Add a simple interleaver implementation (not used yet)

impl/src/layer1/interleaver.c

@@ -0,0 +1,39 @@
+#include "interleaver.h"
+
+#include "config.h"
+
+void interleaver_interleave(const float complex *in, float complex *out, size_t n)
+{
+	size_t interleaved_base = 0;
+	size_t interleaved_index = 0;
+
+	/* example for this algorithm with INTERLEAVE_DISTANCE = 5:
+	 * original: abcdefghijklmn
+	 * output:   adgjmbehkncfil
+	 */
+	for(size_t orig_index = 0; orig_index < n; orig_index++) {
+		out[interleaved_index] = in[orig_index];
+
+		interleaved_index += INTERLEAVE_DISTANCE;
+		if(interleaved_index >= n) {
+			interleaved_base++;
+			interleaved_index = interleaved_base;
+		}
+	}
+}
+
+void interleaver_deinterleave(const float complex *in, float complex *out, size_t n)
+{
+	size_t interleaved_base = 0;
+	size_t interleaved_index = 0;
+
+	for(size_t orig_index = 0; orig_index < n; orig_index++) {
+		out[orig_index] = in[interleaved_index];
+
+		interleaved_index += INTERLEAVE_DISTANCE;
+		if(interleaved_index >= n) {
+			interleaved_base++;
+			interleaved_index = interleaved_base;
+		}
+	}
+}

impl/src/layer1/interleaver.h

@@ -0,0 +1,11 @@
+#ifndef INTERLEAVER_H
+#define INTERLEAVER_H
+
+#include <complex.h>
+#include <stddef.h>
+
+void interleaver_interleave(const float complex *in, float complex *out, size_t n);
+
+void interleaver_deinterleave(const float complex *in, float complex *out, size_t n);
+
+#endif // INTERLEAVER_H

impl/test/CMakeLists.txt

@@ -201,3 +201,17 @@ add_executable(
 target_link_libraries(
 	test_packet_queue
 )
+
+#------------------------------------
+
+add_executable(
+	test_interleaver
+	../src/layer1/interleaver.c
+	../src/layer1/interleaver.h
+	../src/config.h
+	test_interleaver.c
+)
+
+target_link_libraries(
+	test_interleaver
+)

impl/test/test_interleaver.c

@@ -0,0 +1,26 @@
+#include <assert.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+#include <layer1/interleaver.h>
+
+
+int main(void)
+{
+	const size_t N = 100;
+	float complex orig[N];
+	float complex interleaved[N];
+	float complex deinterleaved[N];
+
+	for(size_t i = 0; i < N; i++) {
+		orig[i] = (float complex)i;
+	}
+
+	interleaver_interleave(orig, interleaved, N);
+	interleaver_deinterleave(interleaved, deinterleaved, N);
+
+	for(size_t i = 0; i < N; i++) {
+		printf("%5zu %5.1f %5.1f %5.1f\n", i, crealf(orig[i]), crealf(interleaved[i]), crealf(deinterleaved[i]));
+		assert(orig[i] == deinterleaved[i]);
+	}
+}