1 files changed, 49 insertions, 0 deletions
diff --git a/src/libs/sig/ops_sin.c b/src/libs/sig/ops_sin.c
new file mode 100644
index 0000000..b228b49
--- /dev/null
+++ b/src/libs/sig/ops_sin.c
@@ -0,0 +1,49 @@
+#include <assert.h>
+#include <math.h>
+
+#include "sig.h"
+
+
+typedef struct ops_sin_ctxt_t {
+	float	hz;
+} ops_sin_ctxt_t;
+
+
+static size_t ops_sin_size(va_list ap)
+{
+	return sizeof(ops_sin_ctxt_t);
+}
+
+
+static void ops_sin_init(void *context, va_list ap)
+{
+	ops_sin_ctxt_t	*ctxt = context;
+
+	assert(ctxt);
+
+	ctxt->hz = va_arg(ap, double);
+	assert(ctxt->hz >= .0001f);
+}
+
+
+static float ops_sin_output(void *context, unsigned ticks_ms)
+{
+	ops_sin_ctxt_t	*ctxt = context;
+	float		rads_per_ms, rads;
+	unsigned	ms_per_cycle;
+
+	assert(ctxt);
+
+	ms_per_cycle = ctxt->hz * 1000.f;
+	rads_per_ms = (M_PI * 2.f) * ctxt->hz * .001f;
+	rads = (float)(ticks_ms % ms_per_cycle) * rads_per_ms;
+
+	return sinf(rads);
+}
+
+
+sig_ops_t	sig_ops_sin = {
+	.size = ops_sin_size,
+	.init = ops_sin_init,
+	.output = ops_sin_output,
+};