Opensource ML embedded evaluation kit
Change-Id: I12e807f19f5cacad7cef82572b6dd48252fd61fd
diff --git a/source/application/main/include/AudioUtils.hpp b/source/application/main/include/AudioUtils.hpp
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+/*
+ * Copyright (c) 2021 Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef AUDIO_UTILS_HPP
+#define AUDIO_UTILS_HPP
+
+#include <cstddef>
+#include <cstdint>
+
+namespace arm {
+namespace app {
+namespace audio {
+
+ template<class T>
+ class SlidingWindow {
+ public:
+
+ /**
+ * @brief Creates the window slider through the given data.
+ *
+ * @param[in] data Pointer to the data to slide through.
+ * @param[in] dataSize Size in T type elements wise.
+ * @param[in] windowSize Sliding window size in T type wise elements.
+ * @param[in] stride Stride size in T type wise elements.
+ */
+ SlidingWindow(T *data, size_t dataSize,
+ size_t windowSize, size_t stride) {
+ m_start = data;
+ m_dataSize = dataSize;
+ m_size = windowSize;
+ m_stride = stride;
+ }
+
+ SlidingWindow() = default;
+
+ ~SlidingWindow() = default;
+
+ /**
+ * @brief Get the next data window.
+ * @return Pointer to the next window, if next window is not available nullptr is returned.
+ */
+ virtual T *Next() {
+ if (HasNext()) {
+ m_count++;
+ return m_start + Index() * m_stride;
+ } else {
+ return nullptr;
+ }
+ }
+
+ /**
+ * @brief Checks if the next data portion is available.
+ * @return true if next data portion is available.
+ */
+ virtual bool HasNext() {
+ return m_size + m_count * m_stride <= m_dataSize;
+ }
+
+ /**
+ * @brief Reset the slider to the initial position.
+ */
+ virtual void Reset() {
+ m_count = 0;
+ }
+
+ /**
+ * @brief Resets the slider to the start of the new data.
+ * New data size MUST be the same as the old one.
+ * @param[in] newStart Pointer to the new data to slide through.
+ */
+ virtual void Reset(T *newStart) {
+ m_start = newStart;
+ Reset();
+ }
+
+ /**
+ * @brief Gets current index of the sliding window.
+ * @return Current position of the sliding window in number of strides.
+ */
+ size_t Index() {
+ return m_count == 0? 0: m_count - 1;
+ }
+
+ /**
+ * @brief Gets the index from the start of the data where the next window will begin.
+ * While Index() returns the index of sliding window itself this function
+ * returns the index of the data element itself.
+ * @return Index from the start of the data where the next sliding window will begin.
+ */
+ virtual uint32_t NextWindowStartIndex() {
+ return m_count == 0? 0: ((m_count) * m_stride);
+ }
+
+ /**
+ * @brief Go to given sliding window index.
+ * @param[in] index New position of the sliding window. If index is invalid
+ * (greater than possible range of strides) then next call to Next() will return nullptr.
+ */
+ void FastForward(size_t index) {
+ m_count = index;
+ }
+
+ /**
+ * @brief Calculates whole number of times the window can stride through the given data.
+ * @return Maximum number of whole strides.
+ */
+ size_t TotalStrides() {
+ if (m_size > m_dataSize) {
+ return 0;
+ }
+ return ((m_dataSize - m_size)/m_stride);
+ }
+
+ /**
+ * @brief Calculates number of times the window can stride through the given data.
+ * May not be a whole number.
+ * @return Number of strides to cover all data.
+ */
+ float FractionalTotalStrides() {
+ if (this->m_dataSize < this->m_size) {
+ return 0;
+ } else {
+ return ((this->m_dataSize - this->m_size)/ static_cast<float>(this->m_stride));
+ }
+ }
+
+ protected:
+ T *m_start = nullptr;
+ size_t m_dataSize = 0;
+ size_t m_size = 0;
+ size_t m_stride = 0;
+ size_t m_count = 0;
+ };
+
+ /*
+ * Sliding window for ASR will cover the whole of the input, even if
+ * this means the last window is not a full window length.
+ */
+ template<class T>
+ class ASRSlidingWindow : public SlidingWindow<T> {
+ public:
+ using SlidingWindow<T>::SlidingWindow;
+
+ /**
+ * @brief Checks if the next data portion is available.
+ * @return true if next data portion is available.
+ */
+ bool HasNext() {
+ return this->m_count < 1 + this->FractionalTotalStrides() && (this->NextWindowStartIndex() < this->m_dataSize);
+ }
+ };
+
+
+} /* namespace audio */
+} /* namespace app */
+} /* namespace arm */
+
+#endif /* AUDIO_UTILS_HPP */
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