From f7ab563da007de2a4ca61a1b5befe3f618abf937 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Mon, 29 Mar 2021 15:52:02 +0200
Subject: [PATCH] zita-convolver: prepare for non-power-of-two processing

---
 libs/zita-convolver/zita-convolver.cc         | 53 +++++++++++++++++++
 .../zita-convolver/zita-convolver.h           |  2 +
 2 files changed, 55 insertions(+)

diff --git a/libs/zita-convolver/zita-convolver.cc b/libs/zita-convolver/zita-convolver.cc
index 4563220ada..96a00c05d5 100644
--- a/libs/zita-convolver/zita-convolver.cc
+++ b/libs/zita-convolver/zita-convolver.cc
@@ -307,6 +307,29 @@ Convproc::process ()
 	return f;
 }
 
+int
+Convproc::tailonly (uint32_t n_samples)
+{
+	uint32_t k;
+	int      f = 0;
+
+	if (_state != ST_PROC) {
+		return 0;
+	}
+
+	uint32_t outoffs = _outoffs;
+	outoffs += _quantum;
+	if (outoffs == _minpart) {
+		for (k = 0; k < _nout; k++) {
+			memset (_outbuff[k], 0, n_samples * sizeof (float));
+		}
+		for (k = 0; k < _nlevels; k++) {
+			f |= _convlev[k]->readtail (n_samples);
+		}
+	}
+	return f;
+}
+
 int
 Convproc::stop_process (void)
 {
@@ -810,6 +833,36 @@ Convlevel::readout ()
 	return (_wait > 1) ? _bits : 0;
 }
 
+int
+Convlevel::readtail (uint32_t n_samples)
+{
+	Outnode const* Y;
+
+	uint32_t opind   = _opind;
+	uint32_t outoffs = _outoffs + _outsize;
+	if (outoffs == _parsize) {
+
+		while (_wait) {
+			_done.wait ();
+			_wait--;
+		}
+
+		outoffs = 0;
+		if (++opind == 3) {
+			opind = 0;
+		}
+	}
+
+	for (Y = _out_list; Y; Y = Y->_next) {
+		float const* const p = Y->_buff[opind] + outoffs;
+		float* const       q = _outbuff[Y->_out];
+		for (uint32_t i = 0; i < n_samples; i++) {
+			q[i] += p[i];
+		}
+	}
+	return 0;
+}
+
 void
 Convlevel::print (FILE* F)
 {
diff --git a/libs/zita-convolver/zita-convolver/zita-convolver.h b/libs/zita-convolver/zita-convolver/zita-convolver.h
index 128e426e85..81fa0c8321 100644
--- a/libs/zita-convolver/zita-convolver/zita-convolver.h
+++ b/libs/zita-convolver/zita-convolver/zita-convolver.h
@@ -272,6 +272,7 @@ private:
 	void process ();
 
 	int readout ();
+	int readtail (uint32_t n_samples);
 
 	void stop (void);
 
@@ -392,6 +393,7 @@ public:
 	int start_process (int abspri, int policy);
 
 	int process ();
+	int tailonly (uint32_t n_samples);
 
 	int stop_process (void);