M7350v1_en_gpl

base/services/sensorservice/Android.mk

@@ -0,0 +1,34 @@
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= \
+	GravitySensor.cpp \
+	LinearAccelerationSensor.cpp \
+	RotationVectorSensor.cpp \
+    SensorService.cpp \
+    SensorInterface.cpp \
+    SensorDevice.cpp \
+    SecondOrderLowPassFilter.cpp
+
+LOCAL_CFLAGS:= -DLOG_TAG=\"SensorService\"
+
+# need "-lrt" on Linux simulator to pick up clock_gettime
+ifeq ($(TARGET_SIMULATOR),true)
+	ifeq ($(HOST_OS),linux)
+		LOCAL_LDLIBS += -lrt -lpthread
+	endif
+endif
+
+LOCAL_SHARED_LIBRARIES := \
+	libcutils \
+	libhardware \
+	libutils \
+	libbinder \
+	libui \
+	libgui
+
+LOCAL_PRELINK_MODULE := false
+
+LOCAL_MODULE:= libsensorservice
+
+include $(BUILD_SHARED_LIBRARY)

base/services/sensorservice/GravitySensor.cpp

@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "GravitySensor.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+GravitySensor::GravitySensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mAccTime(0),
+      mLowPass(M_SQRT1_2, 1.5f),
+      mX(mLowPass), mY(mLowPass), mZ(mLowPass)
+
+{
+    for (size_t i=0 ; i<count ; i++) {
+        if (list[i].type == SENSOR_TYPE_ACCELEROMETER) {
+            mAccelerometer = Sensor(list + i);
+            break;
+        }
+    }
+}
+
+bool GravitySensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    const static double NS2S = 1.0 / 1000000000.0;
+    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        float x, y, z;
+        const double now = event.timestamp * NS2S;
+        if (mAccTime == 0) {
+            x = mX.init(event.acceleration.x);
+            y = mY.init(event.acceleration.y);
+            z = mZ.init(event.acceleration.z);
+        } else {
+            double dT = now - mAccTime;
+            mLowPass.setSamplingPeriod(dT);
+            x = mX(event.acceleration.x);
+            y = mY(event.acceleration.y);
+            z = mZ(event.acceleration.z);
+        }
+        mAccTime = now;
+        *outEvent = event;
+        outEvent->data[0] = x;
+        outEvent->data[1] = y;
+        outEvent->data[2] = z;
+        outEvent->sensor = '_grv';
+        outEvent->type = SENSOR_TYPE_GRAVITY;
+        return true;
+    }
+    return false;
+}
+status_t GravitySensor::activate(void* ident, bool enabled) {
+    status_t err = mSensorDevice.activate(this, mAccelerometer.getHandle(), enabled);
+    if (err == NO_ERROR) {
+        if (enabled) {
+            mAccTime = 0;
+        }
+    }
+    return err;
+}
+
+status_t GravitySensor::setDelay(void* ident, int handle, int64_t ns)
+{
+    return mSensorDevice.setDelay(this, mAccelerometer.getHandle(), ns);
+}
+
+Sensor GravitySensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Gravity Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_grv';
+    hwSensor.type       = SENSOR_TYPE_GRAVITY;
+    hwSensor.maxRange   = mAccelerometer.getMaxValue();
+    hwSensor.resolution = mAccelerometer.getResolution();
+    hwSensor.power      = mAccelerometer.getPowerUsage();
+    hwSensor.minDelay   = mAccelerometer.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+

base/services/sensorservice/GravitySensor.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2010 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_GRAVITY_SENSOR_H
+#define ANDROID_GRAVITY_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+#include "SensorInterface.h"
+#include "SecondOrderLowPassFilter.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class GravitySensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    Sensor mAccelerometer;
+    double mAccTime;
+
+    SecondOrderLowPassFilter mLowPass;
+    CascadedBiquadFilter mX, mY, mZ;
+
+public:
+    GravitySensor(sensor_t const* list, size_t count);
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_GRAVITY_SENSOR_H

base/services/sensorservice/LinearAccelerationSensor.cpp

@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "LinearAccelerationSensor.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+LinearAccelerationSensor::LinearAccelerationSensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mGravitySensor(list, count)
+{
+    mData[0] = mData[1] = mData[2] = 0;
+}
+
+bool LinearAccelerationSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    bool result = mGravitySensor.process(outEvent, event);
+    if (result) {
+        if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+            mData[0] = event.acceleration.x;
+            mData[1] = event.acceleration.y;
+            mData[2] = event.acceleration.z;
+        }
+        outEvent->data[0] = mData[0] - outEvent->data[0];
+        outEvent->data[1] = mData[1] - outEvent->data[1];
+        outEvent->data[2] = mData[2] - outEvent->data[2];
+        outEvent->sensor = '_lin';
+        outEvent->type = SENSOR_TYPE_LINEAR_ACCELERATION;
+    }
+    return result;
+}
+
+status_t LinearAccelerationSensor::activate(void* ident, bool enabled) {
+    return mGravitySensor.activate(ident, enabled);
+}
+
+status_t LinearAccelerationSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mGravitySensor.setDelay(ident, handle, ns);
+}
+
+Sensor LinearAccelerationSensor::getSensor() const {
+    Sensor gsensor(mGravitySensor.getSensor());
+    sensor_t hwSensor;
+    hwSensor.name       = "Linear Acceleration Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_lin';
+    hwSensor.type       = SENSOR_TYPE_LINEAR_ACCELERATION;
+    hwSensor.maxRange   = gsensor.getMaxValue();
+    hwSensor.resolution = gsensor.getResolution();
+    hwSensor.power      = gsensor.getPowerUsage();
+    hwSensor.minDelay   = gsensor.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+

base/services/sensorservice/LinearAccelerationSensor.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2010 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_LINEAR_ACCELERATION_SENSOR_H
+#define ANDROID_LINEAR_ACCELERATION_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+#include "SensorInterface.h"
+#include "GravitySensor.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class LinearAccelerationSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    GravitySensor mGravitySensor;
+    float mData[3];
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+public:
+    LinearAccelerationSensor(sensor_t const* list, size_t count);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_LINEAR_ACCELERATION_SENSOR_H

