Adding MacBook Pro accelerometer support.

chrome/browser/device_orientation/accelerometer_mac.cc

Index: chrome/browser/device_orientation/accelerometer_mac.cc
diff --git a/chrome/browser/device_orientation/accelerometer_mac.cc b/chrome/browser/device_orientation/accelerometer_mac.cc
new file mode 100644
index 0000000000000000000000000000000000000000..eb09907109f67aacbc7dec00ca645269f07b83a9
--- /dev/null
+++ b/chrome/browser/device_orientation/accelerometer_mac.cc
@@ -0,0 +1,335 @@
+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// This file is based on the SMSLib library.
+//
+// SMSLib Sudden Motion Sensor Access Library
+// Copyright (c) 2010 Suitable Systems
+// All rights reserved.
+//
+// Developed by: Daniel Griscom
+//               Suitable Systems
+//               http://www.suitable.com
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal with the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// - Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimers.
+//
+// - Redistributions in binary form must reproduce the above copyright
+// notice, this list of conditions and the following disclaimers in the
+// documentation and/or other materials provided with the distribution.
+//
+// - Neither the names of Suitable Systems nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this Software without specific prior written permission.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+// IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR
+// ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+// SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE SOFTWARE.
+//
+// For more information about SMSLib, see
+//    <http://www.suitable.com/tools/smslib.html>
+// or contact
+//    Daniel Griscom
+//    Suitable Systems
+//    1 Centre Street, Suite 204
+//    Wakefield, MA 01880
+//    (781) 665-0053
+
+#include "chrome/browser/device_orientation/accelerometer_mac.h"
+
+#include <math.h>  // For isfinite.
+#include <sys/sysctl.h>
+
+#include "base/logging.h"
+#include "base/scoped_ptr.h"
+#include "chrome/browser/device_orientation/orientation.h"
+
+namespace device_orientation {
+
+// Per-axis sensor data.
+struct AccelerometerMac::AxisData {
+  // Non-zero if the axis is valid in this sensor.
+  int enabled;
+
+  // Location in struct of first byte.
+  int index;
+
+  // Number of bytes of the axis data.
+  int size;
+
+  // Value meaning "zero g".
+  float zero_g;
+
+  // (can be negative if the sensor axis is reversed).
+  float one_g;
+};
+
+// Sudden Motion Sensor descriptor.
+struct AccelerometerMac::SensorDescriptor {
+  // Prefix of model to be tested.
+  const char* model_name;
+
+  // Name of device to be read.
+  const char* service_name;
+
+  // Kernel function index.
+  unsigned int function;
+
+  // Size of record to be sent/received.
+  unsigned int record_size;
+
+  // Description of three axes (x,y,z).
+  AxisData axes[3];
+};
+
+// Supported sensor descriptors. Add entries here to enhance compatibility.
+// All non-tested entries from SMSLib have been removed.
+const AccelerometerMac::SensorDescriptor
+    AccelerometerMac::kSupportedSensors[] = {
+  // Tested by leandrogracia on a 15'' MacBook Pro.
+  { "MacBookPro5,4", "SMCMotionSensor", 5, 40, {
+    { 1, 0, 2, 0,  251 },
+    { 1, 2, 2, 0,  251 },
+    { 1, 4, 2, 0,  251 }
+  } },
+
+  // Tested by leandrogracia on a 13'' MacBook Pro.
+  { "MacBookPro5,5", "SMCMotionSensor", 5, 40, {
+    { 1, 0, 2, 0, -251 },
+    { 1, 2, 2, 0, -251 },
+    { 1, 4, 2, 0,  251 }
+  } },
+
+  // Generic MacBook accelerometer sensor data.
+  // Added for forward compatibility (there may be problems with inverted axes).
+  {"", "SMCMotionSensor", 5, 40, {
+    { 1, 0, 2, 0, -251 },
+    { 1, 2, 2, 0, -251 },
+    { 1, 4, 2, 0,  251 }
+  } }
+};
+
+// Create a AccelerometerMac object and return NULL if no valid sensor found.
