Kenji Arai / mbed-os_TYBLE16

mbed-os5 only for TYBLE16

Dependents:   TYBLE16_simple_data_logger TYBLE16_MP3_Air

platform/SharedPtr.h@0:5b88d5760320, 2019-12-17 (annotated)

Committer:
kenjiArai
Date:
Tue Dec 17 23:23:45 2019 +0000
Revision:
0:5b88d5760320
Child:
1:9db0e321a9f4
mbed-os5 only for TYBLE16

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kenjiArai 0:5b88d5760320 1 /* mbed Microcontroller Library
kenjiArai 0:5b88d5760320 2 * Copyright (c) 2006-2018 ARM Limited
kenjiArai 0:5b88d5760320 3 * SPDX-License-Identifier: Apache-2.0
kenjiArai 0:5b88d5760320 4 *
kenjiArai 0:5b88d5760320 5 * Licensed under the Apache License, Version 2.0 (the "License");
kenjiArai 0:5b88d5760320 6 * you may not use this file except in compliance with the License.
kenjiArai 0:5b88d5760320 7 * You may obtain a copy of the License at
kenjiArai 0:5b88d5760320 8 *
kenjiArai 0:5b88d5760320 9 * http://www.apache.org/licenses/LICENSE-2.0
kenjiArai 0:5b88d5760320 10 *
kenjiArai 0:5b88d5760320 11 * Unless required by applicable law or agreed to in writing, software
kenjiArai 0:5b88d5760320 12 * distributed under the License is distributed on an "AS IS" BASIS,
kenjiArai 0:5b88d5760320 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
kenjiArai 0:5b88d5760320 14 * See the License for the specific language governing permissions and
kenjiArai 0:5b88d5760320 15 * limitations under the License.
kenjiArai 0:5b88d5760320 16 */
kenjiArai 0:5b88d5760320 17
kenjiArai 0:5b88d5760320 18 #ifndef __SHAREDPTR_H__
kenjiArai 0:5b88d5760320 19 #define __SHAREDPTR_H__
kenjiArai 0:5b88d5760320 20
kenjiArai 0:5b88d5760320 21 #include <stdlib.h>
kenjiArai 0:5b88d5760320 22
kenjiArai 0:5b88d5760320 23 #include <stdint.h>
kenjiArai 0:5b88d5760320 24 #include <stddef.h>
kenjiArai 0:5b88d5760320 25
kenjiArai 0:5b88d5760320 26 #include "platform/mbed_atomic.h"
kenjiArai 0:5b88d5760320 27
kenjiArai 0:5b88d5760320 28 namespace mbed {
kenjiArai 0:5b88d5760320 29
kenjiArai 0:5b88d5760320 30 /** Shared pointer class.
kenjiArai 0:5b88d5760320 31 *
kenjiArai 0:5b88d5760320 32 * A shared pointer is a "smart" pointer that retains ownership of an object using
kenjiArai 0:5b88d5760320 33 * reference counting across all smart pointers referencing that object.
kenjiArai 0:5b88d5760320 34 *
kenjiArai 0:5b88d5760320 35 * @code
kenjiArai 0:5b88d5760320 36 * #include "platform/SharedPtr.h"
kenjiArai 0:5b88d5760320 37 *
kenjiArai 0:5b88d5760320 38 * void test() {
kenjiArai 0:5b88d5760320 39 * struct MyStruct { int a; };
kenjiArai 0:5b88d5760320 40 *
kenjiArai 0:5b88d5760320 41 * // Create shared pointer
kenjiArai 0:5b88d5760320 42 * SharedPtr<MyStruct> ptr( new MyStruct );
kenjiArai 0:5b88d5760320 43 *
kenjiArai 0:5b88d5760320 44 * // Increase reference count
kenjiArai 0:5b88d5760320 45 * SharedPtr<MyStruct> ptr2( ptr );
kenjiArai 0:5b88d5760320 46 *
kenjiArai 0:5b88d5760320 47 * ptr = NULL; // Reference to the struct instance is still held by ptr2
kenjiArai 0:5b88d5760320 48 *
kenjiArai 0:5b88d5760320 49 * ptr2 = NULL; // The raw pointer is freed
kenjiArai 0:5b88d5760320 50 * }
kenjiArai 0:5b88d5760320 51 * @endcode
kenjiArai 0:5b88d5760320 52 *
kenjiArai 0:5b88d5760320 53 *
kenjiArai 0:5b88d5760320 54 * It is similar to the std::shared_ptr class introduced in C++11;
kenjiArai 0:5b88d5760320 55 * however, this is not a compatible implementation (no weak pointer, no make_shared, no custom deleters and so on.)
