// -*- Mode: C++; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- // vim:tabstop=4:shiftwidth=4:expandtab: /* * Copyright (C) 2004-2007 Wu Yongwei * * This software is provided 'as-is', without any express or implied * warranty. In no event will the authors be held liable for any * damages arising from the use of this software. * * Permission is granted to anyone to use this software for any purpose, * including commercial applications, and to alter it and redistribute * it freely, subject to the following restrictions: * * 1. The origin of this software must not be misrepresented; you must * not claim that you wrote the original software. If you use this * software in a product, an acknowledgement in the product * documentation would be appreciated but is not required. * 2. Altered source versions must be plainly marked as such, and must * not be misrepresented as being the original software. * 3. This notice may not be removed or altered from any source * distribution. * * This file is part of Stones of Nvwa: * http://sourceforge.net/projects/nvwa * */ /** * @file fast_mutex.h * * A fast mutex implementation for POSIX and Win32. * * @version 1.18, 2005/05/06 * @author Wu Yongwei * */ #ifndef _FAST_MUTEX_H #define _FAST_MUTEX_H # if !defined(_NOTHREADS) # if !defined(_WIN32THREADS) && \ (defined(_WIN32) && defined(_MT)) // Automatically use _WIN32THREADS when specifying -MT/-MD in MSVC, // or -mthreads in MinGW GCC. # define _WIN32THREADS # elif !defined(_PTHREADS) && \ defined(_REENTRANT) // Automatically use _PTHREADS when specifying -pthread in GCC. // N.B. I do not detect on _PTHREAD_H since libstdc++-v3 under // Linux will silently include anyway. # define _PTHREADS # endif # endif # if !defined(_PTHREADS) && !defined(_WIN32THREADS) && !defined(_NOTHREADS) # define _NOTHREADS # endif # if defined(_NOTHREADS) # if defined(_PTHREADS) || defined(_WIN32THREADS) # undef _NOTHREADS # error "Cannot define multi-threaded mode with -D_NOTHREADS" # if defined(__MINGW32__) && defined(_WIN32THREADS) && !defined(_MT) # error "Be sure to specify -mthreads with -D_WIN32THREADS" # endif # endif # endif # ifndef _FAST_MUTEX_CHECK_INITIALIZATION /** * Macro to control whether to check for initialization status for each * lock/unlock operation. Defining it to a non-zero value will enable * the check, so that the construction/destruction of a static object * using a static fast_mutex not yet constructed or already destroyed * will work (with lock/unlock operations ignored). Defining it to zero * will disable to check. */ # define _FAST_MUTEX_CHECK_INITIALIZATION 1 # endif # if defined(_PTHREADS) && defined(_WIN32THREADS) // Some C++ libraries have _PTHREADS defined even on Win32 platforms. // Thus this hack. # undef _PTHREADS # endif # ifdef _DEBUG # include # include /** Macro for fast_mutex assertions. Real version (for debug mode). */ # define _FAST_MUTEX_ASSERT(_Expr, _Msg) \ if (!(_Expr)) { \ fprintf(stderr, "fast_mutex::%s\n", _Msg); \ abort(); \ } # else /** Macro for fast_mutex assertions. Fake version (for release mode). */ # define _FAST_MUTEX_ASSERT(_Expr, _Msg) \ ((void)0) # endif # ifdef _PTHREADS # include /** * Macro alias to `volatile' semantics. Here it is truly volatile since * it is in a multi-threaded (POSIX threads) environment. */ # define __VOLATILE volatile /** * Class for non-reentrant fast mutexes. This is the implementation * for POSIX threads. */ class fast_mutex { pthread_mutex_t _M_mtx_impl; # if _FAST_MUTEX_CHECK_INITIALIZATION bool _M_initialized; # endif # ifdef _DEBUG bool _M_locked; # endif public: fast_mutex() # ifdef _DEBUG : _M_locked(false) # endif { ::pthread_mutex_init(&_M_mtx_impl, NULL); # if _FAST_MUTEX_CHECK_INITIALIZATION _M_initialized = true; # endif } ~fast_mutex() { _FAST_MUTEX_ASSERT(!