mirror of https://github.com/CGAL/cgal
445 lines
13 KiB
C++
445 lines
13 KiB
C++
/*
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* Copyright (c) 1997-1999
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* Silicon Graphics Computer Systems, Inc.
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*
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* Copyright (c) 1999
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* Boris Fomitchev
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*
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* This material is provided "as is", with absolutely no warranty expressed
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* or implied. Any use is at your own risk.
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*
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* Permission to use or copy this software for any purpose is hereby granted
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* without fee, provided the above notices are retained on all copies.
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* Permission to modify the code and to distribute modified code is granted,
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* provided the above notices are retained, and a notice that the code was
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* modified is included with the above copyright notice.
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*
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*/
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// WARNING: This is an internal header file, included by other C++
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// standard library headers. You should not attempt to use this header
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// file directly.
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// Stl_config.h should be included before this file.
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#ifndef __SGI_STL_INTERNAL_THREADS_H
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#define __SGI_STL_INTERNAL_THREADS_H
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// Supported threading models are native SGI, pthreads, uithreads
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// (similar to pthreads, but based on an earlier draft of the Posix
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// threads standard), and Win32 threads. Uithread support by Jochen
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// Schlick, 1999, and Solaris threads generalized to them.
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#ifndef __STL_CONFIG_H
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#include <stl_config.h>
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#endif
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# if ! defined (__STLPORT_CSTDDEF)
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# include <cstddef>
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# endif
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#if defined(__STL_SGI_THREADS)
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#include <mutex.h>
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#include <time.h>
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#elif defined(__STL_PTHREADS)
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#include <pthread.h>
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#elif defined(__STL_WIN32THREADS)
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# if !defined (__STLPORT_WINDOWS_H_INCLUDED) && ! defined (_WINDOWS_)
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# ifndef __STL_MSVC
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# define NOMINMAX
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# ifdef __STL_USE_MFC
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# include <afx.h>
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# else
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# include <windows.h>
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# endif
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# else
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// This section serves as a replacement for windows.h header for Visual C++
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extern "C" {
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# if (defined(_M_MRX000) || defined(_M_ALPHA) \
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|| (defined(_M_PPC) && (_MSC_VER >= 1000))) && !defined(RC_INVOKED)
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# define InterlockedIncrement _InterlockedIncrement
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# define InterlockedDecrement _InterlockedDecrement
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# define InterlockedExchange _InterlockedExchange
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# define __STL_STDCALL
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# else
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# ifdef _MAC
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# define __STL_STDCALL _cdecl
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# else
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# define __STL_STDCALL __stdcall
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# endif
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# endif
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__STL_IMPORT_DECLSPEC long __STL_STDCALL InterlockedIncrement(long*);
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__STL_IMPORT_DECLSPEC long __STL_STDCALL InterlockedDecrement(long*);
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__STL_IMPORT_DECLSPEC long __STL_STDCALL InterlockedExchange(long*, long);
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__STL_IMPORT_DECLSPEC void __STL_STDCALL Sleep(unsigned long);
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# if defined (InterlockedIncrement)
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# pragma intrinsic(_InterlockedIncrement)
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# pragma intrinsic(_InterlockedDecrement)
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# pragma intrinsic(_InterlockedExchange)
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# endif
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} /* extern "C" */
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# endif /* STL_MSVC */
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# undef min
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# undef max
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# define __STLPORT_WINDOWS_H_INCLUDED
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# endif /* _WINDOWS_ */
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#elif defined (__STL_UITHREADS)
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// this inclusion is potential hazard to bring up all sorts
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// of old-style headers. Let's assume vendor already know how
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// to deal with that.
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#include <ctime>
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#include <cstdio>
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#include <cwchar>
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#include <synch.h>
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#endif
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__STL_BEGIN_NAMESPACE
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// Class _Refcount_Base provides a type, _RC_t, a data member,
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// _M_ref_count, and member functions _M_incr and _M_decr, which perform
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// atomic preincrement/predecrement. The constructor initializes
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// _M_ref_count.
