MLECO-2079 Adding the C++ KWS example

Signed-off-by: Eanna O Cathain <eanna.ocathain@arm.com>
Change-Id: I81899bbfaada32f478c2e2fc6441eabb94d8d0fc

1 files changed, 40 insertions, 0 deletions

diff --git a/samples/KeywordSpotting/src/DsCNNPreprocessor.cpp b/samples/KeywordSpotting/src/DsCNNPreprocessor.cpp
new file mode 100644
index 0000000000..8215feeeb5
--- /dev/null
+++ b/samples/KeywordSpotting/src/DsCNNPreprocessor.cpp
@@ -0,0 +1,40 @@
+//
+// Copyright © 2021 Arm Ltd and Contributors. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+#include <cmath>
+#include <numeric>
+#include <algorithm>
+#include <memory>
+#include "MathUtils.hpp"
+#include "SlidingWindow.hpp"
+#include "DsCNNPreprocessor.hpp"
+
+std::vector<int8_t> kws::DsCNNPreprocessor::Invoke(const float* audioData, size_t dataSize,
+                                                   int quantOffset, float quantScale) 
+{
+    auto window = SlidingWindow<const float>(
+            audioData, dataSize,
+            this->m_windowLen, this->m_windowStride);
+
+    uint32_t mfccBufIdx = 0;
+    std::vector<int8_t> outputBuffer;
+    // While we can slide over the window
+    while (window.HasNext()) 
+    {
+        const float* mfccWindow = window.Next();
+        auto mfccAudioData = std::vector<float>(mfccWindow, mfccWindow + this->m_windowLen);
+
+        auto mfcc = this->m_mfcc->MfccComputeQuant<int8_t>(mfccAudioData, quantScale, quantOffset);
+
+        std::copy(mfcc.begin(), mfcc.end(), std::back_inserter(outputBuffer));
+
+        ++mfccBufIdx;
+    }
+
+    return outputBuffer;
+}
+
+kws::DsCNNPreprocessor::DsCNNPreprocessor(const uint32_t windowLen, const uint32_t windowStride,
+                                          std::unique_ptr<DsCnnMFCC> mfccInst) :
+        m_windowLen{windowLen}, m_windowStride{windowStride}, m_mfcc{std::move(mfccInst)} {}