Windows2003-3790/enduser/netmeeting/av/callcont/tstable.h
2020-09-30 16:53:55 +02:00

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/****************************************************************************
*
*
* INTEL Corporation Prorietary Information
*
* This listing is supplied under the terms of a license agreement
* with INTEL Corporation and may not be copied nor disclosed except
* in accordance with the terms of that agreement.
*
* Copyright (c) 1996 Intel Corporation.
*
*
* Abstract:
*
* Notes:
*
***************************************************************************/
#ifndef __TSTABLE_H
#define __TSTABLE_H
typedef struct _LOCK_ENTRY
{
HANDLE hLock;
int iLockCount;
BOOL bCleanup,
bDeleted;
WORD wNextFree,
wUniqueID;
} LOCK_ENTRY, *PLOCK_ENTRY;
// definition of an invalid ID
#define TSTABLE_INVALID_ID (DWORD) 0xFFFFFFFF
// return codes that the callback function used in conjunction with EnumerateEntries can return
const DWORD CALLBACK_CONTINUE = 1;
const DWORD CALLBACK_ABORT = 2;
const DWORD CALLBACK_DELETE_ENTRY = 3;
const DWORD CALLBACK_DELETE_ENTRY_AND_OBJECT = 4;
// used in call to Lock
#define TSTABLE_INVALID_UNIQUE_ID (WORD) 0xFFFF
#define TSTABLE_INVALID_INDEX (WORD) 0xFFFF
// This is a compare function that we aren't using right now. It
// will be useful in the future if there is a reason to search
// the table
typedef INT (*ENTRY_COMPARE) (LPVOID ptr1, LPVOID ptr2);
template <class EntryData> class TSTable
{
typedef DWORD (*TABLE_CALLBACK) (EntryData* ptr, LPVOID context);
public:
TSTable (WORD _size);
~TSTable ();
BOOL Resize (WORD wNewSize);
BOOL CreateAndLock (EntryData* pEntryData,
LPDWORD lpdwID);
BOOL Validate (DWORD_PTR dwID);
EntryData *Lock (DWORD_PTR dwID,
DWORD timeout = INFINITE);
BOOL Unlock (DWORD_PTR dwID);
BOOL Delete (DWORD_PTR dwID,
BOOL bCleanup = FALSE);
EntryData *EnumerateEntries(TABLE_CALLBACK callBackFunc,
void* context,
BOOL bUnlockTable = FALSE);
BOOL IsInitialized () {return bInitialized;}
WORD GetSize () {return wNumUsed;}
private:
// data
EntryData** pDataTable;
PLOCK_ENTRY pLockTable;
CRITICAL_SECTION csTableLock;
WORD wSize,
wNumUsed,
wFirstFree,
wLastFree,
wUniqueID;
BOOL bInitialized;
// private methods
BOOL LockEntry (WORD wIndex,
DWORD timeout = INFINITE);
BOOL UnLockEntry(WORD wIndex);
void LockTable () { EnterCriticalSection(&csTableLock); };
void UnLockTable() { LeaveCriticalSection(&csTableLock); };
WORD GenerateUniqueID();
DWORD MakeID(WORD wIndex, WORD wUniqueID)
{
DWORD theID = wUniqueID;
theID = (theID << 16) & 0xFFFF0000;
theID |= wIndex;
return(theID);
};
void BreakID(DWORD_PTR theID, WORD* pwIndex, WORD* pwUID)
{
*pwIndex = (WORD) (theID & 0x0000FFFF);
*pwUID = (WORD) ((theID >> 16) & 0x0000FFFF);
};
};
/*
** TSTable::TSTable
*
* FILENAME: c:\msdev\projects\firewalls\inc\tstable.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
TSTable<EntryData>::TSTable(WORD _size) :
wSize(_size),
wNumUsed((WORD) 0),
wFirstFree((WORD) 0),
wLastFree((WORD) (_size - 1)),
wUniqueID((WORD) 0),
bInitialized(TRUE),
pDataTable(NULL),
pLockTable(NULL)
{
WORD wIndex;
// Create the table lock
InitializeCriticalSection(&csTableLock);
// Lock the table
LockTable();
// Create the data table
pDataTable = new EntryData*[wSize];
if(pDataTable == NULL)
{
bInitialized = FALSE;
return;
}
// Init the pointers
for (wIndex = 0; wIndex < wSize; wIndex++)
{
pDataTable[wIndex] = NULL;
}
// Create the lock table
pLockTable = new LOCK_ENTRY[wSize];
if (pLockTable == NULL)
{
bInitialized = FALSE;
return;
}
// Initialize the lock table entries...each entry begins with
// a NULL mutex handle, a zero lock count and it's next free is
// the next successive entry.
for (wIndex = 0; wIndex < wSize; wIndex++ )
{
pLockTable[wIndex].hLock = NULL;
pLockTable[wIndex].iLockCount = 0;
pLockTable[wIndex].wNextFree = (WORD) (wIndex + 1);
}
// note: the wNextFree in the last table entry points to an invalid index, however,
// this is OK since if the table ever fills, it is automatically resized making what
// was an invalid index, the index into the first entry of newly added part of the
// enlargened table. Trust me...
