new module bw_allpass1 (untested)
This commit is contained in:
Stefano D'Angelo
parent
c5c031c915
commit
03f3b8a67f
2
TODO
2
TODO
@ -15,7 +15,7 @@ code:
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* fix vst3 mapped values (visible in Ableton Live) and short names
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* polish examples (ranges, etc.)
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* change name of vst3 template folders to something that doesn't look like a vst3 folder itself
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* how can we only compute bit depth reduction when the input changes in bw_fx_bitcrush?
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* compute bit depth reduction only when input changes? (state)
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build system:
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* make makefiles handle paths with spaces etc
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195
include/bw_allpass1.h
Normal file
195
include/bw_allpass1.h
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@ -0,0 +1,195 @@
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/*
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* Brickworks
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*
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* Copyright (C) 2022 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 {{{ 0.3.0 }}}
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* requires {{{ bw_config bw_common bw_math }}}
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* description {{{
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* First-order allpass filter.
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* }}}
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* changelog {{{
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* <ul>
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* <li>Version <strong>0.3.0</strong>:
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* <ul>
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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_ALLPASS1_H
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#define _BW_ALLPASS1_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_allpass1_coeffs
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* ```>>> */
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typedef struct _bw_allpass1_coeffs bw_allpass1_coeffs;
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/*! <<<```
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* Coefficients and related.
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*
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* #### bw_allpass1_state
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* ```>>> */
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typedef struct _bw_allpass1_state bw_allpass1_state;
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/*! <<<```
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* Internal state and related.
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*
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* #### bw_allpass1_init()
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* ```>>> */
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static inline void bw_allpass1_init(bw_allpass1_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Initializes input parameter values in `coeffs`.
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*
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* #### bw_allpass1_set_sample_rate()
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* ```>>> */
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static inline void bw_allpass1_set_sample_rate(bw_allpass1_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_allpass1_reset_coeffs()
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* ```>>> */
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static inline void bw_allpass1_reset_coeffs(bw_allpass1_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_allpass1_reset_state()
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* ```>>> */
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static inline void bw_allpass1_reset_state(const bw_allpass1_coeffs *BW_RESTRICT coeffs, bw_allpass1_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_allpass1_update_coeffs_ctrl()
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* ```>>> */
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static inline void bw_allpass1_update_coeffs_ctrl(bw_allpass1_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_allpass1_update_coeffs_audio()
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* ```>>> */
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static inline void bw_allpass1_update_coeffs_audio(bw_allpass1_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_allpass1_process1()
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* ```>>> */
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static inline float bw_allpass1_process1(const bw_allpass1_coeffs *BW_RESTRICT coeffs, bw_allpass1_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_allpass1_process()
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* ```>>> */
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static inline void bw_allpass1_process(bw_allpass1_coeffs *BW_RESTRICT coeffs, bw_allpass1_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_allpass1_set_cutoff()
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* ```>>> */
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static inline void bw_allpass1_set_cutoff(bw_allpass1_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the cutoff frequency `value` (Hz) in `coeffs`.
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*
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* Default value: `1e3f`.
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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_math.h>
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struct _bw_allpass1_coeffs {
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// Coefficients
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float t_k;
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float t;
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float X_k;
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// Parameters
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float cutoff;
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float cutoff_prev;
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};
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struct _bw_allpass1_state {
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float lp_z1;
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float X_z1;
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};
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static inline void bw_allpass1_init(bw_allpass1_coeffs *BW_RESTRICT coeffs) {
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coeffs->cutoff = 1e3f;
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}
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static inline void bw_allpass1_set_sample_rate(bw_allpass1_coeffs *BW_RESTRICT coeffs, float sample_rate) {
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coeffs->t_k = 3.141592653589793f / sample_rate;
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}
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static inline void bw_allpass1_reset_coeffs(bw_allpass1_coeffs *BW_RESTRICT coeffs) {
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coeffs->cutoff_prev = -1.f;
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bw_allpass1_update_coeffs_ctrl(coeffs);
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}
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static inline void bw_allpass1_reset_state(const bw_allpass1_coeffs *BW_RESTRICT coeffs, bw_allpass1_state *BW_RESTRICT state) {
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state->lp_z1 = 0.f;
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state->X_z1 = 0.f;
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}
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static inline void bw_allpass1_update_coeffs_ctrl(bw_allpass1_coeffs *BW_RESTRICT coeffs) {
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if (coeffs->cutoff != coeffs->cutoff_prev) {
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coeffs->t = bw_tanf_3(coeffs->t_k * coeffs->cutoff);
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coeffs->X_k = bw_rcpf_2(1,f + coeffs->t);
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coeffs->cutoff_prev = coeffs->cutoff;
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}
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}
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static inline void bw_allpass1_update_coeffs_audio(bw_allpass1_coeffs *BW_RESTRICT coeffs) {
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}
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static inline float bw_allpass1_process1(const bw_allpass1_coeffs *BW_RESTRICT coeffs, bw_allpass1_state *BW_RESTRICT state, float x) {
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const float X = coeffs->X_k * (x - state->lp_z1 - coeffs->t * state->X_z1);
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const float lp = x - X;
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state->X_z1 = X;
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state->lp_z1 = lp;
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return lp + lp - x;
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}
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static inline void bw_allpass1_process(bw_allpass1_coeffs *BW_RESTRICT coeffs, bw_allpass1_state *BW_RESTRICT state, const float *x, float *y, int n_samples) {
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for (int i = 0; i < n_samples; i++)
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y[i] = bw_allpass1_process1(coeffs, state, x[i]);
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}
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static inline void bw_allpass1_set_cutoff(bw_allpass1_coeffs *BW_RESTRICT coeffs, float value) {
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coeffs->cutoff = 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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