【ミューテックス管理クラス】
ロック操作を管理する。
【概要】
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Mutex(void); |
ミューテックスを生成する。
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uint8_t lock(int32_t timeout = WAIT_INFINITE); |
ミューテックスをロックする。成功するとWAIT_OBJECTを返す。ロックを獲得できない場合、マイナスのタイムアウト指定では永久に待ち続け、ゼロ指定ではWAIT_TIMEOUTを即座に返す。１以上の指定時はその指定時間後にWAIT_TIMEOUTを返す。
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bool unlock(void); |
ミューテックスをアンロックする。待ち状態にあるタスクがロックを獲得する。
【ソース・コード】
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/* mutex.h - Mutex Function Class Copyright (c) 2021 Sasapea's Lab. All right reserved. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifndef __MUTEX_H #define __MUTEX_H #include <stdint.h> #include <stdbool.h> class Mutex : public Wait { private: size_t _count; TASK_T *_task; public: Mutex(void); ~Mutex(void); uint8_t lock(int32_t timeout = WAIT_INFINITE); bool unlock(void); }; #endif |
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/* mutex.h - Mutex Function Class Copyright (c) 2021 Sasapea's Lab. All right reserved. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <stdint.h> #include <stdbool.h> #include <util/atomic.h> #include "avros.h" Mutex::Mutex(void) : _count(0) , _task(nullptr) { } Mutex::~Mutex(void) { } uint8_t Mutex::lock(int32_t timeout) { uint8_t rv = WAIT_TIMEOUT; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { if ((_count == 0) || (_task == Task::current())) { ++_count; _task = Task::current(); rv = WAIT_OBJECT; } else if (timeout) { rv = Wait::sleep(timeout); if (rv == WAIT_OBJECT) { _task = Task::current(); _count = 1; } } } return rv; } bool Mutex::unlock(void) { bool rv = false; ATOMIC_BLOCK(ATOMIC_RESTORESTATE) { if (_count && (_task == Task::current())) { if (--_count == 0) Wait::wakeup(); rv = true; } } return rv; } |
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