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// Hack for SGI o32 compilers.
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#if defined(__STL_SGI_THREADS) && !defined(__add_and_fetch) && \
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(__mips < 3 || !(defined (_ABIN32) || defined(_ABI64)))
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# define __add_and_fetch(__l,__v) add_then_test((unsigned long*)__l,__v)
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# define __test_and_set(__l,__v) test_and_set(__l,__v)
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#endif /* o32 */
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struct __STL_CLASS_DECLSPEC _Refcount_Base
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{
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// The type _RC_t
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# ifdef __STL_WIN32THREADS
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typedef long _RC_t;
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# else
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typedef size_t _RC_t;
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#endif
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// The data member _M_ref_count
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volatile _RC_t _M_ref_count;
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// Constructor
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# ifdef __STL_PTHREADS
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pthread_mutex_t _M_ref_count_lock;
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_Refcount_Base(_RC_t __n) : _M_ref_count(__n)
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{ pthread_mutex_init(&_M_ref_count_lock, 0); }
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# elif defined (__STL_UITHREADS)
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mutex_t _M_ref_count_lock;
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_Refcount_Base(_RC_t __n) : _M_ref_count(__n)
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{ mutex_init(&_M_ref_count_lock,0,NULL); }
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# else
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_Refcount_Base(_RC_t __n) : _M_ref_count(__n) {}
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# endif
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// _M_incr and _M_decr
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# ifdef __STL_SGI_THREADS
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void _M_incr() { __add_and_fetch(&_M_ref_count, 1); }
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_RC_t _M_decr() { return __add_and_fetch(&_M_ref_count, (size_t) -1); }
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# elif defined (__STL_WIN32THREADS)
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void _M_incr() { InterlockedIncrement((_RC_t*)&_M_ref_count); }
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_RC_t _M_decr() { return InterlockedDecrement((_RC_t*)&_M_ref_count); }
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# elif defined(__STL_PTHREADS)
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void _M_incr() {
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pthread_mutex_lock(&_M_ref_count_lock);
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++_M_ref_count;
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pthread_mutex_unlock(&_M_ref_count_lock);
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}
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_RC_t _M_decr() {
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pthread_mutex_lock(&_M_ref_count_lock);
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volatile _RC_t __tmp = --_M_ref_count;
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pthread_mutex_unlock(&_M_ref_count_lock);
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return __tmp;
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}
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# elif defined (__STL_UITHREADS)
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void _M_incr() {
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mutex_lock(&_M_ref_count_lock);
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++_M_ref_count;
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mutex_unlock(&_M_ref_count_lock);
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}
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_RC_t _M_decr() {
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mutex_lock(&_M_ref_count_lock);
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volatile _RC_t __tmp = --_M_ref_count;
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mutex_unlock(&_M_ref_count_lock);
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return __tmp;
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}
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# else /* No threads */
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void _M_incr() { ++_M_ref_count; }
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_RC_t _M_decr() { return --_M_ref_count; }
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# endif
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};
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// Atomic swap on unsigned long
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// This is guaranteed to behave as though it were atomic only if all
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// possibly concurrent updates use _Atomic_swap.
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// In some cases the operation is emulated with a lock.
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# ifdef __STL_SGI_THREADS
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inline unsigned long _Atomic_swap(unsigned long * __p, unsigned long __q) {
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# if __mips < 3 || !(defined (_ABIN32) || defined(_ABI64))
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return test_and_set(__p, __q);
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# else
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return __test_and_set(__p, (unsigned long)__q);
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# endif
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}
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# elif defined(__STL_WIN32THREADS)
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inline unsigned long _Atomic_swap(unsigned long * __p, unsigned long __q) {
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return (unsigned long) InterlockedExchange((long*)__p, (long)__q);
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}
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# elif defined(__STL_PTHREADS)
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// We use a template here only to get a unique initialized instance.
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template<int __dummy>
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struct _Swap_lock_struct {
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static pthread_mutex_t _S_swap_lock;
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};
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// This should be portable, but performance is expected
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// to be quite awful. This really needs platform specific
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// code.
