143 lines
4.7 KiB
C
143 lines
4.7 KiB
C
//---------------------------------------------------------------------------------------------------------------------------------
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// File: InterlockedSList.h
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//
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// Contents: Contains a portable abstraction for interlocked, singly
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// linked list.
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//
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// Microsoft Drivers 5.10 for PHP for SQL Server
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// Copyright(c) Microsoft Corporation
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// All rights reserved.
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// MIT License
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// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files(the ""Software""),
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// to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and / or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions :
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// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
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// THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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// IN THE SOFTWARE.
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//---------------------------------------------------------------------------------------------------------------------------------
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#ifndef __INTERLOCKEDSLIST_H__
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#define __INTERLOCKEDSLIST_H__
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#include "interlockedatomic.h"
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#define SLIST_ENTRY SINGLE_LIST_ENTRY
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#define PSLIST_ENTRY PSINGLE_LIST_ENTRY
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typedef struct _SINGLE_LIST_ENTRY {
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// Want a volatile pointer to non-volatile data so place after all type info
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struct _SINGLE_LIST_ENTRY * volatile Next;
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} SINGLE_LIST_ENTRY, *PSINGLE_LIST_ENTRY;
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typedef union _SLIST_HEADER {
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// Provides 8 byte alignment for 32-bit builds. Technically, not needed for
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// current implementation below but leaving for future use.
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ULONGLONG Alignment;
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struct {
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// Want a volatile pointer to non-volatile data so place after all type info
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PSLIST_ENTRY volatile Head;
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volatile LONG Depth;
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volatile LONG Mutex;
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} List;
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} SLIST_HEADER, *PSLIST_HEADER;
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inline VOID InitializeSListHead( PSLIST_HEADER slist )
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{
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assert( NULL != slist );
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slist->List.Head = NULL;
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slist->List.Depth = 0;
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slist->List.Mutex = 0;
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}
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inline PSLIST_ENTRY InterlockedPopEntrySList( PSLIST_HEADER slist )
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{
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assert( NULL != slist );
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// Exit prior to 'mutex' if we think it is empty
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// Some callers (like sqlncli/msdart/dll/dynslist.h) rely on a NULL
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// result from Pop to indicate the list is empty. This early exit
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// is an optimization and not technically needed for correctness.
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PSLIST_ENTRY oldHead = slist->List.Head;
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if ( NULL == oldHead )
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{
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return NULL;
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}
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while ( 0 != slist->List.Mutex || 0 != InterlockedCompareExchange( &slist->List.Mutex, 1, 0 ) )
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{
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// Spin until 'mutex' is free
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}
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// We have the 'mutex' so proceed with update
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oldHead = slist->List.Head;
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if ( NULL != oldHead )
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{
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slist->List.Head = oldHead->Next;
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--(slist->List.Depth);
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assert( 0 <= slist->List.Depth );
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}
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// Free the 'mutex'
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slist->List.Mutex = 0;
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return oldHead;
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}
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inline PSLIST_ENTRY InterlockedPushEntrySList( PSLIST_HEADER slist, PSLIST_ENTRY newEntry )
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{
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assert( NULL != slist );
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while ( 0 != slist->List.Mutex || 0 != InterlockedCompareExchange( &slist->List.Mutex, 1, 0 ) )
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{
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// Spin until 'mutex' is free
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}
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// We have the 'mutex' so proceed with update
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PSLIST_ENTRY oldHead = slist->List.Head;
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newEntry->Next = oldHead;
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slist->List.Head = newEntry;
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++(slist->List.Depth);
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// Free the 'mutex'
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slist->List.Mutex = 0;
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return oldHead;
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}
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inline PSLIST_ENTRY InterlockedFlushSList( PSLIST_HEADER slist )
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{
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assert( NULL != slist );
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while ( 0 != slist->List.Mutex || 0 != InterlockedCompareExchange( &slist->List.Mutex, 1, 0 ) )
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{
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// Spin until 'mutex' is free
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}
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// We have the 'mutex' so proceed with update
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PSLIST_ENTRY oldHead = slist->List.Head;
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slist->List.Head = NULL;
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slist->List.Depth = 0;
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// Free the 'mutex'
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slist->List.Mutex = 0;
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return oldHead;
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}
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// If the list has more than USHORT nodes then this method
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// will not return reliable results.
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inline USHORT QueryDepthSList( PSLIST_HEADER slist )
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{
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assert( NULL != slist );
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return static_cast<USHORT>(slist->List.Depth);
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}
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#endif // __INTERLOCKEDSLIST_H__
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