| /* |
| * 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); |
| } |
| |
| |
| 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 that will cover the whole length of the input, even if |
| * this means the last window is not a full window length. |
| */ |
| template<class T> |
| class FractionalSlidingWindow : 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); |
| } |
| |
| /** |
| * @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)); |
| } |
| } |
| }; |
| |
| |
| } /* namespace audio */ |
| } /* namespace app */ |
| } /* namespace arm */ |
| |
| #endif /* AUDIO_UTILS_HPP */ |