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inline unsigned long _Atomic_swap(unsigned long * __p, unsigned long __q) {
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pthread_mutex_lock(&_Swap_lock_struct<0>::_S_swap_lock);
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unsigned long __result = *__p;
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*__p = __q;
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pthread_mutex_unlock(&_Swap_lock_struct<0>::_S_swap_lock);
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return __result;
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}
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# elif defined (__STL_UITHREADS)
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// any better solutions ?
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// We use a template here only to get a unique initialized instance.
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template<int __dummy>
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struct _Swap_lock_struct {
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static mutex_t _S_swap_lock;
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};
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// This should be portable, but performance is expected
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// to be quite awful. This really needs platform specific
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// code.
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inline unsigned long _Atomic_swap(unsigned long * __p, unsigned long __q) {
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mutex_lock(&_Swap_lock_struct<0>::_S_swap_lock);
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unsigned long __result = *__p;
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*__p = __q;
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mutex_unlock(&_Swap_lock_struct<0>::_S_swap_lock);
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return __result;
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}
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# else
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static inline unsigned long _Atomic_swap(unsigned long * __p, unsigned long __q) {
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unsigned long __result = *__p;
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*__p = __q;
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return __result;
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}
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# endif
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// Locking class. The constructor initializes the lock, the destructor
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// destroys it. There are explicit member functions for acquiring and
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// releasing the lock.
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// VC++ does not like {} initializers for structs with constructors,
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// and, as {} functionality is crucial for default allocator, we
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// make this base class just for it. It exports _Init and _Destroy functions to
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// _STL_mutex_lock. For non-static cases, clients should use _STL_mutex_lock.
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struct __STL_CLASS_DECLSPEC _STL_mutex_base
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{
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#if defined(__STL_SGI_THREADS) || defined(__STL_WIN32THREADS)
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// It should be relatively easy to get this to work on any modern Unix.
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volatile unsigned long _M_lock;
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inline void _M_initialize() { _M_lock=0; }
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inline void _M_destroy() {}
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static inline void _S_nsec_sleep(int __log_nsec) {
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# ifdef __STL_SGI_THREADS
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struct timespec __ts;
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/* Max sleep is 2**27nsec ~ 60msec */
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__ts.tv_sec = 0;
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__ts.tv_nsec = 1 << __log_nsec;
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nanosleep(&__ts, 0);
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# elif defined(__STL_WIN32THREADS)
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if (__log_nsec <= 20) {
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Sleep(0);
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} else {
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Sleep(1 << (__log_nsec - 20));
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}
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# else
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# error unimplemented
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# endif
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}
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void _M_acquire_lock() {
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// spins if we suspect uniprocessor
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# define __low_spin_max 30
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// spins for multiprocessor
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# define __high_spin_max 1000
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static unsigned __spin_max = __low_spin_max;
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static unsigned __last_spins = 0;
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volatile unsigned long* __lock = &this->_M_lock;
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if (_Atomic_swap((unsigned long*)__lock, 1)) {
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unsigned __my_spin_max;
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unsigned __my_last_spins;
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volatile unsigned __junk = 17; // Value doesn't matter.
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unsigned __i;
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__my_spin_max = __spin_max;
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__my_last_spins = __last_spins;
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__junk = 17;
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for (__i = 0; __i < __my_spin_max; ++__i) {
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if (__i < __my_last_spins/2 || *__lock) {
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__junk *= __junk; __junk *= __junk;
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__junk *= __junk; __junk *= __junk;
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} else {
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if (!_Atomic_swap((unsigned long*)__lock, 1)) {
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// got it!
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// Spinning worked. Thus we're probably not being scheduled
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// against the other process with which we were contending.
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// Thus it makes sense to spin longer the next time.
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__last_spins = __i;
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__spin_max = __high_spin_max;
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return;
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}
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}
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}
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// We are probably being scheduled against the other process. Sleep.
