1 #ifndef DALI_INTERNAL_MESSAGE_BUFFER_H
2 #define DALI_INTERNAL_MESSAGE_BUFFER_H
5 * Copyright (c) 2021 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
30 * Utility class to reserve a buffer for storing messages.
35 using WordType = std::ptrdiff_t;
38 * Create a new MessageBuffer
39 * @param[in] The smallest capacity which the buffer will allocate, with respect to the size of type "char".
40 * @note The buffer will not allocate memory until the first call to ReserveMessageSlot().
42 MessageBuffer(std::size_t initialCapacity);
45 * Non-virtual destructor; not suitable as a base class
50 * Reserve space for another message in the buffer.
51 * @pre size is greater than zero.
52 * @param[in] size The message size with respect to the size of type "char".
53 * @return A pointer to the address allocated for the message, aligned to a word boundary
55 uint32_t* ReserveMessageSlot(std::size_t size);
58 * Query the capacity of the message buffer.
59 * @return The capacity with respect to the size of type "char".
61 std::size_t GetCapacity() const;
64 * Used to iterate though the messages in the buffer.
70 Iterator(WordType* current);
72 // Inlined for performance
75 // Valid until end marker has been found
76 return 0 != mMessageSize;
79 // Inlined for performance
82 return (0 != mMessageSize) ? mCurrent : nullptr;
85 // Inlined for performance
88 // Jump to next object and read size
89 mCurrent += mMessageSize;
90 mMessageSize = *mCurrent++;
94 Iterator(const Iterator& copy);
98 Iterator& operator=(const Iterator& rhs);
102 std::size_t mMessageSize;
106 * Returns an iterator to the first message in the buffer.
107 * There is no past-the-end iterator; use Iterator::IsValid() to determine when the has been reached.
108 * @note Adding more messages with ReserveMessageSlot() may corrupt this iterator.
109 * @return The iterator.
111 Iterator Begin() const;
114 * Sets the size of the buffer to zero (does not deallocate memory)
120 MessageBuffer(const MessageBuffer&);
123 MessageBuffer& operator=(const MessageBuffer& rhs);
126 * Helper to increase the capacity of the buffer.
127 * @pre The newCapacity is greater than mCapacity.
128 * @param[in] The newCapacity
130 void IncreaseCapacity(std::size_t newCapacity);
133 std::size_t mInitialCapacity; ///< The capacity to allocate during first call to ReserveMessageSlot
135 WordType* mData; ///< The data allocated for the message buffer
136 WordType* mNextSlot; ///< The next free location in the buffer
138 std::size_t mCapacity; ///< The memory allocated with respect to sizeof(WordType)
139 std::size_t mSize; ///< The memory reserved for messages with respect to sizeof(WordType)
142 } // namespace Internal
146 #endif // DALI_INTERNAL_MESSAGE_BUFFER_H