finalized bw_clip + examples + stronger debug + uncheck coeffs in

process1

examples/fx_clip/src/bw_example_fx_clip.c

@@ -33,7 +33,7 @@ void bw_example_fx_clip_set_sample_rate(bw_example_fx_clip *instance, float samp
 
 void bw_example_fx_clip_reset(bw_example_fx_clip *instance) {
 	bw_clip_reset_coeffs(&instance->clip_coeffs);
-	bw_clip_reset_state(&instance->clip_coeffs, &instance->clip_state);
+	bw_clip_reset_state(&instance->clip_coeffs, &instance->clip_state, 0.f);
 	bw_src_int_reset_state(&instance->src_up_coeffs, &instance->src_up_state, 0.f);
 	bw_src_int_reset_state(&instance->src_down_coeffs, &instance->src_down_state, 0.f);
 }

examples/fx_clip/vst3/Makefile

@@ -4,3 +4,6 @@ NAME := bw_example_fx_clip
 SOURCES = ${SOURCES_COMMON} ${ROOT_DIR}/../src/bw_example_fx_clip.c
 
 include ${ROOT_DIR}/../../common/vst3/vst3.mk
+
+CXXFLAGS += -DRELEASE=1 -DNDEBUG -DBW_NO_DEBUG
+#CXXFLAGS += -DDEVELOPMENT=1 -DBW_DEBUG_DEEP

examples/fxpp_clip/vst3/Makefile

@@ -4,3 +4,6 @@ NAME := bw_example_fxpp_clip
 SOURCES = ${SOURCES_COMMON} ${ROOT_DIR}/../src/bw_example_fxpp_clip.cpp
 
 include ${ROOT_DIR}/../../common/vst3/vst3.mk
+
+CXXFLAGS += -DRELEASE=1 -DNDEBUG -DBW_NO_DEBUG
+#CXXFLAGS += -DDEVELOPMENT=1 -DBW_DEBUG_DEEP

