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diff --git a/apps/OboeTester/app/src/main/cpp/synth/SawtoothOscillator.h b/apps/OboeTester/app/src/main/cpp/synth/SawtoothOscillator.h
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+++ b/apps/OboeTester/app/src/main/cpp/synth/SawtoothOscillator.h
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+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * This code was translated from the JSyn Java code.
+ * JSyn is Copyright 2009 Phil Burk, Mobileer Inc
+ * JSyn is licensed under the Apache License, Version 2.0
+ */
+
+#ifndef SYNTHMARK_SAWTOOTH_OSCILLATOR_H
+#define SYNTHMARK_SAWTOOTH_OSCILLATOR_H
+
+#include <cstdint>
+#include <math.h>
+#include "SynthTools.h"
+#include "UnitGenerator.h"
+#include "DifferentiatedParabola.h"
+
+namespace marksynth {
+/**
+ * Simple phasor that can be used to implement other oscillators.
+ * Note that this is NON-bandlimited and should not be used
+ * directly as a sound source.
+ */
+class SawtoothOscillator : public UnitGenerator
+{
+public:
+    SawtoothOscillator()
+    : mPhase(0) {}
+
+    virtual ~SawtoothOscillator() = default;
+
+    void generate(synth_float_t frequency, int32_t numSamples) {
+        synth_float_t phase = mPhase;
+        synth_float_t phaseIncrement = 2.0 * frequency * mSamplePeriod;
+        for (int i = 0; i < numSamples; i++) {
+            output[i] = translatePhase(phase, phaseIncrement);
+            phase += phaseIncrement;
+            if (phase > 1.0) {
+                phase -= 2.0;
+            }
+        }
+        mPhase = phase;
+    }
+
+    void generate(synth_float_t *frequencies, int32_t numSamples) {
+        synth_float_t phase = mPhase;
+        for (int i = 0; i < numSamples; i++) {
+            synth_float_t phaseIncrement = 2.0 * frequencies[i] * mSamplePeriod;
+            output[i] = translatePhase(phase, phaseIncrement);
+            phase += phaseIncrement;
+            if (phase > 1.0) {
+                phase -= 2.0;
+            }
+        }
+        mPhase = phase;
+    }
+
+    virtual synth_float_t translatePhase(synth_float_t phase, synth_float_t phaseIncrement) {
+        (void) phaseIncrement;
+        return phase;
+    }
+
+private:
+    synth_float_t mPhase; // between -1.0 and +1.0
+};
+
+};
+#endif // SYNTHMARK_SAWTOOTH_OSCILLATOR_H