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/* mbed Microcontroller Library
 * Copyright (c) 2006-2013 ARM Limited
 *
 * 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 __GAP_ADVERTISING_DATA_H__
#define __GAP_ADVERTISING_DATA_H__

#include <stdint.h>
#include <string.h>

#include "blecommon.h"

#define GAP_ADVERTISING_DATA_MAX_PAYLOAD        (31)

/**************************************************************************/
/*!
    \brief
    This class provides several helper functions to generate properly
    formatted GAP Advertising and Scan Response data payloads.

    \note
    See Bluetooth Specification 4.0 (Vol. 3), Part C, Sections 11 and 18
    for further information on Advertising and Scan Response data.

    \par Advertising and Scan Response Payloads
    Advertising data and Scan Response data are organized around a set of
    data types called 'AD types' in Bluetooth 4.0 (see the Bluetooth Core
    Specification v4.0, Vol. 3, Part C, Sections 11 and 18).

    \par
    Each AD type has its own standardized assigned number, as defined
    by the Bluetooth SIG:
    https://www.bluetooth.org/en-us/specification/assigned-numbers/generic-access-profile

    \par
    For convenience, all appropriate AD types are encapsulated
    in GapAdvertisingData::DataType.

    \par
    Before the AD Types and their payload (if any) can be inserted into
    the Advertising or Scan Response frames, they need to be formatted as
    follows:

    \li \c Record length (1 byte).
    \li \c AD Type (1 byte).
    \li \c AD payload (optional; only present if record length > 1).

    \par
    This class takes care of properly formatting the payload, performs
    some basic checks on the payload length, and tries to avoid common
    errors like adding an exclusive AD field twice in the Advertising
    or Scan Response payload.

    \par EXAMPLE

    \code

    // ToDo

    \endcode
*/
/**************************************************************************/
class GapAdvertisingData
{
public:
    /**********************************************************************/
    /*!
        \brief
        A list of Advertising Data types commonly used by peripherals.
        These AD types are used to describe the capabilities of the
        peripheral, and are inserted inside the advertising or scan
        response payloads.

        \par Source
        \li \c Bluetooth Core Specification 4.0 (Vol. 3), Part C, Section 11, 18
        \li \c https://www.bluetooth.org/en-us/specification/assigned-numbers/generic-access-profile
    */
    /**********************************************************************/
    enum DataType_t {
        FLAGS                              = 0x01, /**< \ref *Flags */
        INCOMPLETE_LIST_16BIT_SERVICE_IDS  = 0x02, /**< Incomplete list of 16-bit Service IDs */
        COMPLETE_LIST_16BIT_SERVICE_IDS    = 0x03, /**< Complete list of 16-bit Service IDs */
        INCOMPLETE_LIST_32BIT_SERVICE_IDS  = 0x04, /**< Incomplete list of 32-bit Service IDs (not relevant for Bluetooth 4.0) */
        COMPLETE_LIST_32BIT_SERVICE_IDS    = 0x05, /**< Complete list of 32-bit Service IDs (not relevant for Bluetooth 4.0) */
        INCOMPLETE_LIST_128BIT_SERVICE_IDS = 0x06, /**< Incomplete list of 128-bit Service IDs */
        COMPLETE_LIST_128BIT_SERVICE_IDS   = 0x07, /**< Complete list of 128-bit Service IDs */
        SHORTENED_LOCAL_NAME               = 0x08, /**< Shortened Local Name */
        COMPLETE_LOCAL_NAME                = 0x09, /**< Complete Local Name */
        TX_POWER_LEVEL                     = 0x0A, /**< TX Power Level (in dBm) */
        DEVICE_ID                          = 0x10, /**< Device ID */
        SLAVE_CONNECTION_INTERVAL_RANGE    = 0x12, /**< Slave Connection Interval Range */
        LIST_128BIT_SOLICITATION_IDS       = 0x15, /**< List of 128 bit service UUIDs the device is looking for */
        SERVICE_DATA                       = 0x16, /**< Service Data */
        APPEARANCE                         = 0x19, /**< \ref Appearance */
        ADVERTISING_INTERVAL               = 0x1A, /**< Advertising Interval */
        MANUFACTURER_SPECIFIC_DATA         = 0xFF  /**< Manufacturer Specific Data */
    };
    typedef enum DataType_t DataType; /* Deprecated type alias. This may be dropped in a future release. */

    /**********************************************************************/
    /*!
        \brief
        A list of values for the FLAGS AD Type.

