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Diffstat (limited to 'source/application/main/include/AudioUtils.hpp')
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1 files changed, 171 insertions, 0 deletions
diff --git a/source/application/main/include/AudioUtils.hpp b/source/application/main/include/AudioUtils.hpp new file mode 100644 index 0000000..cba981d --- /dev/null +++ b/source/application/main/include/AudioUtils.hpp @@ -0,0 +1,171 @@ +/* + * 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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