Руслан Бредун / Mbed 2 deprecated stm32-sensor-base2

test

Dependencies:   mbed Watchdog

Dependents:   STM32-MC_node

mbed/platform/SharedPtr.h@0:d383e2dee0f7, 2020-07-06 (annotated)

Committer:
ommpy
Date:
Mon Jul 06 17:18:59 2020 +0530
Revision:
0:d383e2dee0f7
first commit

Who changed what in which revision?

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ommpy 0:d383e2dee0f7 1 /* mbed Microcontroller Library
ommpy 0:d383e2dee0f7 2 * Copyright (c) 2006-2018 ARM Limited
ommpy 0:d383e2dee0f7 3 * SPDX-License-Identifier: Apache-2.0
ommpy 0:d383e2dee0f7 4 *
ommpy 0:d383e2dee0f7 5 * Licensed under the Apache License, Version 2.0 (the "License");
ommpy 0:d383e2dee0f7 6 * you may not use this file except in compliance with the License.
ommpy 0:d383e2dee0f7 7 * You may obtain a copy of the License at
ommpy 0:d383e2dee0f7 8 *
ommpy 0:d383e2dee0f7 9 * http://www.apache.org/licenses/LICENSE-2.0
ommpy 0:d383e2dee0f7 10 *
ommpy 0:d383e2dee0f7 11 * Unless required by applicable law or agreed to in writing, software
ommpy 0:d383e2dee0f7 12 * distributed under the License is distributed on an "AS IS" BASIS,
ommpy 0:d383e2dee0f7 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
ommpy 0:d383e2dee0f7 14 * See the License for the specific language governing permissions and
ommpy 0:d383e2dee0f7 15 * limitations under the License.
ommpy 0:d383e2dee0f7 16 */
ommpy 0:d383e2dee0f7 17
ommpy 0:d383e2dee0f7 18 #ifndef __SHAREDPTR_H__
ommpy 0:d383e2dee0f7 19 #define __SHAREDPTR_H__
ommpy 0:d383e2dee0f7 20
ommpy 0:d383e2dee0f7 21 #include <stdlib.h>
ommpy 0:d383e2dee0f7 22
ommpy 0:d383e2dee0f7 23 #include <stdint.h>
ommpy 0:d383e2dee0f7 24 #include <stddef.h>
ommpy 0:d383e2dee0f7 25
ommpy 0:d383e2dee0f7 26 #include "platform/mbed_critical.h"
ommpy 0:d383e2dee0f7 27
ommpy 0:d383e2dee0f7 28 namespace mbed {
ommpy 0:d383e2dee0f7 29
ommpy 0:d383e2dee0f7 30 /** Shared pointer class.
ommpy 0:d383e2dee0f7 31 *
ommpy 0:d383e2dee0f7 32 * A shared pointer is a "smart" pointer that retains ownership of an object using
ommpy 0:d383e2dee0f7 33 * reference counting across all smart pointers referencing that object.
ommpy 0:d383e2dee0f7 34 *
ommpy 0:d383e2dee0f7 35 * @code
ommpy 0:d383e2dee0f7 36 * #include "platform/SharedPtr.h"
ommpy 0:d383e2dee0f7 37 *
ommpy 0:d383e2dee0f7 38 * void test() {
ommpy 0:d383e2dee0f7 39 * struct MyStruct { int a; };
ommpy 0:d383e2dee0f7 40 *
ommpy 0:d383e2dee0f7 41 * // Create shared pointer
ommpy 0:d383e2dee0f7 42 * SharedPtr<MyStruct> ptr( new MyStruct );
ommpy 0:d383e2dee0f7 43 *
ommpy 0:d383e2dee0f7 44 * // Increase reference count
ommpy 0:d383e2dee0f7 45 * SharedPtr<MyStruct> ptr2( ptr );
ommpy 0:d383e2dee0f7 46 *
ommpy 0:d383e2dee0f7 47 * ptr = NULL; // Reference to the struct instance is still held by ptr2
ommpy 0:d383e2dee0f7 48 *
ommpy 0:d383e2dee0f7 49 * ptr2 = NULL; // The raw pointer is freed
ommpy 0:d383e2dee0f7 50 * }
ommpy 0:d383e2dee0f7 51 * @endcode
ommpy 0:d383e2dee0f7 52 *
ommpy 0:d383e2dee0f7 53 *
ommpy 0:d383e2dee0f7 54 * It is similar to the std::shared_ptr class introduced in C++11;
ommpy 0:d383e2dee0f7 55 * however, this is not a compatible implementation (no weak pointer, no make_shared, no custom deleters and so on.)
