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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+
+#ifndef WebAudioUtils_h_
+#define WebAudioUtils_h_
+
+#include <cmath>
+#include <limits>
+#include <type_traits>
+#include "mozilla/FloatingPoint.h"
+#include "mozilla/Logging.h"
+#include "MediaSegment.h"
+
+// Forward declaration
+typedef struct SpeexResamplerState_ SpeexResamplerState;
+
+namespace mozilla {
+
+class AudioNodeTrack;
+
+extern LazyLogModule gWebAudioAPILog;
+#define WEB_AUDIO_API_LOG(...) \
+ MOZ_LOG(gWebAudioAPILog, LogLevel::Debug, (__VA_ARGS__))
+
+namespace dom {
+
+struct AudioTimelineEvent;
+
+namespace WebAudioUtils {
+// 32 is the minimum required by the spec for createBuffer() and
+// createScriptProcessor() and matches what is used by Blink. The limit
+// protects against large memory allocations.
+const size_t MaxChannelCount = 32;
+// AudioContext::CreateBuffer() "must support sample-rates in at least the
+// range 22050 to 96000."
+const uint32_t MinSampleRate = 8000;
+const uint32_t MaxSampleRate = 192000;
+
+inline bool FuzzyEqual(float v1, float v2) { return fabsf(v1 - v2) < 1e-7f; }
+inline bool FuzzyEqual(double v1, double v2) { return fabs(v1 - v2) < 1e-7; }
+
+/**
+ * Converts an AudioTimelineEvent's floating point time values to tick values
+ * with respect to a destination AudioNodeTrack.
+ *
+ * This needs to be called for each AudioTimelineEvent that gets sent to an
+ * AudioNodeEngine, on the engine side where the AudioTimlineEvent is
+ * received. This means that such engines need to be aware of their
+ * destination tracks as well.
+ */
+void ConvertAudioTimelineEventToTicks(AudioTimelineEvent& aEvent,
+ AudioNodeTrack* aDest);
+
+/**
+ * Converts a linear value to decibels. Returns aMinDecibels if the linear
+ * value is 0.
+ */
+inline float ConvertLinearToDecibels(float aLinearValue, float aMinDecibels) {
+ return aLinearValue ? 20.0f * std::log10(aLinearValue) : aMinDecibels;
+}
+
+/**
+ * Converts a decibel value to a linear value.
+ */
+inline float ConvertDecibelsToLinear(float aDecibels) {
+ return std::pow(10.0f, 0.05f * aDecibels);
+}
+
+/**
+ * Converts a decibel to a linear value.
+ */
+inline float ConvertDecibelToLinear(float aDecibel) {
+ return std::pow(10.0f, 0.05f * aDecibel);
+}
+
+inline void FixNaN(double& aDouble) {
+ if (std::isnan(aDouble) || std::isinf(aDouble)) {
+ aDouble = 0.0;
+ }
+}
+
+inline double DiscreteTimeConstantForSampleRate(double timeConstant,
+ double sampleRate) {
+ return 1.0 - std::exp(-1.0 / (sampleRate * timeConstant));
+}
+
+inline bool IsTimeValid(double aTime) {
+ return aTime >= 0 && aTime <= (MEDIA_TIME_MAX >> TRACK_RATE_MAX_BITS);
+}
+
+/**
+ * Converts a floating point value to an integral type in a safe and
+ * platform agnostic way. The following program demonstrates the kinds
+ * of ways things can go wrong depending on the CPU architecture you're
+ * compiling for:
+ *
+ * #include <stdio.h>
+ * volatile float r;
+ * int main()
+ * {
+ * unsigned int q;
+ * r = 1e100;
+ * q = r;
+ * printf("%f %d\n", r, q);
+ * r = -1e100;
+ * q = r;
+ * printf("%f %d\n", r, q);
+ * r = 1e15;
+ * q = r;
+ * printf("%f %x\n", r, q);
+ * r = 0/0.;
+ * q = r;
+ * printf("%f %d\n", r, q);
+ * }
+ *
+ * This program, when compiled for unsigned int, generates the following
+ * results depending on the architecture:
+ *
+ * x86 and x86-64
+ * ---
+ * inf 0
+ * -inf 0
+ * 999999995904.000000 -727384064 d4a50000
+ * nan 0
+ *
+ * ARM
+ * ---
+ * inf -1
+ * -inf 0
+ * 999999995904.000000 -1
+ * nan 0
+ *
+ * When compiled for int, this program generates the following results:
+ *
+ * x86 and x86-64
+ * ---
+ * inf -2147483648
+ * -inf -2147483648
+ * 999999995904.000000 -2147483648
+ * nan -2147483648
+ *
+ * ARM
+ * ---
+ * inf 2147483647
+ * -inf -2147483648
+ * 999999995904.000000 2147483647
+ * nan 0
+ *
+ * Note that the caller is responsible to make sure that the value
+ * passed to this function is not a NaN. This function will abort if
+ * it sees a NaN.
+ */
+template <typename IntType, typename FloatType>
+IntType TruncateFloatToInt(FloatType f) {
+ using std::numeric_limits;
+ static_assert(std::is_integral_v<IntType> == true,
+ "IntType must be an integral type");
+ static_assert(std::is_floating_point_v<FloatType> == true,
+ "FloatType must be a floating point type");
+
+ if (std::isnan(f)) {
+ // It is the responsibility of the caller to deal with NaN values.
+ // If we ever get to this point, we have a serious bug to fix.
+ MOZ_CRASH("We should never see a NaN here");
+ }
+
+ // If the floating point value is outside of the range of maximum
+ // integral value for this type, just clamp to the maximum value.
+ // The equality case must also return max() due to loss of precision when
+ // converting max() to float.
+ if (f >= FloatType(numeric_limits<IntType>::max())) {
+ return numeric_limits<IntType>::max();
+ }
+
+ if (f <= FloatType(numeric_limits<IntType>::min())) {
+ // If the floating point value is outside of the range of minimum
+ // integral value for this type, just clamp to the minimum value.
+ return numeric_limits<IntType>::min();
+ }
+
+ // Otherwise, this conversion must be well defined.
+ return IntType(f);
+}
+
+void Shutdown();
+
+int SpeexResamplerProcess(SpeexResamplerState* aResampler, uint32_t aChannel,
+ const float* aIn, uint32_t* aInLen, float* aOut,
+ uint32_t* aOutLen);
+
+int SpeexResamplerProcess(SpeexResamplerState* aResampler, uint32_t aChannel,
+ const int16_t* aIn, uint32_t* aInLen, float* aOut,
+ uint32_t* aOutLen);
+
+int SpeexResamplerProcess(SpeexResamplerState* aResampler, uint32_t aChannel,
+ const int16_t* aIn, uint32_t* aInLen, int16_t* aOut,
+ uint32_t* aOutLen);
+
+void LogToDeveloperConsole(uint64_t aWindowID, const char* aKey);
+
+} // namespace WebAudioUtils
+
+} // namespace dom
+} // namespace mozilla
+
+#endif