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Diffstat (limited to 'samples/SpeechRecognition/include/SlidingWindow.hpp')
-rw-r--r-- | samples/SpeechRecognition/include/SlidingWindow.hpp | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/samples/SpeechRecognition/include/SlidingWindow.hpp b/samples/SpeechRecognition/include/SlidingWindow.hpp new file mode 100644 index 0000000000..791a0b7fc0 --- /dev/null +++ b/samples/SpeechRecognition/include/SlidingWindow.hpp @@ -0,0 +1,161 @@ +// +// Copyright © 2020 Arm Ltd and Contributors. All rights reserved. +// SPDX-License-Identifier: MIT +// + +#pragma once + +template<class T> +class SlidingWindow +{ +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; +public: + + /** + * Creates the window slider through the given data. + * + * @param data pointer to the data to slide through. + * @param dataSize size in T type elements wise. + * @param windowSize sliding window size in T type wise elements. + * @param 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; + + /** + * 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; + } + } + + /** + * 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); + } + + /** + * Resest the slider to the initial position. + */ + virtual void Reset() + { + m_count = 0; + } + + /** + * Resest the slider to the initial position. + */ + virtual size_t GetWindowSize() + { + return m_size; + } + + /** + * Resets the slider to the start of the new data. + * New data size MUST be the same as the old one. + * @param newStart pointer to the new data to slide through. + */ + virtual void Reset(T* newStart) + { + m_start = newStart; + Reset(); + } + + /** + * 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; + } + + /** + * 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 size_t NextWindowStartIndex() + { + return m_count == 0? 0: ((m_count) * m_stride); + } + + /** + * Go to given sliding window index. + * @param 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; + } + + /** + * Calculates whole number of times the window can stride through the given data. + * @return maximum number of strides. + */ + size_t TotalStrides() + { + if (m_size > m_dataSize) + { + return 0; + } + return ((m_dataSize - m_size)/m_stride); + } + + /** + * 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_size > this->m_dataSize) + { + return this->m_dataSize / this->m_size; + } + else + { + return ((this->m_dataSize - this->m_size)/ static_cast<float>(this->m_stride)); + } + + } + + /** + * Calculates the remaining data left to be processed + * @return The remaining unprocessed data + */ + int RemainingData() + { + return this->m_dataSize - this->NextWindowStartIndex(); + } +};
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