SquidgeDSP/core/Clipper.cpp

#include "Clipper.hpp"
#include <cmath>

Clipper::Clipper(float init_clip, ClipperMode init_mode)
    : threshold_(init_clip), mode_(init_mode) {}

void Clipper::process(const float *in, float *out, uint32_t frames) {
  for (uint32_t i = 0; i < frames; ++i) {
    out[i] = clip(in[i]);
  }
}
void Clipper::processStereo(const float *inLeft, const float *inRight,
                            float *outLeft, float *outRight, uint32_t frames) {
  for (uint32_t i = 0; i < frames; ++i) {
    outLeft[i] = clip(inLeft[i]);
    outRight[i] = clip(inRight[i]);
  }
}

float Clipper::clip(const float in) {
  switch (mode_) {
  case kClipperModeHard: {
    return std::fmin(std::fmax(in, -threshold_), threshold_);
  }
  default:
  case kClipperModeSoft: {
    float normalized = (in / threshold_) * 0.75f;
    return std::tanh(normalized) * threshold_;
  }
  case kClipperModeFold: {
    float x = in;
    while (x > threshold_ || x < -threshold_) {
      if (x > threshold_) {
        x = 2.0f * threshold_ - x;
      } else if (x < -threshold_) {
        x = -2.0f * threshold_ - x;
      }
    }
    return x;
  }
  }
}