/* * Brickworks * * Copyright (C) 2022 Orastron Srl unipersonale * * Brickworks is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, version 3 of the License. * * Brickworks is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * * File author: Stefano D'Angelo */ /*! * module_type {{{ dsp }}} * version {{{ 0.2.0 }}} * requires {{{ bw_config bw_common bw_math }}} * description {{{ * Slew-rate limiter with separate maximum increasing and decreasing rates. * }}} * changelog {{{ * * }}} */ #ifndef _BW_SLEW_LIM_H #define _BW_SLEW_LIM_H #ifdef __cplusplus extern "C" { #endif #include /*! api {{{ * #### bw_slew_lim_coeffs * ```>>> */ typedef struct _bw_slew_lim_coeffs bw_slew_lim_coeffs; /*! <<<``` * Coefficients. * * ### bw_slew_lim_state * >>> */ typedef struct _bw_slew_lim_state bw_slew_lim_state; /*! <<<``` * State. * * #### bw_slew_lim_init() * ```>>> */ static inline void bw_slew_lim_init(bw_slew_lim_coeffs *BW_RESTRICT coeffs); /*! <<<``` * Initializes `coeffs`. * * #### bw_slew_lim_set_sample_rate() * ```>>> */ static inline void bw_slew_lim_set_sample_rate(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float sample_rate); /*! <<<``` * Sets the `sample_rate` (Hz) value for the given `coeffs`. * * #### bw_slew_lim_reset_state() * ```>>> */ static inline void bw_slew_lim_reset_state(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float y_z1); /*! <<<``` * Resets the given `state` to the initial state using the given `coeffs`. * >>> */ static inline void bw_slew_lim_reset_coeffs(bw_slew_lim_coeffs *BW_RESTRICT coeffs); static inline void bw_slew_lim_update_coeffs_ctrl(bw_slew_lim_coeffs *BW_RESTRICT coeffs); static inline void bw_slew_lim_update_coeffs_audio(bw_slew_lim_coeffs *BW_RESTRICT coeffs); static inline float bw_slew_lim_process1(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x); static inline float bw_slew_lim_process1_up(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x); static inline float bw_slew_lim_process1_down(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x); /*! ... * #### bw_slew_lim_process() * ```>>> */ static inline void bw_slew_lim_process(bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, const float *x, float *y, int n_samples); /*! <<<``` * Lets the given `instance` process `n_samples` samples from the input * buffer `x` and fills the corresponding `n_samples` samples in the output * buffer `y`. * >>> */ /*! ... * #### bw_slew_lim_set_max_rate() * ```>>> */ static inline void bw_slew_lim_set_max_rate(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value); /*! <<<``` * Sets both the maximum increasing and decreasing variation rate to the * given `value` (1/s) for the given `instance`. * * `value` represents the maximum variation per second and must be * non-negative. * * This is equivalent to calling both `bw_slew_lim_set_max_inc_rate()` and * `bw_slew_lim_set_max_dec_rate()` with same `instance` and `value`. * * Default value: `INFINITY`. * >>> */ /*! ... * #### bw_slew_lim_set_max_rate_up() * ```>>> */ static inline void bw_slew_lim_set_max_rate_up(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value); /*! <<<``` * Sets the maximum increasing variation rate to the given `value` (1/s) for * the given `instance`. * * `value` represents the maximum variation per second and must be * non-negative. * * Default value: `INFINITY`. * >>> */ /*! ... * #### bw_slew_lim_set_max_inc_rate() * ```>>> */ static inline void bw_slew_lim_set_max_rate_down(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value); /*! <<<``` * Sets the maximum decreasing variation rate to the given `value` (1/s) for * the given `instance`. * * `value` represents the maximum variation per second and must be * non-negative. * * Default