Diff: mbed-os/features/FEATURE_BLE/ble/GattAttribute.h

Revision:

0:9fca2b23d0ba

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/features/FEATURE_BLE/ble/GattAttribute.h	Sat Feb 23 12:13:36 2019 +0000
@@ -0,0 +1,255 @@
+/* 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 MBED_GATT_ATTRIBUTE_H__
+#define MBED_GATT_ATTRIBUTE_H__
+
+#include "UUID.h"
+#include "BLETypes.h"
+
+/**
+ * @addtogroup ble
+ * @{
+ * @addtogroup gatt
+ * @{
+ * @addtogroup server
+ * @{
+ */
+
+/**
+ * Representation of a GattServer attribute.
+ *
+ * Attributes are the building block of GATT servers: services are attributes,
+ * characteristics are groups of attributes and characteristic descriptors are
+ * attributes, too.
+ *
+ * @par Typed values
+ *
+ * Attributes are typed values composed of a type and its associated value. The
+ * attribute type identifies the attribute purpose. A UUID read by the client
+ * during the discovery of the GATT server models the attribute type. The value of the
+ * attribute is an array of bytes; its length may be fixed or variable.
+ *
+ * As an example, a primary service is declared by an attribute with the type
+ * 0x2800, and the value of the attribute is the UUID of the service.
+ *
+ * @par Attribute Access
+ *
+ * The GATT server is an array of attributes in which a unique index identifies
+ * each of the attributes within the array. That index is called the attribute
+ * handle, and clients use it to access to attributes within the server.
+ *
+ * @note Attributes do not contain information related to their permissions,
+ * grouping or semantic. Higher level specifications define these concepts.
+ */
+class GattAttribute {
+public:
+    /**
+     * Representation of an attribute handle.
+     *
+     * Each attribute in a GattServer has a unique handle that clients can use
+     * to identify the attribute. The underlying BLE stack usually
+     * generates and assigns handles to attributes.
+     */
+    typedef ble::attribute_handle_t Handle_t;
+
+    /**
+     * Invalid attribute handle.
+     */
+    static const Handle_t INVALID_HANDLE = 0x0000;
+
+public:
+    /**
+     * Construct an attribute.
+     *
+     * Application code uses attributes to model characteristic descriptors and
+     * characteristics values.
+     *
+     * @param[in] uuid The type of the attribute.
+     * @param[in] valuePtr Pointer to the memory buffer, which contains the
+     * initial value of the attribute. The constructor does not make a copy of
+     * the attribute buffer; as a consequence, the memory buffer must remain
+     * valid during the lifetime of the attribute.
+     * @param[in] len The length in bytes of this attribute's value.
+     * @param[in] maxLen The length in bytes of the memory buffer containing the
+     * attribute value. It must be greater than or equal to @p len.
+     * @param[in] hasVariableLen Flag that indicates whether the attribute's value
+     * length can change throughout time.
+     *
+     * @par Example
+     *
+     * @code
+     * // declare a value of 2 bytes within a 10 bytes buffer
+     * const uint8_t attribute_value[10] = { 10, 50 };
+     * GattAttribute attr = GattAttribute(
+     *    0x2A19, // attribute type
+     *    attribute_value,
+     *    2, // length of the current value
+     *    sizeof(attribute_value), // length of the buffer containing the value
+     *    true // variable length
+     * );
+     * @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() {
+    }
+
+public:
+    /**
+     * Get the attribute's handle in the ATT table.
+     *
+     * @note The GattServer sets the attribute's handle when services are
+     * inserted.
+     *
+     * @return The attribute's handle.
+     */
+    Handle_t getHandle(void) const
+    {
+        return _handle;
+    }
+
+    /**
+     * Get the UUID of the attribute.
+     *
+     * The UUID identifies the type of the attribute.
+     *
+     * @return The attribute.
+     */
+    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.
+     *
+     * @important note Do not use this function.
+     *
+     * @return A pointer to the current length of the attribute value.
+     */
+    uint16_t *getLengthPtr(void)
+    {
+        return &_len;
+    }
+
+    /**
+     * Set the attribute handle.
+     *
+     * @important The GattServer uses this function internally.
+     * Application code must not use it.
+     *
+     * @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 throughout time.
+     *
+     * @return true if the attribute value has a variable length and false
+     * otherwise.
+     */
+    bool hasVariableLength(void) const
+    {
+        return _hasVariableLen;
+    }
+
+private:
+    /**
+     * Characteristic's UUID.
+     */
+    UUID _uuid;
+
+    /**
+     * Pointer to the attribute's value.
+     */
+    uint8_t *_valuePtr;
+
+    /**
+     * Length in byte of the buffer containing the attribute value.
+     */
+    uint16_t _lenMax;
+
+    /**
+     * Current length of the value pointed to by GattAttribute::_valuePtr.
+     */
+    uint16_t _len;
+
+    /**
+     * Whether the length of the value can change throughout 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 MBED_GATT_ATTRIBUTE_H__ */