include/bw_clip.h

@@ -48,6 +48,12 @@
  *      <li>Version <strong>1.0.0</strong>:
  *        <ul>
  *          <li>Changed default value for gain compensation to off.</li>
+ *          <li>Added initial input value to
+ *              <code>bw_clip_reset_state()</code>.</li>
+ *          <li>Added <code>bw_clip_reset_state_multi()</code> and updated C++
+ *              API in this regard.</li>
+ *          <li>Now <code>bw_clip_reset_state()</code> returns the initial
+ *              output value.</li>
  *          <li>Added overloaded C++ <code>reset()</code> functions taking
  *              arrays as arguments.</li>
  *          <li><code>bw_clip_process()</code> and
@@ -59,6 +65,8 @@
  *          <li>Added overloaded C++ <code>process()</code> function taking
  *              C-style arrays as arguments.</li>
  *          <li>Removed usage of reserved identifiers.</li>
+ *          <li>Clearly specified parameter validity ranges.</li>
+ *          <li>Added debugging code.</li>
  *        </ul>
  *      </li>
  *      <li>Version <strong>0.6.0</strong>:
@@ -99,45 +107,79 @@ typedef struct bw_clip_state bw_clip_state;
  *
  *    #### bw_clip_init()
  *  ```>>> */
-static inline void bw_clip_init(bw_clip_coeffs *BW_RESTRICT coeffs);
+static inline void bw_clip_init(
+	bw_clip_coeffs * BW_RESTRICT coeffs);
 /*! <<<```
  *    Initializes input parameter values in `coeffs`.
  *
  *    #### bw_clip_set_sample_rate()
  *  ```>>> */
-static inline void bw_clip_set_sample_rate(bw_clip_coeffs *BW_RESTRICT coeffs, float sample_rate);
+static inline void bw_clip_set_sample_rate(
+	bw_clip_coeffs * BW_RESTRICT coeffs,
+	float                        sample_rate);
 /*! <<<```
  *    Sets the `sample_rate` (Hz) value in `coeffs`.
  *
  *    #### bw_clip_reset_coeffs()
  *  ```>>> */
-static inline void bw_clip_reset_coeffs(bw_clip_coeffs *BW_RESTRICT coeffs);
+static inline void bw_clip_reset_coeffs(
+	bw_clip_coeffs * BW_RESTRICT coeffs);
 /*! <<<```
  *    Resets coefficients in `coeffs` to assume their target values.
  *
  *    #### bw_clip_reset_state()
  *  ```>>> */
-static inline void bw_clip_reset_state(const bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT state, float x_0);
+static inline float bw_clip_reset_state(
+	const bw_clip_coeffs * BW_RESTRICT coeffs,
+	bw_clip_state * BW_RESTRICT        state,
+	float                              x_0);
 /*! <<<```
  *    Resets the given `state` to its initial values using the given `coeffs`
- *    and the quiescent/initial input value `x_0`.
+ *    and the initial input value `x_0`.
+ *
+ *    Returns the corresponding initial output value.
+ *
+ *    #### bw_clip_reset_state_multi()
+ *  ```>>> */
+static inline void bw_clip_reset_state_multi(
+	const bw_clip_coeffs * BW_RESTRICT              coeffs,
+	bw_clip_state * BW_RESTRICT const * BW_RESTRICT state,
+	const float *                                   x_0,
+	float *                                         y_0,
+	size_t                                          n_channels);
+/*! <<<```
+ *    Resets each of the `n_channels` `state`s to its initial values using the
+ *    given `coeffs` and the corresponding initial input value in the `x_0`
+ *    array.
+ *
+ *    The corresponding initial output values are written into the `y_0` array,
+ *    if not `NULL`.
  *
  *    #### bw_clip_update_coeffs_ctrl()
  *  ```>>> */
-static inline void bw_clip_update_coeffs_ctrl(bw_clip_coeffs *BW_RESTRICT coeffs);
+static inline void bw_clip_update_coeffs_ctrl(
+	bw_clip_coeffs * BW_RESTRICT coeffs);
 /*! <<<```
  *    Triggers control-rate update of coefficients in `coeffs`.
  *
  *    #### bw_clip_update_coeffs_audio()
  *  ```>>> */
-static inline void bw_clip_update_coeffs_audio(bw_clip_coeffs *BW_RESTRICT coeffs);
+static inline void bw_clip_update_coeffs_audio(
+	bw_clip_coeffs * BW_RESTRICT coeffs);
 /*! <<<```
  *    Triggers audio-rate update of coefficients in `coeffs`.
  *
  *    #### bw_clip_process1()
  *  ```>>> */
-static inline float bw_clip_process1(const bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT state, float x);
+static inline float bw_clip_process1(
-static inline float bw_clip_process1_comp(const bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT state, float x);
+	const bw_clip_coeffs * BW_RESTRICT coeffs,
+	bw_clip_state * BW_RESTRICT        state,
+	float                              x);
+
+static inline float bw_clip_process1_comp(
+	const bw_clip_coeffs * BW_RESTRICT coeffs,
+	bw_clip_state * BW_RESTRICT        state,
+	float                              x);
 /*! <<<```
  *    These function process one input sample `x` using `coeffs`, while using
  *    and updating `state`. They return the corresponding output sample.
@@ -146,9 +188,16 @@ static inline float bw_clip_process1_comp(const bw_clip_coeffs *BW_RESTRICT coef
  *     * `bw_clip_process1()` assumes that gain compensation is disabled;
  *     * `bw_clip_process1_comp()` assumes that gain compensation is enabled.
  *
+ *    The actual gain compensation parameter value is ignored.
+ *
  *    #### bw_clip_process()
  *  ```>>> */
-static inline void bw_clip_process(bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT state, const float *x, float *y, size_t n_samples);
+static inline void bw_clip_process(
+	bw_clip_coeffs * BW_RESTRICT coeffs,
+	bw_clip_state * BW_RESTRICT  state,
+	const float *                x,
+	float *                      y,
+	size_t                       n_samples);
 /*! <<<```
  *    Processes the first `n_samples` of the input buffer `x` and fills the
  *    first `n_samples` of the output buffer `y`, while using and updating both
@@ -156,7 +205,13 @@ static inline void bw_clip_process(bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_s
  *
  *    #### bw_clip_process_multi()
  *  ```>>> */
-static inline void bw_clip_process_multi(bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT const *BW_RESTRICT state, const float * const *x, float * const *y, size_t n_channels, size_t n_samples);
+static inline void bw_clip_process_multi(
+	bw_clip_coeffs * BW_RESTRICT                    coeffs,
+	bw_clip_state * BW_RESTRICT const * BW_RESTRICT state,
+	const float * const *                           x,
+	float * const *                                 y,
+	size_t                                          n_channels,
+	size_t                                          n_samples);
 /*! <<<```
  *    Processes the first `n_samples` of the `n_channels` input buffers `x` and
  *    fills the first `n_samples` of the `n_channels` output buffers `y`, while
@@ -165,30 +220,66 @@ static inline void bw_clip_process_multi(bw_clip_coeffs *BW_RESTRICT coeffs, bw_
  *
  *    #### bw_clip_set_bias()
  *  ```>>> */
-static inline void bw_clip_set_bias(bw_clip_coeffs *BW_RESTRICT coeffs, float value);
+static inline void bw_clip_set_bias(
+	bw_clip_coeffs * BW_RESTRICT coeffs,
+	float                        value);
 /*! <<<```
  *    Sets the input bias `value` in `coeffs`.
  *
+ *    Valid range: [`-1e12f`, `1e12f`].
+ *
  *    Default value: `0.f`.
  *
  *    #### bw_clip_set_gain()
  *  ```>>> */
-static inline void bw_clip_set_gain(bw_clip_coeffs *BW_RESTRICT coeffs, float value);
+static inline void bw_clip_set_gain(
+	bw_clip_coeffs * BW_RESTRICT coeffs,
+	float                        value);
 /*! <<<```
  *    Sets the gain `value` in `coeffs`.
  *
- *    Do not set it to `0.f`, obviously.
+ *    Valid range: [`1e-12f`, `1e12f`].
  *
  *    Default value: `1.f`.
  *
  *    #### bw_clip_set_gain_compensation()
  *  ```>>> */
-static inline void bw_clip_set_gain_compensation(bw_clip_coeffs *BW_RESTRICT coeffs, char value);
+static inline void bw_clip_set_gain_compensation(
+	bw_clip_coeffs * BW_RESTRICT coeffs,
+	char                         value);
 /*! <<<```
  *    Sets whether the output should be divided by gain (`value` non-`0`) or not
  *    (`0`).
  *
  *    Default value: `0` (off).
+ *
+ *    #### bw_clip_coeffs_is_valid()
+ *  ```>>> */
+static inline char bw_clip_coeffs_is_valid(
+	const bw_clip_coeffs * BW_RESTRICT coeffs);
+/*! <<<```
+ *    Tries to determine whether `coeffs` is valid and returns non-`0` if it
+ *    seems to be the case and `0` if it is certainly not. False positives are
+ *    possible, false negatives are not.
+ *
+ *    `coeffs` must at least point to a readable memory block of size greater
+ *    than or equal to that of `bw_clip_coeffs`.
+ *
+ *    #### bw_clip_state_is_valid()
+ *  ```>>> */
+static inline char bw_clip_state_is_valid(
+	const bw_clip_coeffs * BW_RESTRICT coeffs,
+	const bw_clip_state * BW_RESTRICT  state);
+/*! <<<```
+ *    Tries to determine whether `state` is valid and returns non-`0` if it
+ *    seems to be the case and `0` if it is certainly not. False positives are
+ *    possible, false negatives are not.
+ *
+ *    If `coeffs` is not `NULL` extra cross-checks might be performed (`state`
+ *    is supposed to be associated to `coeffs`).
+ *
+ *    `state` must at least point to a readable memory block of size greater
+ *    than or equal to that of `bw_clip_state`.
  *  }}} */
 
 #ifdef __cplusplus
@@ -207,42 +298,89 @@ static inline void bw_clip_set_gain_compensation(bw_clip_coeffs *BW_RESTRICT coe
 extern "C" {
 #endif
 
