From 38ab363275a8dd70988eadab7c84071d69a740fc Mon Sep 17 00:00:00 2001
From: Christian Spielberger <christian.spielberger@gmail.com>
Date: Wed, 27 Apr 2022 17:05:34 +0200
Subject: [PATCH] au: add util function calc_nsamp() (#42)

---
 CMakeLists.txt   |  1 +
 include/rem_au.h |  2 ++
 src/au/mod.mk    |  2 +-
 src/au/util.c    | 23 +++++++++++++++++++++++
 4 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 src/au/util.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 49a8311..043bab9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -62,6 +62,7 @@ add_definitions(-DVERSION="${PROJECT_VERSION}")
 add_library(${PROJECT_NAME}
   src/aac/aac.c
   src/au/fmt.c
+  src/au/util.c
   src/aubuf/aubuf.c
   src/aubuf/ajb.c
   src/auconv/auconv.c
diff --git a/include/rem_au.h b/include/rem_au.h
index 47c7836..8174acb 100644
--- a/include/rem_au.h
+++ b/include/rem_au.h
@@ -18,3 +18,5 @@ enum aufmt {
 
 size_t      aufmt_sample_size(enum aufmt fmt);
 const char *aufmt_name(enum aufmt fmt);
+
+uint32_t calc_nsamp(uint32_t srate, uint8_t channels, uint16_t ptime);
diff --git a/src/au/mod.mk b/src/au/mod.mk
index d300f31..5e86454 100644
--- a/src/au/mod.mk
+++ b/src/au/mod.mk
@@ -4,4 +4,4 @@
 # Copyright (C) 2010 Creytiv.com
 #
 
-SRCS	+= au/fmt.c
+SRCS	+= au/fmt.c au/util.c
diff --git a/src/au/util.c b/src/au/util.c
new file mode 100644
index 0000000..dddf19c
--- /dev/null
+++ b/src/au/util.c
@@ -0,0 +1,23 @@
+/**
+ * @file util.c  Audio utility functions
+ *
+ * Copyright (C) 2022 Commend.com - c.spielberger@commend.com
+ */
+
+#include <re.h>
+#include <rem_au.h>
+
+
+/**
+ * Calculate number of samples from sample rate, channels and packet time
+ *
+ * @param srate    Sample rate in [Hz]
+ * @param channels Number of channels
+ * @param ptime    Packet time in [ms]
+ *
+ * @return Number of samples
+ */
+uint32_t calc_nsamp(uint32_t srate, uint8_t channels, uint16_t ptime)
+{
+	return srate * channels * ptime / 1000;
+}