base/services/sensorservice/RotationVectorSensor.cpp

@@ -0,0 +1,169 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "RotationVectorSensor.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+template <typename T>
+static inline T clamp(T v) {
+    return v < 0 ? 0 : v;
+}
+
+RotationVectorSensor::RotationVectorSensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mALowPass(M_SQRT1_2, 1.5f),
+      mAX(mALowPass), mAY(mALowPass), mAZ(mALowPass),
+      mMLowPass(M_SQRT1_2, 1.5f),
+      mMX(mMLowPass), mMY(mMLowPass), mMZ(mMLowPass)
+{
+    for (size_t i=0 ; i<count ; i++) {
+        if (list[i].type == SENSOR_TYPE_ACCELEROMETER) {
+            mAcc = Sensor(list + i);
+        }
+        if (list[i].type == SENSOR_TYPE_MAGNETIC_FIELD) {
+            mMag = Sensor(list + i);
+        }
+    }
+    memset(mMagData, 0, sizeof(mMagData));
+}
+
+bool RotationVectorSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    const static double NS2S = 1.0 / 1000000000.0;
+    if (event.type == SENSOR_TYPE_MAGNETIC_FIELD) {
+        const double now = event.timestamp * NS2S;
+        if (mMagTime == 0) {
+            mMagData[0] = mMX.init(event.magnetic.x);
+            mMagData[1] = mMY.init(event.magnetic.y);
+            mMagData[2] = mMZ.init(event.magnetic.z);
+        } else {
+            double dT = now - mMagTime;
+            mMLowPass.setSamplingPeriod(dT);
+            mMagData[0] = mMX(event.magnetic.x);
+            mMagData[1] = mMY(event.magnetic.y);
+            mMagData[2] = mMZ(event.magnetic.z);
+        }
+        mMagTime = now;
+    }
+    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        const double now = event.timestamp * NS2S;
+        float Ax, Ay, Az;
+        if (mAccTime == 0) {
+            Ax = mAX.init(event.acceleration.x);
+            Ay = mAY.init(event.acceleration.y);
+            Az = mAZ.init(event.acceleration.z);
+        } else {
+            double dT = now - mAccTime;
+            mALowPass.setSamplingPeriod(dT);
+            Ax = mAX(event.acceleration.x);
+            Ay = mAY(event.acceleration.y);
+            Az = mAZ(event.acceleration.z);
+        }
+        mAccTime = now;
+        const float Ex = mMagData[0];
+        const float Ey = mMagData[1];
+        const float Ez = mMagData[2];
+        float Hx = Ey*Az - Ez*Ay;
+        float Hy = Ez*Ax - Ex*Az;
+        float Hz = Ex*Ay - Ey*Ax;
+        const float normH = sqrtf(Hx*Hx + Hy*Hy + Hz*Hz);
+        if (normH < 0.1f) {
+            // device is close to free fall (or in space?), or close to
+            // magnetic north pole. Typical values are  > 100.
+            return false;
+        }
+        const float invH = 1.0f / normH;
+        const float invA = 1.0f / sqrtf(Ax*Ax + Ay*Ay + Az*Az);
+        Hx *= invH;
+        Hy *= invH;
+        Hz *= invH;
+        Ax *= invA;
+        Ay *= invA;
+        Az *= invA;
+        const float Mx = Ay*Hz - Az*Hy;
+        const float My = Az*Hx - Ax*Hz;
+        const float Mz = Ax*Hy - Ay*Hx;
+
+        // matrix to rotation vector (normalized quaternion)
+        float qw = sqrtf( clamp( Hx + My + Az + 1) * 0.25f );
+        float qx = sqrtf( clamp( Hx - My - Az + 1) * 0.25f );
+        float qy = sqrtf( clamp(-Hx + My - Az + 1) * 0.25f );
+        float qz = sqrtf( clamp(-Hx - My + Az + 1) * 0.25f );
+        qx = copysignf(qx, Ay - Mz);
+        qy = copysignf(qy, Hz - Ax);
+        qz = copysignf(qz, Mx - Hy);
+
+        // this quaternion is guaranteed to be normalized, by construction
+        // of the rotation matrix.
+
+        *outEvent = event;
+        outEvent->data[0] = qx;
+        outEvent->data[1] = qy;
+        outEvent->data[2] = qz;
+        outEvent->data[3] = qw;
+        outEvent->sensor = '_rov';
+        outEvent->type = SENSOR_TYPE_ROTATION_VECTOR;
+        return true;
+    }
+    return false;
+}
+
+status_t RotationVectorSensor::activate(void* ident, bool enabled) {
+    mSensorDevice.activate(this, mAcc.getHandle(), enabled);
+    mSensorDevice.activate(this, mMag.getHandle(), enabled);
+    if (enabled) {
+        mMagTime = 0;
+        mAccTime = 0;
+    }
+    return NO_ERROR;
+}
+
+status_t RotationVectorSensor::setDelay(void* ident, int handle, int64_t ns)
+{
+    mSensorDevice.setDelay(this, mAcc.getHandle(), ns);
+    mSensorDevice.setDelay(this, mMag.getHandle(), ns);
+    return NO_ERROR;
+}
+
+Sensor RotationVectorSensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Rotation Vector Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_rov';
+    hwSensor.type       = SENSOR_TYPE_ROTATION_VECTOR;
+    hwSensor.maxRange   = 1;
+    hwSensor.resolution = 1.0f / (1<<24);
+    hwSensor.power      = mAcc.getPowerUsage() + mMag.getPowerUsage();
+    hwSensor.minDelay   = mAcc.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+

base/services/sensorservice/RotationVectorSensor.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2010 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_ROTATION_VECTOR_SENSOR_H
+#define ANDROID_ROTATION_VECTOR_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+#include "SensorInterface.h"
+#include "SecondOrderLowPassFilter.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class RotationVectorSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    Sensor mAcc;
+    Sensor mMag;
+    float mMagData[3];
+    double mAccTime;
+    double mMagTime;
+    SecondOrderLowPassFilter mALowPass;
+    CascadedBiquadFilter mAX, mAY, mAZ;
+    SecondOrderLowPassFilter mMLowPass;
+    CascadedBiquadFilter mMX, mMY, mMZ;
+
+public:
+    RotationVectorSensor(sensor_t const* list, size_t count);
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_ROTATION_VECTOR_SENSOR_H