        \note
        You can use more than one value in the FLAGS AD Type (ex.
        LE_GENERAL_DISCOVERABLE and BREDR_NOT_SUPPORTED).

        \par Source
        \li \c Bluetooth Core Specification 4.0 (Vol. 3), Part C, Section 18.1
    */
    /**********************************************************************/
    enum Flags_t {
        LE_LIMITED_DISCOVERABLE = 0x01, /**< *Peripheral device is discoverable for a limited period of time. */
        LE_GENERAL_DISCOVERABLE = 0x02, /**< Peripheral device is discoverable at any moment. */
        BREDR_NOT_SUPPORTED     = 0x04, /**< Peripheral device is LE only. */
        SIMULTANEOUS_LE_BREDR_C = 0x08, /**< Not relevant - central mode only. */
        SIMULTANEOUS_LE_BREDR_H = 0x10  /**< Not relevant - central mode only. */
    };
    typedef enum Flags_t Flags; /* Deprecated type alias. This may be dropped in a future release. */

    /**********************************************************************/
    /*!
        \brief
        A list of values for the APPEARANCE AD Type, which describes the
        physical shape or appearance of the device.

        \par Source
        \li \c Bluetooth Core Specification Supplement, Part A, Section 1.12
        \li \c Bluetooth Core Specification 4.0 (Vol. 3), Part C, Section 12.2
        \li \c https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.gap.appearance.xml
    */
    /**********************************************************************/
    enum Appearance_t {
        UNKNOWN                                        = 0,     /**< Unknown or unspecified appearance type. */
        GENERIC_PHONE                                  = 64,    /**< Generic Phone. */
        GENERIC_COMPUTER                               = 128,   /**< Generic Computer. */
        GENERIC_WATCH                                  = 192,   /**< Generic Watch. */
        WATCH_SPORTS_WATCH                             = 193,   /**< Sports Watch. */
        GENERIC_CLOCK                                  = 256,   /**< Generic Clock. */
        GENERIC_DISPLAY                                = 320,   /**< Generic Display. */
        GENERIC_REMOTE_CONTROL                         = 384,   /**< Generic Remote Control. */
        GENERIC_EYE_GLASSES                            = 448,   /**< Generic Eye Glasses. */
        GENERIC_TAG                                    = 512,   /**< Generic Tag. */
        GENERIC_KEYRING                                = 576,   /**< Generic Keyring. */
        GENERIC_MEDIA_PLAYER                           = 640,   /**< Generic Media Player. */
        GENERIC_BARCODE_SCANNER                        = 704,   /**< Generic Barcode Scanner. */
        GENERIC_THERMOMETER                            = 768,   /**< Generic Thermometer. */
        THERMOMETER_EAR                                = 769,   /**< Ear Thermometer. */
        GENERIC_HEART_RATE_SENSOR                      = 832,   /**< Generic Heart Rate Sensor. */
        HEART_RATE_SENSOR_HEART_RATE_BELT              = 833,   /**< Belt Heart Rate Sensor. */
        GENERIC_BLOOD_PRESSURE                         = 896,   /**< Generic Blood Pressure. */
        BLOOD_PRESSURE_ARM                             = 897,   /**< Arm Blood Pressure. */
        BLOOD_PRESSURE_WRIST                           = 898,   /**< Wrist Blood Pressure. */
        HUMAN_INTERFACE_DEVICE_HID                     = 960,   /**< Human Interface Device (HID). */
        KEYBOARD                                       = 961,   /**< Keyboard. */
        MOUSE                                          = 962,   /**< Mouse. */
        JOYSTICK                                       = 963,   /**< Joystick. */
        GAMEPAD                                        = 964,   /**< Gamepad. */
        DIGITIZER_TABLET                               = 965,   /**< Digitizer Tablet. */
