BLE: Add ArrayView in utilities.

Author: pan-

features/FEATURE_BLE/ble/ArrayView.h

@@ -0,0 +1,165 @@
+/* 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>
+
+namespace ble {
+
+/**
+ * Immutable view to an array.
+ */
+template<typename T>
+struct ArrayView {
+
+    /**
+     * construct an array view to an empty array
+     */
+    ArrayView() : _array(0), _size(0) { }
+
+    /**
+     * construct an array view from a pointer.
+     * and its size.
+     */
+    ArrayView(T* array_ptr, size_t array_size) :
+    	_array(array_ptr), _size(array_size) { }
+
+    /**
+     * Construct an array view from the reference to an array.
+     */
+    template<size_t Size>
+    ArrayView(T (&elements)[Size]):
+		_array(elements), _size(Size) { }
+
+    /**
+     * Return the size of the array viewed.
+     */
+    size_t size() const {
+    	return _size;
+    }
+
+    /**
+     * Access to a mutable element of the array.
+     */
+    T& operator[](size_t index) {
+    	return _array[index];
+    }
+
+    /**
+     * Access to an immutable element of the array.
+     */
+    const T& operator[](size_t index) const  {
+    	return _array[index];
+    }
+
+    /**
+     * Get the pointer to the array
+     */
+    T* data() {
+        return _array;
+    }
+
+    /**
+     * Get the pointer to the const array
+     */
+    const T* data() const {
+        return _array;
+    }
+
+    /**
+     * Equality operator
+     */
+    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
+     */
+    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 C/C++ array.
+ * This helper avoid the typing of template parameter when ArrayView are
+ * created 'inline'.
+ * @param elements The array viewed.
+ * @return The array_view to elements.
+ */
+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.
+ * This helper avoid the typing of template parameter when ArrayView are
+ * created 'inline'.
+ * @param array_ptr The pointer to the array to view.
+ * @param array_size The size of the array.
+ * @return The array_view to array_ptr with a size of array_size.
+ */
+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 C/C++ array.
+ * This helper avoid the typing of template parameter when ArrayView are
+ * created 'inline'.
+ * @param elements The array viewed.
+ * @return The ArrayView to elements.
+ */
+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.
+ * This helper avoid the typing of template parameter when ArrayView are
+ * created 'inline'.
+ * @param array_ptr The pointer to the array to view.
+ * @param array_size The size of the array.
+ * @return The ArrayView to array_ptr with a size of array_size.
+ */
+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_ */