spectrum example: Fix warnings about deprecated QList<T>::toSet()

Use std::unique() to obtain a sorted, unique list, fixing:
engine.cpp:572:49: warning: 'QSet<T> QList<T>::toSet() const [with T = int]' is deprecated: Use QSet<T>(list.begin(), list.end()) instead. [-Wdeprecated-declarations]
engine.cpp:579:43: warning: 'QSet<T> QList<T>::toSet() const [with T = int]' is deprecated: Use QSet<T>(list.begin(), list.end()) instead. [-Wdeprecated-declarations]

Change-Id: I7bc1b5ed4f3bf56897cc1e187833c11cb8560500
Reviewed-by: VaL Doroshchuk <valentyn.doroshchuk@qt.io>

1 files changed, 4 insertions, 2 deletions

diff --git a/examples/multimedia/spectrum/app/engine.cpp b/examples/multimedia/spectrum/app/engine.cpp
index fd977785b..d188259dc 100644
--- a/examples/multimedia/spectrum/app/engine.cpp
+++ b/examples/multimedia/spectrum/app/engine.cpp
@@ -569,15 +569,17 @@ bool Engine::selectFormat()
             sampleRatesList += m_audioInputDevice.supportedSampleRates();
 
         sampleRatesList += m_audioOutputDevice.supportedSampleRates();
-        sampleRatesList = sampleRatesList.toSet().toList(); // remove duplicates
         std::sort(sampleRatesList.begin(), sampleRatesList.end());
+        const auto uniqueRatesEnd = std::unique(sampleRatesList.begin(), sampleRatesList.end());
+        sampleRatesList.erase(uniqueRatesEnd, sampleRatesList.end());
         ENGINE_DEBUG << "Engine::initialize frequenciesList" << sampleRatesList;
 
         QList<int> channelsList;
         channelsList += m_audioInputDevice.supportedChannelCounts();
         channelsList += m_audioOutputDevice.supportedChannelCounts();
-        channelsList = channelsList.toSet().toList();
         std::sort(channelsList.begin(), channelsList.end());
+        const auto uniqueChannelsEnd = std::unique(channelsList.begin(), channelsList.end());
+        channelsList.erase(uniqueChannelsEnd, channelsList.end());
         ENGINE_DEBUG << "Engine::initialize channelsList" << channelsList;
 
         QAudioFormat format;