1 files changed, 116 insertions, 0 deletions
diff --git a/dom/media/gtest/TestAudioSampleFormat.cpp b/dom/media/gtest/TestAudioSampleFormat.cpp
new file mode 100644
index 0000000000..4737a73a23
--- /dev/null
+++ b/dom/media/gtest/TestAudioSampleFormat.cpp
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ *
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AudioSampleFormat.h"
+#include "gtest/gtest.h"
+#include <type_traits>
+
+using namespace mozilla;
+
+template <typename T>
+constexpr T LowestSample() {
+  if constexpr (std::is_integral_v<T>) {
+    return std::numeric_limits<T>::lowest();
+  } else {
+    return -1.0f;
+  }
+}
+
+// When converting a sample-type to another sample-type, this returns the
+// maximum value possible in the destination format
+template <typename Dest>
+constexpr Dest HighestSample() {
+  if constexpr (std::is_integral_v<Dest>) {
+    return std::numeric_limits<Dest>::max();
+  } else {
+    return +1.0f;
+  }
+}
+
+// When converting a sample-type to another sample-type, this returns the
+// maximum value expected in the destination format
+template <typename Dest, typename Source>
+constexpr Dest HighestSampleExpected() {
+  // When converting small integer samples to large integer sample, the higher
+  // bound isn't reached because of positive / negative integer assymetry.
+  if constexpr (std::is_same_v<Source, uint8_t> &&
+                std::is_same_v<Dest, int16_t>) {
+    return 32512;  // INT16_MAX - 2 << 7 + 1
+  } else if constexpr (std::is_same_v<Source, uint8_t> &&
+                       std::is_same_v<Dest, int32_t>) {
+    return 2130706432;  // INT32_MAX - (2 << 23) + 1
+  } else if constexpr (std::is_same_v<Source, int16_t> &&
+                       std::is_same_v<Dest, int32_t>) {
+    return 2147418112;  // INT32_MAX - UINT16_MAX
+  }
+
+  if constexpr (std::is_integral_v<Dest>) {
+    return std::numeric_limits<Dest>::max();
+  } else {
+    return +1.0f;
+  }
+}
+
+template <typename Source, typename Dest>
+void TestSampleTypePair() {
+  std::cout << __PRETTY_FUNCTION__ << std::endl;
+
+  ASSERT_EQ(LowestSample<Dest>(),
+            ConvertAudioSample<Dest>(LowestSample<Source>()));
+  Dest expected = HighestSampleExpected<Dest, Source>();
+  ASSERT_EQ(expected, ConvertAudioSample<Dest>(HighestSample<Source>()));
+  ASSERT_EQ(Bias<Dest>(), ConvertAudioSample<Dest>(Bias<Source>()));
+}
+
+template <typename T>
+void TestSampleType24bits() {
+  std::cout << __PRETTY_FUNCTION__ << std::endl;
+
+  int32_t max_sample_24bits = (2 << 22) - 1;
+  int32_t min_sample_24bits = -(2 << 22);
+  int32_t silence_24bits = 0;
+
+  ASSERT_EQ(LowestSample<T>(), Int24ToAudioSample<T>(min_sample_24bits));
+  ASSERT_EQ(Int24ToAudioSample<T>(min_sample_24bits), LowestSample<T>());
+  if constexpr (std::is_same_v<T, int32_t>) {
+    // Quantization issue: 2147483392 + (2<<8 - 1) == INT32_MAX
+    // See comment on HighestSampleExpected above
+    const int32_t HIGHEST_FROM_24BITS = 2147483392;
+    ASSERT_EQ(HIGHEST_FROM_24BITS, Int24ToAudioSample<T>(max_sample_24bits));
+    ASSERT_EQ(Int24ToAudioSample<T>(max_sample_24bits), HIGHEST_FROM_24BITS);
+  } else {
+    ASSERT_EQ(HighestSample<T>(), Int24ToAudioSample<T>(max_sample_24bits));
+    ASSERT_EQ(Int24ToAudioSample<T>(max_sample_24bits), HighestSample<T>());
+  }
+  ASSERT_EQ(Bias<T>(), Int24ToAudioSample<T>(silence_24bits));
+  ASSERT_EQ(Int24ToAudioSample<T>(silence_24bits), Bias<T>());
+}
+
+TEST(AudioSampleFormat, Boundaries)
+{
+  TestSampleTypePair<uint8_t, uint8_t>();
+  TestSampleTypePair<uint8_t, int16_t>();
+  TestSampleTypePair<uint8_t, int32_t>();
+  TestSampleTypePair<uint8_t, float>();
+  TestSampleTypePair<int16_t, uint8_t>();
+  TestSampleTypePair<int16_t, int16_t>();
+  TestSampleTypePair<int16_t, int32_t>();
+  TestSampleTypePair<int16_t, float>();
+  TestSampleTypePair<int32_t, uint8_t>();
+  TestSampleTypePair<int32_t, int16_t>();
+  TestSampleTypePair<int32_t, int32_t>();
+  TestSampleTypePair<int32_t, float>();
+  TestSampleTypePair<float, uint8_t>();
+  TestSampleTypePair<float, int16_t>();
+  TestSampleTypePair<float, int32_t>();
+  TestSampleTypePair<float, float>();
+
+  // Separately test 24-bit audio stored in 32-bits integers.
+  TestSampleType24bits<uint8_t>();
+  TestSampleType24bits<int16_t>();
+  TestSampleType24bits<int32_t>();
+  TestSampleType24bits<float>();
+}