 use crate::borrow::ToOwned;
 use crate::boxed::Box;
@@ -485,6 +486,40 @@ impl<T> [T] {
         }
         buf
     }
+
+    /// Replaces all matches of a predicate with another slice.
+    #[unstable(feature = "slice_needle_methods", issue = "56345")]
+    #[inline]
+    #[must_use = "this returns the replaced slice as a new allocation, \
+                  without modifying the original"]
+    pub fn replace<'s: 'a, 'a, F>(&'s self, from: F, to: &'a [T]) -> Vec<T>
+    where
+        T: Clone,
+        F: Needle<&'a [T]>,
+        F::Searcher: Searcher<[T]>, // FIXME: RFC 2089
+        F::Consumer: Consumer<[T]>, // FIXME: RFC 2089
+    {
+        let mut result = Vec::with_capacity(self.len());
+        ext::replace_with(self, from, |_| to, |s| result.extend_from_slice(s));
+        result
+    }
+
+    /// Replaces first N matches of a predicate with another slice.
+    #[unstable(feature = "slice_needle_methods", issue = "56345")]
+    #[inline]
+    #[must_use = "this returns the replaced slice as a new allocation, \
+                  without modifying the original"]
+    pub fn replacen<'s: 'a, 'a, F>(&'s self, from: F, to: &'a [T], count: usize) -> Vec<T>
+    where
+        T: Clone,
+        F: Needle<&'a [T]>,
+        F::Searcher: Searcher<[T]>, // FIXME: RFC 2089
+        F::Consumer: Consumer<[T]>, // FIXME: RFC 2089
+    {
+        let mut result = Vec::with_capacity(self.len());
+        ext::replacen_with(self, from, |_| to, count, |s| result.extend_from_slice(s));
+        result
+    }
 }
 
 #[lang = "slice_u8_alloc"]

src/liballoc/tests/lib.rs

@@ -10,6 +10,7 @@
 #![feature(unboxed_closures)]
 #![feature(vecdeque_rotate)]
 #![feature(mut_str_needle_methods)]
+#![feature(slice_needle_methods)]
 
 use std::hash::{Hash, Hasher};
 use std::collections::hash_map::DefaultHasher;

src/liballoc/tests/slice.rs

@@ -5,6 +5,7 @@ use std::panic;
 use std::rc::Rc;
 use std::sync::atomic::{Ordering::Relaxed, AtomicUsize};
 use std::thread;
+use std::f64::NAN;
 
 use rand::{Rng, RngCore, thread_rng};
 use rand::seq::SliceRandom;
@@ -1655,3 +1656,60 @@ fn repeat_generic_slice() {
         vec![1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4]
     );
 }
+
+#[test]
+fn test_match_indices_simple() {
+    let haystack = &[1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 2.0, 3.0, 2.0, 4.0, 8.0][..];
+    let needle = &[2.0, 3.0][..];
+
+    assert_eq!(haystack.match_indices(needle).collect::<Vec<_>>(), vec![
+        (1, needle),
+        (8, needle),
+    ]);
+}
+
+#[test]
+fn test_match_indices_nan_haystack() {
+    let haystack = &[1.0, 2.0, NAN, 1.0, 2.0, NAN, 1.0, NAN, NAN, NAN, 2.0, 1.0, 2.0][..];
+    let needle = &[1.0, 2.0][..];
+
+    assert_eq!(haystack.match_indices(needle).collect::<Vec<_>>(), vec![
+        (0, needle),
+        (3, needle),
+        (11, needle),
+    ]);
+}
+
+#[test]
+fn test_match_indices_nan_needle() {
+    let haystack = &[1.0, 2.0, NAN, 1.0, 2.0, NAN, 1.0, NAN, NAN, NAN, 2.0, 1.0, 2.0][..];
+    let needle = &[1.0, 2.0][..];
+
+    assert_eq!(haystack.match_indices(needle).collect::<Vec<_>>(), vec![
+        (0, needle),
+        (3, needle),
+        (11, needle),
+    ]);
+}
+
+#[test]
+fn test_match_indices_negative_zero() {
+    let haystack = &[1.0, 2.0, NAN, 1.0, 2.0, NAN, 1.0, NAN, NAN, NAN, 2.0, 1.0, 2.0][..];
+    let needle = &[1.0, 2.0][..];
+
+    assert_eq!(haystack.match_indices(needle).collect::<Vec<_>>(), vec![
+        (0, needle),
+        (3, needle),
+        (11, needle),
+    ]);
+}
+
+#[test]
+fn test_replace() {
+    let haystack = &b" empowering everyone to build reliable and efficient software."[..];
+
+    assert_eq!(
+        haystack.replace(&b" e"[..], b" **E**"),
+        b" **E**mpowering **E**veryone to build reliable and **E**fficient software.".to_vec()
+    );
+}