From 60fdac141d9667edf5cf0d08a2e1720748bac605 Mon Sep 17 00:00:00 2001
From: Ryan Pavlik <ryan.pavlik@collabora.com>
Date: Wed, 22 May 2019 16:09:43 -0500
Subject: [PATCH] Simplify IdList::Add(). NFC.

Offloads most of the work onto standard algorithms to make it
more self-evidently correct.
---
 src/dsc.h | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/dsc.h b/src/dsc.h
index a244be0b..042d1d02 100644
--- a/src/dsc.h
+++ b/src/dsc.h
@@ -399,16 +399,14 @@ public:
         if(n >= elemsAllocated) {
             ReserveMore((elemsAllocated + 32)*2 - n);
         }
-        auto newIndex = LowerBoundIndex(*t);
-        if (newIndex < n) {
-            H hm = elem[newIndex].h;
-            ssassert(hm.v != t->h.v, "Handle isn't unique");
-        }
-        int i = static_cast<int>(newIndex);
-        new(&elem[n]) T();
-        std::move_backward(elem + i, elem + n, elem + n + 1);
-        elem[i] = *t;
-        n++;
+        // Look to see if we already have something with the same handle value.
+        ssassert(FindByIdNoOops(t->h) == nullptr, "Handle isn't unique");
+
+        // Copy-construct at the end of the list.
+        new(&elem[n]) T(*t);
+        ++n;
+        // The item we just added is trivially sorted, so "merge"
+        std::inplace_merge(begin(), end() - 1, end(), Compare());
     }
 
     T *FindById(H h) {