base/services/sensorservice/SecondOrderLowPassFilter.cpp

@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <math.h>
+
+#include <cutils/log.h>
+
+#include "SecondOrderLowPassFilter.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+SecondOrderLowPassFilter::SecondOrderLowPassFilter(float Q, float fc)
+    : iQ(1.0f / Q), fc(fc)
+{
+}
+
+void SecondOrderLowPassFilter::setSamplingPeriod(float dT)
+{
+    K = tanf(float(M_PI) * fc * dT);
+    iD = 1.0f / (K*K + K*iQ + 1);
+    a0 = K*K*iD;
+    a1 = 2.0f * a0;
+    b1 = 2.0f*(K*K - 1)*iD;
+    b2 = (K*K - K*iQ + 1)*iD;
+}
+
+// ---------------------------------------------------------------------------
+
+BiquadFilter::BiquadFilter(const SecondOrderLowPassFilter& s)
+    : s(s)
+{
+}
+
+float BiquadFilter::init(float x)
+{
+    x1 = x2 = x;
+    y1 = y2 = x;
+    return x;
+}
+
+float BiquadFilter::operator()(float x)
+{
+    float y = (x + x2)*s.a0 + x1*s.a1 - y1*s.b1 - y2*s.b2;
+    x2 = x1;
+    y2 = y1;
+    x1 = x;
+    y1 = y;
+    return y;
+}
+
+// ---------------------------------------------------------------------------
+
+CascadedBiquadFilter::CascadedBiquadFilter(const SecondOrderLowPassFilter& s)
+    : mA(s), mB(s)
+{
+}
+
+float CascadedBiquadFilter::init(float x)
+{
+    mA.init(x);
+    mB.init(x);
+    return x;
+}
+
+float CascadedBiquadFilter::operator()(float x)
+{
+    return mB(mA(x));
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android

base/services/sensorservice/SecondOrderLowPassFilter.h

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2010 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_SECOND_ORDER_LOW_PASS_FILTER_H
+#define ANDROID_SECOND_ORDER_LOW_PASS_FILTER_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class BiquadFilter;
+
+/*
+ * State of a 2nd order low-pass IIR filter
+ */
+class SecondOrderLowPassFilter {
+    friend class BiquadFilter;
+    float iQ, fc;
+    float K, iD;
+    float a0, a1;
+    float b1, b2;
+public:
+    SecondOrderLowPassFilter(float Q, float fc);
+    void setSamplingPeriod(float dT);
+};
+
+/*
+ * Implements a Biquad IIR filter
+ */
+class BiquadFilter {
+    float x1, x2;
+    float y1, y2;
+    const SecondOrderLowPassFilter& s;
+public:
+    BiquadFilter(const SecondOrderLowPassFilter& s);
+    float init(float in);
+    float operator()(float in);
+};
+
+/*
+ * Two cascaded biquad IIR filters
+ * (4-poles IIR)
+ */
+class CascadedBiquadFilter {
+    BiquadFilter mA;
+    BiquadFilter mB;
+public:
+    CascadedBiquadFilter(const SecondOrderLowPassFilter& s);
+    float init(float in);
+    float operator()(float in);
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SECOND_ORDER_LOW_PASS_FILTER_H

base/services/sensorservice/SensorDevice.cpp

@@ -0,0 +1,241 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Atomic.h>
+#include <utils/Errors.h>
+#include <utils/Singleton.h>
+
+#include <binder/BinderService.h>
+#include <binder/Parcel.h>
+#include <binder/IServiceManager.h>
+
+#include <hardware/sensors.h>
+
+#include "SensorDevice.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+class BatteryService : public Singleton<BatteryService> {
+    static const int TRANSACTION_noteStartSensor = IBinder::FIRST_CALL_TRANSACTION + 3;
+    static const int TRANSACTION_noteStopSensor = IBinder::FIRST_CALL_TRANSACTION + 4;
+    static const String16 DESCRIPTOR;
+
+    friend class Singleton<BatteryService>;
+    sp<IBinder> mBatteryStatService;
+
+    BatteryService() {
+        const sp<IServiceManager> sm(defaultServiceManager());
+        if (sm != NULL) {
+            const String16 name("batteryinfo");
+            mBatteryStatService = sm->getService(name);
+        }
+    }
+
+    status_t noteStartSensor(int uid, int handle) {
+        Parcel data, reply;
+        data.writeInterfaceToken(DESCRIPTOR);
+        data.writeInt32(uid);
+        data.writeInt32(handle);
+        status_t err = mBatteryStatService->transact(
+                TRANSACTION_noteStartSensor, data, &reply, 0);
+        err = reply.readExceptionCode();
+        return err;
+    }
+
+    status_t noteStopSensor(int uid, int handle) {
+        Parcel data, reply;
+        data.writeInterfaceToken(DESCRIPTOR);
+        data.writeInt32(uid);
+        data.writeInt32(handle);
+        status_t err = mBatteryStatService->transact(
+                TRANSACTION_noteStopSensor, data, &reply, 0);
+        err = reply.readExceptionCode();
+        return err;
+    }
+
+public:
+    void enableSensor(int handle) {
+        if (mBatteryStatService != 0) {
+            int uid = IPCThreadState::self()->getCallingUid();
+            int64_t identity = IPCThreadState::self()->clearCallingIdentity();
+            noteStartSensor(uid, handle);
+            IPCThreadState::self()->restoreCallingIdentity(identity);
+        }
+    }
+    void disableSensor(int handle) {
+        if (mBatteryStatService != 0) {
+            int uid = IPCThreadState::self()->getCallingUid();
+            int64_t identity = IPCThreadState::self()->clearCallingIdentity();
+            noteStopSensor(uid, handle);
+            IPCThreadState::self()->restoreCallingIdentity(identity);
+        }
+    }
+};
+
+const String16 BatteryService::DESCRIPTOR("com.android.internal.app.IBatteryStats");
+
+ANDROID_SINGLETON_STATIC_INSTANCE(BatteryService)
+
+// ---------------------------------------------------------------------------
+
+ANDROID_SINGLETON_STATIC_INSTANCE(SensorDevice)
+
+SensorDevice::SensorDevice()
+    :  mSensorDevice(0),
+       mSensorModule(0)
+{
+    status_t err = hw_get_module(SENSORS_HARDWARE_MODULE_ID,
+            (hw_module_t const**)&mSensorModule);
+
+    LOGE_IF(err, "couldn't load %s module (%s)",
+            SENSORS_HARDWARE_MODULE_ID, strerror(-err));
+
+    if (mSensorModule) {
+        err = sensors_open(&mSensorModule->common, &mSensorDevice);
+
+        LOGE_IF(err, "couldn't open device for module %s (%s)",
+                SENSORS_HARDWARE_MODULE_ID, strerror(-err));
+
+        if (mSensorDevice) {
+            sensor_t const* list;
+            ssize_t count = mSensorModule->get_sensors_list(mSensorModule, &list);
+            mActivationCount.setCapacity(count);
+            Info model;
+            for (size_t i=0 ; i<size_t(count) ; i++) {
+                mActivationCount.add(list[i].handle, model);
+                mSensorDevice->activate(mSensorDevice, list[i].handle, 0);
+            }
+        }
+    }
+}
+
+void SensorDevice::dump(String8& result, char* buffer, size_t SIZE)
+{
+    if (!mSensorModule) return;
+    sensor_t const* list;
+    ssize_t count = mSensorModule->get_sensors_list(mSensorModule, &list);
+
+    snprintf(buffer, SIZE, "%d h/w sensors:\n", int(count));
+    result.append(buffer);
+
+    Mutex::Autolock _l(mLock);
+    for (size_t i=0 ; i<size_t(count) ; i++) {
+        snprintf(buffer, SIZE, "handle=0x%08x, active-count=%d\n",
+                list[i].handle,
+                mActivationCount.valueFor(list[i].handle).rates.size());
+        result.append(buffer);
+    }
+}
+
+ssize_t SensorDevice::getSensorList(sensor_t const** list) {
+    if (!mSensorModule) return NO_INIT;
+    ssize_t count = mSensorModule->get_sensors_list(mSensorModule, list);
+    return count;
+}
+
+status_t SensorDevice::initCheck() const {
+    return mSensorDevice && mSensorModule ? NO_ERROR : NO_INIT;
+}
+
+ssize_t SensorDevice::poll(sensors_event_t* buffer, size_t count) {
+    if (!mSensorDevice) return NO_INIT;
+    return mSensorDevice->poll(mSensorDevice, buffer, count);
+}
+
+status_t SensorDevice::activate(void* ident, int handle, int enabled)
+{
+    if (!mSensorDevice) return NO_INIT;
+    status_t err(NO_ERROR);
+    bool actuateHardware = false;
+
+    Info& info( mActivationCount.editValueFor(handle) );
+    if (enabled) {
+        Mutex::Autolock _l(mLock);
+        if (info.rates.indexOfKey(ident) < 0) {
+            info.rates.add(ident, DEFAULT_EVENTS_PERIOD);
+            actuateHardware = true;
+        } else {
+            // sensor was already activated for this ident
+        }
+    } else {
+        Mutex::Autolock _l(mLock);
+        if (info.rates.removeItem(ident) >= 0) {
+            if (info.rates.size() == 0) {
+                actuateHardware = true;
+            }
+        } else {
+            // sensor wasn't enabled for this ident
+        }
+    }
+
+    if (actuateHardware) {
+        err = mSensorDevice->activate(mSensorDevice, handle, enabled);
+        if (enabled) {
+            LOGE_IF(err, "Error activating sensor %d (%s)", handle, strerror(-err));
+            if (err == 0) {
+                BatteryService::getInstance().enableSensor(handle);
+            }
+        } else {
+            if (err == 0) {
+                BatteryService::getInstance().disableSensor(handle);
+            }
+        }
+    }
+
+    if (!actuateHardware || enabled) {
+        Mutex::Autolock _l(mLock);
+        nsecs_t ns = info.rates.valueAt(0);
+        for (size_t i=1 ; i<info.rates.size() ; i++) {
+            if (info.rates.valueAt(i) < ns) {
+                nsecs_t cur = info.rates.valueAt(i);
+                if (cur < ns) {
+                    ns = cur;
+                }
+            }
+        }
+        mSensorDevice->setDelay(mSensorDevice, handle, ns);
+    }
+
+    return err;
+}
+
+status_t SensorDevice::setDelay(void* ident, int handle, int64_t ns)
+{
+    if (!mSensorDevice) return NO_INIT;
+    Info& info( mActivationCount.editValueFor(handle) );
+    { // scope for lock
+        Mutex::Autolock _l(mLock);
+        ssize_t index = info.rates.indexOfKey(ident);
+        if (index < 0) return BAD_INDEX;
+        info.rates.editValueAt(index) = ns;
+        ns = info.rates.valueAt(0);
+        for (size_t i=1 ; i<info.rates.size() ; i++) {
+            nsecs_t cur = info.rates.valueAt(i);
+            if (cur < ns) {
+                ns = cur;
+            }
+        }
+    }
+    return mSensorDevice->setDelay(mSensorDevice, handle, ns);
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+

