GattAttribute.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef __GATT_ATTRIBUTE_H__
00018 #define __GATT_ATTRIBUTE_H__
00019 
00020 #include "UUID.h"
00021 
00022 /**
00023  * Instances of this class encapsulate the data that belongs to a Bluetooth Low
00024  * Energy attribute.
00025  */
00026 class GattAttribute {
00027 public:
00028     /**
00029      * Type for the handle or ID of the attribute in the ATT table. These are
00030      * unique and are usually generated by the underlying BLE stack.
00031      */
00032     typedef uint16_t Handle_t;
00033     /**
00034      * Define the value of an invalid attribute handle.
00035      */
00036     static const Handle_t INVALID_HANDLE = 0x0000;
00037 
00038 public:
00039     /**
00040      *  @brief  Creates a new GattAttribute using the specified
00041      *          UUID, value length, and inital value.
00042      *
00043      *  @param[in]  uuid
00044      *              The UUID to use for this attribute.
00045      *  @param[in]  valuePtr
00046      *              The memory holding the initial value.
00047      *  @param[in]  len
00048      *              The length in bytes of this attribute's value.
00049      *  @param[in]  maxLen
00050      *              The max length in bytes of this attribute's value.
00051      *  @param[in]  hasVariableLen
00052      *              Whether the attribute's value length changes overtime.
00053      *
00054      *  @section EXAMPLE
00055      *
00056      *  @code
00057      *
00058      *  // UUID = 0x2A19, Min length 2, Max len = 2
00059      *  GattAttribute attr = GattAttribute(0x2A19, &someValue, 2, 2);
00060      *
00061      *  @endcode
00062      */
00063     GattAttribute(const UUID &uuid, uint8_t *valuePtr = NULL, uint16_t len = 0, uint16_t maxLen = 0, bool hasVariableLen = true) :
00064         _uuid(uuid), _valuePtr(valuePtr), _lenMax(maxLen), _len(len), _hasVariableLen(hasVariableLen), _handle() {
00065         /* Empty */
00066     }
00067 
00068 public:
00069     /**
00070      * Get the attribute's handle in the ATT table.
00071      *
00072      * @return The attribute's handle.
00073      */
00074     Handle_t getHandle(void) const {
00075         return _handle;
00076     }
00077 
00078     /**
00079      * The UUID of the characteristic that this attribute belongs to.
00080      *
00081      * @return The characteristic's UUID.
00082      */
00083     const UUID &getUUID(void) const {
00084         return _uuid;
00085     }
00086 
00087     /**
00088      * Get the current length of the attribute value.
00089      *
00090      * @return The current length of the attribute value.
00091      */
00092     uint16_t getLength(void) const {
00093         return _len;
00094     }
00095 
00096     /**
00097      * Get the maximum length of the attribute value.
00098      *
00099      * The maximum length of the attribute value.
00100      */
00101     uint16_t getMaxLength(void) const {
00102         return _lenMax;
00103     }
00104 
00105     /**
00106      * Get a pointer to the current length of the attribute value.
00107      *
00108      * @return A pointer to the current length of the attribute value.
00109      */
00110     uint16_t *getLengthPtr(void) {
00111         return &_len;
00112     }
00113 
00114     /**
00115      * Set the attribute handle.
00116      *
00117      * @param[in] id
00118      *              The new attribute handle.
00119      */
00120     void setHandle(Handle_t id) {
00121         _handle = id;
00122     }
00123 
00124     /**
00125      * Get a pointer to the attribute value.
00126      *
00127      * @return A pointer to the attribute value.
00128      */
00129     uint8_t *getValuePtr(void) {
00130         return _valuePtr;
00131     }
00132 
00133     /**
00134      * Check whether the length of the attribute's value can change over time.
00135      *
00136      * @return true if the attribute has variable length, false otherwise.
00137      */
00138     bool hasVariableLength(void) const {
00139         return _hasVariableLen;
00140     }
00141 
00142 private:
00143     /**
00144      * Characteristic's UUID.
00145      */
00146     UUID      _uuid;
00147     /**
00148      * Pointer to the attribute's value.
00149      */
00150     uint8_t  *_valuePtr;
00151     /**
00152      * Maximum length of the value pointed to by GattAttribute::_valuePtr.
00153      */
00154     uint16_t  _lenMax;
00155     /**
00156      * Current length of the value pointed to by GattAttribute::_valuePtr.
00157      */
00158     uint16_t  _len;
00159     /**
00160      * Whether the length of the value can change over time.
00161      */
00162     bool      _hasVariableLen;
00163     /**
00164      * The attribute's handle in the ATT table.
00165      */
00166     Handle_t  _handle;
00167 
00168 private:
00169     /* Disallow copy and assignment. */
00170     GattAttribute(const GattAttribute &);
00171     GattAttribute& operator=(const GattAttribute &);
00172 };
00173 
00174 #endif /* ifndef __GATT_ATTRIBUTE_H__ */