kenjiArai 0:5b88d5760320 56 *
kenjiArai 0:5b88d5760320 57 * Usage: SharedPtr<Class> ptr(new Class())
kenjiArai 0:5b88d5760320 58 *
kenjiArai 0:5b88d5760320 59 * When ptr is passed around by value, the copy constructor and
kenjiArai 0:5b88d5760320 60 * destructor manages the reference count of the raw pointer.
kenjiArai 0:5b88d5760320 61 * If the counter reaches zero, delete is called on the raw pointer.
kenjiArai 0:5b88d5760320 62 *
kenjiArai 0:5b88d5760320 63 * To avoid loops, use "weak" references by calling the original
kenjiArai 0:5b88d5760320 64 * pointer directly through ptr.get().
kenjiArai 0:5b88d5760320 65 */
kenjiArai 0:5b88d5760320 66
kenjiArai 0:5b88d5760320 67 template <class T>
kenjiArai 0:5b88d5760320 68 class SharedPtr {
kenjiArai 0:5b88d5760320 69 public:
kenjiArai 0:5b88d5760320 70 /**
kenjiArai 0:5b88d5760320 71 * @brief Create empty SharedPtr not pointing to anything.
kenjiArai 0:5b88d5760320 72 * @details Used for variable declaration.
kenjiArai 0:5b88d5760320 73 */
kenjiArai 0:5b88d5760320 74 SharedPtr(): _ptr(NULL), _counter(NULL)
kenjiArai 0:5b88d5760320 75 {
kenjiArai 0:5b88d5760320 76 }
kenjiArai 0:5b88d5760320 77
kenjiArai 0:5b88d5760320 78 /**
kenjiArai 0:5b88d5760320 79 * @brief Create new SharedPtr
kenjiArai 0:5b88d5760320 80 * @param ptr Pointer to take control over
kenjiArai 0:5b88d5760320 81 */
kenjiArai 0:5b88d5760320 82 SharedPtr(T *ptr): _ptr(ptr), _counter(NULL)
kenjiArai 0:5b88d5760320 83 {
kenjiArai 0:5b88d5760320 84 // Allocate counter on the heap, so it can be shared
kenjiArai 0:5b88d5760320 85 if (_ptr != NULL) {
kenjiArai 0:5b88d5760320 86 _counter = new uint32_t;
kenjiArai 0:5b88d5760320 87 *_counter = 1;
kenjiArai 0:5b88d5760320 88 }
kenjiArai 0:5b88d5760320 89 }
kenjiArai 0:5b88d5760320 90
kenjiArai 0:5b88d5760320 91 /**
kenjiArai 0:5b88d5760320 92 * @brief Destructor.
kenjiArai 0:5b88d5760320 93 * @details Decrement reference counter, and delete object if no longer pointed to.
kenjiArai 0:5b88d5760320 94 */
kenjiArai 0:5b88d5760320 95 ~SharedPtr()
kenjiArai 0:5b88d5760320 96 {
kenjiArai 0:5b88d5760320 97 decrement_counter();
kenjiArai 0:5b88d5760320 98 }
kenjiArai 0:5b88d5760320 99
kenjiArai 0:5b88d5760320 100 /**
kenjiArai 0:5b88d5760320 101 * @brief Copy constructor.
kenjiArai 0:5b88d5760320 102 * @details Create new SharedPtr from other SharedPtr by
kenjiArai 0:5b88d5760320 103 * copying pointer to original object and pointer to counter.
kenjiArai 0:5b88d5760320 104 * @param source Object being copied from.
