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#include <assert.h>
#include <stdarg.h>
#include <stdlib.h>
#include "sig.h"
typedef struct sig_t {
const sig_ops_t *ops;
void *ctxt[];
} sig_t;
/* return a new signal generator of ops type, configured according to va_list */
sig_t * sig_new(const sig_ops_t *ops, ...)
{
static const sig_ops_t null_ops;
size_t ctxt_size = 0;
sig_t *sig;
va_list ap;
if (!ops)
ops = &null_ops;
va_start(ap, ops);
if (ops->size)
ctxt_size = ops->size(ap);
va_end(ap);
sig = calloc(1, sizeof(sig_t) + ctxt_size);
if (!sig)
return NULL;
va_start(ap, ops);
if (ops->init)
ops->init(&sig->ctxt, ap);
va_end(ap);
sig->ops = ops;
return sig;
}
/* free a signal generator, always returns NULL */
sig_t * sig_free(sig_t *sig)
{
if (sig) {
if (sig->ops->destroy)
sig->ops->destroy(&sig->ctxt);
free(sig);
}
return NULL;
}
/* produce the value for time ticks_ms from the supplied signal generator,
* the returned value should always be kept in the range 0-1.
*/
float sig_output(sig_t *sig, unsigned ticks_ms)
{
assert(sig);
assert(sig->ops);
if (sig->ops->output)
return sig->ops->output(sig->ctxt, ticks_ms);
return 0;
}
#ifdef TESTING
#include <stdio.h>
int main(int argc, char *argv[])
{
sig_t *sig;
sig = sig_new(NULL);
printf("null output=%f\n", sig_output(sig, 0));
sig = sig_free(sig);
sig = sig_new(&sig_ops_sin, 2.f);
for (unsigned i = 0; i < 1000; i++)
printf("sin 2hz output %i=%f\n", i, sig_output(sig, i));
sig = sig_free(sig);
sig = sig_new(&sig_ops_mult,
sig_new(&sig_ops_sin, 1.f), /* LFO @ 1hz */
sig_new(&sig_ops_sin, 100.f) /* oscillator @ 100hz */
);
for (unsigned i = 0; i < 1000; i++)
printf("sin 100hz * 1hz output %i=%f\n", i, sig_output(sig, i));
sig = sig_free(sig);
}
#endif
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