343 lines
11 KiB
C
343 lines
11 KiB
C
/*
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* Brickworks
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*
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* Copyright (C) 2022, 2023 Orastron Srl unipersonale
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*
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* Brickworks is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 3 of the License.
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*
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* Brickworks is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Brickworks. If not, see <http://www.gnu.org/licenses/>.
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*
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* File author: Stefano D'Angelo
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*/
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/*!
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* module_type {{{ dsp }}}
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* version {{{ 0.4.0 }}}
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* requires {{{
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* bw_buf bw_config bw_common bw_delay bw_gain bw_math bw_one_pole
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* }}}
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* description {{{
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* Comb filter / delay effect with feedforward and feedback paths.
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*
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* Essentially an implementation of the structure described in
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*
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* J. Dattorro, "Effect Design, Part 2: Delay-Line Modulation and Chorus",
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* J. Audio Eng. Soc., vol. 45, no. 10, pp. 764-788, October 1997.
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*
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* Unlike in the original paper, the feedback signal is not subtracted but
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* rather added to the input.
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* }}}
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* changelog {{{
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* <ul>
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* <li>Version <strong>0.4.0</strong>:
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* <li>First release.</li>
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* </ul>
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* </li>
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* </ul>
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* }}}
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*/
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#ifndef _BW_COMB_H
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#define _BW_COMB_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <bw_common.h>
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/*! api {{{
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* #### bw_comb_coeffs
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* ```>>> */
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typedef struct _bw_comb_coeffs bw_comb_coeffs;
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/*! <<<```
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* Coefficients and related.
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*
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* ### bw_comb_state
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* ```>>> */
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typedef struct _bw_comb_state bw_comb_state;
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/*! <<<```
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* Internal state and related.
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*
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* #### bw_comb_init()
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* ```>>> */
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static inline void bw_comb_init(bw_comb_coeffs *BW_RESTRICT coeffs, float max_delay);
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/*! <<<```
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* Initializes input parameter values in `coeffs` using `max_delay` (s) as
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* the maximum delay time.
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*
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* #### bw_comb_set_sample_rate()
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* ```>>> */
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static inline void bw_comb_set_sample_rate(bw_comb_coeffs *BW_RESTRICT coeffs, float sample_rate);
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/*! <<<```
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* Sets the `sample_rate` (Hz) value in `coeffs`.
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*
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* #### bw_comb_mem_req()
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* ```>>> */
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static inline BW_SIZE_T bw_comb_mem_req(bw_comb_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Returns the size, in bytes, of contiguous memory to be supplied to
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* `bw_comb_mem_set()` using `coeffs`.
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*
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* #### bw_comb_mem_set()
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* ```>>> */
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static inline void bw_comb_mem_set(bw_comb_state *BW_RESTRICT state, void *mem);
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/*! <<<```
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* Associates the contiguous memory block `mem` to the given `state`.
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*
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* #### bw_comb_reset_coeffs()
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* ```>>> */
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static inline void bw_comb_reset_coeffs(bw_comb_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Resets coefficients in `coeffs` to assume their target values.
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*
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* #### bw_comb_reset_state()
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* ```>>> */
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static inline void bw_comb_reset_state(const bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state);
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/*! <<<```
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* Resets the given `state` to its initial values using the given `coeffs`.
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*
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* #### bw_comb_update_coeffs_ctrl()
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* ```>>> */
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static inline void bw_comb_update_coeffs_ctrl(bw_comb_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Triggers control-rate update of coefficients in `coeffs`.
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*
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* #### bw_comb_update_coeffs_audio()
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* ```>>> */
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static inline void bw_comb_update_coeffs_audio(bw_comb_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Triggers audio-rate update of coefficients in `coeffs`.
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*
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* #### bw_comb_process1()
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* ```>>> */
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static inline float bw_comb_process1(const bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state, float x);
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/*! <<<```
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* Processes one input sample `x` using `coeffs`, while using and updating
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* `state`. Returns the corresponding output sample.
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*
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* #### bw_comb_process()
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* ```>>> */
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static inline void bw_comb_process(bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state, const float *x, float *y, int n_samples);
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/*! <<<```
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* Processes the first `n_samples` of the input buffer `x` and fills the
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* first `n_samples` of the output buffer `y`, while using and updating both
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* `coeffs` and `state` (control and audio rate).
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*
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* #### bw_comb_set_delay_ff()
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* ```>>> */
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static inline void bw_comb_set_delay_ff(bw_comb_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the feedforward delay time `value` (s) in `coeffs`.
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*
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* Default value: `0.f`.
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*
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* #### bw_comb_set_delay_fb()
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* ```>>> */
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static inline void bw_comb_set_delay_fb(bw_comb_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the feedback delay time `value` (s) in `coeffs`.
