AudioFlinger: Split off audio processing library

Test: native AudioResampler test, general playback test
Bug: 31015569
Change-Id: Ifb248f4402a583438d756c014dcd7a4577aef713
diff --git a/media/libaudioprocessing/AudioResamplerCubic.h b/media/libaudioprocessing/AudioResamplerCubic.h
new file mode 100644
index 0000000..defaf33
--- /dev/null
+++ b/media/libaudioprocessing/AudioResamplerCubic.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2007 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.
+ */
+
+#ifndef ANDROID_AUDIO_RESAMPLER_CUBIC_H
+#define ANDROID_AUDIO_RESAMPLER_CUBIC_H
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <android/log.h>
+
+#include <media/AudioResampler.h>
+
+namespace android {
+// ----------------------------------------------------------------------------
+
+class AudioResamplerCubic : public AudioResampler {
+public:
+    AudioResamplerCubic(int inChannelCount, int32_t sampleRate) :
+        AudioResampler(inChannelCount, sampleRate, MED_QUALITY) {
+    }
+    virtual size_t resample(int32_t* out, size_t outFrameCount,
+            AudioBufferProvider* provider);
+private:
+    // number of bits used in interpolation multiply - 14 bits avoids overflow
+    static const int kNumInterpBits = 14;
+
+    // bits to shift the phase fraction down to avoid overflow
+    static const int kPreInterpShift = kNumPhaseBits - kNumInterpBits;
+    typedef struct {
+        int32_t a, b, c, y0, y1, y2, y3;
+    } state;
+    void init();
+    size_t resampleMono16(int32_t* out, size_t outFrameCount,
+            AudioBufferProvider* provider);
+    size_t resampleStereo16(int32_t* out, size_t outFrameCount,
+            AudioBufferProvider* provider);
+    static inline int32_t interp(state* p, int32_t x) {
+        return (((((p->a * x >> 14) + p->b) * x >> 14) + p->c) * x >> 14) + p->y1;
+    }
+    static inline void advance(state* p, int16_t in) {
+        p->y0 = p->y1;
+        p->y1 = p->y2;
+        p->y2 = p->y3;
+        p->y3 = in;
+        p->a = (3 * (p->y1 - p->y2) - p->y0 + p->y3) >> 1;
+        p->b = (p->y2 << 1) + p->y0 - (((5 * p->y1 + p->y3)) >> 1);
+        p->c = (p->y2 - p->y0) >> 1;
+    }
+    state left, right;
+};
+
+// ----------------------------------------------------------------------------
+} // namespace android
+
+#endif /*ANDROID_AUDIO_RESAMPLER_CUBIC_H*/