+DataFetcher* AccelerometerMac::Create() {
+  scoped_ptr<AccelerometerMac> accelerometer(new AccelerometerMac);
+  return accelerometer->Init() ? accelerometer.release() : NULL;
+}
+
+AccelerometerMac::~AccelerometerMac() {
+  IOServiceClose(io_connection_);
+}
+
+AccelerometerMac::AccelerometerMac()
+    : sensor_(NULL),
+      io_connection_(0) {
+}
+
+//  Retrieve per-axis accelerometer values.
+//
+//  Axes and angles are defined according to the W3C DeviceOrientation Draft.
+//  See here: http://dev.w3.org/geo/api/spec-source-orientation.html
+//
+//  Note: only beta and gamma angles are provided. Alpha is set to zero.
+//
+//  Returns false in case of error or non-properly initialized object.
+//
+bool AccelerometerMac::GetOrientation(Orientation* orientation) {
+  DCHECK(sensor_);
+
+  // Reset output record memory buffer.
+  std::fill(output_record_.begin(), output_record_.end(), 0x00);
+
+  // Read record data from memory.
+  const size_t kInputSize = sensor_->record_size;
+  size_t output_size = sensor_->record_size;
+
+  if (IOConnectCallStructMethod(io_connection_, sensor_->function,
+      static_cast<const char *>(&input_record_[0]), kInputSize,
+      &output_record_[0], &output_size) != KERN_SUCCESS) {
+    return false;
+  }
+
+  // Calculate per-axis calibrated values.
+  float axis_value[3];
+
+  for (int i = 0; i < 3; ++i) {
+    int sensor_value = 0;
+    int size  = sensor_->axes[i].size;
+    int index = sensor_->axes[i].index;
+
+    // Important Note: little endian is assumed as this code is mac-only
+    //                 and PowerPC is currently not supported.
+    memcpy(&sensor_value, &output_record_[index], size);
+
+    sensor_value = ExtendSign(sensor_value, size);
+
+    // Correct value using the current calibration.
+    axis_value[i] = static_cast<float>(sensor_value - sensor_->axes[i].zero_g) /
+                    sensor_->axes[i].one_g;
+
+    // Make sure we reject any NaN or infinite values.
+    if (!isfinite(axis_value[i]))
+      return false;
+
+    // Clamp value to the [-1, 1] range.
+    if (axis_value[i] < -1.0)
+      axis_value[i] = -1.0;
+    else if (axis_value[i] > 1.0)
+      axis_value[i] = 1.0;
+  }
+
+  // Transform the accelerometer values to W3C draft angles.
+  //
+  // Accelerometer values are just dot products of the sensor axes
+  // by the gravity vector 'g' with the result for the z axis inverted.
+  //
+  // To understand this transformation calculate the 3rd row of the z-x-y
+  // Euler angles rotation matrix (because of the 'g' vector, only 3rd row
+  // affects to the result). Note that z-x-y matrix means R = Ry * Rx * Rz.
+  // Then, assume alpha = 0 and you get this:
+  //
+  // x_acc = sin(gamma)
+  // y_acc = - cos(gamma) * sin(beta)
+  // z_acc = cos(beta) * cos(gamma)
+  //
+  // After that the rest is just a bit of trigonometry.
+  //
+  // Also note that alpha can't be provided but it's assumed to be always zero.
+  // This is necessary in order to provide enough information to solve
+  // the equations.
+  //
+  const double kRad2deg = 180.0 / M_PI;
+
+  orientation->alpha_ = 0.0;
+  orientation->beta_  = kRad2deg * atan2(-axis_value[1], axis_value[2]);
+  orientation->gamma_ = kRad2deg * asin(axis_value[0]);
+
+  // Make sure that the interval boundaries comply with the specification.