+#ifdef BW_DEBUG_DEEP
+enum bw_clip_coeffs_state {
+	bw_clip_coeffs_state_invalid,
+	bw_clip_coeffs_state_init,
+	bw_clip_coeffs_state_set_sample_rate,
+	bw_clip_coeffs_state_reset_coeffs
+};
+#endif
+
 struct bw_clip_coeffs {
+#ifdef BW_DEBUG_DEEP
+	uint32_t			hash;
+	enum bw_clip_coeffs_state	state;
+	uint32_t			reset_id;
+#endif
+
 	// Sub-components
-	bw_one_pole_coeffs	smooth_coeffs;
+	bw_one_pole_coeffs		smooth_coeffs;
-	bw_one_pole_state	smooth_bias_state;
+	bw_one_pole_state		smooth_bias_state;
-	bw_one_pole_state	smooth_gain_state;
+	bw_one_pole_state		smooth_gain_state;
 	
 	// Coefficients
-	float			bias_dc;
+	float				bias_dc;
-	float			inv_gain;
+	float				inv_gain;
 
 	// Parameters
-	float			bias;
+	float				bias;
-	float			gain;
+	float				gain;
-	char			gain_compensation;
+	char				gain_compensation;
 };
 
 struct bw_clip_state {
-	float	x_z1;
+#ifdef BW_DEBUG_DEEP
-	float	F_z1;
+	uint32_t	hash;
+	uint32_t	coeffs_reset_id;
+#endif
+
+	// States
+	float		x_z1;
+	float		F_z1;
 };
 
-static inline void bw_clip_init(bw_clip_coeffs *BW_RESTRICT coeffs) {
+static inline void bw_clip_init(
+		bw_clip_coeffs * BW_RESTRICT coeffs) {
+	BW_ASSERT(coeffs != NULL);
+
 	bw_one_pole_init(&coeffs->smooth_coeffs);
 	bw_one_pole_set_tau(&coeffs->smooth_coeffs, 0.005f);
 	bw_one_pole_set_sticky_thresh(&coeffs->smooth_coeffs, 1e-3f);
 	coeffs->bias = 0.f;
 	coeffs->gain = 1.f;
 	coeffs->gain_compensation = 0;
+
+#ifdef BW_DEBUG_DEEP
+	coeffs->hash = bw_hash_sdbm("bw_clip_coeffs");
+	coeffs->state = bw_clip_coeffs_state_init;
+	coeffs->reset_id = coeffs->hash + 1;
+#endif
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state == bw_clip_coeffs_state_init);
 }
 
-static inline void bw_clip_set_sample_rate(bw_clip_coeffs *BW_RESTRICT coeffs, float sample_rate) {
+static inline void bw_clip_set_sample_rate(
+		bw_clip_coeffs * BW_RESTRICT coeffs,
+		float                        sample_rate) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_init);
+	BW_ASSERT(bw_is_finite(sample_rate) && sample_rate > 0.f);
+
 	bw_one_pole_set_sample_rate(&coeffs->smooth_coeffs, sample_rate);
 	bw_one_pole_reset_coeffs(&coeffs->smooth_coeffs);
+
+#ifdef BW_DEBUG_DEEP
+	coeffs->state = bw_clip_coeffs_state_set_sample_rate;
+#endif
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state == bw_clip_coeffs_state_set_sample_rate);
 }
 
-static inline void bw_clip_do_update_coeffs(bw_clip_coeffs *BW_RESTRICT coeffs, char force) {
+static inline void bw_clip_do_update_coeffs(
+		bw_clip_coeffs * BW_RESTRICT coeffs,
+		char                         force) {
 	float bias_cur = bw_one_pole_get_y_z1(&coeffs->smooth_bias_state);
 	if (force || coeffs->bias != bias_cur) {
 		bias_cur = bw_one_pole_process1_sticky_abs(&coeffs->smooth_coeffs, &coeffs->smooth_bias_state, coeffs->bias);
@@ -255,44 +393,162 @@ static inline void bw_clip_do_update_coeffs(bw_clip_coeffs *BW_RESTRICT coeffs,
 	}
 }
 
-static inline void bw_clip_reset_coeffs(bw_clip_coeffs *BW_RESTRICT coeffs) {
+static inline void bw_clip_reset_coeffs(
+		bw_clip_coeffs * BW_RESTRICT coeffs) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_set_sample_rate);
+
 	bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_bias_state, coeffs->bias);
 	bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_gain_state, coeffs->gain);
 	bw_clip_do_update_coeffs(coeffs, 1);
+
+#ifdef BW_DEBUG_DEEP
+	coeffs->state = bw_clip_coeffs_state_reset_coeffs;
+	coeffs->reset_id++;
+#endif
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state == bw_clip_coeffs_state_reset_coeffs);
 }
 
-static inline void bw_clip_reset_state(const bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT state, float x_0) {
+static inline float bw_clip_reset_state(
+		const bw_clip_coeffs * BW_RESTRICT coeffs,
+		bw_clip_state * BW_RESTRICT        state,
+		float                              x_0) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT(state != NULL);
+	BW_ASSERT(bw_is_finite(x_0));
+
 	const float x = bw_one_pole_get_y_z1(&coeffs->smooth_gain_state) * x_0 + bw_one_pole_get_y_z1(&coeffs->smooth_bias_state);
 	const float a = bw_absf(x_0);
+	const float yb = bw_clipf(x, -1.f, 1.f);
+	const float y = yb - coeffs->bias_dc;
 	state->x_z1 = x;
 	state->F_z1 = a > 1.f ? a - 0.5f : 0.5f * a * a;
+
+#ifdef BW_DEBUG_DEEP
+	state->hash = bw_hash_sdbm("bw_clip_state");
+	state->coeffs_reset_id = coeffs->reset_id;
+#endif
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT_DEEP(bw_clip_state_is_valid(coeffs, state));
+	BW_ASSERT(bw_is_finite(y));
+
+	return y;
 }
 