base/services/sensorservice/SensorDevice.h

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2010 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_SENSOR_DEVICE_H
+#define ANDROID_SENSOR_DEVICE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/KeyedVector.h>
+#include <utils/Singleton.h>
+#include <utils/String8.h>
+
+#include <gui/Sensor.h>
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+static const nsecs_t DEFAULT_EVENTS_PERIOD = 200000000; //    5 Hz
+
+class SensorDevice : public Singleton<SensorDevice> {
+    friend class Singleton<SensorDevice>;
+    struct sensors_poll_device_t* mSensorDevice;
+    struct sensors_module_t* mSensorModule;
+    Mutex mLock; // protect mActivationCount[].rates
+    // fixed-size array after construction
+    struct Info {
+        Info() { }
+        KeyedVector<void*, nsecs_t> rates;
+    };
+    DefaultKeyedVector<int, Info> mActivationCount;
+
+    SensorDevice();
+public:
+    ssize_t getSensorList(sensor_t const** list);
+    status_t initCheck() const;
+    ssize_t poll(sensors_event_t* buffer, size_t count);
+    status_t activate(void* ident, int handle, int enabled);
+    status_t setDelay(void* ident, int handle, int64_t ns);
+    void dump(String8& result, char* buffer, size_t SIZE);
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_DEVICE_H

base/services/sensorservice/SensorInterface.cpp

@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <cutils/log.h>
+
+#include "SensorInterface.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+SensorInterface::~SensorInterface()
+{
+}
+
+// ---------------------------------------------------------------------------
+
+HardwareSensor::HardwareSensor(const sensor_t& sensor)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensor(&sensor)
+{
+    LOGI("%s", sensor.name);
+}
+
+HardwareSensor::~HardwareSensor() {
+}
+
+bool HardwareSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event) {
+    *outEvent = event;
+    return true;
+}
+
+status_t HardwareSensor::activate(void* ident, bool enabled) {
+    return mSensorDevice.activate(ident, mSensor.getHandle(), enabled);
+}
+
+status_t HardwareSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mSensorDevice.setDelay(ident, handle, ns);
+}
+
+Sensor HardwareSensor::getSensor() const {
+    return mSensor;
+}
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android

base/services/sensorservice/SensorInterface.h

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2010 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_SENSOR_INTERFACE_H
+#define ANDROID_SENSOR_INTERFACE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Singleton.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorInterface {
+public:
+    virtual ~SensorInterface();
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event) = 0;
+
+    virtual status_t activate(void* ident, bool enabled) = 0;
+    virtual status_t setDelay(void* ident, int handle, int64_t ns) = 0;
+    virtual Sensor getSensor() const = 0;
+    virtual bool isVirtual() const = 0;
+};
+
+// ---------------------------------------------------------------------------
+
+class HardwareSensor : public SensorInterface
+{
+    SensorDevice& mSensorDevice;
+    Sensor mSensor;
+
+public:
+    HardwareSensor(const sensor_t& sensor);
+
+    virtual ~HardwareSensor();
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return false; }
+};
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_INTERFACE_H