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__spin_max = __low_spin_max;
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for (__i = 0 ;; ++__i) {
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int __log_nsec = __i + 6;
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if (__log_nsec > 27) __log_nsec = 27;
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if (!_Atomic_swap((unsigned long *)__lock, 1)) {
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break;
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}
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_S_nsec_sleep(__log_nsec);
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}
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} /* first _Atomic_swap */
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}
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inline void _M_release_lock() {
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volatile unsigned long* __lock = &_M_lock;
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# if defined(__STL_SGI_THREADS) && defined(__GNUC__) && __mips >= 3
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asm("sync");
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*__lock = 0;
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# elif defined(__STL_SGI_THREADS) && __mips >= 3 \
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&& (defined (_ABIN32) || defined(_ABI64))
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__lock_release(__lock);
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# else
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*__lock = 0;
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// This is not sufficient on many multiprocessors, since
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// writes to protected variables and the lock may be reordered.
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# endif
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}
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// We no longer use win32 critical sections.
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// They appear to be slower in the contention-free case,
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// and they appear difficult to initialize without introducing a race.
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#elif defined(__STL_PTHREADS)
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pthread_mutex_t _M_lock;
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inline void _M_initialize() {
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pthread_mutex_init(&_M_lock, NULL);
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}
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inline void _M_destroy() {
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pthread_mutex_destroy(&_M_lock);
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}
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inline void _M_acquire_lock() { pthread_mutex_lock(&_M_lock); }
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inline void _M_release_lock() { pthread_mutex_unlock(&_M_lock); }
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#elif defined (__STL_UITHREADS)
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mutex_t _M_lock;
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inline void _M_initialize() {
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mutex_init(&_M_lock,0,NULL);
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}
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inline void _M_destroy() {
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mutex_destroy(&_M_lock);
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}
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inline void _M_acquire_lock() { mutex_lock(&_M_lock); }
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inline void _M_release_lock() { mutex_unlock(&_M_lock); }
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#else /* No threads */
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inline void _M_initialize() {}
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inline void _M_destroy() {}
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inline void _M_acquire_lock() {}
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inline void _M_release_lock() {}
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#endif
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};
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// Well - behaving class, does not need static initializer
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struct __STL_CLASS_DECLSPEC _STL_mutex_lock : public _STL_mutex_base {
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inline _STL_mutex_lock() {
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_M_initialize();
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}
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inline ~_STL_mutex_lock() {
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_M_destroy();
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}
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private:
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_STL_mutex_lock(const _STL_mutex_lock&);
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void operator=(const _STL_mutex_lock&);
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};
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#ifdef __STL_PTHREADS
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// Pthreads locks must be statically initialized to something other than
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// the default value of zero.
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# define __STL_MUTEX_INITIALIZER = { PTHREAD_MUTEX_INITIALIZER }
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#elif defined(__STL_SGI_THREADS) || defined(__STL_WIN32THREADS)
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# define __STL_MUTEX_INITIALIZER = { 0 }
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#elif defined (__STL_UITHREADS)
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# define __STL_MUTEX_INITIALIZER = { DEFAULTMUTEX }
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#else
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# define __STL_MUTEX_INITIALIZER
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#endif
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// A locking class that uses _STL_mutex_lock. The constructor takes
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// a reference to an _STL_mutex_lock, and acquires a lock. The destructor
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// releases the lock.
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// It's not clear that this is exactly the right functionality.
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// It will probably change in the future.
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struct __STL_CLASS_DECLSPEC _STL_auto_lock
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{
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_STL_mutex_base& _M_lock;
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_STL_auto_lock(_STL_mutex_base& __lock) : _M_lock(__lock)
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{ _M_lock._M_acquire_lock(); }
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~_STL_auto_lock() { _M_lock._M_release_lock(); }
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private:
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void operator=(const _STL_auto_lock&);
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_STL_auto_lock(const _STL_auto_lock&);
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};
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__STL_END_NAMESPACE
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# if !defined (__STL_LINK_TIME_INSTANTIATION)
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# include <stl_threads.c>
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# endif
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#endif /* __SGI_STL_INTERNAL_THREADS_H */
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// Local Variables:
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// mode:C++
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// End:
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