-static inline void bw_clip_update_coeffs_ctrl(bw_clip_coeffs *BW_RESTRICT coeffs) {
+static inline void bw_clip_reset_state_multi(
+		const bw_clip_coeffs * BW_RESTRICT              coeffs,
+		bw_clip_state * BW_RESTRICT const * BW_RESTRICT state,
+		const float *                                   x_0,
+		float *                                         y_0,
+		size_t                                          n_channels) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT(state != NULL);
+	BW_ASSERT(x_0 != NULL);
+
+	if (y_0 != NULL)
+		for (size_t i = 0; i < n_channels; i++)
+			y_0[i] = bw_clip_reset_state(coeffs, state[i], x_0[i]);
+	else
+		for (size_t i = 0; i < n_channels; i++)
+			bw_clip_reset_state(coeffs, state[i], x_0[i]);
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT_DEEP(y_0 != NULL ? bw_has_only_finite(y_0, n_channels) : 1);
+}
+
+static inline void bw_clip_update_coeffs_ctrl(
+		bw_clip_coeffs * BW_RESTRICT coeffs) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+
 	(void)coeffs;
 }
 
-static inline void bw_clip_update_coeffs_audio(bw_clip_coeffs *BW_RESTRICT coeffs) {
+static inline void bw_clip_update_coeffs_audio(
+		bw_clip_coeffs * BW_RESTRICT coeffs) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+
 	bw_clip_do_update_coeffs(coeffs, 0);
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
 }
 
-static inline float bw_clip_process1(const bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT state, float x) {
+static inline float bw_clip_process1(
+		const bw_clip_coeffs * BW_RESTRICT coeffs,
+		bw_clip_state * BW_RESTRICT        state,
+		float                              x) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT(state != NULL);
+	BW_ASSERT_DEEP(bw_clip_state_is_valid(coeffs, state));
+	BW_ASSERT(bw_is_finite(x));
+
 	x = bw_one_pole_get_y_z1(&coeffs->smooth_gain_state) * x + bw_one_pole_get_y_z1(&coeffs->smooth_bias_state);
 	const float a = bw_absf(x);
 	const float F = a > 1.f ? a - 0.5f : 0.5f * a * a;
 	const float d = x - state->x_z1;
-	const float y = d * d < 1e-6f ? bw_clipf(0.5f * (x + state->x_z1), -1.f, 1.f) : (F - state->F_z1) * bw_rcpf(d);
+	const float yb = d * d < 1e-6f ? bw_clipf(0.5f * (x + state->x_z1), -1.f, 1.f) : (F - state->F_z1) * bw_rcpf(d);
+	const float y = yb - coeffs->bias_dc;
 	state->x_z1 = x;
 	state->F_z1 = F;
-	return y - coeffs->bias_dc;
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT_DEEP(bw_clip_state_is_valid(coeffs, state));
+	BW_ASSERT(bw_is_finite(y));
+
+	return y;
 }
 
-static inline float bw_clip_process1_comp(const bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT state, float x) {
+static inline float bw_clip_process1_comp(
-	float y = bw_clip_process1(coeffs, state, x);
+		const bw_clip_coeffs * BW_RESTRICT coeffs,
-	return coeffs->inv_gain * y;
+		bw_clip_state * BW_RESTRICT        state,
+		float                              x) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT(state != NULL);
+	BW_ASSERT_DEEP(bw_clip_state_is_valid(coeffs, state));
+	BW_ASSERT(bw_is_finite(x));
+
+	const float y = coeffs->inv_gain * bw_clip_process1(coeffs, state, x);
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT_DEEP(bw_clip_state_is_valid(coeffs, state));
+	BW_ASSERT(bw_is_finite(y));
+
+	return y;
 }
 
-static inline void bw_clip_process(bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT state, const float *x, float *y, size_t n_samples) {
+static inline void bw_clip_process(
+		bw_clip_coeffs * BW_RESTRICT coeffs,
+		bw_clip_state * BW_RESTRICT  state,
+		const float *                x,
+		float *                      y,
+		size_t                       n_samples) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT(state != NULL);
+	BW_ASSERT_DEEP(bw_clip_state_is_valid(coeffs, state));
+	BW_ASSERT(x != NULL);
+	BW_ASSERT_DEEP(bw_has_only_finite(x, n_samples));
+	BW_ASSERT(y != NULL);
+
 	if (coeffs->gain_compensation)
 		for (size_t i = 0; i < n_samples; i++) {
 			bw_clip_update_coeffs_audio(coeffs);
@@ -303,9 +559,27 @@ static inline void bw_clip_process(bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_s
 			bw_clip_update_coeffs_audio(coeffs);
 			y[i] = bw_clip_process1(coeffs, state, x[i]);
 		}
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT_DEEP(bw_clip_state_is_valid(coeffs, state));
+	BW_ASSERT_DEEP(bw_has_only_finite(y, n_samples));
 }
 
-static inline void bw_clip_process_multi(bw_clip_coeffs *BW_RESTRICT coeffs, bw_clip_state *BW_RESTRICT const *BW_RESTRICT state, const float * const *x, float * const *y, size_t n_channels, size_t n_samples) {
+static inline void bw_clip_process_multi(
+		bw_clip_coeffs * BW_RESTRICT                    coeffs,
+		bw_clip_state * BW_RESTRICT const * BW_RESTRICT state,
+		const float * const *                           x,
+		float * const *                                 y,
+		size_t                                          n_channels,
+		size_t                                          n_samples) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
+	BW_ASSERT(state != NULL);
+	BW_ASSERT(x != NULL);
+	BW_ASSERT(y != NULL);
+
 	if (coeffs->gain_compensation)
 		for (size_t i = 0; i < n_samples; i++) {
 			bw_clip_update_coeffs_audio(coeffs);
@@ -318,18 +592,106 @@ static inline void bw_clip_process_multi(bw_clip_coeffs *BW_RESTRICT coeffs, bw_
 			for (size_t j = 0; j < n_channels; j++)
 				y[j][i] = bw_clip_process1(coeffs, state[j], x[j][i]);
 		}
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_reset_coeffs);
 }
 