+  if (orientation->beta_ >= 180.0)
+    orientation->beta_  -= 360.0;
+  if (orientation->gamma_ >= 90.0)
+    orientation->gamma_ -= 180.0;
+
+  DCHECK_GE(orientation->beta_, -180.0);
+  DCHECK_LT(orientation->beta_,  180.0);
+  DCHECK_GE(orientation->gamma_, -90.0);
+  DCHECK_LT(orientation->gamma_,  90.0);
+
+  orientation->can_provide_alpha_ = false;
+  orientation->can_provide_beta_  = true;
+  orientation->can_provide_gamma_ = true;
+
+  return true;
+}
+
+// Probe the local hardware looking for a supported sensor device
+// and initialize an I/O connection to it.
+bool AccelerometerMac::Init() {
+  // Allocate local variables for model name string (size from SMSLib).
+  static const int kNameSize = 32;
+  char local_model[kNameSize];
+
+  // Request model name to the kernel.
+  size_t name_size = kNameSize;
+  int params[2] = { CTL_HW, HW_MODEL };
+  if (sysctl(params, 2, local_model, &name_size, NULL, 0) != 0)
+    return NULL;
+
+  const SensorDescriptor* sensor_candidate = NULL;
+
+  // Look for the current model in the supported sensor list.
+  io_object_t device = 0;
+  const int kNumSensors = arraysize(kSupportedSensors);
+
+  for (int i = 0; i < kNumSensors; ++i) {
+    // Check if the supported sensor model name is a prefix
+    // of the local hardware model (empty names are accepted).
+    const char* p1 = kSupportedSensors[i].model_name;
+    for (const char* p2 = local_model; *p1 != '\0' && *p1 == *p2; ++p1, ++p2)
+      continue;
+    if (*p1 != '\0')
+      continue;
+
+    // Local hardware found in the supported sensor list.
+    sensor_candidate = &kSupportedSensors[i];
+
+    // Get a dictionary of the services matching to the one in the sensor.
+    CFMutableDictionaryRef dict =
+        IOServiceMatching(sensor_candidate->service_name);
+    if (dict == NULL)
+      continue;
+
+    // Get an iterator for the matching services.
+    io_iterator_t device_iterator;
+    if (IOServiceGetMatchingServices(kIOMasterPortDefault, dict,
+        &device_iterator) != KERN_SUCCESS) {
+      continue;
+    }
+
+    // Get the first device in the list.
+    if ((device = IOIteratorNext(device_iterator)) == 0)
+      continue;
+
+    // Try to open device.
+    kern_return_t result;
+    result = IOServiceOpen(device, mach_task_self(), 0, &io_connection_);
+    IOObjectRelease(device);
+    if (result != KERN_SUCCESS || io_connection_ == 0)
+      return false;
+
+    // Local sensor service confirmed by IOKit.
+    sensor_ = sensor_candidate;
+    break;
+  }
+
+  if (sensor_ == NULL)
+    return false;
+
+  // Allocate and initialize input/output records.
+  input_record_.resize(sensor_->record_size, 0x01);
+  output_record_.resize(sensor_->record_size, 0x00);
+
+  // Try to retrieve the current orientation.
+  Orientation test_orientation;
+  return GetOrientation(&test_orientation);
+}
+
+// Extend the sign of an integer of less than 32 bits to a 32-bit integer.
+int AccelerometerMac::ExtendSign(int value, size_t size) {
+  switch (size) {
+  case 1:
+    if (value & 0x00000080)
+      return value | 0xffffff00;
+    break;
+
+  case 2:
+    if (value & 0x00008000)
+      return value | 0xffff0000;
+    break;
+
+  case 3:
+    if (value & 0x00800000)
+      return value | 0xff000000;
+    break;
+
+  default:
+    LOG(FATAL) << "Invalid integer size for sign extension: " << size;
+  }
+
+  return value;
+}
+
+}  // namespace device_orientation