Change almost all other uses of qrand() to QRandomGenerator

The vast majority is actually switched to QRandomGenerator::bounded(),
which gives a mostly uniform distribution over the [0, bound)
range. There are very few floating point cases left, as many of those
that did use floating point did not need to, after all. (I did leave
some that were too ugly for me to understand)

This commit also found a couple of calls to rand() instead of qrand().

This commit does not include changes to SSL code that continues to use
qrand() (job for someone else):
  src/network/ssl/qsslkey_qt.cpp
  src/network/ssl/qsslsocket_mac.cpp
  tests/auto/network/ssl/qsslsocket/tst_qsslsocket.cpp

Change-Id: Icd0e0d4b27cb4e5eb892fffd14b5285d43f4afbf
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

4 files changed, 6 insertions, 8 deletions

diff --git a/examples/corelib/threads/queuedcustomtype/main.cpp b/examples/corelib/threads/queuedcustomtype/main.cpp
index 7084b7538a..1f25fafa1b 100644
--- a/examples/corelib/threads/queuedcustomtype/main.cpp
+++ b/examples/corelib/threads/queuedcustomtype/main.cpp
@@ -126,7 +126,6 @@ int main(int argc, char *argv[])
 //! [main start] //! [register meta-type for queued communications]
     qRegisterMetaType<Block>();
 //! [register meta-type for queued communications]
-    qsrand(QTime::currentTime().elapsed());
 
     Window window;
     window.show();
diff --git a/examples/corelib/threads/queuedcustomtype/renderthread.cpp b/examples/corelib/threads/queuedcustomtype/renderthread.cpp
index f894dd587f..67cedf1e74 100644
--- a/examples/corelib/threads/queuedcustomtype/renderthread.cpp
+++ b/examples/corelib/threads/queuedcustomtype/renderthread.cpp
@@ -50,6 +50,8 @@
 
 #include "renderthread.h"
 
+#include <QRandomGenerator>
+
 RenderThread::RenderThread(QObject *parent)
     : QThread(parent)
 {
@@ -82,9 +84,9 @@ void RenderThread::run()
     for (int s = size; s > 0; --s) {
         for (int c = 0; c < 400; ++c) {
 //![processing the image (start)]
-            int x1 = qMax(0, (qrand() % m_image.width()) - s/2);
+            int x1 = qMax(0, QRandomGenerator::global()->bounded(m_image.width()) - s/2);
             int x2 = qMin(x1 + s/2 + 1, m_image.width());
-            int y1 = qMax(0, (qrand() % m_image.height()) - s/2);
+            int y1 = qMax(0, QRandomGenerator::global()->bounded(m_image.height()) - s/2);
             int y2 = qMin(y1 + s/2 + 1, m_image.height());
             int n = 0;
             int red = 0;
diff --git a/examples/corelib/threads/semaphores/semaphores.cpp b/examples/corelib/threads/semaphores/semaphores.cpp
index 37dd4cda20..145624bb0b 100644
--- a/examples/corelib/threads/semaphores/semaphores.cpp
+++ b/examples/corelib/threads/semaphores/semaphores.cpp
@@ -70,10 +70,9 @@ class Producer : public QThread
 public:
     void run() override
     {
-        qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
         for (int i = 0; i < DataSize; ++i) {
             freeBytes.acquire();
-            buffer[i % BufferSize] = "ACGT"[(int)qrand() % 4];
+            buffer[i % BufferSize] = "ACGT"[QRandomGenerator::global()->bounded(4)];
             usedBytes.release();
         }
     }
diff --git a/examples/corelib/threads/waitconditions/waitconditions.cpp b/examples/corelib/threads/waitconditions/waitconditions.cpp
index 9eab28f94c..963ee03a76 100644
--- a/examples/corelib/threads/waitconditions/waitconditions.cpp
+++ b/examples/corelib/threads/waitconditions/waitconditions.cpp
@@ -76,15 +76,13 @@ public:
 
     void run() override
     {
-        qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
-
         for (int i = 0; i < DataSize; ++i) {
             mutex.lock();
             if (numUsedBytes == BufferSize)
                 bufferNotFull.wait(&mutex);
             mutex.unlock();
 
-            buffer[i % BufferSize] = "ACGT"[(int)qrand() % 4];
+            buffer[i % BufferSize] = "ACGT"[QRandomGenerator::global()->bounded(4)];
 
             mutex.lock();
             ++numUsedBytes;