btcore/src/device_class.cc

/******************************************************************************
 *
 *  Copyright 2014 Google, Inc.
 *
 *  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 <arpa/inet.h>
#include <base/logging.h>
#include <endian.h>
#include <string.h>

#include "btcore/include/device_class.h"
#include "check.h"

typedef struct _bt_device_class_t {
  uint32_t unused : 2;  // LSBs
  uint32_t minor_device : 6;
  uint32_t major_device : 5;
  uint32_t major_service : 11;  // MSBs
} __attribute__((__packed__)) _bt_device_class_t;

// Convenience to interpret raw device class bytes.
#define DC(x) ((_bt_device_class_t*)(x))

// Ensure the internal device class implementation and public one
// have equal size.
static_assert(sizeof(_bt_device_class_t) == sizeof(bt_device_class_t),
              "Internal and external device class implementation should have "
              "the same size");

// [Major Service Classes]
// (https://www.bluetooth.org/en-us/specification/assigned-numbers/baseband)
enum {
  DC_LIMITED_DISCOVERABLE_MODE = 0x0001,
  DC_RESERVED14 = 0x0002,
  DC_RESERVED15 = 0x0004,
  DC_POSITIONING = 0x0008,
  DC_NETWORKING = 0x0010,
  DC_RENDERING = 0x0020,
  DC_CAPTURING = 0x0040,
  DC_OBJECT_TRANSFER = 0x0080,
  DC_AUDIO = 0x0100,
  DC_TELEPHONY = 0x0200,
  DC_INFORMATION = 0x0400,
};

static bool device_class_get_major_service_(const bt_device_class_t* dc,
                                            int bitmask);
static void device_class_clr_major_service_(bt_device_class_t* dc, int bitmask);
static void device_class_set_major_service_(bt_device_class_t* dc, int bitmask);

void device_class_from_stream(bt_device_class_t* dc, const uint8_t* data) {
  CHECK(dc != NULL);
  CHECK(data != NULL);
  *dc = *(bt_device_class_t*)data;
}

int device_class_to_stream(const bt_device_class_t* dc, uint8_t* data,
                           size_t len) {
  CHECK(dc != NULL);
  CHECK(data != NULL);
  CHECK(len >= sizeof(bt_device_class_t));
  for (size_t i = 0; i < sizeof(bt_device_class_t); ++i) {
    data[i] = dc->_[i];
  }
  return sizeof(bt_device_class_t);
}

void device_class_from_int(bt_device_class_t* dc, int data) {
  CHECK(dc != NULL);
  CHECK(data != 0);
  // Careful with endianess.
  dc->_[0] = data & 0xff;
  dc->_[1] = (data >> 8) & 0xff;
  dc->_[2] = (data >> 16) & 0xff;
}

int device_class_to_int(const bt_device_class_t* dc) {
  CHECK(dc != NULL);
  // Careful with endianess.
  int val = 0;
  memcpy(&val, dc, sizeof(*dc));
  return static_cast<int>(le32toh(val) & 0xffffff);
}

bool device_class_equals(const bt_device_class_t* p1,
                         const bt_device_class_t* p2) {
  CHECK(p1 != NULL);
  CHECK(p2 != NULL);
  return (memcmp(p1, p2, sizeof(bt_device_class_t)) == 0);
}

bool device_class_copy(bt_device_class_t* dest, const bt_device_class_t* src) {
  CHECK(dest != NULL);
  CHECK(src != NULL);
  return (memcpy(dest, src, sizeof(bt_device_class_t)) == dest);
}

int device_class_get_major_device(const bt_device_class_t* dc) {
  CHECK(dc != NULL);
  return DC(dc)->major_device;
}

void device_class_set_major_device(bt_device_class_t* dc, int val) {
  CHECK(dc != NULL);
  DC(dc)->major_device = val;
}

int device_class_get_minor_device(const bt_device_class_t* dc) {
  CHECK(dc != NULL);
  return DC(dc)->minor_device;
}

void device_class_set_minor_device(bt_device_class_t* dc, int val) {
  CHECK(dc != NULL);
  DC(dc)->minor_device = val;
}

bool device_class_get_information(const bt_device_class_t* dc) {
  CHECK(dc != NULL);
  return device_class_get_major_service_(dc, DC_INFORMATION);
}

void device_class_set_information(bt_device_class_t* dc, bool set) {
  CHECK(dc != NULL);
  if (set)
    device_class_set_major_service_(dc, DC_INFORMATION);
  else
    device_class_clr_major_service_(dc, DC_INFORMATION);
}

bool device_class_get_limited(const bt_device_class_t* dc) {
  CHECK(dc != NULL);
  return device_class_get_major_service_(dc, DC_LIMITED_DISCOVERABLE_MODE);
}

void device_class_set_limited(bt_device_class_t* dc, bool set) {
  CHECK(dc != NULL);
  if (set)
    device_class_set_major_service_(dc, DC_LIMITED_DISCOVERABLE_MODE);
  else
    device_class_clr_major_service_(dc, DC_LIMITED_DISCOVERABLE_MODE);
}

static bool device_class_get_major_service_(const bt_device_class_t* dc,
                                            int bitmask) {
  return (DC(dc)->major_service & bitmask);
}

static void device_class_clr_major_service_(bt_device_class_t* dc,
                                            int bitmask) {
  DC(dc)->major_service &= ~bitmask;
}

static void device_class_set_major_service_(bt_device_class_t* dc,
                                            int bitmask) {
  DC(dc)->major_service |= bitmask;
}