make helper funcs inline; drop std::span for algo

1 files changed, 12 insertions, 4 deletions

diff --git a/examples/7_iir_echo.cpp b/examples/7_iir_echo.cpp
index 57e5605..75bf56e 100644
--- a/examples/7_iir_echo.cpp
+++ b/examples/7_iir_echo.cpp
@@ -1,9 +1,17 @@
-Sample *process_data(Samples samples)
+/**
+ * 7_iir_echo.cpp
+ * Written by Clyne Sullivan.
+ *
+ * This filter produces an echo of the given input. There are two parameters:
+ * alpha controls the feedback gain, and D controls the echo/delay length.
+ */
+
+Sample* process_data(Samples samples)
 {
 	constexpr float alpha = 0.75;
 	constexpr unsigned int D = 100;
 
-	static Sample output[samples.size()];
+	static Samples output;
 	static Sample prev[D]; // prev[0] = output[0 - D]
 
 	// Do calculations with previous output
@@ -11,12 +19,12 @@ Sample *process_data(Samples samples)
 		output[i] = samples[i] + alpha * (prev[i] - 2048);
 
 	// Do calculations with current samples
-	for (unsigned int i = D; i < samples.size(); i++)
+	for (unsigned int i = D; i < SIZE; i++)
 		output[i] = samples[i] + alpha * (output[i - D] - 2048);
 
 	// Save outputs for next computation
 	for (unsigned int i = 0; i < D; i++)
-		prev[i] = output[samples.size() - (D - i)];
+		prev[i] = output[SIZE - (D - i)];
 
 	return output;
 }