// Unlock the table
UnLockTable();
}
/*
** TSTable::~TSTable
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
TSTable<EntryData>::~TSTable()
{
DWORD wIndex;
// Lock the table
LockTable();
// Delete the data table
if (pDataTable != NULL)
{
delete pDataTable;
}
// Delete the lock table
if (pLockTable != NULL)
{
// Destroy the mutexes
for (wIndex = 0; wIndex < wSize; wIndex++)
{
if (pLockTable[wIndex].hLock != NULL)
{
CloseHandle(pLockTable[wIndex].hLock);
}
}
delete pLockTable;
}
// Unlock the table
UnLockTable();
// Destroy the table lock
DeleteCriticalSection(&csTableLock);
bInitialized = FALSE;
}
/*
** TSTable::CreateAndLock
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
BOOL TSTable<EntryData>::CreateAndLock(EntryData* pEntryData,
LPDWORD lpdwID)
{
BOOL bRetCode = FALSE;
WORD wIndex;
// If the pointer passed in is bad, then don't even try to do anything for them
if (pEntryData == NULL || lpdwID == NULL)
{
goto EXIT;
}
// Lock the table
LockTable();
// If the table is full, then resize it.
if (wNumUsed >= wSize - 1)
{
goto EXIT;
}
// Get the first free entry
wIndex = wFirstFree;
// Create the mutex for the object
if ((pLockTable[wIndex].hLock = CreateMutexA(NULL, FALSE, NULL)) == NULL)
{
goto EXIT;
}
// Lock the entry (no need checking the return code as the entire
// table is locked) - since this is a new entry, that means that nobody
// could have locked the entry already.
LockEntry(wIndex, 0);
// Copy pointer to the data table
pDataTable[wIndex] = pEntryData;
// Init the corresponding lock table entry
pLockTable[wIndex].bDeleted = FALSE;
pLockTable[wIndex].iLockCount = 1;
pLockTable[wIndex].wUniqueID = GenerateUniqueID();
// Set the id for the caller
*lpdwID = MakeID(wIndex, pLockTable[wIndex].wUniqueID);
// Bump up the count of number used
wNumUsed++;
// Fix the next free index
wFirstFree = pLockTable[wIndex].wNextFree;
// Signal success
bRetCode = TRUE;
EXIT:
// Unlock the table
UnLockTable();
return bRetCode;
}
/*
** TSTable::Lock
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
EntryData* TSTable<EntryData>::Lock(DWORD_PTR dwID,
DWORD timeout)
{
EntryData* pEntryData = NULL;
WORD wIndex,
wUID;
BreakID(dwID, &wIndex, &wUID);
// Lock the table
LockTable();
// Verify the index is within bounds
if (wIndex >= wSize)
{
goto EXIT;
}
// Verify that the entry is actually valid (ie the lock in non-NULL,
// the object status is valid, and the unique ID matches).
if (pLockTable[wIndex].hLock == NULL ||
pLockTable[wIndex].bDeleted == TRUE ||
pLockTable[wIndex].wUniqueID != wUID)
{
goto EXIT;
}
// If the timeout is INFINITE, then try to lock the entry using a more
// "thread friendly" method. If a timeout is specified, then don't do
// the spin lock since it could be implemented at a higher level.
if(timeout == INFINITE)
{
// simulate infinity with a pseudo "spin lock"
// This is more "thread friendly" in that it unlocks the table allowing some
// other thread that is trying to unlock the same entry to be able to lock the
// table.
