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94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
// Copyright 2019, 2022, Collabora, Ltd.
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// SPDX-License-Identifier: BSL-1.0
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/*!
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* @file
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* @brief Low-pass IIR filter for integers - C wrapper
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* @author Ryan Pavlik <ryan.pavlik@collabora.com>
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* @author Malek Hodroj <pocmalek@gmail.com>
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* @ingroup aux_math
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*/
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#pragma once
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#include <stdint.h>
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#include <stdbool.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*!
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* An IIR (low pass) filter for integer values.
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*
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* Wraps xrt::auxiliary::math::IntegerLowPassIIRFilter - see that if you need a different scalar type.
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*
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*/
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struct m_lowpass_integer;
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/*!
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* Constructor
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*
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* @note Taking alpha, not a cutoff frequency, here, because it's easier with the rational math.
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*
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* Together, the two parameters specify the alpha value used to blend between new input and existing state. Larger
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* values mean more influence from new input.
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*
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* @param alpha_numerator The numerator of the alpha value. Must be greater than 0 and less than @p alpha_denominator
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* @param alpha_denominator The denominator of the alpha value. Must be greater than 0.
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*
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* @return null if a parameter is out of range
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*
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* @public @memberof m_lowpass_integer
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*/
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struct m_lowpass_integer *
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m_lowpass_integer_create(int64_t alpha_numerator, int64_t alpha_denominator);
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/*!
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* Filter a sample
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*
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* @param mli self-pointer
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* @param sample The value to filter
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*
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* @public @memberof m_lowpass_integer
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*/
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void
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m_lowpass_integer_add_sample(struct m_lowpass_integer *mli, int64_t sample);
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/*!
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* Get the filtered value.
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*
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* Probably 0 or other meaningless value if it's not initialized: see @ref m_lowpass_integer_is_initialized
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*
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* @param mli self-pointer
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*
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* @public @memberof m_lowpass_integer
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*/
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int64_t
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m_lowpass_integer_get_state(const struct m_lowpass_integer *mli);
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/*!
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* Get whether we have initialized state.
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*
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* @param mli self-pointer
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*
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* @public @memberof m_lowpass_integer
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*/
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bool
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m_lowpass_integer_is_initialized(const struct m_lowpass_integer *mli);
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/*!
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* Destroy a lowpass integer filter.
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*
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* Does null checks.
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*
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* @param ptr_to_mli Address of your lowpass integer filter. Will be set to zero.
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*
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* @public @memberof m_lowpass_integer
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*/
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void
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m_lowpass_integer_destroy(struct m_lowpass_integer **ptr_to_mli);
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#ifdef __cplusplus
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}
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#endif
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