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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 ASR_WAV2LETTER_POSTPROCESS_HPP
#define ASR_WAV2LETTER_POSTPROCESS_HPP
#include "TensorFlowLiteMicro.hpp" /* TensorFlow headers. */
#include "hal.h" /* stdout facility. */
namespace arm {
namespace app {
namespace audio {
namespace asr {
/**
* @brief Helper class to manage tensor post-processing for "wav2letter"
* output.
*/
class Postprocess {
public:
/**
* @brief Constructor
* @param[in] contextLen Left and right context length for
* output tensor.
* @param[in] innerLen This is the length of the section
* between left and right context.
**/
Postprocess(uint32_t contextLen,
uint32_t innerLen,
uint32_t blankTokenIdx);
Postprocess() = delete;
~Postprocess() = default;
/**
* @brief Erases the required part of the tensor based
* on context lengths set up during initialisation.
* @param[in] tensor Pointer to the tensor.
* @param[in] axisIdx Index of the axis on which erase is
* performed.
* @param[in] lastIteration Flag to signal this is the
* last iteration in which case
* the right context is preserved.
* @return true if successful, false otherwise.
*/
bool Invoke(TfLiteTensor* tensor,
uint32_t axisIdx,
bool lastIteration = false);
private:
uint32_t _m_contextLen; /* lengths of left and right contexts. */
uint32_t _m_innerLen; /* Length of inner context. */
uint32_t _m_totalLen; /* Total length of the required axis. */
uint32_t _m_countIterations; /* Current number of iterations. */
uint32_t _m_blankTokenIdx; /* Index of the labels blank token. */
/**
* @brief Checks if the tensor and axis index are valid
* inputs to the object - based on how it has been
* initialised.
* @return true if valid, false otherwise.
*/
bool _IsInputValid(TfLiteTensor* tensor,
uint32_t axisIdx) const;
/**
* @brief Gets the tensor data element size in bytes based
* on the tensor type.
* @return Size in bytes, 0 if not supported.
*/
uint32_t _GetTensorElementSize(TfLiteTensor* tensor);
/**
* @brief Erases sections from the data assuming row-wise
* arrangement along the context axis.
* @return true if successful, false otherwise.
*/
bool _EraseSectionsRowWise(uint8_t* ptrData,
uint32_t strideSzBytes,
bool lastIteration);
/**
* @brief Erases sections from the data assuming col-wise
* arrangement along the context axis.
* @return true if successful, false otherwise.
*/
bool _EraseSectionsColWise(uint8_t* ptrData,
uint32_t strideSzBytes,
bool lastIteration);
};
} /* namespace asr */
} /* namespace audio */
} /* namespace app */
} /* namespace arm */
#endif /* ASR_WAV2LETTER_POSTPROCESS_HPP */
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