161 lines
4.2 KiB
C++
161 lines
4.2 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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// Name: wx/atomic.h
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// Purpose: functions to manipulate atomically integers and pointers
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// Author: Armel Asselin
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// Created: 12/13/2006
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// RCS-ID: $Id: atomic.h 53954 2008-06-02 20:42:23Z VZ $
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// Copyright: (c) Armel Asselin
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// Licence: wxWindows licence
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/////////////////////////////////////////////////////////////////////////////
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#ifndef _WX_ATOMIC_H_
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#define _WX_ATOMIC_H_
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// ----------------------------------------------------------------------------
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// headers
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// ----------------------------------------------------------------------------
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// get the value of wxUSE_THREADS configuration flag
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#include "wx/defs.h"
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// constraints on the various functions:
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// - wxAtomicDec must return a zero value if the value is zero once
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// decremented else it must return any non-zero value (the true value is OK
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// but not necessary).
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#if wxUSE_THREADS
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#if defined(HAVE_GCC_ATOMIC_BUILTINS)
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// NB: we intentionally don't use Linux's asm/atomic.h header, because it's
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// an internal kernel header that doesn't always work in userspace:
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// http://bugs.mysql.com/bug.php?id=28456
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// http://golubenco.org/blog/atomic-operations/
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inline void wxAtomicInc (wxUint32 &value)
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{
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__sync_fetch_and_add(&value, 1);
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}
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inline wxUint32 wxAtomicDec (wxUint32 &value)
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{
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return __sync_sub_and_fetch(&value, 1);
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}
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#elif defined(__WXMSW__)
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// include standard Windows headers
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#include "wx/msw/wrapwin.h"
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inline void wxAtomicInc (wxUint32 &value)
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{
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InterlockedIncrement ((LONG*)&value);
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}
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inline wxUint32 wxAtomicDec (wxUint32 &value)
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{
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return InterlockedDecrement ((LONG*)&value);
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}
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#elif defined(__WXMAC__) || defined(__DARWIN__)
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#include "libkern/OSAtomic.h"
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inline void wxAtomicInc (wxUint32 &value)
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{
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OSAtomicIncrement32 ((int32_t*)&value);
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}
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inline wxUint32 wxAtomicDec (wxUint32 &value)
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{
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return OSAtomicDecrement32 ((int32_t*)&value);
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}
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#elif defined (__SOLARIS__)
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#include <atomic.h>
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inline void wxAtomicInc (wxUint32 &value)
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{
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atomic_add_32 ((uint32_t*)&value, 1);
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}
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inline wxUint32 wxAtomicDec (wxUint32 &value)
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{
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return atomic_add_32_nv ((uint32_t*)&value, (uint32_t)-1);
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}
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#else // unknown platform
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// it will result in inclusion if the generic implementation code a bit later in this page
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#define wxNEEDS_GENERIC_ATOMIC_OPS
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#endif // unknown platform
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#else // else of wxUSE_THREADS
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// if no threads are used we can safely use simple ++/--
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inline void wxAtomicInc (wxUint32 &value) { ++value; }
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inline wxUint32 wxAtomicDec (wxUint32 &value) { return --value; }
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#endif // !wxUSE_THREADS
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// ----------------------------------------------------------------------------
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// proxies to actual implementations, but for various other types with same
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// behaviour
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// ----------------------------------------------------------------------------
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#ifdef wxNEEDS_GENERIC_ATOMIC_OPS
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#include "wx/thread.h" // for wxCriticalSection
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class wxAtomicInt32
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{
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public:
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wxAtomicInt32() { } // non initialized for consistency with basic int type
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wxAtomicInt32(wxInt32 v) : m_value(v) { }
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wxAtomicInt32(const wxAtomicInt32& a) : m_value(a.m_value) {}
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operator wxInt32() const { return m_value; }
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operator volatile wxInt32&() { return m_value; }
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wxAtomicInt32& operator=(wxInt32 v) { m_value = v; return *this; }
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void Inc()
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{
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wxCriticalSectionLocker lock(m_locker);
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++m_value;
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}
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wxInt32 Dec()
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{
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wxCriticalSectionLocker lock(m_locker);
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return --m_value;
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}
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private:
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volatile wxInt32 m_value;
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wxCriticalSection m_locker;
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};
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inline void wxAtomicInc(wxAtomicInt32 &value) { value.Inc(); }
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inline wxInt32 wxAtomicDec(wxAtomicInt32 &value) { return value.Dec(); }
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#else // !wxNEEDS_GENERIC_ATOMIC_OPS
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#define wxHAS_ATOMIC_OPS
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inline void wxAtomicInc(wxInt32 &value) { wxAtomicInc((wxUint32&)value); }
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inline wxInt32 wxAtomicDec(wxInt32 &value) { return wxAtomicDec((wxUint32&)value); }
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typedef wxInt32 wxAtomicInt32;
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#endif // wxNEEDS_GENERIC_ATOMIC_OPS
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// all the native implementations use 32 bits currently
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// for a 64 bits implementation we could use (a future) wxAtomicInt64 as
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// default type
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typedef wxAtomicInt32 wxAtomicInt;
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#endif // _WX_ATOMIC_H_
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