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

Revision:

0:9fca2b23d0ba

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/features/FEATURE_BLE/ble/ArrayView.h	Sat Feb 23 12:13:36 2019 +0000
@@ -0,0 +1,272 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017-2017 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 BLE_ARRAY_VIEW_H_
+#define BLE_ARRAY_VIEW_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+/**
+ * @addtogroup ble
+ * @{
+ * @addtogroup common
+ * @{
+ */
+
+/**
+ * @file
+ */
+
+namespace ble {
+
+/**
+ * Immutable view to an array.
+ *
+ * Array views encapsulate the pointer to an array and its size into a single
+ * object; however, it does not manage the lifetime of the array viewed.
+ * You can use instances of ArrayView to replace the traditional pair of pointer
+ * and size arguments in function calls.
+ *
+ * You can use the size member function to query the number of elements present
+ * in the array, and overloads of the subscript operator allow code using
+ * this object to access to the content of the array viewed.
+ *
+ * @note You can create ArrayView instances with the help of the function
+ * template make_ArrayView() and make_const_ArrayView().
+ *
+ * @tparam T type of objects held by the array.
+ */
+template<typename T>
+struct ArrayView {
+
+    /**
+     * Construct a view to an empty array.
+     *
+     * @post a call to size() will return 0, and data() will return NULL.
+     */
+    ArrayView() : _array(0), _size(0) { }
+
+    /**
+     * Construct an array view from a pointer to a buffer and its size.
+     *
+     * @param array_ptr Pointer to the array data
+     * @param array_size Number of elements of T present in the array.
+     *
+     * @post a call to size() will return array_size and data() will return
+     * array_tpr.
+     */
+    ArrayView(T* array_ptr, size_t array_size) :
+    	_array(array_ptr), _size(array_size) { }
+
+    /**
+     * Construct an array view from the reference to an array.
+     *
+     * @param elements Reference to the array viewed.
+     *
+     * @tparam Size Number of elements of T presents in the array.
+     *
+     * @post a call to size() will return Size, and data() will return
+     * a pointer to elements.
+     */
+    template<size_t Size>
+    ArrayView(T (&elements)[Size]):
+		_array(elements), _size(Size) { }
+
+    /**
+     * Return the size of the array viewed.
+     *
+     * @return The number of elements present in the array viewed.
+     */
+    size_t size() const
+    {
+    	return _size;
+    }
+
+    /**
+     * Access to a mutable element of the array.
+     *
+     * @param index Element index to access.
+     *
+     * @return A reference to the element at the index specified in input.
+     *
+     * @pre index shall be less than size().
+     */
+    T& operator[](size_t index)
+    {
+    	return _array[index];
+    }
+
+    /**
+     * Access to an immutable element of the array.
+     *
+     * @param index Element index to access.
+     *
+     * @return A const reference to the element at the index specified in input.
+     *
+     * @pre index shall be less than size().
+     */
+    const T& operator[](size_t index) const
+    {
+    	return _array[index];
+    }
+
+    /**
+     * Get the raw pointer to the array.
+     *
+     * @return The raw pointer to the array.
+     */
+    T* data()
+    {
+        return _array;
+    }
+
+    /**
+     * Get the raw const pointer to the array.
+     *
+     * @return The raw pointer to the array.
+     */
+    const T* data() const
+    {
+        return _array;
+    }
+
+    /**
+     * Equality operator.
+     *
+     * @param lhs Left hand side of the binary operation.
+     * @param rhs Right hand side of the binary operation.
+     *
+     * @return True if arrays in input have the same size and the same content
+     * and false otherwise.
+     */
+    friend bool operator==(const ArrayView& lhs, const ArrayView& rhs)
+    {
+    	if (lhs.size() != rhs.size()) {
+    		return false;
+    	}
+
+    	if (lhs.data() == rhs.data()) {
+    		return true;
+    	}
+
+    	return memcmp(lhs.data(), rhs.data(), lhs.size()) == 0;
+    }
+
+    /**
+     * Not equal operator
+     *
+     * @param lhs Left hand side of the binary operation.
+     * @param rhs Right hand side of the binary operation.
+     *
+     * @return True if arrays in input do not have the same size or the same
+     * content and false otherwise.
+     */
+    friend bool operator!=(const ArrayView& lhs, const ArrayView& rhs)
+    {
+    	return !(lhs == rhs);
+    }
+
+private:
+    T* const _array;
+    const size_t _size;
+};
+
+
+/**
+ * Generate an array view from a reference to a C/C++ array.
+ *
+ * @tparam T Type of elements held in elements.
+ * @tparam Size Number of items held in elements.
+ *
+ * @param elements The reference to the array viewed.
+ *
+ * @return The ArrayView to elements.
+ *
+ * @note This helper avoids the typing of template parameter when ArrayView is
+ * created 'inline'.
+ */
+template<typename T, size_t Size>
+ArrayView<T> make_ArrayView(T (&elements)[Size])
+{
+    return ArrayView<T>(elements);
+}
+
+/**
+ * Generate an array view from a C/C++ pointer and the size of the array.
+ *
+ * @tparam T Type of elements held in array_ptr.
+ *
+ * @param array_ptr The pointer to the array to viewed.
+ * @param array_size The number of T elements in the array.
+ *
+ * @return The ArrayView to array_ptr with a size of array_size.
+ *
+ * @note This helper avoids the typing of template parameter when ArrayView is
+ * created 'inline'.
+ */
+template<typename T>
+ArrayView<T> make_ArrayView(T* array_ptr, size_t array_size)
+{
+    return ArrayView<T>(array_ptr, array_size);
+}
+
+/**
+ * Generate a const array view from a reference to a C/C++ array.
+ *
+ * @tparam T Type of elements held in elements.
+ * @tparam Size Number of items held in elements.
+ *
+ * @param elements The array viewed.
+ * @return The ArrayView to elements.
+ *
+ * @note This helper avoids the typing of template parameter when ArrayView is
+ * created 'inline'.
+ */
+template<typename T, size_t Size>
+ArrayView<const T> make_const_ArrayView(T (&elements)[Size])
+{
+    return ArrayView<const T>(elements);
+}
+
+/**
+ * Generate a const array view from a C/C++ pointer and the size of the array.
+ *
+ * @tparam T Type of elements held in array_ptr.
+ *
+ * @param array_ptr The pointer to the array to viewed.
+ * @param array_size The number of T elements in the array.
+ *
+ * @return The ArrayView to array_ptr with a size of array_size.
+ *
+ * @note This helper avoids the typing of template parameter when ArrayView is
+ * created 'inline'.
+ */
+template<typename T>
+ArrayView<const T> make_const_ArrayView(T* array_ptr, size_t array_size)
+{
+    return ArrayView<const T>(array_ptr, array_size);
+}
+
+} // namespace ble
+
+/**
+ * @}
+ * @}
+ */
+
+
+#endif /* BLE_ARRAY_VIEW_H_ */