while(LockEntry(wIndex, 0) == FALSE)
{
UnLockTable();
// give up the rest of this thread quantum, allowing others to run and potentially
// unlock the entry
Sleep(0);
LockTable();
// If the entry has been replaced, deleted or marked for deletion then
// bag it (give up)
if((pLockTable[wIndex].wUniqueID != wUID) ||
(pLockTable[wIndex].hLock == NULL) ||
(pLockTable[wIndex].bDeleted == TRUE))
{
goto EXIT;
}
}
// we got the lock
pEntryData = pDataTable[wIndex];
}
// Otherwise, do a normal lock
else
{
if (LockEntry(wIndex, timeout) == TRUE)
{
pEntryData = pDataTable[wIndex];
}
}
EXIT:
// Unlock the table
UnLockTable();
return pEntryData;
}
/*
** TSTable::Unlock
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
BOOL TSTable<EntryData>::Unlock(DWORD_PTR dwID)
{
BOOL bRetCode = TRUE;
WORD wIndex,
wUID;
BreakID(dwID, &wIndex, &wUID);
// Lock the table
LockTable();
// Verify the id is within bounds
if (wIndex >= wSize)
{
bRetCode = FALSE;
goto EXIT;
}
// verify that the UID matches
if (pLockTable[wIndex].wUniqueID != wUID)
{
bRetCode = FALSE;
goto EXIT;
}
// Verify that the lock is actually valid and that the entry has not been
// deleted
if (pLockTable[wIndex].hLock == NULL)
{
goto EXIT;
}
// Make sure that that thread has the lock on the entry
if ((bRetCode = LockEntry(wIndex, 0)) == TRUE)
{
// if this table entry is marked for delete and the lock count is less than 2
// (since the thread could have called delete after unlocking the entry...although
// this is a no-no) then clean up the table entry
if (pLockTable[wIndex].bDeleted == TRUE &&
pLockTable[wIndex].iLockCount <= 2)
{
// If the caller specifed cleanup on delete, then get rid of memory
if (pLockTable[wIndex].bCleanup == TRUE)
{
delete pDataTable[wIndex];
}
// Set the pointer to NULL
pDataTable[wIndex] = NULL;
// Decrement the count of used entries
wNumUsed--;
// Fix the entry so that it's next free index is what is currently
// the next free pointed to by the current last free entry.
// Then update the last free entry's next pointer, and finally,
// update the last free index to this entry
pLockTable[wIndex].wNextFree = pLockTable[wLastFree].wNextFree;
pLockTable[wLastFree].wNextFree = wIndex;
wLastFree = wIndex;
}
// Do two unlocks on the entry ... one for the original lock and another for
// the lock we obtained during the test
UnLockEntry(wIndex);
UnLockEntry(wIndex);
// Since the entire table is locked, then we can get away with this. If
// the code is ever changed so that the entire table is not locked during
// these operations, then this will cause a race condition.
// If we got rid of the data, then close the handle to the mutex and
// set the handle to NULL
if (pDataTable[wIndex] == NULL)
{
CloseHandle(pLockTable[wIndex].hLock);
pLockTable[wIndex].hLock = NULL;
}
}
EXIT:
// Unlock the table
UnLockTable();
return bRetCode;
}
/*
** TSTable::Delete
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
BOOL TSTable<EntryData>::Delete(DWORD_PTR dwID,
BOOL bCleanup)
{
BOOL bRetCode = TRUE;
WORD wIndex,
wUID;
BreakID(dwID, &wIndex, &wUID);
// Lock the table
LockTable();
// Verify that the ID is within bounds
if (wIndex >= wSize)
{
bRetCode = FALSE;
goto EXIT;
}
// verify that the UID matches
if (pLockTable[wIndex].wUniqueID != wUID)
{
bRetCode = FALSE;
goto EXIT;
}
// Verify that the entry is valid
if (pDataTable[wIndex] == NULL)
{
bRetCode = FALSE;
goto EXIT;
}
// Try to lock the entry (ie check to see if we had the entry locked)
if (LockEntry(wIndex, 0) == TRUE)
{
// mark it for deletion, set the cleanp flag and then unlock it
pLockTable[wIndex].bDeleted = TRUE;
pLockTable[wIndex].bCleanup = bCleanup;
UnLockEntry(wIndex);
// Note: this function does not call ::Unlock() on behalf of the user.
// Thus, the entry is only marked as deleted at this point and can no
// longer be locked by any threads (including the one that marked it for delete).
// The thread that marked the entry as deleted must call ::Unlock() to actually
// free up the entry.
}
EXIT:
// Unlock the table
UnLockTable();
return bRetCode;
}
/*
** TSTable::Lock
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION: Validates that an object still exists. Can be called
* regardless if caller has entry locked or not.