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*
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* Default value: `0.f`.
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*
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* #### bw_comb_set_coeff_blend()
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* ```>>> */
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static inline void bw_comb_set_coeff_blend(bw_comb_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the blend coefficient `value` in `coeffs`.
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*
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* Default value: `1.f`.
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*
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* #### bw_comb_set_coeff_ff()
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* ```>>> */
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static inline void bw_comb_set_coeff_ff(bw_comb_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the feedforward coefficient `value` in `coeffs`.
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*
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* Default value: `0.f`.
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*
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* #### bw_comb_set_coeff_fb()
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* ```>>> */
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static inline void bw_comb_set_coeff_fb(bw_comb_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the feedback coefficient `value` in `coeffs`.
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*
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* Default value: `0.f`.
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* }}} */
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/*** Implementation ***/
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/* WARNING: This part of the file is not part of the public API. Its content may
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* change at any time in future versions. Please, do not use it directly. */
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#include <bw_delay.h>
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#include <bw_gain.h>
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#include <bw_one_pole.h>
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#include <bw_math.h>
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struct _bw_comb_coeffs {
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// Sub-components
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bw_delay_coeffs delay_coeffs;
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bw_gain_coeffs blend_coeffs;
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bw_gain_coeffs ff_coeffs;
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bw_gain_coeffs fb_coeffs;
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bw_one_pole_coeffs smooth_coeffs;
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bw_one_pole_state smooth_delay_ff_state;
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bw_one_pole_state smooth_delay_fb_state;
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// Coefficients
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float fs;
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BW_SIZE_T dffi;
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float dfff;
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BW_SIZE_T dfbi;
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float dfbf;
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// Parameters
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float delay_ff;
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float delay_fb;
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};
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struct _bw_comb_state {
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// Sub-components
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bw_delay_state delay_state;
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};
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static inline void bw_comb_init(bw_comb_coeffs *BW_RESTRICT coeffs, float max_delay) {
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bw_delay_init(&coeffs->delay_coeffs, max_delay);
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bw_gain_init(&coeffs->blend_coeffs);
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bw_gain_init(&coeffs->ff_coeffs);
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bw_gain_init(&coeffs->fb_coeffs);
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bw_one_pole_init(&coeffs->smooth_coeffs);
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bw_one_pole_set_tau(&coeffs->smooth_coeffs, 0.05f);
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bw_one_pole_set_sticky_thresh(&coeffs->smooth_coeffs, 1e-6f);
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bw_gain_set_gain_lin(&coeffs->ff_coeffs, 0.f);
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bw_gain_set_gain_lin(&coeffs->fb_coeffs, 0.f);
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coeffs->delay_ff = 0.f;
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coeffs->delay_fb = 0.f;
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}
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static inline void bw_comb_set_sample_rate(bw_comb_coeffs *BW_RESTRICT coeffs, float sample_rate) {
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bw_delay_set_sample_rate(&coeffs->delay_coeffs, sample_rate);
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bw_gain_set_sample_rate(&coeffs->blend_coeffs, sample_rate);
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bw_gain_set_sample_rate(&coeffs->ff_coeffs, sample_rate);
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bw_gain_set_sample_rate(&coeffs->fb_coeffs, sample_rate);
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bw_one_pole_set_sample_rate(&coeffs->smooth_coeffs, sample_rate);
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bw_one_pole_reset_coeffs(&coeffs->smooth_coeffs);
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coeffs->fs = sample_rate;
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}
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static inline BW_SIZE_T bw_comb_mem_req(bw_comb_coeffs *BW_RESTRICT coeffs) {
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return bw_delay_mem_req(&coeffs->delay_coeffs);
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}
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static inline void bw_comb_mem_set(bw_comb_state *BW_RESTRICT state, void *mem) {
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bw_delay_mem_set(&state->delay_state, mem);
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}
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static inline void _bw_comb_do_update_coeffs(bw_comb_coeffs *BW_RESTRICT coeffs, char force) {
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float delay_ff_cur = bw_one_pole_get_y_z1(&coeffs->smooth_delay_ff_state);
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float delay_fb_cur = bw_one_pole_get_y_z1(&coeffs->smooth_delay_fb_state);
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if (force || delay_ff_cur != coeffs->delay_ff) {
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delay_ff_cur = bw_one_pole_process1_sticky_abs(&coeffs->smooth_coeffs, &coeffs->smooth_delay_ff_state, coeffs->delay_ff);
