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// Zigzag
//
// zigzag
//
// ZigZag Filter
//
//
//
// Inputs: 1
// Outputs: 2
// Constants: 1
#include "ts.h"
typedef struct {
fp_t threshold;
} ts_zigzag_params_t;
ts_parameter_t const ts_zigzag_p = { .n_inputs = 1, .n_outputs = 2, .n_constants = 1, .params_size = sizeof(ts_zigzag_params_t) };
uint_t ts_zigzag_offset( ts_constant_t const *c )
{
( void )c;
return ( 0 );
}
int ts_zigzag(
fp_t * const *y, uint_t y_n,
fp_t const * const *x, uint_t x_n,
uint_t n, ts_constant_t const *c
)
{
TS_PROLOGUE( ts_zigzag_p );
if ( !c ) return -1;
fp_t threshold = ((ts_zigzag_params_t const *)c)->threshold;
if (threshold <= 0 || isnan(threshold) || isinf(threshold)) return -1;
y[0][0] = x[0][0];
y[1][0] = 0;
for( uint_t i = 1; i < n; ++i )
{
fp_t last_zz = y[0][i - 1];
fp_t dir = y[1][i - 1];
fp_t change = last_zz != 0 ? ( x[0][i] - last_zz ) / last_zz * 100.0 : 0;
if( dir == 0 )
{
if( change >= threshold )
{
y[0][i] = x[0][i];
y[1][i] = 1;
}
else if( change <= -threshold )
{
y[0][i] = x[0][i];
y[1][i] = -1;
}
else
{
y[0][i] = last_zz;
y[1][i] = 0;
}
}
else if( dir == 1 )
{
if( change <= -threshold )
{
y[0][i] = x[0][i];
y[1][i] = -1;
}
else
{
y[0][i] = last_zz;
y[1][i] = 1;
}
}
else
{
if( change >= threshold )
{
y[0][i] = x[0][i];
y[1][i] = 1;
}
else
{
y[0][i] = last_zz;
y[1][i] = -1;
}
}
}
return 0;
}
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