-static inline void bw_clip_set_bias(bw_clip_coeffs *BW_RESTRICT coeffs, float value) {
+static inline void bw_clip_set_bias(
+		bw_clip_coeffs * BW_RESTRICT coeffs,
+		float                        value) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_init);
+	BW_ASSERT(bw_is_finite(value));
+	BW_ASSERT(value >= -1e12f && value <= 1e12f);
+
 	coeffs->bias = value;
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_init);
 }
 
-static inline void bw_clip_set_gain(bw_clip_coeffs *BW_RESTRICT coeffs, float value) {
+static inline void bw_clip_set_gain(
+		bw_clip_coeffs * BW_RESTRICT coeffs,
+		float                        value) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_init);
+	BW_ASSERT(bw_is_finite(value));
+	BW_ASSERT(value >= 1e-12f && value <= 1e12f);
+
 	coeffs->gain = value;
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_init);
 }
 
-static inline void bw_clip_set_gain_compensation(bw_clip_coeffs *BW_RESTRICT coeffs, char value) {
+static inline void bw_clip_set_gain_compensation(
+		bw_clip_coeffs * BW_RESTRICT coeffs,
+		char                         value) {
+	BW_ASSERT(coeffs != NULL);
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_init);
+
 	coeffs->gain_compensation = value;
+
+	BW_ASSERT_DEEP(bw_clip_coeffs_is_valid(coeffs));
+	BW_ASSERT_DEEP(coeffs->state >= bw_clip_coeffs_state_init);
+}
+
+static inline char bw_clip_coeffs_is_valid(
+		const bw_clip_coeffs * BW_RESTRICT coeffs) {
+	BW_ASSERT(coeffs != NULL);
+
+#ifdef BW_DEBUG_DEEP
+	if (coeffs->hash != bw_hash_sdbm("bw_clip_coeffs"))
+		return 0;
+	if (coeffs->state < bw_clip_coeffs_state_init || coeffs->state > bw_clip_coeffs_state_reset_coeffs)
+		return 0;
+#endif
+
+	if (!bw_is_finite(coeffs->bias) || coeffs->bias < -1e12f || coeffs->bias > 1e12f)
+		return 0;
+	if (!bw_is_finite(coeffs->gain) || coeffs->gain < 1e-12f || coeffs->gain > 1e12f)
+		return 0;
+
+	if (!bw_one_pole_coeffs_is_valid(&coeffs->smooth_coeffs))
+		return 0;
+
+#ifdef BW_DEBUG_DEEP
+	if (coeffs->state >= bw_clip_coeffs_state_reset_coeffs) {
+		if (!bw_one_pole_state_is_valid(&coeffs->smooth_coeffs, &coeffs->smooth_bias_state))
+			return 0;
+		if (!bw_one_pole_state_is_valid(&coeffs->smooth_coeffs, &coeffs->smooth_gain_state))
+			return 0;
+
+		if (!bw_is_finite(coeffs->bias_dc) || coeffs->bias_dc < -1.f || coeffs->bias_dc > 1.f)
+			return 0;
+		if (!bw_is_finite(coeffs->inv_gain) || coeffs->inv_gain <= 0.f)
+			return 0;
+	}
+#endif
+
+	return 1;
+}
+
+static inline char bw_clip_state_is_valid(
+		const bw_clip_coeffs * BW_RESTRICT coeffs,
+		const bw_clip_state * BW_RESTRICT  state) {
+	BW_ASSERT(state != NULL);
+
+#ifdef BW_DEBUG_DEEP
+	if (state->hash != bw_hash_sdbm("bw_clip_state"))
+		return 0;
+
+	if (coeffs != NULL && coeffs->reset_id != state->coeffs_reset_id)
+		return 0;
+#endif
+
+	(void)coeffs;
+
+	return bw_is_finite(state->x_z1) && bw_is_finite(state->F_z1);
 }
 
 #ifdef __cplusplus
@@ -349,22 +711,43 @@ class Clip {
 public:
 	Clip();
 
-	void setSampleRate(float sampleRate);
+	void setSampleRate(
-	void reset(float x_0 = 0.f);
+		float sampleRate);
-	void reset(const float *BW_RESTRICT x_0);
-	void reset(const std::array<float, N_CHANNELS> x_0);
-	void process(
-		const float * const *x,
-		float * const *y,
-		size_t nSamples);
-	void process(
-		const std::array<const float *, N_CHANNELS> x,
-		const std::array<float *, N_CHANNELS> y,
-		size_t nSamples);
 
