Address feedback, add test.

rem/aufile/aufile.c

@@ -260,18 +260,18 @@ size_t aufile_get_length(struct aufile *af, const struct aufile_prm *prm)
 	switch (prm->fmt) {
 		case AUFMT_PCMA:
 		case AUFMT_PCMU:
-			return af->datasize / prm->channels * 1000
-				/ prm->srate;
+			return af->datasize * 1000 /
+				(prm->channels * prm->srate);
 		case AUFMT_S16LE:
-			return af->datasize / 2 / prm->channels * 1000
-				/ prm->srate;
+			return af->datasize * 1000 /
+				(prm->channels * prm->srate * 2);
 		case AUFMT_S24_3LE:
-			return af->datasize / 3 / prm->channels * 1000
-				/ prm->srate;
+			return af->datasize * 1000 /
+				(prm->channels * prm->srate * 3);
 		case AUFMT_S32LE:
 		case AUFMT_FLOAT:
-			return af->datasize / 4 / prm->channels * 1000
-				/ prm->srate;
+			return af->datasize * 1000 /
+				(prm->channels * prm->srate * 4);
 		default:
 			return 0;
 	}

test/CMakeLists.txt

@@ -70,6 +70,7 @@ set(SRCS
   aes.c
   async.c
   aubuf.c
+  aulength.c
   aulevel.c
   auresamp.c
   av1.c

test/aulength.c

@@ -0,0 +1,36 @@
+/**
+ * @file src/aulength.c audio file duration test
+ *
+ * Copyright (C) 2023 Lars Immisch
+ */
+
+#include <re.h>
+#include <rem.h>
+#include "test.h"
+
+
+#define DEBUG_MODULE "aulength"
+#define DEBUG_LEVEL 5
+#include <re_dbg.h>
+
+
+int test_aulength(void)
+{
+	struct aufile *af;
+	struct aufile_prm prm;
+	char path[256];
+
+	re_snprintf(path, sizeof(path), "%s/beep.wav", test_datapath());
+
+	int err = aufile_open(&af, &prm, path, AUFILE_READ);
+	if (err)
+		return err;
+
+	size_t length = aufile_get_length(af, &prm);
+	TEST_EQUALS(67, length);
+
+out:
+	mem_deref(af);
+
+	return err;
+}

test/test.c

@@ -53,6 +53,7 @@ static const struct test tests[] = {
 	TEST(test_aes),
 	TEST(test_aes_gcm),
 	TEST(test_aubuf),
+	TEST(test_aulength),
 	TEST(test_aulevel),
 	TEST(test_auresamp),
 	TEST(test_async),

test/test.h

@@ -159,6 +159,7 @@ int test_aes(void);
 int test_aes_gcm(void);
 int test_aubuf(void);
 int test_aulevel(void);
+int test_aulength(void);
 int test_auresamp(void);
 int test_async(void);
 int test_av1(void);