nuclear@3: /************************************************************************************
nuclear@3: 
nuclear@3: Filename    :   OVR_Atomic.cpp
nuclear@3: Content     :   Contains atomic operations and inline fastest locking
nuclear@3:                 functionality. Will contain #ifdefs for OS efficiency.
nuclear@3:                 Have non-thread-safe implementation if not available.
nuclear@3: Created     :   September 19, 2012
nuclear@3: Notes       : 
nuclear@3: 
nuclear@3: Copyright   :   Copyright 2012 Oculus VR, Inc. All Rights reserved.
nuclear@3: 
nuclear@3: Use of this software is subject to the terms of the Oculus license
nuclear@3: agreement provided at the time of installation or download, or which
nuclear@3: otherwise accompanies this software in either electronic or hard copy form.
nuclear@3: 
nuclear@3: ************************************************************************************/
nuclear@3: 
nuclear@3: #include "OVR_Atomic.h"
nuclear@3: 
nuclear@3: #ifdef OVR_ENABLE_THREADS
nuclear@3: 
nuclear@3: // Include Windows 8-Metro compatible Synchronization API
nuclear@3: #if defined(OVR_OS_WIN32) && defined(NTDDI_WIN8) && (NTDDI_VERSION >= NTDDI_WIN8)
nuclear@3: #include <synchapi.h>
nuclear@3: #endif
nuclear@3: 
nuclear@3: 
nuclear@3: namespace OVR {
nuclear@3: 
nuclear@3: // ***** Windows Lock implementation
nuclear@3: 
nuclear@3: #if defined(OVR_OS_WIN32)
nuclear@3: 
nuclear@3: // ***** Standard Win32 Lock implementation
nuclear@3: 
nuclear@3: // Constructors
nuclear@3: Lock::Lock(unsigned spinCount)
nuclear@3: {
nuclear@3: #if defined(NTDDI_WIN8) && (NTDDI_VERSION >= NTDDI_WIN8)
nuclear@3:    // On Windows 8 we use InitializeCriticalSectionEx due to Metro-Compatibility
nuclear@3:    InitializeCriticalSectionEx(&cs, spinCount,
nuclear@3:                                OVR_DEBUG_SELECT(NULL, CRITICAL_SECTION_NO_DEBUG_INFO));
nuclear@3: #else
nuclear@3:     // Spin count init critical section function prototype for Window NT
nuclear@3:     typedef BOOL (WINAPI *Function_InitializeCriticalSectionAndSpinCount) 
nuclear@3:                  (LPCRITICAL_SECTION lpCriticalSection, DWORD dwSpinCount);
nuclear@3: 
nuclear@3: 
nuclear@3:     // Try to load function dynamically so that we don't require NT
nuclear@3:     // On Windows NT we will use InitializeCriticalSectionAndSpinCount
nuclear@3:     static  bool initTried = 0;
nuclear@3:     static  Function_InitializeCriticalSectionAndSpinCount pInitFn = 0;
nuclear@3: 
nuclear@3:     if (!initTried)
nuclear@3:     {
nuclear@3:         HMODULE hmodule = ::LoadLibrary(OVR_STR("kernel32.dll"));
nuclear@3:         pInitFn     = (Function_InitializeCriticalSectionAndSpinCount)
nuclear@3:                       ::GetProcAddress(hmodule, "InitializeCriticalSectionAndSpinCount");
nuclear@3:         initTried   = true;
nuclear@3:     }
nuclear@3: 
nuclear@3:     // Initialize the critical section
nuclear@3:     if (pInitFn)
nuclear@3:         pInitFn(&cs, spinCount);
nuclear@3:     else
nuclear@3:         ::InitializeCriticalSection(&cs);
nuclear@3: #endif
nuclear@3:    
nuclear@3: }
nuclear@3: 
nuclear@3: 
nuclear@3: Lock::~Lock()
nuclear@3: {
nuclear@3:     DeleteCriticalSection(&cs);
nuclear@3: }
nuclear@3: 
nuclear@3: 
nuclear@3: #endif
nuclear@3: 
nuclear@3: } // OVR
nuclear@3: 
nuclear@3: #endif // OVR_ENABLE_THREADS