//filter_amp.c:

/*
 *      Copyright (C) Philipp 'ph3-der-loewe' Schafft - 2008-2013
 *
 *  This file is part of libroardsp a part of RoarAudio,
 *  a cross-platform sound system for both, home and professional use.
 *  See README for details.
 *
 *  This file is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 3
 *  as published by the Free Software Foundation.
 *
 *  libroardsp 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
 *  along with this software; see the file COPYING.  If not, write to
 *  the Free Software Foundation, 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#include "libroardsp.h"

#ifdef ROAR_HAVE_LIBM
int roardsp_responsecurve_init  (struct roardsp_filter * filter, struct roar_stream * stream, int id) {
 struct roardsp_responsecurve * self = roar_mm_malloc(sizeof(struct roardsp_responsecurve));

 (void)stream, (void)id;

 ROAR_DBG("roardsp_responsecurve_init(filter=%p, stream=%p, id=%i) = ?", filter, stream, id);

 if ( self == NULL )
  return -1;

 memset(self, 0, sizeof(struct roardsp_responsecurve));

 filter->inst = (void*) self;

 roardsp_filter_reset(filter, ROARDSP_RESET_FULL);

 return 0;
}

int roardsp_responsecurve_uninit(struct roardsp_filter * filter) {

 roar_mm_free(filter->inst);
 return 0;
}

static double __func_pass(double i, double N) {
 (void)N;
 return i;
}

static double __func_linear(double i, double N) {
 return -pow(1. - i, N + 1.) + 1.;
}

static double __func_ilinear(double i, double N) {
 return pow(i, N + 1.);
}

static double __func_sin(double i, double N) {
 return pow(sin(M_PI_2 * i), N);
}

static double __func_isin(double i, double N) {
 return 1. - pow(sin((1. - i) * M_PI_2), N);
}

static double __func_cos(double i, double N) {
 (void)N;
 return 0.5 - cos(i * M_PI)/2.;
}

static double __func_icos(double i, double N) {
 (void)N;
 return 2.*i - 0.5 + cos(i * M_PI)/2.;
}

static inline double _oddify(double x, double N, double (*func)(double, double)) {
 if ( x < 0. ) {
  return -func(0. - x, N);
 } else {
  return func(x, N);
 }
}

static inline double _calc(double x, struct roardsp_responsecurve * self, double N) {
 double (*func)(double, double) = NULL;
 enum roardsp_responsecurve_mode mode;

 if ( x > 0. ) {
  mode = self->mode_pos;
 } else {
  mode = self->mode_neg;
 }

 switch (mode) {
  case ROARDSP_RESPONSECURVE_MODE_PASS: func = __func_pass; break;
  case ROARDSP_RESPONSECURVE_MODE_LIN:  func = __func_linear; break;
  case ROARDSP_RESPONSECURVE_MODE_ILIN: func = __func_ilinear; break;
  case ROARDSP_RESPONSECURVE_MODE_SIN:  func = __func_sin; break;
  case ROARDSP_RESPONSECURVE_MODE_ISIN: func = __func_isin; break;
  case ROARDSP_RESPONSECURVE_MODE_COS:  func = __func_cos; break;
  case ROARDSP_RESPONSECURVE_MODE_ICOS: func = __func_icos; break;
  default: func = __func_linear; break;
 }

 return _oddify(x, N, func);
}

#define _calcX(bits,fact) \
int roardsp_responsecurve_calc##bits  (struct roardsp_filter * filter, void * data, size_t samples) { \
 struct roardsp_responsecurve * self = (struct roardsp_responsecurve *) filter->inst; \
 int##bits##_t * samp = (int##bits##_t *) data; \
 register double s; \
 size_t i; \
\
 for (i = 0; i < samples; i++) { \
  s        = samp[i]; \
  s       /= (double)(fact); \
  s        = _calc(s, self, self->N); \
  s       *= (double)(fact); \
  samp[i]  = s; \
 }; \
\
 return 0; \
}

_calcX(8,128.)
_calcX(16,32768.)
_calcX(32,2147483648.)

int roardsp_responsecurve_ctl   (struct roardsp_filter * filter, int cmd, void * data) {
 struct roardsp_responsecurve * self = (struct roardsp_responsecurve *) filter->inst;
 int32_t old;

 if ( cmd == ROARDSP_FCTL_N ) {
  old = self->N;
  self->N = *(int32_t*)data;
  *(int32_t*)data = old;
 } else if ( cmd == ROARDSP_FCTL_MODE ) {
  old = self->mode_pos;
  self->mode_pos = *(int32_t*)data;
  *(int32_t*)data = old;
 } else if ( cmd == ROARDSP_FCTL_Q ) {
  old = self->mode_neg;
  self->mode_neg = *(int32_t*)data;
  *(int32_t*)data = old;
 } else {
  return -1;
 }


 return 0;
}

int roardsp_responsecurve_reset (struct roardsp_filter * filter, int what) {
 struct roardsp_responsecurve * self;

 if ( filter == NULL )
  return -1;

 if ( filter->inst == NULL )
  return -1;

 self = filter->inst;

 switch (what) {
  case ROARDSP_RESET_NONE:
  case ROARDSP_RESET_STATE:
    return  0;
   break;
  case ROARDSP_RESET_FULL:
    self->mode_pos = self->mode_neg = ROARDSP_RESPONSECURVE_MODE_LIN;
    self->N    = 1;
    return  0;
   break;
  default:
    return -1;
 }

 return -1;
}
#endif

//ll