base/services/sensorservice/SensorService.cpp

@@ -0,0 +1,547 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/SortedVector.h>
+#include <utils/KeyedVector.h>
+#include <utils/threads.h>
+#include <utils/Atomic.h>
+#include <utils/Errors.h>
+#include <utils/RefBase.h>
+#include <utils/Singleton.h>
+#include <utils/String16.h>
+
+#include <binder/BinderService.h>
+#include <binder/IServiceManager.h>
+
+#include <gui/ISensorServer.h>
+#include <gui/ISensorEventConnection.h>
+
+#include <hardware/sensors.h>
+
+#include "SensorService.h"
+#include "GravitySensor.h"
+#include "LinearAccelerationSensor.h"
+#include "RotationVectorSensor.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+SensorService::SensorService()
+    : Thread(false),
+      mDump("android.permission.DUMP"),
+      mInitCheck(NO_INIT)
+{
+}
+
+void SensorService::onFirstRef()
+{
+    LOGD("nuSensorService starting...");
+
+    SensorDevice& dev(SensorDevice::getInstance());
+
+    if (dev.initCheck() == NO_ERROR) {
+        uint32_t virtualSensorsNeeds =
+                (1<<SENSOR_TYPE_GRAVITY) |
+                (1<<SENSOR_TYPE_LINEAR_ACCELERATION) |
+                (1<<SENSOR_TYPE_ROTATION_VECTOR);
+        sensor_t const* list;
+        int count = dev.getSensorList(&list);
+        mLastEventSeen.setCapacity(count);
+        for (int i=0 ; i<count ; i++) {
+            registerSensor( new HardwareSensor(list[i]) );
+            switch (list[i].type) {
+                case SENSOR_TYPE_GRAVITY:
+                case SENSOR_TYPE_LINEAR_ACCELERATION:
+                case SENSOR_TYPE_ROTATION_VECTOR:
+                    virtualSensorsNeeds &= ~(1<<list[i].type);
+                    break;
+            }
+        }
+
+        if (virtualSensorsNeeds & (1<<SENSOR_TYPE_GRAVITY)) {
+            registerVirtualSensor( new GravitySensor(list, count) );
+        }
+        if (virtualSensorsNeeds & (1<<SENSOR_TYPE_LINEAR_ACCELERATION)) {
+            registerVirtualSensor( new LinearAccelerationSensor(list, count) );
+        }
+        if (virtualSensorsNeeds & (1<<SENSOR_TYPE_ROTATION_VECTOR)) {
+            registerVirtualSensor( new RotationVectorSensor(list, count) );
+        }
+
+        run("SensorService", PRIORITY_URGENT_DISPLAY);
+        mInitCheck = NO_ERROR;
+    }
+}
+
+void SensorService::registerSensor(SensorInterface* s)
+{
+    sensors_event_t event;
+    memset(&event, 0, sizeof(event));
+
+    const Sensor sensor(s->getSensor());
+    // add to the sensor list (returned to clients)
+    mSensorList.add(sensor);
+    // add to our handle->SensorInterface mapping
+    mSensorMap.add(sensor.getHandle(), s);
+    // create an entry in the mLastEventSeen array
+    mLastEventSeen.add(sensor.getHandle(), event);
+}
+
+void SensorService::registerVirtualSensor(SensorInterface* s)
+{
+    registerSensor(s);
+    mVirtualSensorList.add( s );
+}
+
+SensorService::~SensorService()
+{
+    for (size_t i=0 ; i<mSensorMap.size() ; i++)
+        delete mSensorMap.valueAt(i);
+}
+
+status_t SensorService::dump(int fd, const Vector<String16>& args)
+{
+    const size_t SIZE = 1024;
+    char buffer[SIZE];
+    String8 result;
+    if (!mDump.checkCalling()) {
+        snprintf(buffer, SIZE, "Permission Denial: "
+                "can't dump SurfaceFlinger from pid=%d, uid=%d\n",
+                IPCThreadState::self()->getCallingPid(),
+                IPCThreadState::self()->getCallingUid());
+        result.append(buffer);
+    } else {
+        Mutex::Autolock _l(mLock);
+        snprintf(buffer, SIZE, "Sensor List:\n");
+        result.append(buffer);
+        for (size_t i=0 ; i<mSensorList.size() ; i++) {
+            const Sensor& s(mSensorList[i]);
+            const sensors_event_t& e(mLastEventSeen.valueFor(s.getHandle()));
+            snprintf(buffer, SIZE, "%-48s| %-32s | 0x%08x | maxRate=%7.2fHz | last=<%5.1f,%5.1f,%5.1f>\n",
+                    s.getName().string(),
+                    s.getVendor().string(),
+                    s.getHandle(),
+                    s.getMinDelay() ? (1000000.0f / s.getMinDelay()) : 0.0f,
+                    e.data[0], e.data[1], e.data[2]);
+            result.append(buffer);
+        }
+        SensorDevice::getInstance().dump(result, buffer, SIZE);
+
+        snprintf(buffer, SIZE, "%d active connections\n",
+                mActiveConnections.size());
+        result.append(buffer);
+        snprintf(buffer, SIZE, "Active sensors:\n");
+        result.append(buffer);
+        for (size_t i=0 ; i<mActiveSensors.size() ; i++) {
+            int handle = mActiveSensors.keyAt(i);
+            snprintf(buffer, SIZE, "%s (handle=0x%08x, connections=%d)\n",
+                    getSensorName(handle).string(),
+                    handle,
+                    mActiveSensors.valueAt(i)->getNumConnections());
+            result.append(buffer);
+        }
+    }
+    write(fd, result.string(), result.size());
+    return NO_ERROR;
+}
+
+bool SensorService::threadLoop()
+{
+    LOGD("nuSensorService thread starting...");
+
+    const size_t numEventMax = 16 * (1 + mVirtualSensorList.size());
+    sensors_event_t buffer[numEventMax];
+    sensors_event_t scratch[numEventMax];
+    SensorDevice& device(SensorDevice::getInstance());
+    const size_t vcount = mVirtualSensorList.size();
+
+    ssize_t count;
+    do {
+        count = device.poll(buffer, numEventMax);
+        if (count<0) {
+            LOGE("sensor poll failed (%s)", strerror(-count));
+            break;
+        }
+
+        recordLastValue(buffer, count);
+
+        // handle virtual sensors
+        if (count && vcount) {
+            const DefaultKeyedVector<int, SensorInterface*> virtualSensors(