ommpy 0:d383e2dee0f7 56 *
ommpy 0:d383e2dee0f7 57 * Usage: SharedPtr<Class> ptr(new Class())
ommpy 0:d383e2dee0f7 58 *
ommpy 0:d383e2dee0f7 59 * When ptr is passed around by value, the copy constructor and
ommpy 0:d383e2dee0f7 60 * destructor manages the reference count of the raw pointer.
ommpy 0:d383e2dee0f7 61 * If the counter reaches zero, delete is called on the raw pointer.
ommpy 0:d383e2dee0f7 62 *
ommpy 0:d383e2dee0f7 63 * To avoid loops, use "weak" references by calling the original
ommpy 0:d383e2dee0f7 64 * pointer directly through ptr.get().
ommpy 0:d383e2dee0f7 65 */
ommpy 0:d383e2dee0f7 66
ommpy 0:d383e2dee0f7 67 template <class T>
ommpy 0:d383e2dee0f7 68 class SharedPtr {
ommpy 0:d383e2dee0f7 69 public:
ommpy 0:d383e2dee0f7 70 /**
ommpy 0:d383e2dee0f7 71 * @brief Create empty SharedPtr not pointing to anything.
ommpy 0:d383e2dee0f7 72 * @details Used for variable declaration.
ommpy 0:d383e2dee0f7 73 */
ommpy 0:d383e2dee0f7 74 SharedPtr(): _ptr(NULL), _counter(NULL)
ommpy 0:d383e2dee0f7 75 {
ommpy 0:d383e2dee0f7 76 }
ommpy 0:d383e2dee0f7 77
ommpy 0:d383e2dee0f7 78 /**
ommpy 0:d383e2dee0f7 79 * @brief Create new SharedPtr
ommpy 0:d383e2dee0f7 80 * @param ptr Pointer to take control over
ommpy 0:d383e2dee0f7 81 */
ommpy 0:d383e2dee0f7 82 SharedPtr(T *ptr): _ptr(ptr), _counter(NULL)
ommpy 0:d383e2dee0f7 83 {
ommpy 0:d383e2dee0f7 84 // Allocate counter on the heap, so it can be shared
ommpy 0:d383e2dee0f7 85 if (_ptr != NULL) {
ommpy 0:d383e2dee0f7 86 _counter = new uint32_t;
ommpy 0:d383e2dee0f7 87 *_counter = 1;
ommpy 0:d383e2dee0f7 88 }
ommpy 0:d383e2dee0f7 89 }
ommpy 0:d383e2dee0f7 90
ommpy 0:d383e2dee0f7 91 /**
ommpy 0:d383e2dee0f7 92 * @brief Destructor.
ommpy 0:d383e2dee0f7 93 * @details Decrement reference counter, and delete object if no longer pointed to.
ommpy 0:d383e2dee0f7 94 */
ommpy 0:d383e2dee0f7 95 ~SharedPtr()
ommpy 0:d383e2dee0f7 96 {
ommpy 0:d383e2dee0f7 97 decrement_counter();
ommpy 0:d383e2dee0f7 98 }
ommpy 0:d383e2dee0f7 99
ommpy 0:d383e2dee0f7 100 /**
ommpy 0:d383e2dee0f7 101 * @brief Copy constructor.
ommpy 0:d383e2dee0f7 102 * @details Create new SharedPtr from other SharedPtr by
ommpy 0:d383e2dee0f7 103 * copying pointer to original object and pointer to counter.
ommpy 0:d383e2dee0f7 104 * @param source Object being copied from.
ommpy 0:d383e2dee0f7 105 */
ommpy 0:d383e2dee0f7 106 SharedPtr(const SharedPtr &source): _ptr(source._ptr), _counter(source._counter)
ommpy 0:d383e2dee0f7 107 {
ommpy 0:d383e2dee0f7 108 // Increment reference counter
ommpy 0:d383e2dee0f7 109 if (_ptr != NULL) {
ommpy 0:d383e2dee0f7 110 core_util_atomic_incr_u32(_counter, 1);
ommpy 0:d383e2dee0f7 111 }
ommpy 0:d383e2dee0f7 112 }
ommpy 0:d383e2dee0f7 113
ommpy 0:d383e2dee0f7 114 /**
ommpy 0:d383e2dee0f7 115 * @brief Assignment operator.
