From e30c1c3fbf8f70336d985b2b73e5b0f45f3b95f5 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Fri, 8 Jan 2021 01:39:02 +0300
Subject: Simplify highlighting infra

This also fixes the killer whale bug
---
 crates/stdx/src/lib.rs | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

(limited to 'crates/stdx')

diff --git a/crates/stdx/src/lib.rs b/crates/stdx/src/lib.rs
index 5332edb09..5aacdb16e 100644
--- a/crates/stdx/src/lib.rs
+++ b/crates/stdx/src/lib.rs
@@ -1,5 +1,5 @@
 //! Missing batteries for standard libraries.
-use std::{ops, process, time::Instant};
+use std::{cmp::Ordering, ops, process, time::Instant};
 
 mod macros;
 pub mod panic_context;
@@ -117,7 +117,12 @@ impl<'a> Iterator for LinesWithEnds<'a> {
     }
 }
 
-// https://github.com/rust-lang/rust/issues/73831
+/// Returns `idx` such that:
+///
+///     ∀ x in slice[..idx]:  pred(x)
+///  && ∀ x in slice[idx..]: !pred(x)
+///
+/// https://github.com/rust-lang/rust/issues/73831
 pub fn partition_point<T, P>(slice: &[T], mut pred: P) -> usize
 where
     P: FnMut(&T) -> bool,
@@ -147,6 +152,15 @@ where
     left
 }
 
+pub fn equal_range_by<T, F>(slice: &[T], mut key: F) -> (usize, usize)
+where
+    F: FnMut(&T) -> Ordering,
+{
+    let start = partition_point(slice, |it| key(it) == Ordering::Less);
+    let len = partition_point(&slice[start..], |it| key(it) == Ordering::Equal);
+    (start, len)
+}
+
 pub struct JodChild(pub process::Child);
 
 impl ops::Deref for JodChild {
-- 
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