+                    getActiveVirtualSensors());
+            const size_t activeVirtualSensorCount = virtualSensors.size();
+            if (activeVirtualSensorCount) {
+                size_t k = 0;
+                for (size_t i=0 ; i<size_t(count) ; i++) {
+                    sensors_event_t const * const event = buffer;
+                    for (size_t j=0 ; j<activeVirtualSensorCount ; j++) {
+                        sensors_event_t out;
+                        if (virtualSensors.valueAt(j)->process(&out, event[i])) {
+                            buffer[count + k] = out;
+                            k++;
+                        }
+                    }
+                }
+                if (k) {
+                    // record the last synthesized values
+                    recordLastValue(&buffer[count], k);
+                    count += k;
+                    // sort the buffer by time-stamps
+                    sortEventBuffer(buffer, count);
+                }
+            }
+        }
+
+        // send our events to clients...
+        const SortedVector< wp<SensorEventConnection> > activeConnections(
+                getActiveConnections());
+        size_t numConnections = activeConnections.size();
+        for (size_t i=0 ; i<numConnections ; i++) {
+            sp<SensorEventConnection> connection(
+                    activeConnections[i].promote());
+            if (connection != 0) {
+                connection->sendEvents(buffer, count, scratch);
+            }
+        }
+    } while (count >= 0 || Thread::exitPending());
+
+    LOGW("Exiting SensorService::threadLoop!");
+    return false;
+}
+
+void SensorService::recordLastValue(
+        sensors_event_t const * buffer, size_t count)
+{
+    Mutex::Autolock _l(mLock);
+
+    // record the last event for each sensor
+    int32_t prev = buffer[0].sensor;
+    for (size_t i=1 ; i<count ; i++) {
+        // record the last event of each sensor type in this buffer
+        int32_t curr = buffer[i].sensor;
+        if (curr != prev) {
+            mLastEventSeen.editValueFor(prev) = buffer[i-1];
+            prev = curr;
+        }
+    }
+    mLastEventSeen.editValueFor(prev) = buffer[count-1];
+}
+
+void SensorService::sortEventBuffer(sensors_event_t* buffer, size_t count)
+{
+    struct compar {
+        static int cmp(void const* lhs, void const* rhs) {
+            sensors_event_t const* l = static_cast<sensors_event_t const*>(lhs);
+            sensors_event_t const* r = static_cast<sensors_event_t const*>(rhs);
+            return r->timestamp - l->timestamp;
+        }
+    };
+    qsort(buffer, count, sizeof(sensors_event_t), compar::cmp);
+}
+
+SortedVector< wp<SensorService::SensorEventConnection> >
+SensorService::getActiveConnections() const
+{
+    Mutex::Autolock _l(mLock);
+    return mActiveConnections;
+}
+
+DefaultKeyedVector<int, SensorInterface*>
+SensorService::getActiveVirtualSensors() const
+{
+    Mutex::Autolock _l(mLock);
+    return mActiveVirtualSensors;
+}
+
+String8 SensorService::getSensorName(int handle) const {
+    size_t count = mSensorList.size();
+    for (size_t i=0 ; i<count ; i++) {
+        const Sensor& sensor(mSensorList[i]);
+        if (sensor.getHandle() == handle) {
+            return sensor.getName();
+        }
+    }
+    String8 result("unknown");
+    return result;
+}
+
+Vector<Sensor> SensorService::getSensorList()
+{
+    return mSensorList;
+}
+
+sp<ISensorEventConnection> SensorService::createSensorEventConnection()
+{
+    sp<SensorEventConnection> result(new SensorEventConnection(this));
+    return result;
+}
+
+void SensorService::cleanupConnection(SensorEventConnection* c)
+{
+    Mutex::Autolock _l(mLock);
+    const wp<SensorEventConnection> connection(c);
+    size_t size = mActiveSensors.size();
+    for (size_t i=0 ; i<size ; ) {
+        int handle = mActiveSensors.keyAt(i);
+        if (c->hasSensor(handle)) {
+            SensorInterface* sensor = mSensorMap.valueFor( handle );
+            if (sensor) {
+                sensor->activate(c, false);
+            }
+        }
+        SensorRecord* rec = mActiveSensors.valueAt(i);
+        if (rec && rec->removeConnection(connection)) {
+            mActiveSensors.removeItemsAt(i, 1);
+            mActiveVirtualSensors.removeItem(handle);
+            delete rec;
+            size--;
+        } else {
+            i++;
+        }
+    }
+    mActiveConnections.remove(connection);
+}
+
+status_t SensorService::enable(const sp<SensorEventConnection>& connection,
+        int handle)
+{
+    if (mInitCheck != NO_ERROR)
+        return mInitCheck;
+
+    Mutex::Autolock _l(mLock);
+    SensorInterface* sensor = mSensorMap.valueFor(handle);
+    status_t err = sensor ? sensor->activate(connection.get(), true) : status_t(BAD_VALUE);
+    if (err == NO_ERROR) {
+        SensorRecord* rec = mActiveSensors.valueFor(handle);
+        if (rec == 0) {
+            rec = new SensorRecord(connection);
+            mActiveSensors.add(handle, rec);
+            if (sensor->isVirtual()) {
+                mActiveVirtualSensors.add(handle, sensor);
+            }
+        } else {
+            if (rec->addConnection(connection)) {
+                // this sensor is already activated, but we are adding a
+                // connection that uses it. Immediately send down the last
+                // known value of the requested sensor.
+                sensors_event_t scratch;
+                sensors_event_t& event(mLastEventSeen.editValueFor(handle));
+                if (event.version == sizeof(sensors_event_t)) {
+                    connection->sendEvents(&event, 1);
+                }
+            }
+        }
+        if (err == NO_ERROR) {