ommpy 0:d383e2dee0f7 116 * @details Cleanup previous reference and assign new pointer and counter.
ommpy 0:d383e2dee0f7 117 * @param source Object being assigned from.
ommpy 0:d383e2dee0f7 118 * @return Object being assigned.
ommpy 0:d383e2dee0f7 119 */
ommpy 0:d383e2dee0f7 120 SharedPtr operator=(const SharedPtr &source)
ommpy 0:d383e2dee0f7 121 {
ommpy 0:d383e2dee0f7 122 if (this != &source) {
ommpy 0:d383e2dee0f7 123 // Clean up by decrementing counter
ommpy 0:d383e2dee0f7 124 decrement_counter();
ommpy 0:d383e2dee0f7 125
ommpy 0:d383e2dee0f7 126 // Assign new values
ommpy 0:d383e2dee0f7 127 _ptr = source.get();
ommpy 0:d383e2dee0f7 128 _counter = source.get_counter();
ommpy 0:d383e2dee0f7 129
ommpy 0:d383e2dee0f7 130 // Increment new counter
ommpy 0:d383e2dee0f7 131 if (_ptr != NULL) {
ommpy 0:d383e2dee0f7 132 core_util_atomic_incr_u32(_counter, 1);
ommpy 0:d383e2dee0f7 133 }
ommpy 0:d383e2dee0f7 134 }
ommpy 0:d383e2dee0f7 135
ommpy 0:d383e2dee0f7 136 return *this;
ommpy 0:d383e2dee0f7 137 }
ommpy 0:d383e2dee0f7 138
ommpy 0:d383e2dee0f7 139 /**
ommpy 0:d383e2dee0f7 140 * @brief Replaces the managed pointer with a new unmanaged pointer.
ommpy 0:d383e2dee0f7 141 * @param[in] ptr the new raw pointer to manage.
ommpy 0:d383e2dee0f7 142 */
ommpy 0:d383e2dee0f7 143 void reset(T *ptr)
ommpy 0:d383e2dee0f7 144 {
ommpy 0:d383e2dee0f7 145 // Clean up by decrementing counter
ommpy 0:d383e2dee0f7 146 decrement_counter();
ommpy 0:d383e2dee0f7 147
ommpy 0:d383e2dee0f7 148 _ptr = ptr;
ommpy 0:d383e2dee0f7 149 if (ptr != NULL) {
ommpy 0:d383e2dee0f7 150 // Allocate counter on the heap, so it can be shared
ommpy 0:d383e2dee0f7 151 _counter = new uint32_t;
ommpy 0:d383e2dee0f7 152 *_counter = 1;
ommpy 0:d383e2dee0f7 153 } else {
ommpy 0:d383e2dee0f7 154 _counter = NULL;
ommpy 0:d383e2dee0f7 155 }
ommpy 0:d383e2dee0f7 156 }
ommpy 0:d383e2dee0f7 157
ommpy 0:d383e2dee0f7 158 /**
ommpy 0:d383e2dee0f7 159 * @brief Replace the managed pointer with a NULL pointer.
ommpy 0:d383e2dee0f7 160 */
ommpy 0:d383e2dee0f7 161 void reset()
ommpy 0:d383e2dee0f7 162 {
ommpy 0:d383e2dee0f7 163 reset(NULL);
ommpy 0:d383e2dee0f7 164 }
ommpy 0:d383e2dee0f7 165
ommpy 0:d383e2dee0f7 166 /**
ommpy 0:d383e2dee0f7 167 * @brief Raw pointer accessor.
ommpy 0:d383e2dee0f7 168 * @details Get raw pointer to object pointed to.
ommpy 0:d383e2dee0f7 169 * @return Pointer.
ommpy 0:d383e2dee0f7 170 */
ommpy 0:d383e2dee0f7 171 T *get() const
ommpy 0:d383e2dee0f7 172 {
ommpy 0:d383e2dee0f7 173 return _ptr;
ommpy 0:d383e2dee0f7 174 }
ommpy 0:d383e2dee0f7 175
ommpy 0:d383e2dee0f7 176 /**
ommpy 0:d383e2dee0f7 177 * @brief Reference count accessor.
