1718de6fe6
Change-Id: I71d38a6494b8235f5669ff53e6bd29e7045d0409 Reviewed-on: https://go-review.googlesource.com/9697 Reviewed-by: David Crawshaw <crawshaw@golang.org>
119 lines
3.2 KiB
Go
119 lines
3.2 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package sensor provides sensor events from various movement sensors.
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package sensor // import "golang.org/x/mobile/sensor"
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import (
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"errors"
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"time"
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)
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// Type represents a sensor type.
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type Type int
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var sensorNames = map[Type]string{
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Accelerometer: "Accelerometer",
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Gyroscope: "Gyrsocope",
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Magnetometer: "Magnetometer",
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}
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// String returns the string representation of the sensor type.
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func (t Type) String() string {
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if n, ok := sensorNames[t]; ok {
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return n
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}
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return "Unknown sensor"
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}
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const (
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Accelerometer = Type(0)
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Gyroscope = Type(1)
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Magnetometer = Type(2)
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)
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// Event represents a sensor event.
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type Event struct {
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// Sensor is the type of the sensor the event is coming from.
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Sensor Type
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// Timestamp is a device specific event time in nanoseconds.
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// Timestamps are not Unix times, they represent a time that is
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// only valid for the device's default sensor.
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Timestamp int64
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// Data is the event data.
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//
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// If the event source is Accelerometer,
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// - Data[0]: acceleration force in x axis in m/s^2
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// - Data[1]: acceleration force in y axis in m/s^2
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// - Data[2]: acceleration force in z axis in m/s^2
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//
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// If the event source is Gyroscope,
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// - Data[0]: rate of rotation around the x axis in rad/s
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// - Data[1]: rate of rotation around the y axis in rad/s
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// - Data[2]: rate of rotation around the z axis in rad/s
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//
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// If the event source is Magnetometer,
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// - Data[0]: force of gravity along the x axis in m/s^2
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// - Data[1]: force of gravity along the y axis in m/s^2
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// - Data[2]: force of gravity along the z axis in m/s^2
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//
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Data []float64
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}
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// Manager multiplexes sensor event data from various sensor sources.
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type Manager struct {
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m *manager // platform-specific implementation of the underlying manager
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}
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// Enable enables a sensor with the specified delay rate.
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// If there are multiple sensors of type t on the device, Enable uses
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// the default one.
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// If there is no default sensor of type t on the device, an error returned.
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// Valid sensor types supported by this package are Accelerometer,
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// Gyroscope, Magnetometer and Altimeter.
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func (m *Manager) Enable(t Type, delay time.Duration) error {
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if m.m == nil {
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m.m = new(manager)
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m.m.initialize()
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}
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if t < 0 || int(t) >= len(sensorNames) {
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return errors.New("sensor: unknown sensor type")
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}
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return m.m.enable(t, delay)
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}
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// Disable disables to feed the manager with the specified sensor.
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func (m *Manager) Disable(t Type) error {
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if m.m == nil {
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m.m = new(manager)
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m.m.initialize()
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}
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if t < 0 || int(t) >= len(sensorNames) {
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return errors.New("sensor: unknown sensor type")
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}
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return m.m.disable(t)
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}
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// Read reads a series of events from the manager.
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// It may read up to len(e) number of events, but will return
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// less events if timeout occurs.
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func (m *Manager) Read(e []Event) (n int, err error) {
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if m.m == nil {
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m.m = new(manager)
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m.m.initialize()
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}
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return m.m.read(e)
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}
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// Close stops the manager and frees the related resources.
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// Once Close is called, Manager becomes invalid to use.
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func (m *Manager) Close() error {
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if m.m == nil {
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return nil
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}
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return m.m.close()
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}
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