+            // connection now active
+            if (connection->addSensor(handle)) {
+                // the sensor was added (which means it wasn't already there)
+                // so, see if this connection becomes active
+                if (mActiveConnections.indexOf(connection) < 0) {
+                    mActiveConnections.add(connection);
+                }
+            }
+        }
+    }
+    return err;
+}
+
+status_t SensorService::disable(const sp<SensorEventConnection>& connection,
+        int handle)
+{
+    if (mInitCheck != NO_ERROR)
+        return mInitCheck;
+
+    status_t err = NO_ERROR;
+    Mutex::Autolock _l(mLock);
+    SensorRecord* rec = mActiveSensors.valueFor(handle);
+    if (rec) {
+        // see if this connection becomes inactive
+        connection->removeSensor(handle);
+        if (connection->hasAnySensor() == false) {
+            mActiveConnections.remove(connection);
+        }
+        // see if this sensor becomes inactive
+        if (rec->removeConnection(connection)) {
+            mActiveSensors.removeItem(handle);
+            mActiveVirtualSensors.removeItem(handle);
+            delete rec;
+        }
+        SensorInterface* sensor = mSensorMap.valueFor(handle);
+        err = sensor ? sensor->activate(connection.get(), false) : status_t(BAD_VALUE);
+    }
+    return err;
+}
+
+status_t SensorService::setEventRate(const sp<SensorEventConnection>& connection,
+        int handle, nsecs_t ns)
+{
+    if (mInitCheck != NO_ERROR)
+        return mInitCheck;
+
+    if (ns < 0)
+        return BAD_VALUE;
+
+    if (ns < MINIMUM_EVENTS_PERIOD)
+        ns = MINIMUM_EVENTS_PERIOD;
+
+    SensorInterface* sensor = mSensorMap.valueFor(handle);
+    if (!sensor) return BAD_VALUE;
+    return sensor->setDelay(connection.get(), handle, ns);
+}
+
+// ---------------------------------------------------------------------------
+
+SensorService::SensorRecord::SensorRecord(
+        const sp<SensorEventConnection>& connection)
+{
+    mConnections.add(connection);
+}
+
+bool SensorService::SensorRecord::addConnection(
+        const sp<SensorEventConnection>& connection)
+{
+    if (mConnections.indexOf(connection) < 0) {
+        mConnections.add(connection);
+        return true;
+    }
+    return false;
+}
+
+bool SensorService::SensorRecord::removeConnection(
+        const wp<SensorEventConnection>& connection)
+{
+    ssize_t index = mConnections.indexOf(connection);
+    if (index >= 0) {
+        mConnections.removeItemsAt(index, 1);
+    }
+    return mConnections.size() ? false : true;
+}
+
+// ---------------------------------------------------------------------------
+
+SensorService::SensorEventConnection::SensorEventConnection(
+        const sp<SensorService>& service)
+    : mService(service), mChannel(new SensorChannel())
+{
+}
+
+SensorService::SensorEventConnection::~SensorEventConnection()
+{
+    mService->cleanupConnection(this);
+}
+
+void SensorService::SensorEventConnection::onFirstRef()
+{
+}
+
+bool SensorService::SensorEventConnection::addSensor(int32_t handle) {
+    Mutex::Autolock _l(mConnectionLock);
+    if (mSensorInfo.indexOf(handle) <= 0) {
+        mSensorInfo.add(handle);
+        return true;
+    }
+    return false;
+}
+
+bool SensorService::SensorEventConnection::removeSensor(int32_t handle) {
+    Mutex::Autolock _l(mConnectionLock);
+    if (mSensorInfo.remove(handle) >= 0) {
+        return true;
+    }
+    return false;
+}
+
+bool SensorService::SensorEventConnection::hasSensor(int32_t handle) const {
+    Mutex::Autolock _l(mConnectionLock);
+    return mSensorInfo.indexOf(handle) >= 0;
+}
+
+bool SensorService::SensorEventConnection::hasAnySensor() const {
+    Mutex::Autolock _l(mConnectionLock);
+    return mSensorInfo.size() ? true : false;
+}
+
+status_t SensorService::SensorEventConnection::sendEvents(
+        sensors_event_t const* buffer, size_t numEvents,
+        sensors_event_t* scratch)
+{
+    // filter out events not for this connection
+    size_t count = 0;
+    if (scratch) {
+        Mutex::Autolock _l(mConnectionLock);
+        size_t i=0;
+        while (i<numEvents) {
+            const int32_t curr = buffer[i].sensor;
+            if (mSensorInfo.indexOf(curr) >= 0) {
+                do {
+                    scratch[count++] = buffer[i++];
+                } while ((i<numEvents) && (buffer[i].sensor == curr));
+            } else {
+                i++;
+            }
+        }
+    } else {
+        scratch = const_cast<sensors_event_t *>(buffer);
+        count = numEvents;
+    }
+
+    if (count == 0)
+        return 0;
+
+    ssize_t size = mChannel->write(scratch, count*sizeof(sensors_event_t));
+    if (size == -EAGAIN) {
+        // the destination doesn't accept events anymore, it's probably
+        // full. For now, we just drop the events on the floor.
+        LOGW("dropping %d events on the floor", count);
+        return size;
+    }
+
+    LOGE_IF(size<0, "dropping %d events on the floor (%s)",
+            count, strerror(-size));
+
+    return size < 0 ? status_t(size) : status_t(NO_ERROR);
+}
+
+sp<SensorChannel> SensorService::SensorEventConnection::getSensorChannel() const
+{
+    return mChannel;
+}
+
+status_t SensorService::SensorEventConnection::enableDisable(
+        int handle, bool enabled)
+{
+    status_t err;
+    if (enabled) {
+        err = mService->enable(this, handle);
+    } else {
+        err = mService->disable(this, handle);
+    }
+    return err;
+}
+
+status_t SensorService::SensorEventConnection::setEventRate(
+        int handle, nsecs_t ns)
+{
+    return mService->setEventRate(this, handle, ns);
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+