*
* RETURNS:
*
*/
template <class EntryData>
BOOL TSTable<EntryData>::Validate(DWORD_PTR dwID)
{
BOOL bRetCode = TRUE;
WORD wIndex,
wUID;
BreakID(dwID, &wIndex, &wUID);
// Lock the table
LockTable();
// Verify the index is within bounds
if (wIndex >= wSize)
{
bRetCode = FALSE;
goto EXIT;
}
// Verify that the entry is actually valid (ie the lock in non-NULL,
// the object status is valid, the unique ID matches, and the data ptr is not null).
if (pLockTable[wIndex].hLock == NULL ||
pLockTable[wIndex].bDeleted == TRUE ||
pLockTable[wIndex].wUniqueID != wUID ||
pDataTable[wIndex] == NULL)
{
bRetCode = FALSE;
goto EXIT;
}
EXIT:
// Unlock the table
UnLockTable();
return bRetCode;
}
/*
** TSTable::EnumerateEntries
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
EntryData* TSTable<EntryData>::EnumerateEntries(TABLE_CALLBACK callbackFunc,
LPVOID context,
BOOL bUnlockTable)
{
DWORD dwAction;
WORD wIndex = wSize;
EntryData* pEntryData = NULL;
DWORD dwEntryID;
// Make sure they passed a good function
if (callbackFunc == NULL)
{
goto EXIT;
}
// Lock the table
LockTable();
// Run through the data table and pass the data to the callback function
for (wIndex = 0; wIndex < wSize; wIndex++)
{
// Verify that there is actually data in the entry and that the entry has not
// been marked for deletion.
if (pDataTable[wIndex] == NULL ||
pLockTable[wIndex].bDeleted == TRUE)
{
continue;
}
// Try to lock the entry...if we cannot, then we don't have the lock and
// we will only report entries that we have locked (or are unlocked)
if (LockEntry(wIndex, 0) == FALSE)
{
continue;
}
// build and remember the "full" entry ID so we can use it to unlock the entry
dwEntryID = MakeID(wIndex, pLockTable[wIndex].wUniqueID);
// Save the pointer to the object.
pEntryData = pDataTable[wIndex];
// note: only unlock the table during the callback if we are explicitly asked to (the
// default is not to unlock the table).
if(bUnlockTable == TRUE)
UnLockTable();
// Call their function
dwAction = callbackFunc(pDataTable[wIndex], context);
if(bUnlockTable == TRUE)
LockTable();
// If the action says to delete the entry, then do so...if we are also to delete
// the object, pass in a TRUE.
if (dwAction == CALLBACK_DELETE_ENTRY ||
dwAction == CALLBACK_DELETE_ENTRY_AND_OBJECT)
{
Delete(dwEntryID, (dwAction == CALLBACK_DELETE_ENTRY ? FALSE : TRUE));
}
// If the action says abort, then break the loop...notice that means that
// the entry is still locked
else if (dwAction == CALLBACK_ABORT)
{
goto EXIT;
}
// Unlock the entry...notice we don't use UnLockEntry. The reason is that
// if the entry has been marked as deleted, then we need to have
// it destroyed and UnLockEntry doesn't do that.
Unlock(dwEntryID);
}
EXIT:
// Unlock the table
UnLockTable();
// Return NULL if we processed the entire table...if we were told to abort,
// return a pointer to the entry we stopped on.
return (wIndex == wSize ? NULL : pEntryData);
}
// helper functions - these assume table is locked and index is good
/*
** TSTable::LockEntry
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
BOOL TSTable<EntryData>::LockEntry(WORD wIndex,
DWORD timeout)
{
BOOL bRetCode = TRUE;
DWORD dwRetCode;
// Try to lock the entry. If it succeeds, we'll bump up the lock count. If
// the wait ended because another thread abandoned the mutex, then set the count
// to one.
dwRetCode = WaitForSingleObject(pLockTable[wIndex].hLock, timeout);
if (dwRetCode == WAIT_OBJECT_0)
{
pLockTable[wIndex].iLockCount++;
}
else if (dwRetCode == WAIT_ABANDONED)
{
pLockTable[wIndex].iLockCount = 1;
}
else
{
bRetCode = FALSE;
}
return bRetCode;
}
/*
** TSTable::UnLockEntry
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION:
*
* RETURNS:
*
*/
template <class EntryData>
BOOL TSTable<EntryData>::UnLockEntry(WORD wIndex)
{
BOOL bRetCode;
// Release the mutex...if that succeeds, reduce the count
if((bRetCode = ReleaseMutex(pLockTable[wIndex].hLock)) == TRUE)
{
pLockTable[wIndex].iLockCount--;
}
return bRetCode;
}
/*
** TSTable::GenerateUniqueID
*
* FILENAME: c:\msdev\projects\firewalls\inc\table.h
*
* PARAMETERS:
*
* DESCRIPTION: table should be locked before calling this function.
*
* RETURNS:
*
*/
template <class EntryData>
WORD TSTable<EntryData>::GenerateUniqueID()
{
// table must be locked
if(++wUniqueID == TSTABLE_INVALID_UNIQUE_ID)
wUniqueID++;
return(wUniqueID);
}
#endif