From 8a984ab772dd194e39094e728b869e65912912a7 Mon Sep 17 00:00:00 2001
From: Lars Knoll <lars.knoll@qt.io>
Date: Fri, 7 Feb 2020 13:15:50 +0100
Subject: [PATCH] Deduplicate some code
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Requires one more branch inside the loop, but that should not
really matter performance wise. And it should expand to less code.

Change-Id: I4619dd2a2e6fedf8d109009a5b6d7410ed89f1fb
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
---
 src/corelib/tools/qhash.h | 40 ++++++---------------------------------
 1 file changed, 6 insertions(+), 34 deletions(-)

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 6b0b6525ace..be2f1537fe4 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -439,33 +439,14 @@ struct Data
         spans = new Span[nSpans];
         seed = qGlobalQHashSeed();
     }
-    Data(const Data &other)
+    Data(const Data &other, size_t reserved = 0)
         : size(other.size),
           numBuckets(other.numBuckets),
           seed(other.seed)
     {
-        size_t nSpans = (other.numBuckets + Span::LocalBucketMask) / Span::NEntries;
-        spans = new Span[nSpans];
-
-        for (size_t s = 0; s < nSpans; ++s) {
-            const Span &span = other.spans[s];
-            for (size_t index = 0; index < Span::NEntries; ++index) {
-                if (!span.hasNode(index))
-                    continue;
-                const Node &n = span.at(index);
-                iterator it{ this, s*Span::NEntries + index };
-                Q_ASSERT(it.isUnused());
-
-                Node *newNode = spans[it.span()].insert(it.index());
-                new (newNode) Node(n);
-            }
-        }
-    }
-    Data(const Data &other, size_t reserved)
-        : size(other.size),
-          seed(other.seed)
-    {
-        numBuckets = GrowthPolicy::bucketsForCapacity(qMax(size, reserved));
+        if (reserved)
+            numBuckets = GrowthPolicy::bucketsForCapacity(qMax(size, reserved));
+        bool resized = numBuckets != other.numBuckets;
         size_t nSpans = (numBuckets + Span::LocalBucketMask) / Span::NEntries;
         spans = new Span[nSpans];
 
@@ -475,7 +456,7 @@ struct Data
                 if (!span.hasNode(index))
                     continue;
                 const Node &n = span.at(index);
-                iterator it = find(n.key);
+                iterator it = resized ? find(n.key) : iterator{ this, s*Span::NEntries + index };
                 Q_ASSERT(it.isUnused());
                 Node *newNode = spans[it.span()].insert(it.index());
                 new (newNode) Node(n);
@@ -483,16 +464,7 @@ struct Data
         }
     }
 
-    static Data *detached(Data *d)
-    {
-        if (!d)
-            return new Data;
-        Data *dd = new Data(*d);
-        if (!d->ref.deref())
-            delete d;
-        return dd;
-    }
-    static Data *detached(Data *d, size_t size)
+    static Data *detached(Data *d, size_t size = 0)
     {
         if (!d)
             return new Data(size);