_M_locked, "~fast_mutex(): still locked"); # if _FAST_MUTEX_CHECK_INITIALIZATION _M_initialized = false; # endif ::pthread_mutex_destroy(&_M_mtx_impl); } void lock() { # if _FAST_MUTEX_CHECK_INITIALIZATION if (!_M_initialized) return; # endif ::pthread_mutex_lock(&_M_mtx_impl); # ifdef _DEBUG // The following assertion should _always_ be true for a // real `fast' pthread_mutex. However, this assertion can // help sometimes, when people forget to use `-lpthread' and // glibc provides an empty implementation. Having this // assertion is also more consistent. _FAST_MUTEX_ASSERT(!_M_locked, "lock(): already locked"); _M_locked = true; # endif } void unlock() { # if _FAST_MUTEX_CHECK_INITIALIZATION if (!_M_initialized) return; # endif # ifdef _DEBUG _FAST_MUTEX_ASSERT(_M_locked, "unlock(): not locked"); _M_locked = false; # endif ::pthread_mutex_unlock(&_M_mtx_impl); } private: fast_mutex(const fast_mutex&); fast_mutex& operator=(const fast_mutex&); }; # endif // _PTHREADS # ifdef _WIN32THREADS # include /** * Macro alias to `volatile' semantics. Here it is truly volatile since * it is in a multi-threaded (Win32 threads) environment. */ # define __VOLATILE volatile /** * Class for non-reentrant fast mutexes. This is the implementation * for Win32 threads. */ class fast_mutex { CRITICAL_SECTION _M_mtx_impl; # if _FAST_MUTEX_CHECK_INITIALIZATION bool _M_initialized; # endif # ifdef _DEBUG bool _M_locked; # endif public: fast_mutex() # ifdef _DEBUG : _M_locked(false) # endif { ::InitializeCriticalSection(&_M_mtx_impl); # if _FAST_MUTEX_CHECK_INITIALIZATION _M_initialized = true; # endif } ~fast_mutex() { _FAST_MUTEX_ASSERT(!_M_locked, "~fast_mutex(): still locked"); # if _FAST_MUTEX_CHECK_INITIALIZATION _M_initialized = false; # endif ::DeleteCriticalSection(&_M_mtx_impl); } void lock() { # if _FAST_MUTEX_CHECK_INITIALIZATION if (!_M_initialized) return; # endif ::EnterCriticalSection(&_M_mtx_impl); # ifdef _DEBUG _FAST_MUTEX_ASSERT(!_M_locked, "lock(): already locked"); _M_locked = true; # endif } void unlock() { # if _FAST_MUTEX_CHECK_INITIALIZATION if (!_M_initialized) return; # endif # ifdef _DEBUG _FAST_MUTEX_ASSERT(_M_locked, "unlock(): not locked"); _M_locked = false; # endif ::LeaveCriticalSection(&_M_mtx_impl); } private: fast_mutex(const fast_mutex&); fast_mutex& operator=(const fast_mutex&); }; # endif // _WIN32THREADS # ifdef _NOTHREADS /** * Macro alias to `volatile' semantics. Here it is not truly volatile * since it is in a single-threaded environment. */ # define __VOLATILE /** * Class for non-reentrant fast mutexes. This is the null * implementation for single-threaded environments. */ class fast_mutex { # ifdef _DEBUG bool _M_locked; # endif public: fast_mutex() # ifdef _DEBUG : _M_locked(false) # endif { } ~fast_mutex() { _FAST_MUTEX_ASSERT(!_M_locked, "~fast_mutex(): still locked"); } void lock() { # ifdef _DEBUG _FAST_MUTEX_ASSERT(!_M_locked, "lock(): already locked"); _M_locked = true; # endif } void unlock() { # ifdef _DEBUG _FAST_MUTEX_ASSERT(_M_locked, "unlock(): not locked"); _M_locked = false; # endif } private: fast_mutex(const fast_mutex&); fast_mutex& operator=(const fast_mutex&); }; # endif // _NOTHREADS /** An acquistion-on-initialization lock class based on fast_mutex. */ class fast_mutex_autolock { fast_mutex& _M_mtx; public: explicit fast_mutex_autolock(fast_mutex& __mtx) : _M_mtx(__mtx) { _M_mtx.lock(); } ~fast_mutex_autolock() { _M_mtx.unlock(); } private: fast_mutex_autolock(const fast_mutex_autolock&); fast_mutex_autolock& operator=(const fast_mutex_autolock&); }; #endif // _FAST_MUTEX_H