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GattAttribute.h
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GattAttribute.h
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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 __GATT_ATTRIBUTE_H__
#define __GATT_ATTRIBUTE_H__
#include "UUID.h"
#include "BLETypes.h"
/**
* Instances of this class encapsulate the data that belongs to a Bluetooth Low
* Energy attribute.
*/
class GattAttribute {
public:
/**
* Type for the handle or ID of the attribute in the ATT table. These are
* unique and are usually generated by the underlying BLE stack.
*/
typedef ble::attribute_handle_t Handle_t;
/**
* Define the value of an invalid attribute handle.
*/
static const Handle_t INVALID_HANDLE = 0x0000;
public:
/**
* @brief Creates a new GattAttribute using the specified
* UUID, value length, and inital value.
*
* @param[in] uuid
* The UUID to use for this attribute.
* @param[in] valuePtr
* The memory holding the initial value.
* @param[in] len
* The length in bytes of this attribute's value.
* @param[in] maxLen
* The max length in bytes of this attribute's value.
* @param[in] hasVariableLen
* Whether the attribute's value length changes overtime.
*
* @section EXAMPLE
*
* @code
*
* // UUID = 0x2A19, Min length 2, Max len = 2
* GattAttribute attr = GattAttribute(0x2A19, &someValue, 2, 2);
*
* @endcode
*/
GattAttribute(const UUID &uuid, uint8_t *valuePtr = NULL, uint16_t len = 0, uint16_t maxLen = 0, bool hasVariableLen = true) :
_uuid(uuid), _valuePtr(valuePtr), _lenMax(maxLen), _len(len), _hasVariableLen(hasVariableLen), _handle() {
/* Empty */
}
public:
/**
* Get the attribute's handle in the ATT table.
*
* @return The attribute's handle.
*/
Handle_t getHandle(void) const {
return _handle;
}
/**
* The UUID of the characteristic that this attribute belongs to.
*
* @return The characteristic's UUID.
*/
const UUID &getUUID(void) const {
return _uuid;
}
/**
* Get the current length of the attribute value.
*
* @return The current length of the attribute value.
*/
uint16_t getLength(void) const {
return _len;
}
/**
* Get the maximum length of the attribute value.
*
* The maximum length of the attribute value.
*/
uint16_t getMaxLength(void) const {
return _lenMax;
}
/**
* Get a pointer to the current length of the attribute value.
*
* @return A pointer to the current length of the attribute value.
*/
uint16_t *getLengthPtr(void) {
return &_len;
}
/**
* Set the attribute handle.
*
* @param[in] id
* The new attribute handle.
*/
void setHandle(Handle_t id) {
_handle = id;
}
/**
* Get a pointer to the attribute value.
*
* @return A pointer to the attribute value.
*/
uint8_t *getValuePtr(void) {
return _valuePtr;
}
/**
* Check whether the length of the attribute's value can change over time.
*
* @return true if the attribute has variable length, false otherwise.
*/
bool hasVariableLength(void) const {
return _hasVariableLen;
}
private:
/**
* Characteristic's UUID.
*/
UUID _uuid;
/**
* Pointer to the attribute's value.
*/
uint8_t *_valuePtr;
/**
* Maximum length of the value pointed to by GattAttribute::_valuePtr.
*/
uint16_t _lenMax;
/**
* Current length of the value pointed to by GattAttribute::_valuePtr.
*/
uint16_t _len;
/**
* Whether the length of the value can change over time.
*/
bool _hasVariableLen;
/**
* The attribute's handle in the ATT table.
*/
Handle_t _handle;
private:
/* Disallow copy and assignment. */
GattAttribute(const GattAttribute &);
GattAttribute& operator=(const GattAttribute &);
};
#endif /* ifndef __GATT_ATTRIBUTE_H__ */