value: `INFINITY`. * }}} */ static inline float bw_slew_lim_get_y_z1(const bw_slew_lim_state *BW_RESTRICT state); /*** Implementation ***/ /* WARNING: This part of the file is not part of the public API. Its content may * change at any time in future versions. Please, do not use it directly. */ #include struct _bw_slew_lim_coeffs { // Coefficients float T; float max_inc; float max_dec; // Parameters float max_rate_up; float max_rate_down; }; struct _bw_slew_lim_state { float y_z1; }; static inline void bw_slew_lim_init(bw_slew_lim_coeffs *BW_RESTRICT coeffs) { coeffs->max_inc = INFINITY; coeffs->max_dec = INFINITY; } static inline void bw_slew_lim_set_sample_rate(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float sample_rate) { coeffs->T = 1.f / sample_rate; } static inline void bw_slew_lim_reset_coeffs(bw_slew_lim_coeffs *BW_RESTRICT coeffs) { bw_slew_lim_update_coeffs_ctrl(coeffs); } static inline void bw_slew_lim_reset_state(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float y_z1) { state->y_z1 = y_z1; } static inline void bw_slew_lim_update_coeffs_ctrl(bw_slew_lim_coeffs *BW_RESTRICT coeffs) { // tracking parameter changes is more trouble than it's worth coeffs->max_inc = coeffs->T * coeffs->max_rate_up; coeffs->max_dec = coeffs->T * coeffs->max_rate_down; } static inline void bw_slew_lim_update_coeffs_audio(bw_slew_lim_coeffs *BW_RESTRICT coeffs) { } static inline float bw_slew_lim_process1(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x) { float y = bw_clipf(x, state->y_z1 - coeffs->max_dec, state->y_z1 + coeffs->max_inc); state->y_z1 = y; return y; } static inline float bw_slew_lim_process1_up(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x) { float y = bw_minf(x, state->y_z1 + coeffs->max_inc); state->y_z1 = y; return y; } static inline float bw_slew_lim_process1_down(const bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, float x) { float y = bw_maxf(x, state->y_z1 - coeffs->max_dec); state->y_z1 = y; return y; } static inline void bw_slew_lim_process(bw_slew_lim_coeffs *BW_RESTRICT coeffs, bw_slew_lim_state *BW_RESTRICT state, const float *x, float *y, int n_samples) { bw_slew_lim_update_coeffs_ctrl(coeffs); if (y) { if (coeffs->max_rate_up != INFINITY) { if (coeffs->max_rate_down != INFINITY) for (int i = 0; i < n_samples; i++) y[i] = bw_slew_lim_process1(coeffs, state, x[i]); else for (int i = 0; i < n_samples; i++) y[i] = bw_slew_lim_process1_up(coeffs, state, x[i]); } else { if (coeffs->max_rate_down != INFINITY) for (int i = 0; i < n_samples; i++) y[i] = bw_slew_lim_process1_down(coeffs, state, x[i]); else { for (int i = 0; i < n_samples; i++) y[i] = x[i]; state->y_z1 = x[n_samples - 1]; } } } else { if (coeffs->max_rate_up != INFINITY) { if (coeffs->max_rate_down != INFINITY) for (int i = 0; i < n_samples; i++) bw_slew_lim_process1(coeffs, state, x[i]); else for (int i = 0; i < n_samples; i++) bw_slew_lim_process1_up(coeffs, state, x[i]); } else { if (coeffs->max_rate_down != INFINITY) for (int i = 0; i < n_samples; i++) bw_slew_lim_process1_down(coeffs, state, x[i]); else state->y_z1 = x[n_samples - 1]; } } } static inline void bw_slew_lim_set_max_rate(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value) { bw_slew_lim_set_max_rate_up(coeffs, value); bw_slew_lim_set_max_rate_down(coeffs, value); } static inline void bw_slew_lim_set_max_rate_up(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value) { coeffs->max_rate_up = value; } static inline void bw_slew_lim_set_max_rate_down(bw_slew_lim_coeffs *BW_RESTRICT coeffs, float value) { coeffs->max_rate_down = value; } static inline float bw_slew_lim_get_y_z1(const bw_slew_lim_state *BW_RESTRICT state) { return state->y_z1; } #ifdef __cplusplus } #endif #endif