-	void setBias(float value);
+	void reset(
-	void setGain(float value);
+		float               x0 = 0.f,
-	void setGainCompensation(bool value);
+		float * BW_RESTRICT y0 = nullptr);
+
+	void reset(
+		float                                       x0,
+		std::array<float, N_CHANNELS> * BW_RESTRICT y0);
+
+	void reset(
+		const float * x0,
+		float *       y0 = nullptr);
+
+	void reset(
+		std::array<float, N_CHANNELS>               x0,
+		std::array<float, N_CHANNELS> * BW_RESTRICT y0 = nullptr);
+
+	void process(
+		const float * const * x,
+		float * const *       y,
+		size_t                nSamples);
+
+	void process(
+		std::array<const float *, N_CHANNELS> x,
+		std::array<float *, N_CHANNELS>       y,
+		size_t                                nSamples);
+
+	void setBias(
+		float value);
+
+	void setGain(
+		float value);
+
+	void setGainCompensation(
+		bool value);
 /*! <<<...
  *  }
  *  ```
@@ -376,9 +759,9 @@ public:
  * change at any time in future versions. Please, do not use it directly. */
 
 private:
-	bw_clip_coeffs	 coeffs;
+	bw_clip_coeffs			coeffs;
-	bw_clip_state	 states[N_CHANNELS];
+	bw_clip_state			states[N_CHANNELS];
-	bw_clip_state	*BW_RESTRICT statesP[N_CHANNELS];
+	bw_clip_state * BW_RESTRICT	statesP[N_CHANNELS];
 };
 
 template<size_t N_CHANNELS>
@@ -389,57 +772,77 @@ inline Clip<N_CHANNELS>::Clip() {
 }
 
 template<size_t N_CHANNELS>
-inline void Clip<N_CHANNELS>::setSampleRate(float sampleRate) {
+inline void Clip<N_CHANNELS>::setSampleRate(
+		float sampleRate) {
 	bw_clip_set_sample_rate(&coeffs, sampleRate);
 }
 
 template<size_t N_CHANNELS>
-inline void Clip<N_CHANNELS>::reset(float x_0) {
+inline void Clip<N_CHANNELS>::reset(
+		float               x0,
+		float * BW_RESTRICT y0) {
 	bw_clip_reset_coeffs(&coeffs);
-	for (size_t i = 0; i < N_CHANNELS; i++)
+	if (y0 != nullptr)
-		bw_clip_reset_state(&coeffs, states + i, x_0);
+		for (size_t i = 0; i < N_CHANNELS; i++)
+			y0[i] = bw_clip_reset_state(&coeffs, states + i, x0);
+	else
+		for (size_t i = 0; i < N_CHANNELS; i++)
+			bw_clip_reset_state(&coeffs, states + i, x0);
 }
 
 template<size_t N_CHANNELS>
-inline void Clip<N_CHANNELS>::reset(const float *BW_RESTRICT x_0) {
+inline void Clip<N_CHANNELS>::reset(
-	bw_clip_reset_coeffs(&coeffs);
+		float                                       x0,
-	for (size_t i = 0; i < N_CHANNELS; i++)
+		std::array<float, N_CHANNELS> * BW_RESTRICT y0) {
-		bw_clip_reset_state(&coeffs, states + i, x_0[i]);
+	reset(x0, y0 != nullptr ? y0->data() : nullptr);
 }
 
 template<size_t N_CHANNELS>
-inline void Clip<N_CHANNELS>::reset(const std::array<float, N_CHANNELS> x_0) {
+inline void Clip<N_CHANNELS>::reset(
-	reset(x_0.data());
+		const float * x0,
+		float *       y0) {
+	bw_clip_reset_coeffs(&coeffs);
+	bw_clip_reset_state_multi(&coeffs, statesP, x0, y0, N_CHANNELS);
+}
+
+template<size_t N_CHANNELS>
+inline void Clip<N_CHANNELS>::reset(
+		std::array<float, N_CHANNELS>               x0,
+		std::array<float, N_CHANNELS> * BW_RESTRICT y0) {
+	reset(x0.data(), y0 != nullptr ? y0->data() : nullptr);
 }
 
 template<size_t N_CHANNELS>
 inline void Clip<N_CHANNELS>::process(
-		const float * const *x,
+		const float * const * x,
-		float * const *y,
+		float * const *       y,
-		size_t nSamples) {
+		size_t                nSamples) {
 	bw_clip_process_multi(&coeffs, statesP, x, y, N_CHANNELS, nSamples);
 }
 
 template<size_t N_CHANNELS>
 inline void Clip<N_CHANNELS>::process(
-		const std::array<const float *, N_CHANNELS> x,
+		std::array<const float *, N_CHANNELS> x,
-		const std::array<float *, N_CHANNELS> y,
+		std::array<float *, N_CHANNELS>       y,
-		size_t nSamples) {
+		size_t                                nSamples) {
 	process(x.data(), y.data(), nSamples);
 }
 
 template<size_t N_CHANNELS>
-inline void Clip<N_CHANNELS>::setBias(float value) {
+inline void Clip<N_CHANNELS>::setBias(
+		float value) {
 	bw_clip_set_bias(&coeffs, value);
 }
 
 template<size_t N_CHANNELS>
-inline void Clip<N_CHANNELS>::setGain(float value) {
+inline void Clip<N_CHANNELS>::setGain(
+		float value) {
 	bw_clip_set_gain(&coeffs, value);
 }
 
 template<size_t N_CHANNELS>
-inline void Clip<N_CHANNELS>::setGainCompensation(bool value) {
+inline void Clip<N_CHANNELS>::setGainCompensation(
+		bool value) {
 	bw_clip_set_gain_compensation(&coeffs, value);
 }
 

include/bw_hs1.h

@@ -670,9 +670,9 @@ static inline char bw_hs1_coeffs_is_valid(
 
 	if (!bw_is_finite(coeffs->cutoff) || coeffs->cutoff <= 0.f)
 		return 0;
-	if (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f)
+	if (!bw_is_finite(coeffs->prewarp_k) || (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f))
 		return 0;
-	if (coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
+	if (!bw_is_finite(coeffs->prewarp_freq) || coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
 		return 0;
 	if (!bw_is_finite(coeffs->high_gain) || coeffs->high_gain < 1e-30f || coeffs->high_gain > 1e30f)
 		return 0;

include/bw_hs2.h

@@ -717,9 +717,9 @@ static inline char bw_hs2_coeffs_is_valid(
 
 	if (!bw_is_finite(coeffs->cutoff) || coeffs->cutoff <= 0.f)
 		return 0;
-	if (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f)
+	if (!bw_is_finite(coeffs->prewarp_k) || (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f))
 		return 0;
-	if (coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
+	if (!bw_is_finite(coeffs->prewarp_freq) || coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
 		return 0;
 	if (!bw_is_finite(coeffs->high_gain) || coeffs->high_gain < 1e-30f || coeffs->high_gain > 1e30f)
 		return 0;

include/bw_lp1.h

@@ -46,7 +46,6 @@
  *          <li>Added overloaded C++ <code>process()</code> function taking
  *              C-style arrays as arguments.</li>
  *          <li>Removed usage of reserved identifiers.</li>
- *          <li>Fixed theoretical bug in <code>bw_lp1_init()</code>.</li>
  *          <li>Clearly specified parameter validity ranges.</li>
  *          <li>Added debugging code.</li>
  *        </ul>
@@ -338,7 +337,6 @@ static inline void bw_lp1_init(
 	bw_one_pole_init(&coeffs->smooth_coeffs);
 	bw_one_pole_set_tau(&coeffs->smooth_coeffs, 0.005f);
 	bw_one_pole_set_sticky_thresh(&coeffs->smooth_coeffs, 1e-3f);
-	bw_one_pole_set_sticky_mode(&coeffs->smooth_coeffs, bw_one_pole_sticky_mode_rel);
 	coeffs->cutoff = 1e3f;
 	coeffs->prewarp_k = 1.f;
 	coeffs->prewarp_freq = 1e3f;
@@ -612,11 +610,11 @@ static inline char bw_lp1_coeffs_is_valid(
 		return 0;
 #endif
 
-	if (coeffs->cutoff < 1e-6f || coeffs->cutoff > 1e12f)
+	if (!bw_is_finite(coeffs->cutoff) || coeffs->cutoff < 1e-6f || coeffs->cutoff > 1e12f)
 		return 0;
-	if (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f)
+	if (!bw_is_finite(coeffs->prewarp_k) || (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f))
 		return 0;
-	if (coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
+	if (!bw_is_finite(coeffs->prewarp_freq) || coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
 		return 0;
 
 	if (!bw_one_pole_coeffs_is_valid(&coeffs->smooth_coeffs))

include/bw_ls1.h

@@ -671,9 +671,9 @@ static inline char bw_ls1_coeffs_is_valid(
 
 	if (!bw_is_finite(coeffs->cutoff) || coeffs->cutoff <= 0.f)
 		return 0;
-	if (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f)
+	if (!bw_is_finite(coeffs->prewarp_k) || (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f))
 		return 0;
-	if (coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
+	if (!bw_is_finite(coeffs->prewarp_freq) || coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
 		return 0;
 	if (!bw_is_finite(coeffs->dc_gain) || coeffs->dc_gain < 1e-30f || coeffs->dc_gain > 1e30f)
 		return 0;

include/bw_ls2.h

@@ -708,9 +708,9 @@ static inline char bw_ls2_coeffs_is_valid(
 
 	if (!bw_is_finite(coeffs->cutoff) || coeffs->cutoff <= 0.f)
 		return 0;
-	if (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f)
+	if (!bw_is_finite(coeffs->prewarp_k) || (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f))
 		return 0;
-	if (coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
+	if (!bw_is_finite(coeffs->prewarp_freq) || coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
 		return 0;
 	if (!bw_is_finite(coeffs->dc_gain) || coeffs->dc_gain < 1e-30f || coeffs->dc_gain > 1e30f)
 		return 0;

include/bw_one_pole.h

@@ -247,6 +247,8 @@ static inline float bw_one_pole_process1_asym_sticky_rel(
  *       not `0.f`, and that the distance metric for sticky behavior is set to
  *       `bw_one_pole_sticky_mode_rel`.
  *
+ *    Such assumptions are unchecked even for debugging purposes.
+ *
  *    #### bw_one_pole_process()
  *  ```>>> */
 static inline void bw_one_pole_process(
@@ -651,7 +653,6 @@ static inline float bw_one_pole_process1(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_one_pole_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT_DEEP(coeffs->mA1u == coeffs->mA1d && coeffs->st2 == 0.f);
 