kenjiArai 0:5b88d5760320 105 */
kenjiArai 0:5b88d5760320 106 SharedPtr(const SharedPtr &source): _ptr(source._ptr), _counter(source._counter)
kenjiArai 0:5b88d5760320 107 {
kenjiArai 0:5b88d5760320 108 // Increment reference counter
kenjiArai 0:5b88d5760320 109 if (_ptr != NULL) {
kenjiArai 0:5b88d5760320 110 core_util_atomic_incr_u32(_counter, 1);
kenjiArai 0:5b88d5760320 111 }
kenjiArai 0:5b88d5760320 112 }
kenjiArai 0:5b88d5760320 113
kenjiArai 0:5b88d5760320 114 /**
kenjiArai 0:5b88d5760320 115 * @brief Assignment operator.
kenjiArai 0:5b88d5760320 116 * @details Cleanup previous reference and assign new pointer and counter.
kenjiArai 0:5b88d5760320 117 * @param source Object being assigned from.
kenjiArai 0:5b88d5760320 118 * @return Object being assigned.
kenjiArai 0:5b88d5760320 119 */
kenjiArai 0:5b88d5760320 120 SharedPtr operator=(const SharedPtr &source)
kenjiArai 0:5b88d5760320 121 {
kenjiArai 0:5b88d5760320 122 if (this != &source) {
kenjiArai 0:5b88d5760320 123 // Clean up by decrementing counter
kenjiArai 0:5b88d5760320 124 decrement_counter();
kenjiArai 0:5b88d5760320 125
kenjiArai 0:5b88d5760320 126 // Assign new values
kenjiArai 0:5b88d5760320 127 _ptr = source.get();
kenjiArai 0:5b88d5760320 128 _counter = source.get_counter();
kenjiArai 0:5b88d5760320 129
kenjiArai 0:5b88d5760320 130 // Increment new counter
kenjiArai 0:5b88d5760320 131 if (_ptr != NULL) {
kenjiArai 0:5b88d5760320 132 core_util_atomic_incr_u32(_counter, 1);
kenjiArai 0:5b88d5760320 133 }
kenjiArai 0:5b88d5760320 134 }
kenjiArai 0:5b88d5760320 135
kenjiArai 0:5b88d5760320 136 return *this;
kenjiArai 0:5b88d5760320 137 }
kenjiArai 0:5b88d5760320 138
kenjiArai 0:5b88d5760320 139 /**
kenjiArai 0:5b88d5760320 140 * @brief Replaces the managed pointer with a new unmanaged pointer.
kenjiArai 0:5b88d5760320 141 * @param[in] ptr the new raw pointer to manage.
kenjiArai 0:5b88d5760320 142 */
kenjiArai 0:5b88d5760320 143 void reset(T *ptr)
kenjiArai 0:5b88d5760320 144 {
kenjiArai 0:5b88d5760320 145 // Clean up by decrementing counter
kenjiArai 0:5b88d5760320 146 decrement_counter();
kenjiArai 0:5b88d5760320 147
kenjiArai 0:5b88d5760320 148 _ptr = ptr;
kenjiArai 0:5b88d5760320 149 if (ptr != NULL) {
kenjiArai 0:5b88d5760320 150 // Allocate counter on the heap, so it can be shared
kenjiArai 0:5b88d5760320 151 _counter = new uint32_t;
kenjiArai 0:5b88d5760320 152 *_counter = 1;
kenjiArai 0:5b88d5760320 153 } else {
kenjiArai 0:5b88d5760320 154 _counter = NULL;
kenjiArai 0:5b88d5760320 155 }
kenjiArai 0:5b88d5760320 156 }
kenjiArai 0:5b88d5760320 157
kenjiArai 0:5b88d5760320 158 /**
kenjiArai 0:5b88d5760320 159 * @brief Replace the managed pointer with a NULL pointer.
kenjiArai 0:5b88d5760320 160 */
kenjiArai 0:5b88d5760320 161 void reset()
kenjiArai 0:5b88d5760320 162 {
kenjiArai 0:5b88d5760320 163 reset(NULL);
kenjiArai 0:5b88d5760320 164 }
kenjiArai 0:5b88d5760320 165
kenjiArai 0:5b88d5760320 166 /**
kenjiArai 0:5b88d5760320 167 * @brief Raw pointer accessor.
kenjiArai 0:5b88d5760320 168 * @details Get raw pointer to object pointed to.
kenjiArai 0:5b88d5760320 169 * @return Pointer.
