1 #ifndef DALI_INTERNAL_MESSAGE_BUFFER_H
2 #define DALI_INTERNAL_MESSAGE_BUFFER_H
5 * Copyright (c) 2019 Samsung Electronics Co., Ltd.
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
22 #include <cstddef> // size_t
23 #include <cstdint> // uint32_t
32 * Utility class to reserve a buffer for storing messages.
37 using WordType = std::ptrdiff_t;
40 * Create a new MessageBuffer
41 * @param[in] The smallest capacity which the buffer will allocate, with respect to the size of type "char".
42 * @note The buffer will not allocate memory until the first call to ReserveMessageSlot().
44 MessageBuffer( std::size_t initialCapacity );
47 * Non-virtual destructor; not suitable as a base class
52 * Reserve space for another message in the buffer.
53 * @pre size is greater than zero.
54 * @param[in] size The message size with respect to the size of type "char".
55 * @return A pointer to the address allocated for the message, aligned to a word boundary
57 uint32_t* ReserveMessageSlot( std::size_t size );
60 * Query the capacity of the message buffer.
61 * @return The capacity with respect to the size of type "char".
63 std::size_t GetCapacity() const;
66 * Used to iterate though the messages in the buffer.
73 Iterator(WordType* current);
75 // Inlined for performance
78 // Valid until end marker has been found
79 return 0 != mMessageSize;
82 // Inlined for performance
85 return ( 0 != mMessageSize ) ? mCurrent : NULL;
88 // Inlined for performance
91 // Jump to next object and read size
92 mCurrent += mMessageSize;
93 mMessageSize = *mCurrent++;
97 Iterator(const Iterator& copy);
102 Iterator& operator=(const Iterator& rhs);
107 std::size_t mMessageSize;
111 * Returns an iterator to the first message in the buffer.
112 * There is no past-the-end iterator; use Iterator::IsValid() to determine when the has been reached.
113 * @note Adding more messages with ReserveMessageSlot() may corrupt this iterator.
114 * @return The iterator.
116 Iterator Begin() const;
119 * Sets the size of the buffer to zero (does not deallocate memory)
126 MessageBuffer(const MessageBuffer&);
129 MessageBuffer& operator=(const MessageBuffer& rhs);
132 * Helper to increase the capacity of the buffer.
133 * @pre The newCapacity is greater than mCapacity.
134 * @param[in] The newCapacity
136 void IncreaseCapacity( std::size_t newCapacity );
140 std::size_t mInitialCapacity; ///< The capacity to allocate during first call to ReserveMessageSlot
142 WordType* mData; ///< The data allocated for the message buffer
143 WordType* mNextSlot; ///< The next free location in the buffer
145 std::size_t mCapacity; ///< The memory allocated with respect to sizeof(WordType)
146 std::size_t mSize; ///< The memory reserved for messages with respect to sizeof(WordType)
149 } // namespace Internal
153 #endif // DALI_INTERNAL_MESSAGE_BUFFER_H