From 3439f3a497da84a016a6aea96f17d831f80c6115 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niccol=C3=B2=20Izzo?= <izzo.niccolo@gmail.com>
Date: Sun, 27 Jun 2021 19:00:06 +0200
Subject: [PATCH] Add invert phase DSP filter

---
 openrtx/include/dsp.h | 9 +++++++++
 openrtx/src/dsp.cpp   | 6 ++++--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/openrtx/include/dsp.h b/openrtx/include/dsp.h
index 3d031db3..ce966d2d 100644
--- a/openrtx/include/dsp.h
+++ b/openrtx/include/dsp.h
@@ -54,6 +54,15 @@ void dsp_pwmCompensate(audio_sample_t *buffer, size_t length);
  */
 void dsp_dcRemoval(audio_sample_t *buffer, size_t length);
 
+/*
+ * Inverts the phase of the audio buffer passed as paramenter.
+ * The buffer will be processed in place to save memory.
+ *
+ * @param buffer: the buffer to be used as both source and destination.
+ * @param length: the length of the input buffer.
+ */
+void dsp_invertPhase(audio_sample_t *buffer, uint16_t length);
+
 #ifdef __cplusplus
 }
 
diff --git a/openrtx/src/dsp.cpp b/openrtx/src/dsp.cpp
index d4ff898c..6f367c08 100644
--- a/openrtx/src/dsp.cpp
+++ b/openrtx/src/dsp.cpp
@@ -57,9 +57,11 @@ void dsp_applyFIR(audio_sample_t *buffer,
                   uint16_t length,
                   std::array<float, order> taps)
 {
-    for(int i = length - 1; i >= 0; i--) {
+    for(int i = length - 1; i >= 0; i--)
+    {
         float acc = 0.0f;
-        for(uint16_t j = 0; j < order; j++) {
+        for(uint16_t j = 0; j < order; j++)
+        {
             if (i >= j)
                 acc += buffer[i - j] * taps[j];
         }