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Diffstat (limited to 'distrib/sdl-1.2.12/src/thread/win32/win_ce_semaphore.c')
| -rw-r--r-- | distrib/sdl-1.2.12/src/thread/win32/win_ce_semaphore.c | 216 |
1 files changed, 0 insertions, 216 deletions
diff --git a/distrib/sdl-1.2.12/src/thread/win32/win_ce_semaphore.c b/distrib/sdl-1.2.12/src/thread/win32/win_ce_semaphore.c deleted file mode 100644 index 9db45c4..0000000 --- a/distrib/sdl-1.2.12/src/thread/win32/win_ce_semaphore.c +++ /dev/null @@ -1,216 +0,0 @@ -/* win_ce_semaphore.c - - Copyright (c) 1998, Johnson M. Hart - (with corrections 2001 by Rainer Loritz) - Permission is granted for any and all use providing that this - copyright is properly acknowledged. - There are no assurances of suitability for any use whatsoever. - - WINDOWS CE: There is a collection of Windows CE functions to simulate - semaphores using only a mutex and an event. As Windows CE events cannot - be named, these simulated semaphores cannot be named either. - - Implementation notes: - 1. All required internal data structures are allocated on the process's heap. - 2. Where appropriate, a new error code is returned (see the header - file), or, if the error is a Win32 error, that code is unchanged. - 3. Notice the new handle type "SYNCHHANDLE" that has handles, counters, - and other information. This structure will grow as new objects are added - to this set; some members are specific to only one or two of the objects. - 4. Mutexes are used for critical sections. These could be replaced with - CRITICAL_SECTION objects but then this would give up the time out - capability. - 5. The implementation shows several interesting aspects of synchronization, some - of which are specific to Win32 and some of which are general. These are pointed - out in the comments as appropriate. - 6. The wait function emulates WaitForSingleObject only. An emulation of - WaitForMultipleObjects is much harder to implement outside the kernel, - and it is not clear how to handle a mixture of WCE semaphores and normal - events and mutexes. */ - -#define WIN32_LEAN_AND_MEAN -#include <windows.h> - -#include "win_ce_semaphore.h" - -static SYNCHHANDLE CleanUp (SYNCHHANDLE hSynch, DWORD Flags); - -SYNCHHANDLE CreateSemaphoreCE ( - - LPSECURITY_ATTRIBUTES lpSemaphoreAttributes, /* pointer to security attributes */ - LONG lInitialCount, /* initial count */ - LONG lMaximumCount, /* maximum count */ - LPCTSTR lpName ) - -/* Semaphore for use with Windows CE that does not support them directly. - Requires a counter, a mutex to protect the counter, and an - autoreset event. - - Here are the rules that must always hold between the autoreset event - and the mutex (any violation of these rules by the CE semaphore functions - will, in all likelihood, result in a defect): - 1. No thread can set, pulse, or reset the event, - nor can it access any part of the SYNCHHANDLE structure, - without first gaining ownership of the mutex. - BUT, a thread can wait on the event without owning the mutex - (this is clearly necessary or else the event could never be set). - 2. The event is in a signaled state if and only if the current semaphore - count ("CurCount") is greater than zero. - 3. The semaphore count is always >= 0 and <= the maximum count */ - -{ - SYNCHHANDLE hSynch = NULL, result = NULL; - - __try - { - if (lInitialCount > lMaximumCount || lMaximumCount < 0 || lInitialCount < 0) - { - /* Bad parameters */ - SetLastError (SYNCH_ERROR); - __leave; - } - - hSynch = HeapAlloc (GetProcessHeap(), HEAP_ZERO_MEMORY, SYNCH_HANDLE_SIZE); - if (hSynch == NULL) __leave; - - hSynch->MaxCount = lMaximumCount; - hSynch->CurCount = lInitialCount; - hSynch->lpName = lpName; - - hSynch->hMutex = CreateMutex (lpSemaphoreAttributes, FALSE, NULL); - - WaitForSingleObject (hSynch->hMutex, INFINITE); - /* Create the event. It is initially signaled if and only if the - initial count is > 0 */ - hSynch->hEvent = CreateEvent (lpSemaphoreAttributes, FALSE, - lInitialCount > 0, NULL); - ReleaseMutex (hSynch->hMutex); - hSynch->hSemph = NULL; - } - __finally - { - /* Return with the handle, or, if there was any error, return - a null after closing any open handles and freeing any allocated memory. */ - result=CleanUp(hSynch, 6 /* An event and a mutex, but no semaphore. */); - } - - return result; -} - -BOOL ReleaseSemaphoreCE (SYNCHHANDLE hSemCE, LONG cReleaseCount, LPLONG lpPreviousCount) -/* Windows CE equivalent to ReleaseSemaphore. */ -{ - BOOL Result = TRUE; - - /* Gain access to the object to assure that the release count - would not cause the total count to exceed the maximum. */ - - __try - { - WaitForSingleObject (hSemCE->hMutex, INFINITE); - /* reply only if asked to */ - if (lpPreviousCount!