        CARD_READER                                    = 966,   /**< Card Reader. */
        DIGITAL_PEN                                    = 967,   /**< Digital Pen. */
        BARCODE_SCANNER                                = 968,   /**< Barcode Scanner. */
        GENERIC_GLUCOSE_METER                          = 1024,  /**< Generic Glucose Meter. */
        GENERIC_RUNNING_WALKING_SENSOR                 = 1088,  /**< Generic Running/Walking Sensor. */
        RUNNING_WALKING_SENSOR_IN_SHOE                 = 1089,  /**< In Shoe Running/Walking Sensor. */
        RUNNING_WALKING_SENSOR_ON_SHOE                 = 1090,  /**< On Shoe Running/Walking Sensor. */
        RUNNING_WALKING_SENSOR_ON_HIP                  = 1091,  /**< On Hip Running/Walking Sensor. */
        GENERIC_CYCLING                                = 1152,  /**< Generic Cycling. */
        CYCLING_CYCLING_COMPUTER                       = 1153,  /**< Cycling Computer. */
        CYCLING_SPEED_SENSOR                           = 1154,  /**< Cycling Speed Sensor. */
        CYCLING_CADENCE_SENSOR                         = 1155,  /**< Cycling Cadence Sensor. */
        CYCLING_POWER_SENSOR                           = 1156,  /**< Cycling Power Sensor. */
        CYCLING_SPEED_AND_CADENCE_SENSOR               = 1157,  /**< Cycling Speed and Cadence Sensor. */
        PULSE_OXIMETER_GENERIC                         = 3136,  /**< Generic Pulse Oximeter. */
        PULSE_OXIMETER_FINGERTIP                       = 3137,  /**< Fingertip Pulse Oximeter. */
        PULSE_OXIMETER_WRIST_WORN                      = 3138,  /**< Wrist Worn Pulse Oximeter. */
        GENERIC_WEIGHT_SCALE                           = 3200,  /**< Generic Weight Scale. */
        OUTDOOR_GENERIC                                = 5184,  /**< Generic Outdoor. */
        OUTDOOR_LOCATION_DISPLAY_DEVICE                = 5185,  /**< Outdoor Location Display Device. */
        OUTDOOR_LOCATION_AND_NAVIGATION_DISPLAY_DEVICE = 5186,  /**< Outdoor Location and Navigation Display Device. */
        OUTDOOR_LOCATION_POD                           = 5187,  /**< Outdoor Location Pod. */
        OUTDOOR_LOCATION_AND_NAVIGATION_POD            = 5188   /**< Outdoor Location and Navigation Pod. */
    };
    typedef enum Appearance_t Appearance; /* Deprecated type alias. This may be dropped in a future release. */

    GapAdvertisingData(void) : _payload(), _payloadLen(0), _appearance(GENERIC_TAG) {
        /* empty */
    }

    /**
     * Adds advertising data based on the specified AD type (see DataType).
     * If the supplied AD type is already present in the advertising
     * payload, then the value is updated.
     *
     * @param[in] advDataType  The Advertising 'DataType' to add.
     * @param[in] payload      Pointer to the payload contents.
     * @param[in] len          Size of the payload in bytes.
     *
     * @return BLE_ERROR_BUFFER_OVERFLOW if the new value causes the
     *         advertising buffer to overflow. BLE_ERROR_NONE is returned
     *         on success.
     *
     * @note When the specified AD type is INCOMPLETE_LIST_16BIT_SERVICE_IDS,
     *       COMPLETE_LIST_16BIT_SERVICE_IDS, INCOMPLETE_LIST_32BIT_SERVICE_IDS,
     *       COMPLETE_LIST_32BIT_SERVICE_IDS, INCOMPLETE_LIST_128BIT_SERVICE_IDS,
     *       COMPLETE_LIST_128BIT_SERVICE_IDS or LIST_128BIT_SOLICITATION_IDS the
     *       supplied value is appended to the values previously added to the
     *       payload.
     */
    ble_error_t addData(DataType_t advDataType, const uint8_t *payload, uint8_t len)
    {
        // find field
        uint8_t* field = findField(advDataType);

        if (field) {
            // Field type already exist, either add to field or replace
            return updateFieldPayload(advDataType, payload, len, field);
        } else {
            // field doesn't exists, insert new
            return appendField(advDataType, payload, len);
        }
    }

