From f229bc0caaeda22bfbea9a5f9605b01c69e14cbc Mon Sep 17 00:00:00 2001
From: Gerhard Aigner <gerhard.aigner@gmail.com>
Date: Mon, 23 Dec 2024 07:48:32 +0100
Subject: [PATCH] Improve deleteat!(x,::Integer)

We only need to remove one element from a ChainedVector and can therefore special case the fact that if this element is a single entry in a chunk the chunk can be removed completely. This reliefs us from the slow `cleanup!()` call.
---
 src/chainedvector.jl | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/chainedvector.jl b/src/chainedvector.jl
index a5dd69e..3b08b4f 100644
--- a/src/chainedvector.jl
+++ b/src/chainedvector.jl
@@ -577,12 +577,19 @@ end
 Base.@propagate_inbounds function Base.deleteat!(A::ChainedVector, i::Integer)
     @boundscheck checkbounds(A, i)
     chunk, ix = index(A, i)
-    deleteat!(A.arrays[chunk], ix)
-    for j = chunk:length(A.inds)
+    lastchunk = length(A.inds)
+    if length(A.arrays[chunk]) == 1
+        deleteat!(A.arrays, chunk)
+        deleteat!(A.inds, chunk)
+        lastchunk -= 1
+        resize!(A.arrays, lastchunk)
+        resize!(A.inds, lastchunk)
+    else
+        deleteat!(A.arrays[chunk], ix)
+    end
+    for j = chunk:lastchunk
         @inbounds A.inds[j] -= 1
     end
-    # check if we should remove an empty chunk
-    cleanup!(A)
     return A
 end