kenjiArai 0:5b88d5760320 170 */
kenjiArai 0:5b88d5760320 171 T *get() const
kenjiArai 0:5b88d5760320 172 {
kenjiArai 0:5b88d5760320 173 return _ptr;
kenjiArai 0:5b88d5760320 174 }
kenjiArai 0:5b88d5760320 175
kenjiArai 0:5b88d5760320 176 /**
kenjiArai 0:5b88d5760320 177 * @brief Reference count accessor.
kenjiArai 0:5b88d5760320 178 * @return Reference count.
kenjiArai 0:5b88d5760320 179 */
kenjiArai 0:5b88d5760320 180 uint32_t use_count() const
kenjiArai 0:5b88d5760320 181 {
kenjiArai 0:5b88d5760320 182 if (_ptr != NULL) {
kenjiArai 0:5b88d5760320 183 return core_util_atomic_load_u32(_counter);
kenjiArai 0:5b88d5760320 184 } else {
kenjiArai 0:5b88d5760320 185 return 0;
kenjiArai 0:5b88d5760320 186 }
kenjiArai 0:5b88d5760320 187 }
kenjiArai 0:5b88d5760320 188
kenjiArai 0:5b88d5760320 189 /**
kenjiArai 0:5b88d5760320 190 * @brief Dereference object operator.
kenjiArai 0:5b88d5760320 191 * @details Override to return the object pointed to.
kenjiArai 0:5b88d5760320 192 */
kenjiArai 0:5b88d5760320 193 T &operator*() const
kenjiArai 0:5b88d5760320 194 {
kenjiArai 0:5b88d5760320 195 return *_ptr;
kenjiArai 0:5b88d5760320 196 }
kenjiArai 0:5b88d5760320 197
kenjiArai 0:5b88d5760320 198 /**
kenjiArai 0:5b88d5760320 199 * @brief Dereference object member operator.
kenjiArai 0:5b88d5760320 200 * @details Override to return return member in object pointed to.
kenjiArai 0:5b88d5760320 201 */
kenjiArai 0:5b88d5760320 202 T *operator->() const
kenjiArai 0:5b88d5760320 203 {
kenjiArai 0:5b88d5760320 204 return _ptr;
kenjiArai 0:5b88d5760320 205 }
kenjiArai 0:5b88d5760320 206
kenjiArai 0:5b88d5760320 207 /**
kenjiArai 0:5b88d5760320 208 * @brief Boolean conversion operator.
kenjiArai 0:5b88d5760320 209 * @return Whether or not the pointer is NULL.
kenjiArai 0:5b88d5760320 210 */
kenjiArai 0:5b88d5760320 211 operator bool() const
kenjiArai 0:5b88d5760320 212 {
kenjiArai 0:5b88d5760320 213 return (_ptr != NULL);
kenjiArai 0:5b88d5760320 214 }
kenjiArai 0:5b88d5760320 215
kenjiArai 0:5b88d5760320 216 private:
kenjiArai 0:5b88d5760320 217 /**
kenjiArai 0:5b88d5760320 218 * @brief Get pointer to reference counter.
kenjiArai 0:5b88d5760320 219 * @return Pointer to reference counter.
kenjiArai 0:5b88d5760320 220 */
kenjiArai 0:5b88d5760320 221 uint32_t *get_counter() const
kenjiArai 0:5b88d5760320 222 {
kenjiArai 0:5b88d5760320 223 return _counter;
kenjiArai 0:5b88d5760320 224 }
kenjiArai 0:5b88d5760320 225
kenjiArai 0:5b88d5760320 226 /**
kenjiArai 0:5b88d5760320 227 * @brief Decrement reference counter.
kenjiArai 0:5b88d5760320 228 * @details If count reaches zero, free counter and delete object pointed to.
kenjiArai 0:5b88d5760320 229 * Does not modify our own pointers - assumption is they will be overwritten
kenjiArai 0:5b88d5760320 230 * or destroyed immediately afterwards.