    /**
     * Update a particular ADV field in the advertising payload (based on
     * matching type).
     *
     * @param[in] advDataType  The Advertising 'DataType' to add.
     * @param[in] payload      Pointer to the payload contents.
     * @param[in] len          Size of the payload in bytes.
     *
     * @return BLE_ERROR_UNSPECIFIED if the specified field is not found,
     *         BLE_ERROR_BUFFER_OVERFLOW if the new value causes the
     *         advertising buffer to overflow. BLE_ERROR_NONE is returned
     *         on success.
     */
    ble_error_t updateData(DataType_t advDataType, const uint8_t *payload, uint8_t len)
    {
        // find field
        uint8_t* field = findField(advDataType);

        if (field) {
            // Field type already exist, either add to field or replace
            return updateFieldPayload(advDataType, payload, len, field);
        } else {
            // field doesn't exists, return an error
            return BLE_ERROR_UNSPECIFIED;
        }
    }

    /**
     * Helper function to add APPEARANCE data to the advertising payload.
     *
     * @param  appearance
     *           The APPEARANCE value to add.
     *
     * @return BLE_ERROR_BUFFER_OVERFLOW if the specified data would cause the
     * advertising buffer to overflow, else BLE_ERROR_NONE.
     */
    ble_error_t addAppearance(Appearance appearance = GENERIC_TAG) {
        _appearance = appearance;
        return addData(GapAdvertisingData::APPEARANCE, (uint8_t *)&appearance, 2);
    }

    /**
     * Helper function to add FLAGS data to the advertising payload.
     * @param  flags
     *           LE_LIMITED_DISCOVERABLE
     *             The peripheral is discoverable for a limited period of time.
     *           LE_GENERAL_DISCOVERABLE
     *             The peripheral is permanently discoverable.
     *           BREDR_NOT_SUPPORTED
     *             This peripheral is a Bluetooth Low Energy only device (no EDR support).
     *
     * @return BLE_ERROR_BUFFER_OVERFLOW if the specified data would cause the
     * advertising buffer to overflow, else BLE_ERROR_NONE.
     */
    ble_error_t addFlags(uint8_t flags = LE_GENERAL_DISCOVERABLE) {
        return addData(GapAdvertisingData::FLAGS, &flags, 1);
    }

    /**
     * Helper function to add TX_POWER_LEVEL data to the advertising payload.
     *
     * @return BLE_ERROR_BUFFER_OVERFLOW if the specified data would cause the
     * advertising buffer to overflow, else BLE_ERROR_NONE.
     */
    ble_error_t addTxPower(int8_t txPower) {
        /* To Do: Basic error checking to make sure txPower is in range. */
        return addData(GapAdvertisingData::TX_POWER_LEVEL, (uint8_t *)&txPower, 1);
    }

    /**
     * Clears the payload and resets the payload length counter.
     */
    void        clear(void) {
        memset(&_payload, 0, GAP_ADVERTISING_DATA_MAX_PAYLOAD);
        _payloadLen = 0;
    }

    /**
     * Returns a pointer to the current payload.
     */
    const uint8_t *getPayload(void) const {
        return _payload;
    }

    /**
     * Returns the current payload length (0..31 bytes).
     */
    uint8_t     getPayloadLen(void) const {
        return _payloadLen;
    }

    /**
     * Returns the 16-bit appearance value for this device.
     */
    uint16_t    getAppearance(void) const {
        return (uint16_t)_appearance;
    }