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const BW_SIZE_T len = bw_delay_get_length(&coeffs->delay_coeffs);
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const float dff = bw_maxf(coeffs->fs * delay_ff_cur, 0.f);
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float dffif;
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bw_intfracf(dff, &dffif, &coeffs->dfff);
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coeffs->dffi = (BW_SIZE_T)dffif;
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if (coeffs->dffi >= len) {
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coeffs->dffi = len;
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coeffs->dfff = 0.f;
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}
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}
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if (force || delay_fb_cur != coeffs->delay_fb) {
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delay_fb_cur = bw_one_pole_process1_sticky_abs(&coeffs->smooth_coeffs, &coeffs->smooth_delay_fb_state, coeffs->delay_fb);
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const BW_SIZE_T len = bw_delay_get_length(&coeffs->delay_coeffs);
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const float dfb = bw_maxf(coeffs->fs * delay_fb_cur, 1.f) - 1.f;
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float dfbif;
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bw_intfracf(dfb, &dfbif, &coeffs->dfbf);
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coeffs->dfbi = (BW_SIZE_T)dfbif;
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if (coeffs->dfbi >= len) {
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coeffs->dfbi = len;
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coeffs->dfbf = 0.f;
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}
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}
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}
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static inline void bw_comb_reset_coeffs(bw_comb_coeffs *BW_RESTRICT coeffs) {
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bw_delay_reset_coeffs(&coeffs->delay_coeffs);
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bw_gain_reset_coeffs(&coeffs->blend_coeffs);
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bw_gain_reset_coeffs(&coeffs->ff_coeffs);
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bw_gain_reset_coeffs(&coeffs->fb_coeffs);
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bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_delay_ff_state, coeffs->delay_ff);
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bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_delay_fb_state, coeffs->delay_fb);
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_bw_comb_do_update_coeffs(coeffs, 1);
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}
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static inline void bw_comb_reset_state(const bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state) {
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bw_delay_reset_state(&coeffs->delay_coeffs, &state->delay_state);
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}
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static inline void bw_comb_update_coeffs_ctrl(bw_comb_coeffs *BW_RESTRICT coeffs) {
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bw_gain_update_coeffs_ctrl(&coeffs->blend_coeffs);
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bw_gain_update_coeffs_ctrl(&coeffs->ff_coeffs);
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bw_gain_update_coeffs_ctrl(&coeffs->fb_coeffs);
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}
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static inline void bw_comb_update_coeffs_audio(bw_comb_coeffs *BW_RESTRICT coeffs) {
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bw_gain_update_coeffs_audio(&coeffs->blend_coeffs);
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bw_gain_update_coeffs_audio(&coeffs->ff_coeffs);
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bw_gain_update_coeffs_audio(&coeffs->fb_coeffs);
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_bw_comb_do_update_coeffs(coeffs, 0);
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}
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static inline float bw_comb_process1(const bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state, float x) {
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const float fb = bw_delay_read(&coeffs->delay_coeffs, &state->delay_state, coeffs->dfbi, coeffs->dfbf);
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const float v = x + bw_gain_process1(&coeffs->fb_coeffs, fb);
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bw_delay_write(&coeffs->delay_coeffs, &state->delay_state, v);
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const float ff = bw_delay_read(&coeffs->delay_coeffs, &state->delay_state, coeffs->dffi, coeffs->dfff);
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return bw_gain_process1(&coeffs->blend_coeffs, v) + bw_gain_process1(&coeffs->ff_coeffs, ff);
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}
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static inline void bw_comb_process(bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state, const float *x, float *y, int n_samples) {
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bw_comb_update_coeffs_ctrl(coeffs);
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for (int i = 0; i < n_samples; i++) {
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bw_comb_update_coeffs_audio(coeffs);
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y[i] = bw_comb_process1(coeffs, state, x[i]);
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}
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}
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static inline void bw_comb_set_delay_ff(bw_comb_coeffs *BW_RESTRICT coeffs, float value) {
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coeffs->delay_ff = value;
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}
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static inline void bw_comb_set_delay_fb(bw_comb_coeffs *BW_RESTRICT coeffs, float value) {
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coeffs->delay_fb = value;
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}
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static inline void bw_comb_set_coeff_blend(bw_comb_coeffs *BW_RESTRICT coeffs, float value) {
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bw_gain_set_gain_lin(&coeffs->blend_coeffs, value);
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}
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static inline void bw_comb_set_coeff_ff(bw_comb_coeffs *BW_RESTRICT coeffs, float value) {
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bw_gain_set_gain_lin(&coeffs->ff_coeffs, value);
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}
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static inline void bw_comb_set_coeff_fb(bw_comb_coeffs *BW_RESTRICT coeffs, float value) {
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bw_gain_set_gain_lin(&coeffs->fb_coeffs, value);
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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