base/services/sensorservice/SensorService.h

@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2010 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_SENSOR_SERVICE_H
+#define ANDROID_SENSOR_SERVICE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Vector.h>
+#include <utils/SortedVector.h>
+#include <utils/KeyedVector.h>
+#include <utils/threads.h>
+#include <utils/RefBase.h>
+
+#include <binder/BinderService.h>
+#include <binder/Permission.h>
+
+#include <gui/Sensor.h>
+#include <gui/SensorChannel.h>
+#include <gui/ISensorServer.h>
+#include <gui/ISensorEventConnection.h>
+
+#include "SensorInterface.h"
+
+// ---------------------------------------------------------------------------
+
+struct sensors_poll_device_t;
+struct sensors_module_t;
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorService :
+        public BinderService<SensorService>,
+        public BnSensorServer,
+        protected Thread
+{
+   friend class BinderService<SensorService>;
+
+   static const nsecs_t MINIMUM_EVENTS_PERIOD =   1000000; // 1000 Hz
+
+            SensorService();
+    virtual ~SensorService();
+
+    virtual void onFirstRef();
+
+    // Thread interface
+    virtual bool threadLoop();
+
+    // ISensorServer interface
+    virtual Vector<Sensor> getSensorList();
+    virtual sp<ISensorEventConnection> createSensorEventConnection();
+    virtual status_t dump(int fd, const Vector<String16>& args);
+
+
+    class SensorEventConnection : public BnSensorEventConnection {
+        virtual ~SensorEventConnection();
+        virtual void onFirstRef();
+        virtual sp<SensorChannel> getSensorChannel() const;
+        virtual status_t enableDisable(int handle, bool enabled);
+        virtual status_t setEventRate(int handle, nsecs_t ns);
+
+        sp<SensorService> const mService;
+        sp<SensorChannel> const mChannel;
+        mutable Mutex mConnectionLock;
+
+        // protected by SensorService::mLock
+        SortedVector<int> mSensorInfo;
+
+    public:
+        SensorEventConnection(const sp<SensorService>& service);
+
+        status_t sendEvents(sensors_event_t const* buffer, size_t count,
+                sensors_event_t* scratch = NULL);
+        bool hasSensor(int32_t handle) const;
+        bool hasAnySensor() const;
+        bool addSensor(int32_t handle);
+        bool removeSensor(int32_t handle);
+    };
+
+    class SensorRecord {
+        SortedVector< wp<SensorEventConnection> > mConnections;
+    public:
+        SensorRecord(const sp<SensorEventConnection>& connection);
+        bool addConnection(const sp<SensorEventConnection>& connection);
+        bool removeConnection(const wp<SensorEventConnection>& connection);
+        size_t getNumConnections() const { return mConnections.size(); }
+    };
+
+    SortedVector< wp<SensorEventConnection> > getActiveConnections() const;
+    DefaultKeyedVector<int, SensorInterface*> getActiveVirtualSensors() const;
+
+    String8 getSensorName(int handle) const;
+    void recordLastValue(sensors_event_t const * buffer, size_t count);
+    static void sortEventBuffer(sensors_event_t* buffer, size_t count);
+    void registerSensor(SensorInterface* sensor);
+    void registerVirtualSensor(SensorInterface* sensor);
+
+    // constants
+    Vector<Sensor> mSensorList;
+    DefaultKeyedVector<int, SensorInterface*> mSensorMap;
+    Vector<SensorInterface *> mVirtualSensorList;
+    Permission mDump;
+    status_t mInitCheck;
+
+    // protected by mLock
+    mutable Mutex mLock;
+    DefaultKeyedVector<int, SensorRecord*> mActiveSensors;
+    DefaultKeyedVector<int, SensorInterface*> mActiveVirtualSensors;
+    SortedVector< wp<SensorEventConnection> > mActiveConnections;
+
+    // The size of this vector is constant, only the items are mutable
+    KeyedVector<int32_t, sensors_event_t> mLastEventSeen;
+
+public:
+    static char const* getServiceName() { return "sensorservice"; }
+
+    void cleanupConnection(SensorEventConnection* connection);
+    status_t enable(const sp<SensorEventConnection>& connection, int handle);
+    status_t disable(const sp<SensorEventConnection>& connection, int handle);
+    status_t setEventRate(const sp<SensorEventConnection>& connection, int handle, nsecs_t ns);
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_SERVICE_H

base/services/sensorservice/tests/Android.mk

@@ -0,0 +1,14 @@
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= \
+	sensorservicetest.cpp
+
+LOCAL_SHARED_LIBRARIES := \
+	libcutils libutils libui libgui
+
+LOCAL_MODULE:= test-sensorservice
+
+LOCAL_MODULE_TAGS := optional
+
+include $(BUILD_EXECUTABLE)

base/services/sensorservice/tests/sensorservicetest.cpp

@@ -0,0 +1,103 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#include <android/sensor.h>
+#include <gui/Sensor.h>
+#include <gui/SensorManager.h>
+#include <gui/SensorEventQueue.h>
+#include <utils/Looper.h>
+
+using namespace android;
+
+int receiver(int fd, int events, void* data)
+{
+    sp<SensorEventQueue> q((SensorEventQueue*)data);
+    ssize_t n;
+    ASensorEvent buffer[8];
+
+    static nsecs_t oldTimeStamp = 0;
+
+    while ((n = q->read(buffer, 8)) > 0) {
+        for (int i=0 ; i<n ; i++) {
+            if (buffer[i].type == Sensor::TYPE_GYROSCOPE) {
+                printf("time=%lld, value=<%5.1f,%5.1f,%5.1f>\n",
+                        buffer[i].timestamp,
+                        buffer[i].acceleration.x,
+                        buffer[i].acceleration.y,
+                        buffer[i].acceleration.z);
+            }
+
+            if (oldTimeStamp) {
+                float t = float(buffer[i].timestamp - oldTimeStamp) / s2ns(1);
+                printf("%f ms (%f Hz)\n", t*1000, 1.0/t);
+            }
+            oldTimeStamp = buffer[i].timestamp;
+
+        }
+    }
+    if (n<0 && n != -EAGAIN) {
+        printf("error reading events (%s)\n", strerror(-n));
+    }
+    return 1;
+}
+
+
+int main(int argc, char** argv)
+{
+    SensorManager& mgr(SensorManager::getInstance());
+
+    Sensor const* const* list;
+    ssize_t count = mgr.getSensorList(&list);
+    printf("numSensors=%d\n", int(count));
+
+    sp<SensorEventQueue> q = mgr.createEventQueue();
+    printf("queue=%p\n", q.get());
+
+    Sensor const* accelerometer = mgr.getDefaultSensor(Sensor::TYPE_GYROSCOPE);
+    printf("accelerometer=%p (%s)\n",
+            accelerometer, accelerometer->getName().string());
+    q->enableSensor(accelerometer);
+
+    q->setEventRate(accelerometer, ms2ns(10));
+
+    sp<Looper> loop = new Looper(false);
+    loop->addFd(q->getFd(), 0, ALOOPER_EVENT_INPUT, receiver, q.get());
+
+    do {
+        //printf("about to poll...\n");
+        int32_t ret = loop->pollOnce(-1);
+        switch (ret) {
+            case ALOOPER_POLL_WAKE:
+                //("ALOOPER_POLL_WAKE\n");
+                break;
+            case ALOOPER_POLL_CALLBACK:
+                //("ALOOPER_POLL_CALLBACK\n");
+                break;
+            case ALOOPER_POLL_TIMEOUT:
+                printf("ALOOPER_POLL_TIMEOUT\n");
+                break;
+            case ALOOPER_POLL_ERROR:
+                printf("ALOOPER_POLL_TIMEOUT\n");
+                break;
+            default:
+                printf("ugh? poll returned %d\n", ret);
+                break;
+        }
+    } while (1);
+
+
+    return 0;
+}