From 6274df7db5863bb2b07d9d4f46946fc8455f4547 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Mon, 3 Mar 2025 19:19:16 +0100
Subject: [PATCH] QTriangulator: make primeForCount() safer

Move all the helpers into the function so nothing else can call them
(out of contract).

As a drive-by, adjust the comment to mention this is Qt 5 QHash
snippets; Q6Hash is different these days.

Pick-to: 6.8 6.5
Coverity-Id: 11295
Change-Id: Id1a23030e325076d81592e351dfe804742a21a87
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
(cherry picked from commit 0a9d5bd4767d2dc5900707e23790d79e6f5e0bd0)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/gui/painting/qtriangulator.cpp | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/gui/painting/qtriangulator.cpp b/src/gui/painting/qtriangulator.cpp
index 17799cb0727..03900938744 100644
--- a/src/gui/painting/qtriangulator.cpp
+++ b/src/gui/painting/qtriangulator.cpp
@@ -404,21 +404,21 @@ T QMaxHeap<T>::pop()
 //                                 QInt64Hash                                 //
 //============================================================================//
 
-// Copied from qhash.cpp
-static const uchar prime_deltas[] = {
-    0,  0,  1,  3,  1,  5,  3,  3,  1,  9,  7,  5,  3, 17, 27,  3,
-    1, 29,  3, 21,  7, 17, 15,  9, 43, 35, 15,  0,  0,  0,  0,  0
-};
-
-// Copied from qhash.cpp
-static inline int primeForNumBits(int numBits)
-{
-    return (1 << numBits) + prime_deltas[numBits];
-}
-
 static inline int primeForCount(int count)
 {
     Q_ASSERT(count >= 0); // Q_PRE
+
+    // Copied from Qt 5 qhash.cpp
+    constexpr auto primeForNumBits = [](int numBits) -> int
+    {
+        constexpr uchar prime_deltas[] = {
+            0,  0,  1,  3,  1,  5,  3,  3,  1,  9,  7,  5,  3, 17, 27,  3,
+            1, 29,  3, 21,  7, 17, 15,  9, 43, 35, 15,  0,  0,  0,  0,  0
+        };
+
+        return (1 << numBits) + prime_deltas[numBits];
+    };
+
     int low = 0;
     int high = 32;
     for (int i = 0; i < 5; ++i) {