joey shelton / LED_Demo2

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Dependencies:   MAX44000 PWM_Tone_Library nexpaq_mdk

Fork of LED_Demo by joey shelton

mbd_os/hal/api/SingletonPtr.h@1:55a6170b404f, 2016-09-17 (annotated)

Committer:
nexpaq
Date:
Sat Sep 17 16:32:05 2016 +0000
Revision:
1:55a6170b404f
checking in for sharing

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nexpaq 1:55a6170b404f 1 /* mbed Microcontroller Library
nexpaq 1:55a6170b404f 2 * Copyright (c) 2006-2013 ARM Limited
nexpaq 1:55a6170b404f 3 *
nexpaq 1:55a6170b404f 4 * Licensed under the Apache License, Version 2.0 (the "License");
nexpaq 1:55a6170b404f 5 * you may not use this file except in compliance with the License.
nexpaq 1:55a6170b404f 6 * You may obtain a copy of the License at
nexpaq 1:55a6170b404f 7 *
nexpaq 1:55a6170b404f 8 * http://www.apache.org/licenses/LICENSE-2.0
nexpaq 1:55a6170b404f 9 *
nexpaq 1:55a6170b404f 10 * Unless required by applicable law or agreed to in writing, software
nexpaq 1:55a6170b404f 11 * distributed under the License is distributed on an "AS IS" BASIS,
nexpaq 1:55a6170b404f 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
nexpaq 1:55a6170b404f 13 * See the License for the specific language governing permissions and
nexpaq 1:55a6170b404f 14 * limitations under the License.
nexpaq 1:55a6170b404f 15 */
nexpaq 1:55a6170b404f 16 #ifndef SINGLETONPTR_H
nexpaq 1:55a6170b404f 17 #define SINGLETONPTR_H
nexpaq 1:55a6170b404f 18
nexpaq 1:55a6170b404f 19 #include <stdint.h>
nexpaq 1:55a6170b404f 20 #include <new>
nexpaq 1:55a6170b404f 21 #include "mbed_assert.h"
nexpaq 1:55a6170b404f 22 #ifdef MBED_CONF_RTOS_PRESENT
nexpaq 1:55a6170b404f 23 #include "cmsis_os.h"
nexpaq 1:55a6170b404f 24 #endif
nexpaq 1:55a6170b404f 25
nexpaq 1:55a6170b404f 26 #ifdef MBED_CONF_RTOS_PRESENT
nexpaq 1:55a6170b404f 27 extern osMutexId singleton_mutex_id;
nexpaq 1:55a6170b404f 28 #endif
nexpaq 1:55a6170b404f 29
nexpaq 1:55a6170b404f 30 /** Lock the singleton mutex
nexpaq 1:55a6170b404f 31 *
nexpaq 1:55a6170b404f 32 * This function is typically used to provide
nexpaq 1:55a6170b404f 33 * exclusive access when initializing a
nexpaq 1:55a6170b404f 34 * global object.
nexpaq 1:55a6170b404f 35 */
nexpaq 1:55a6170b404f 36 inline static void singleton_lock(void)
nexpaq 1:55a6170b404f 37 {
nexpaq 1:55a6170b404f 38 #ifdef MBED_CONF_RTOS_PRESENT
nexpaq 1:55a6170b404f 39 osMutexWait(singleton_mutex_id, osWaitForever);
nexpaq 1:55a6170b404f 40 #endif
nexpaq 1:55a6170b404f 41 }
nexpaq 1:55a6170b404f 42
nexpaq 1:55a6170b404f 43 /** Unlock the singleton mutex
nexpaq 1:55a6170b404f 44 *
nexpaq 1:55a6170b404f 45 * This function is typically used to provide
nexpaq 1:55a6170b404f 46 * exclusive access when initializing a
nexpaq 1:55a6170b404f 47 * global object.
nexpaq 1:55a6170b404f 48 */
nexpaq 1:55a6170b404f 49 inline static void singleton_unlock(void)
nexpaq 1:55a6170b404f 50 {
nexpaq 1:55a6170b404f 51 #ifdef MBED_CONF_RTOS_PRESENT
nexpaq 1:55a6170b404f 52 osMutexRelease (singleton_mutex_id);
nexpaq 1:55a6170b404f 53 #endif
nexpaq 1:55a6170b404f 54 }
nexpaq 1:55a6170b404f 55
nexpaq 1:55a6170b404f 56 /** Utility class for creating an using a singleton
nexpaq 1:55a6170b404f 57 *
nexpaq 1:55a6170b404f 58 * @Note Synchronization level: Thread safe
nexpaq 1:55a6170b404f 59 *
nexpaq 1:55a6170b404f 60 * @Note: This class must only be used in a static context -
nexpaq 1:55a6170b404f 61 * this class must never be allocated or created on the
nexpaq 1:55a6170b404f 62 * stack.
nexpaq 1:55a6170b404f 63 *
nexpaq 1:55a6170b404f 64 * @Note: This class is lazily initialized on first use.
nexpaq 1:55a6170b404f 65 * This class is a POD type so if it is not used it will
nexpaq 1:55a6170b404f 66 * be garbage collected.
nexpaq 1:55a6170b404f 67 */
nexpaq 1:55a6170b404f 68 template <class T>
nexpaq 1:55a6170b404f 69 struct SingletonPtr {
nexpaq 1:55a6170b404f 70
nexpaq 1:55a6170b404f 71 /** Get a pointer to the underlying singleton
nexpaq 1:55a6170b404f 72 *
nexpaq 1:55a6170b404f 73 * @returns
nexpaq 1:55a6170b404f 74 * A pointer to the singleton
nexpaq 1:55a6170b404f 75 */
nexpaq 1:55a6170b404f 76 T* get() {
nexpaq 1:55a6170b404f 77 if (NULL == _ptr) {
nexpaq 1:55a6170b404f 78 singleton_lock();
nexpaq 1:55a6170b404f 79 if (NULL == _ptr) {
nexpaq 1:55a6170b404f 80 _ptr = new (_data) T();
nexpaq 1:55a6170b404f 81 }
nexpaq 1:55a6170b404f 82 singleton_unlock();
nexpaq 1:55a6170b404f 83 }
nexpaq 1:55a6170b404f 84 // _ptr was not zero initialized or was
nexpaq 1:55a6170b404f 85 // corrupted if this assert is hit
nexpaq 1:55a6170b404f 86 MBED_ASSERT(_ptr == (T *)&_data);
nexpaq 1:55a6170b404f 87 return _ptr;
nexpaq 1:55a6170b404f 88 }
nexpaq 1:55a6170b404f 89
nexpaq 1:55a6170b404f 90 /** Get a pointer to the underlying singleton
nexpaq 1:55a6170b404f 91 *
nexpaq 1:55a6170b404f 92 * @returns
nexpaq 1:55a6170b404f 93 * A pointer to the singleton
nexpaq 1:55a6170b404f 94 */
nexpaq 1:55a6170b404f 95 T* operator->() {
nexpaq 1:55a6170b404f 96 return get();
nexpaq 1:55a6170b404f 97 }
nexpaq 1:55a6170b404f 98
nexpaq 1:55a6170b404f 99 // This is zero initialized when in global scope
nexpaq 1:55a6170b404f 100 T *_ptr;
nexpaq 1:55a6170b404f 101 // Force data to be 4 byte aligned
nexpaq 1:55a6170b404f 102 uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
nexpaq 1:55a6170b404f 103 };
nexpaq 1:55a6170b404f 104
nexpaq 1:55a6170b404f 105 #endif