ommpy 0:d383e2dee0f7 178 * @return Reference count.
ommpy 0:d383e2dee0f7 179 */
ommpy 0:d383e2dee0f7 180 uint32_t use_count() const
ommpy 0:d383e2dee0f7 181 {
ommpy 0:d383e2dee0f7 182 if (_ptr != NULL) {
ommpy 0:d383e2dee0f7 183 core_util_critical_section_enter();
ommpy 0:d383e2dee0f7 184 uint32_t current_counter = *_counter;
ommpy 0:d383e2dee0f7 185 core_util_critical_section_exit();
ommpy 0:d383e2dee0f7 186 return current_counter;
ommpy 0:d383e2dee0f7 187 } else {
ommpy 0:d383e2dee0f7 188 return 0;
ommpy 0:d383e2dee0f7 189 }
ommpy 0:d383e2dee0f7 190 }
ommpy 0:d383e2dee0f7 191
ommpy 0:d383e2dee0f7 192 /**
ommpy 0:d383e2dee0f7 193 * @brief Dereference object operator.
ommpy 0:d383e2dee0f7 194 * @details Override to return the object pointed to.
ommpy 0:d383e2dee0f7 195 */
ommpy 0:d383e2dee0f7 196 T &operator*() const
ommpy 0:d383e2dee0f7 197 {
ommpy 0:d383e2dee0f7 198 return *_ptr;
ommpy 0:d383e2dee0f7 199 }
ommpy 0:d383e2dee0f7 200
ommpy 0:d383e2dee0f7 201 /**
ommpy 0:d383e2dee0f7 202 * @brief Dereference object member operator.
ommpy 0:d383e2dee0f7 203 * @details Override to return return member in object pointed to.
ommpy 0:d383e2dee0f7 204 */
ommpy 0:d383e2dee0f7 205 T *operator->() const
ommpy 0:d383e2dee0f7 206 {
ommpy 0:d383e2dee0f7 207 return _ptr;
ommpy 0:d383e2dee0f7 208 }
ommpy 0:d383e2dee0f7 209
ommpy 0:d383e2dee0f7 210 /**
ommpy 0:d383e2dee0f7 211 * @brief Boolean conversion operator.
ommpy 0:d383e2dee0f7 212 * @return Whether or not the pointer is NULL.
ommpy 0:d383e2dee0f7 213 */
ommpy 0:d383e2dee0f7 214 operator bool() const
ommpy 0:d383e2dee0f7 215 {
ommpy 0:d383e2dee0f7 216 return (_ptr != NULL);
ommpy 0:d383e2dee0f7 217 }
ommpy 0:d383e2dee0f7 218
ommpy 0:d383e2dee0f7 219 private:
ommpy 0:d383e2dee0f7 220 /**
ommpy 0:d383e2dee0f7 221 * @brief Get pointer to reference counter.
ommpy 0:d383e2dee0f7 222 * @return Pointer to reference counter.
ommpy 0:d383e2dee0f7 223 */
ommpy 0:d383e2dee0f7 224 uint32_t *get_counter() const
ommpy 0:d383e2dee0f7 225 {
ommpy 0:d383e2dee0f7 226 return _counter;
ommpy 0:d383e2dee0f7 227 }
ommpy 0:d383e2dee0f7 228
ommpy 0:d383e2dee0f7 229 /**
ommpy 0:d383e2dee0f7 230 * @brief Decrement reference counter.
ommpy 0:d383e2dee0f7 231 * @details If count reaches zero, free counter and delete object pointed to.
ommpy 0:d383e2dee0f7 232 * Does not modify our own pointers - assumption is they will be overwritten
ommpy 0:d383e2dee0f7 233 * or destroyed immediately afterwards.