 	const float y = x + coeffs->mA1u * (state->y_z1 - x);
 	state->y_z1 = y;
@@ -674,7 +675,6 @@ static inline float bw_one_pole_process1_sticky_abs(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_one_pole_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT_DEEP(coeffs->mA1u == coeffs->mA1d && coeffs->st2 != 0.f && coeffs->sticky_mode == bw_one_pole_sticky_mode_abs);
 
 	float y = x + coeffs->mA1u * (state->y_z1 - x);
 	const float d = y - x;
@@ -700,7 +700,6 @@ static inline float bw_one_pole_process1_sticky_rel(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_one_pole_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT_DEEP(coeffs->mA1u == coeffs->mA1d && coeffs->st2 != 0.f && coeffs->sticky_mode == bw_one_pole_sticky_mode_rel);
 
 	float y = x + coeffs->mA1u * (state->y_z1 - x);
 	const float d = y - x;
@@ -726,7 +725,6 @@ static inline float bw_one_pole_process1_asym(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_one_pole_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT_DEEP(coeffs->mA1u != coeffs->mA1d && coeffs->st2 == 0.f);
 
 	const float y = x + (x >= state->y_z1 ? coeffs->mA1u : coeffs->mA1d) * (state->y_z1 - x);
 	state->y_z1 = y;
@@ -749,7 +747,6 @@ static inline float bw_one_pole_process1_asym_sticky_abs(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_one_pole_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT_DEEP(coeffs->mA1u != coeffs->mA1d && coeffs->st2 != 0.f && coeffs->sticky_mode == bw_one_pole_sticky_mode_abs);
 
 	float y = x + (x >= state->y_z1 ? coeffs->mA1u : coeffs->mA1d) * (state->y_z1 - x);
 	const float d = y - x;
@@ -775,7 +772,6 @@ static inline float bw_one_pole_process1_asym_sticky_rel(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_one_pole_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT_DEEP(coeffs->mA1u != coeffs->mA1d && coeffs->st2 != 0.f && coeffs->sticky_mode == bw_one_pole_sticky_mode_rel);
 
 	float y = x + (x >= state->y_z1 ? coeffs->mA1u : coeffs->mA1d) * (state->y_z1 - x);
 	const float d = y - x;
@@ -1149,7 +1145,7 @@ static inline char bw_one_pole_coeffs_is_valid(
 		return 0;
 	if (coeffs->cutoff_down < 0.f)
 		return 0;
-	if (coeffs->sticky_thresh < 0.f || coeffs->sticky_thresh > 1e18f)
+	if (!bw_is_finite(coeffs->sticky_thresh) || coeffs->sticky_thresh < 0.f || coeffs->sticky_thresh > 1e18f)
 		return 0;
 	if (coeffs->sticky_mode != bw_one_pole_sticky_mode_abs && coeffs->sticky_mode != bw_one_pole_sticky_mode_rel)
 		return 0;

