MLECO-1868: Code static analyzer warnings fixes

Signed-off-by: alexander <alexander.efremov@arm.com>
Change-Id: Ie423e9cad3fabec6ab077ded7236813fe4933dea
diff --git a/source/application/main/include/Mfcc.hpp b/source/application/main/include/Mfcc.hpp
index 6379fab..dcafe62 100644
--- a/source/application/main/include/Mfcc.hpp
+++ b/source/application/main/include/Mfcc.hpp
@@ -52,7 +52,7 @@
         ~MfccParams() = default;
 
         /** @brief  String representation of parameters */
-        std::string Str();
+        std::string Str() const;
     };
 
     /**
@@ -100,7 +100,7 @@
                                         const float quantScale,
                                         const int quantOffset)
         {
-            this->_MfccComputePreFeature(audioData);
+            this->MfccComputePreFeature(audioData);
             float minVal = std::numeric_limits<T>::min();
             float maxVal = std::numeric_limits<T>::max();
 
@@ -154,7 +154,7 @@
          *              bank weights and adding them up to be placed into
          *              bins, according to the filter bank's first and last
          *              indices (pre-computed for each filter bank element
-         *              by _CreateMelFilterBank function).
+         *              by CreateMelFilterBank function).
          * @param[in]   fftVec                  Vector populated with FFT magnitudes.
          * @param[in]   melFilterBank           2D Vector with filter bank weights.
          * @param[in]   filterBankFilterFirst   Vector containing the first indices of filter bank
@@ -168,8 +168,8 @@
         virtual bool ApplyMelFilterBank(
             std::vector<float>&                 fftVec,
             std::vector<std::vector<float>>&    melFilterBank,
-            std::vector<int32_t>&               filterBankFilterFirst,
-            std::vector<int32_t>&               filterBankFilterLast,
+            std::vector<uint32_t>&               filterBankFilterFirst,
+            std::vector<uint32_t>&               filterBankFilterLast,
             std::vector<float>&                 melEnergies);
 
         /**
@@ -214,37 +214,37 @@
         std::vector<float>              _m_windowFunc;
         std::vector<std::vector<float>> _m_melFilterBank;
         std::vector<float>              _m_dctMatrix;
-        std::vector<int32_t>            _m_filterBankFilterFirst;
-        std::vector<int32_t>            _m_filterBankFilterLast;
+        std::vector<uint32_t>           _m_filterBankFilterFirst;
+        std::vector<uint32_t>           _m_filterBankFilterLast;
         bool                            _m_filterBankInitialised;
         arm::app::math::FftInstance     _m_fftInstance;
 
         /**
          * @brief       Initialises the filter banks and the DCT matrix. **/
-        void _InitMelFilterBank();
+        void InitMelFilterBank();
 
         /**
          * @brief       Signals whether the instance of MFCC has had its
          *              required buffers initialised.
          * @return      true if initialised, false otherwise.
          **/
-        bool _IsMelFilterBankInited();
+        bool IsMelFilterBankInited() const;
 
         /**
          * @brief       Create mel filter banks for MFCC calculation.
          * @return      2D vector of floats.
          **/
-        std::vector<std::vector<float>> _CreateMelFilterBank();
+        std::vector<std::vector<float>> CreateMelFilterBank();
 
         /**
          * @brief       Computes and populates internal memeber buffers used
          *              in MFCC feature calculation
          * @param[in]   audioData   1D vector of 16-bit audio data.
          */
-        void _MfccComputePreFeature(const std::vector<int16_t>& audioData);
+        void MfccComputePreFeature(const std::vector<int16_t>& audioData);
 
         /** @brief       Computes the magnitude from an interleaved complex array. */
-        void _ConvertToPowerSpectrum();
+        void ConvertToPowerSpectrum();
 
     };