kenjiArai 0:5b88d5760320 231 */
kenjiArai 0:5b88d5760320 232 void decrement_counter()
kenjiArai 0:5b88d5760320 233 {
kenjiArai 0:5b88d5760320 234 if (_ptr != NULL) {
kenjiArai 0:5b88d5760320 235 if (core_util_atomic_decr_u32(_counter, 1) == 0) {
kenjiArai 0:5b88d5760320 236 delete _counter;
kenjiArai 0:5b88d5760320 237 delete _ptr;
kenjiArai 0:5b88d5760320 238 }
kenjiArai 0:5b88d5760320 239 }
kenjiArai 0:5b88d5760320 240 }
kenjiArai 0:5b88d5760320 241
kenjiArai 0:5b88d5760320 242 private:
kenjiArai 0:5b88d5760320 243 // Pointer to shared object
kenjiArai 0:5b88d5760320 244 T *_ptr;
kenjiArai 0:5b88d5760320 245
kenjiArai 0:5b88d5760320 246 // Pointer to shared reference counter
kenjiArai 0:5b88d5760320 247 uint32_t *_counter;
kenjiArai 0:5b88d5760320 248 };
kenjiArai 0:5b88d5760320 249
kenjiArai 0:5b88d5760320 250 /** Non-member relational operators.
kenjiArai 0:5b88d5760320 251 */
kenjiArai 0:5b88d5760320 252 template <class T, class U>
kenjiArai 0:5b88d5760320 253 bool operator== (const SharedPtr<T> &lhs, const SharedPtr<U> &rhs)
kenjiArai 0:5b88d5760320 254 {
kenjiArai 0:5b88d5760320 255 return (lhs.get() == rhs.get());
kenjiArai 0:5b88d5760320 256 }
kenjiArai 0:5b88d5760320 257
kenjiArai 0:5b88d5760320 258 template <class T, typename U>
kenjiArai 0:5b88d5760320 259 bool operator== (const SharedPtr<T> &lhs, U rhs)
kenjiArai 0:5b88d5760320 260 {
kenjiArai 0:5b88d5760320 261 return (lhs.get() == (T *) rhs);
kenjiArai 0:5b88d5760320 262 }
kenjiArai 0:5b88d5760320 263
kenjiArai 0:5b88d5760320 264 template <class T, typename U>
kenjiArai 0:5b88d5760320 265 bool operator== (U lhs, const SharedPtr<T> &rhs)
kenjiArai 0:5b88d5760320 266 {
kenjiArai 0:5b88d5760320 267 return ((T *) lhs == rhs.get());
kenjiArai 0:5b88d5760320 268 }
kenjiArai 0:5b88d5760320 269
kenjiArai 0:5b88d5760320 270 /** Non-member relational operators.
kenjiArai 0:5b88d5760320 271 */
kenjiArai 0:5b88d5760320 272 template <class T, class U>
kenjiArai 0:5b88d5760320 273 bool operator!= (const SharedPtr<T> &lhs, const SharedPtr<U> &rhs)
kenjiArai 0:5b88d5760320 274 {
kenjiArai 0:5b88d5760320 275 return (lhs.get() != rhs.get());
kenjiArai 0:5b88d5760320 276 }
kenjiArai 0:5b88d5760320 277
kenjiArai 0:5b88d5760320 278 template <class T, typename U>
kenjiArai 0:5b88d5760320 279 bool operator!= (const SharedPtr<T> &lhs, U rhs)
kenjiArai 0:5b88d5760320 280 {
kenjiArai 0:5b88d5760320 281 return (lhs.get() != (T *) rhs);
kenjiArai 0:5b88d5760320 282 }
kenjiArai 0:5b88d5760320 283
kenjiArai 0:5b88d5760320 284 template <class T, typename U>
kenjiArai 0:5b88d5760320 285 bool operator!= (U lhs, const SharedPtr<T> &rhs)
kenjiArai 0:5b88d5760320 286 {
kenjiArai 0:5b88d5760320 287 return ((T *) lhs != rhs.get());
kenjiArai 0:5b88d5760320 288 }
kenjiArai 0:5b88d5760320 289
kenjiArai 0:5b88d5760320 290 } /* namespace mbed */
kenjiArai 0:5b88d5760320 291
kenjiArai 0:5b88d5760320 292 #ifndef MBED_NO_GLOBAL_USING_DIRECTIVE
kenjiArai 0:5b88d5760320 293 using mbed::SharedPtr;
kenjiArai 0:5b88d5760320 294 #endif
kenjiArai 0:5b88d5760320 295
kenjiArai 0:5b88d5760320 296 #endif // __SHAREDPTR_H__