ommpy 0:d383e2dee0f7 234 */
ommpy 0:d383e2dee0f7 235 void decrement_counter()
ommpy 0:d383e2dee0f7 236 {
ommpy 0:d383e2dee0f7 237 if (_ptr != NULL) {
ommpy 0:d383e2dee0f7 238 uint32_t new_value = core_util_atomic_decr_u32(_counter, 1);
ommpy 0:d383e2dee0f7 239 if (new_value == 0) {
ommpy 0:d383e2dee0f7 240 delete _counter;
ommpy 0:d383e2dee0f7 241 delete _ptr;
ommpy 0:d383e2dee0f7 242 }
ommpy 0:d383e2dee0f7 243 }
ommpy 0:d383e2dee0f7 244 }
ommpy 0:d383e2dee0f7 245
ommpy 0:d383e2dee0f7 246 private:
ommpy 0:d383e2dee0f7 247 // Pointer to shared object
ommpy 0:d383e2dee0f7 248 T *_ptr;
ommpy 0:d383e2dee0f7 249
ommpy 0:d383e2dee0f7 250 // Pointer to shared reference counter
ommpy 0:d383e2dee0f7 251 uint32_t *_counter;
ommpy 0:d383e2dee0f7 252 };
ommpy 0:d383e2dee0f7 253
ommpy 0:d383e2dee0f7 254 /** Non-member relational operators.
ommpy 0:d383e2dee0f7 255 */
ommpy 0:d383e2dee0f7 256 template <class T, class U>
ommpy 0:d383e2dee0f7 257 bool operator== (const SharedPtr<T> &lhs, const SharedPtr<U> &rhs)
ommpy 0:d383e2dee0f7 258 {
ommpy 0:d383e2dee0f7 259 return (lhs.get() == rhs.get());
ommpy 0:d383e2dee0f7 260 }
ommpy 0:d383e2dee0f7 261
ommpy 0:d383e2dee0f7 262 template <class T, typename U>
ommpy 0:d383e2dee0f7 263 bool operator== (const SharedPtr<T> &lhs, U rhs)
ommpy 0:d383e2dee0f7 264 {
ommpy 0:d383e2dee0f7 265 return (lhs.get() == (T *) rhs);
ommpy 0:d383e2dee0f7 266 }
ommpy 0:d383e2dee0f7 267
ommpy 0:d383e2dee0f7 268 template <class T, typename U>
ommpy 0:d383e2dee0f7 269 bool operator== (U lhs, const SharedPtr<T> &rhs)
ommpy 0:d383e2dee0f7 270 {
ommpy 0:d383e2dee0f7 271 return ((T *) lhs == rhs.get());
ommpy 0:d383e2dee0f7 272 }
ommpy 0:d383e2dee0f7 273
ommpy 0:d383e2dee0f7 274 /** Non-member relational operators.
ommpy 0:d383e2dee0f7 275 */
ommpy 0:d383e2dee0f7 276 template <class T, class U>
ommpy 0:d383e2dee0f7 277 bool operator!= (const SharedPtr<T> &lhs, const SharedPtr<U> &rhs)
ommpy 0:d383e2dee0f7 278 {
ommpy 0:d383e2dee0f7 279 return (lhs.get() != rhs.get());
ommpy 0:d383e2dee0f7 280 }
ommpy 0:d383e2dee0f7 281
ommpy 0:d383e2dee0f7 282 template <class T, typename U>
ommpy 0:d383e2dee0f7 283 bool operator!= (const SharedPtr<T> &lhs, U rhs)
ommpy 0:d383e2dee0f7 284 {
ommpy 0:d383e2dee0f7 285 return (lhs.get() != (T *) rhs);
ommpy 0:d383e2dee0f7 286 }
ommpy 0:d383e2dee0f7 287
ommpy 0:d383e2dee0f7 288 template <class T, typename U>
ommpy 0:d383e2dee0f7 289 bool operator!= (U lhs, const SharedPtr<T> &rhs)
ommpy 0:d383e2dee0f7 290 {
ommpy 0:d383e2dee0f7 291 return ((T *) lhs != rhs.get());
ommpy 0:d383e2dee0f7 292 }
ommpy 0:d383e2dee0f7 293
ommpy 0:d383e2dee0f7 294 } /* namespace mbed */
ommpy 0:d383e2dee0f7 295
ommpy 0:d383e2dee0f7 296 #ifndef MBED_NO_GLOBAL_USING_DIRECTIVE
ommpy 0:d383e2dee0f7 297 using mbed::SharedPtr;
ommpy 0:d383e2dee0f7 298 #endif
ommpy 0:d383e2dee0f7 299
ommpy 0:d383e2dee0f7 300 #endif // __SHAREDPTR_H__