=NULL) - *lpPreviousCount = hSemCE->CurCount; - if (hSemCE->CurCount + cReleaseCount > hSemCE->MaxCount || cReleaseCount <= 0) - { - SetLastError (SYNCH_ERROR); - Result = FALSE; - __leave; - } - hSemCE->CurCount += cReleaseCount; - - /* Set the autoreset event, releasing exactly one waiting thread, now or - in the future. */ - - SetEvent (hSemCE->hEvent); - } - __finally - { - ReleaseMutex (hSemCE->hMutex); - } - - return Result; -} - -DWORD WaitForSemaphoreCE (SYNCHHANDLE hSemCE, DWORD dwMilliseconds) - /* Windows CE semaphore equivalent of WaitForSingleObject. */ -{ - DWORD WaitResult; - - WaitResult = WaitForSingleObject (hSemCE->hMutex, dwMilliseconds); - if (WaitResult != WAIT_OBJECT_0 && WaitResult != WAIT_ABANDONED_0) return WaitResult; - while (hSemCE->CurCount <= 0) - { - - /* The count is 0, and the thread must wait on the event (which, by - the rules, is currently reset) for semaphore resources to become - available. First, of course, the mutex must be released so that another - thread will be capable of setting the event. */ - - ReleaseMutex (hSemCE->hMutex); - - /* Wait for the event to be signaled, indicating a semaphore state change. - The event is autoreset and signaled with a SetEvent (not PulseEvent) - so exactly one waiting thread (whether or not there is currently - a waiting thread) is released as a result of the SetEvent. */ - - WaitResult = WaitForSingleObject (hSemCE->hEvent, dwMilliseconds); - if (WaitResult != WAIT_OBJECT_0) return WaitResult; - - /* This is where the properties of setting of an autoreset event is critical - to assure that, even if the semaphore state changes between the - preceding Wait and the next, and even if NO threads are waiting - on the event at the time of the SetEvent, at least one thread - will be released. - Pulsing a manual reset event would appear to work, but it would have - a defect which could appear if the semaphore state changed between - the two waits. */ - - WaitResult = WaitForSingleObject (hSemCE->hMutex, dwMilliseconds); - if (WaitResult != WAIT_OBJECT_0 && WaitResult != WAIT_ABANDONED_0) return WaitResult; - - } - /* The count is not zero and this thread owns the mutex. */ - - hSemCE->CurCount--; - /* The event is now unsignaled, BUT, the semaphore count may not be - zero, in which case the event should be signaled again - before releasing the mutex. */ - - if (hSemCE->CurCount > 0) SetEvent (hSemCE->hEvent); - ReleaseMutex (hSemCE->hMutex); - return WaitResult; -} - -BOOL CloseSynchHandle (SYNCHHANDLE hSynch) -/* Close a synchronization handle. - Improvement: Test for a valid handle before dereferencing the handle. */ -{ - BOOL Result = TRUE; - if (hSynch->hEvent != NULL) Result = Result && CloseHandle (hSynch->hEvent); - if (hSynch->hMutex != NULL) Result = Result && CloseHandle (hSynch->hMutex); - if (hSynch->hSemph != NULL) Result = Result && CloseHandle (hSynch->hSemph); - HeapFree (GetProcessHeap (), 0, hSynch); - return (Result); -} - -static SYNCHHANDLE CleanUp (SYNCHHANDLE hSynch, DWORD Flags) -{ /* Prepare to return from a create of a synchronization handle. - If there was any failure, free any allocated resources. - "Flags" indicates which Win32 objects are required in the - synchronization handle. */ - - BOOL ok = TRUE; - - if (hSynch == NULL) return NULL; - if ((Flags & 4) == 1 && (hSynch->hEvent == NULL)) ok = FALSE; - if ((Flags & 2) == 1 && (hSynch->hMutex == NULL)) ok = FALSE; - if ((Flags & 1) == 1 && (hSynch->hEvent == NULL)) ok = FALSE; - if (!ok) - { - CloseSynchHandle (hSynch); - return NULL; - } - /* Everything worked */ - return hSynch; -} |