include/bw_slew_lim.h

@@ -203,6 +203,9 @@ static inline float bw_slew_lim_process1_none(
  *     * `bw_slew_lim_process1_none()` assumes that both the maximum upgoing and
  *       downgoing variation rates are infinite;
  *
+ *    Whether maximum upgoing and downgoing variation rates are actually
+ *    infinite is unchecked even for debugging purposes.
+ *
  *    #### bw_slew_lim_process()
  *  ```>>> */
 static inline void bw_slew_lim_process(
@@ -532,7 +535,7 @@ static inline float bw_slew_lim_process1_up(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_slew_lim_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT(bw_is_finite(coeffs->max_inc) && !bw_is_finite(coeffs->max_dec));
+	BW_ASSERT(bw_is_finite(coeffs->max_inc));
 
 	const float y = bw_minf(x, state->y_z1 + coeffs->max_inc);
 	state->y_z1 = y;
@@ -555,7 +558,7 @@ static inline float bw_slew_lim_process1_down(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_slew_lim_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT(!bw_is_finite(coeffs->max_inc) && bw_is_finite(coeffs->max_dec));
+	BW_ASSERT(bw_is_finite(coeffs->max_dec));
 
 	const float y = bw_maxf(x, state->y_z1 - coeffs->max_dec);
 	state->y_z1 = y;
@@ -578,7 +581,6 @@ static inline float bw_slew_lim_process1_none(
 	BW_ASSERT(state != NULL);
 	BW_ASSERT_DEEP(bw_slew_lim_state_is_valid(coeffs, state));
 	BW_ASSERT(bw_is_finite(x));
-	BW_ASSERT(!bw_is_finite(coeffs->max_inc) && !bw_is_finite(coeffs->max_dec));
 
 	(void)coeffs;
 	state->y_z1 = x;
@@ -800,9 +802,9 @@ static inline char bw_slew_lim_coeffs_is_valid(
 		return 0;
 #endif
 
-	if (coeffs->max_rate_up < 0.f)
+	if (!bw_is_finite(coeffs->max_rate_up) || coeffs->max_rate_up < 0.f)
 		return 0;
-	if (coeffs->max_rate_down < 0.f)
+	if (!bw_is_finite(coeffs->max_rate_down) || coeffs->max_rate_down < 0.f)
 		return 0;
 
 #ifdef BW_DEBUG_DEEP
@@ -812,9 +814,9 @@ static inline char bw_slew_lim_coeffs_is_valid(
 	}
 
 	if (coeffs->state >= bw_slew_lim_coeffs_state_reset_coeffs) {
-		if (coeffs->max_inc < 0.f)
+		if (!bw_is_finite(coeffs->max_inc) || coeffs->max_inc < 0.f)
 			return 0;
-		if (coeffs->max_dec < 0.f)
+		if (!bw_is_finite(coeffs->max_dec) || coeffs->max_dec < 0.f)
 			return 0;
 	}
 #endif

include/bw_svf.h

@@ -40,8 +40,6 @@
  *          <li>Changed model to get positive polarity at the bandpass
  *              output.</li>
  *          <li>Limited actual prewarping frequency to prevent instability.</li>
- *          <li>Now using relative sticky threshold for smoothing all
- *              "continuous" parameters.</li>
  *          <li>Added <code>bw_svf_reset_state_multi()</code> and updated C++
  *              API in this regard.</li>
  *          <li>Now <code>bw_svf_reset_state()</code> returns the initial output
@@ -57,7 +55,6 @@
  *          <li>Added overloaded C++ <code>process()</code> function taking
  *              C-style arrays as arguments.</li>
  *          <li>Removed usage of reserved identifiers.</li>
- *          <li>Fixed theoretical bug in <code>bw_svf_init()</code>.</li>
  *          <li>Clearly specified parameter validity ranges.</li>
  *          <li>Added debugging code.</li>
  *        </ul>
@@ -405,7 +402,6 @@ static inline void bw_svf_init(
 	bw_one_pole_init(&coeffs->smooth_coeffs);
 	bw_one_pole_set_tau(&coeffs->smooth_coeffs, 0.005f);
 	bw_one_pole_set_sticky_thresh(&coeffs->smooth_coeffs, 1e-3f);
-	bw_one_pole_set_sticky_mode(&coeffs->smooth_coeffs, bw_one_pole_sticky_mode_rel);
 	coeffs->cutoff = 1e3f;
 	coeffs->Q = 0.5f;
 	coeffs->prewarp_freq = 1e3f;
@@ -463,7 +459,7 @@ static inline void bw_svf_do_update_coeffs(
 			coeffs->kbl = coeffs->kf * cutoff_cur;
 		}
 		if (Q_changed) {
-			Q_cur = bw_one_pole_process1_sticky_rel(&coeffs->smooth_coeffs, &coeffs->smooth_Q_state, coeffs->Q);
+			Q_cur = bw_one_pole_process1_sticky_abs(&coeffs->smooth_coeffs, &coeffs->smooth_Q_state, coeffs->Q);
 			coeffs->k = bw_rcpf(Q_cur);
 		}
 		coeffs->hp_hb = coeffs->k + coeffs->kbl;
@@ -931,13 +927,13 @@ static inline char bw_svf_coeffs_is_valid(
 		return 0;
 #endif
 
-	if (coeffs->cutoff < 1e-6f || coeffs->cutoff > 1e12f)
+	if (!bw_is_finite(coeffs->cutoff) || coeffs->cutoff < 1e-6f || coeffs->cutoff > 1e12f)
 		return 0;
-	if (coeffs->Q < 1e-6f || coeffs->Q > 1e6f)
+	if (!bw_is_finite(coeffs->Q) || coeffs->Q < 1e-6f || coeffs->Q > 1e6f)
 		return 0;
-	if (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f)
+	if (!bw_is_finite(coeffs->prewarp_k) || (coeffs->prewarp_k != 0.f && coeffs->prewarp_k != 1.f))
 		return 0;
-	if (coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
+	if (!bw_is_finite(coeffs->prewarp_freq) || coeffs->prewarp_freq < 1e-6f || coeffs->prewarp_freq > 1e12f)
 		return 0;
 
 	if (!bw_one_pole_coeffs_is_valid(&coeffs->smooth_coeffs))