    /**
     * Search advertisement data for field.
     * Returns pointer to the first element in the field if found, NULL otherwise.
     * Where the first element is the length of the field.
     */
    const uint8_t* findField(DataType_t type) const {
        return findField(type);
    }

private:
    /**
     * Append advertising data based on the specified AD type (see DataType)
     */
    ble_error_t appendField(DataType advDataType, const uint8_t *payload, uint8_t len)
    {
        /* Make sure we don't exceed the 31 byte payload limit */
        if (_payloadLen + len + 2 > GAP_ADVERTISING_DATA_MAX_PAYLOAD) {
            return BLE_ERROR_BUFFER_OVERFLOW;
        }

        /* Field length. */
        memset(&_payload[_payloadLen], len + 1, 1);
        _payloadLen++;

        /* Field ID. */
        memset(&_payload[_payloadLen], (uint8_t)advDataType, 1);
        _payloadLen++;

        /* Payload. */
        memcpy(&_payload[_payloadLen], payload, len);
        _payloadLen += len;

        return BLE_ERROR_NONE;
    }

    /**
     * Search advertisement data for field.
     * Returns pointer to the first element in the field if found, NULL otherwise.
     * Where the first element is the length of the field.
     */
    uint8_t* findField(DataType_t type) {
        // scan through advertisement data
        for (uint8_t idx = 0; idx < _payloadLen; ) {
            uint8_t fieldType = _payload[idx + 1];

            if (fieldType == type) {
                return &_payload[idx];
            }

            // advance to next field
            idx += _payload[idx] + 1;
        }

        // field not found
        return NULL;
    }

    /**
     * Given the a pointer to a field in the advertising payload it replaces
     * the existing data in the field with the supplied data.
     * Returns BLE_ERROR_NONE on success.
     */
    ble_error_t updateFieldPayload(DataType_t advDataType, const uint8_t *payload, uint8_t len, uint8_t* field)
    {
        ble_error_t result = BLE_ERROR_BUFFER_OVERFLOW;

        switch(advDataType) {
            // These fields will have the new data appended if there is sufficient space
            case INCOMPLETE_LIST_16BIT_SERVICE_IDS:
            case COMPLETE_LIST_16BIT_SERVICE_IDS:
            case INCOMPLETE_LIST_32BIT_SERVICE_IDS:
            case COMPLETE_LIST_32BIT_SERVICE_IDS:
            case INCOMPLETE_LIST_128BIT_SERVICE_IDS:
            case COMPLETE_LIST_128BIT_SERVICE_IDS:
            case LIST_128BIT_SOLICITATION_IDS: {
                // check if data fits
                if ((_payloadLen + len) <= GAP_ADVERTISING_DATA_MAX_PAYLOAD) {
                    // make room for new field by moving the remainder of the
                    // advertisement payload "to the right" starting after the
                    // TYPE field.
                    uint8_t* end = &_payload[_payloadLen];

                    while (&field[1] < end) {
                        end[len] = *end;
                        end--;
                    }

                    // insert new data
                    for (uint8_t idx = 0; idx < len; idx++) {
                        field[2 + idx] = payload[idx];
                    }

                    // increment lengths
                    field[0] += len;
                    _payloadLen += len;

                    result = BLE_ERROR_NONE;
                }

                break;
            }
            //  These fields will be overwritten with the new value
            default: {
                // current field length, with the type subtracted
                uint8_t dataLength = field[0] - 1;

                // new data has same length, do in-order replacement
                if (len == dataLength) {
                    for (uint8_t idx = 0; idx < dataLength; idx++) {
                        field[2 + idx] = payload[idx];
                    }
                } else {
                    // check if data fits
                    if ((_payloadLen - dataLength + len) <= GAP_ADVERTISING_DATA_MAX_PAYLOAD) {

                        // remove old field
                        while ((field + dataLength + 2) < &_payload[_payloadLen]) {
                            *field = field[dataLength + 2];
                            field++;
                        }

                        // reduce length
                        _payloadLen -= dataLength + 2;

                        // add new field
                        result = appendField(advDataType, payload, len);
                    }
                }

                break;
            }
        }

        return result;
    }

    uint8_t  _payload[GAP_ADVERTISING_DATA_MAX_PAYLOAD];
    uint8_t  _payloadLen;
    uint16_t _appearance;
};

#endif // ifndef __GAP_ADVERTISING_DATA_H__