src/synth_math.h


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#ifndef SYNTH_MATH_H
#define SYNTH_MATH_H

#include <stddef.h>

// do I really want inline? used to be static
inline long long
gcd(long long a, long long b)
{
  long long rem;
  rem=a-(a/b*b);
  if(rem==0)
    return b;
  else
    gcd(b, rem);

  // unreachable
  return 0;
}
 
// Function to return LCM of two numbers
inline long long
lcm(long long a, long long b)
{
  return (a / gcd(a, b)) * b;
}

static float
clamp(float f, int min, int max)
{
  if (f <= min) return min + 0.0001;
  if (f >= max)  return max - 0.0001;
  return f;
}

/* 1d convolution */
inline void
convole(float *signal, float *filter,
        size_t signal_size, size_t filter_size, float *out) {
  for (size_t i = 0; i < filter_size + signal_size; i++) {
    size_t kmin, kmax, k;
    out[i] = 0;
    /* find overlap */
    kmin = (i >= filter_size - 1) ? i - (filter_size - 1) : 0;
    kmax = (i < signal_size - 1) ? i : signal_size - 1;

    /* Add the overlaping values */
    for (k = kmin; k <= kmax; k++) {
      out[i] += signal[k] * filter[i - k];
    }
  }
}

#endif /* SYNTH_MATH_H */