195 lines
4.4 KiB
C
195 lines
4.4 KiB
C
/**
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* WinPR: Windows Portable Runtime
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* Reference Count Table
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*
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* Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <winpr/config.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <winpr/crt.h>
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#include <winpr/collections.h>
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/**
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* C reference counting
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* http://msdn.microsoft.com/en-us/library/windows/desktop/ms693431/
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*/
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static wReference* ReferenceTable_FindEntry(wReferenceTable* referenceTable, void* ptr)
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{
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UINT32 index = 0;
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BOOL found = FALSE;
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wReference* reference = NULL;
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for (index = 0; index < referenceTable->size; index++)
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{
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reference = &referenceTable->array[index];
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if (reference->Pointer == ptr)
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found = TRUE;
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}
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return (found) ? reference : NULL;
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}
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static wReference* ReferenceTable_GetFreeEntry(wReferenceTable* referenceTable)
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{
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UINT32 index = 0;
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BOOL found = FALSE;
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wReference* reference = NULL;
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for (index = 0; index < referenceTable->size; index++)
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{
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reference = &referenceTable->array[index];
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if (reference->Pointer == NULL)
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{
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reference->Count = 0;
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found = TRUE;
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}
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}
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if (!found)
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{
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UINT32 new_size;
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wReference* new_ref;
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if (!referenceTable->size)
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{
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free(referenceTable->array);
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referenceTable->array = NULL;
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return NULL;
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}
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new_size = referenceTable->size * 2;
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new_ref = (wReference*)realloc(referenceTable->array, sizeof(wReference) * new_size);
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if (!new_ref)
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return NULL;
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referenceTable->size = new_size;
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referenceTable->array = new_ref;
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ZeroMemory(&referenceTable->array[(referenceTable->size / 2)],
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sizeof(wReference) * (referenceTable->size / 2));
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return ReferenceTable_GetFreeEntry(referenceTable);
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}
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return reference;
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}
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UINT32 ReferenceTable_Add(wReferenceTable* referenceTable, void* ptr)
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{
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UINT32 count = 0;
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wReference* reference = NULL;
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if (referenceTable->synchronized)
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EnterCriticalSection(&referenceTable->lock);
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reference = ReferenceTable_FindEntry(referenceTable, ptr);
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if (!reference)
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{
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reference = ReferenceTable_GetFreeEntry(referenceTable);
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reference->Pointer = ptr;
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reference->Count = 0;
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}
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count = ++(reference->Count);
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if (referenceTable->synchronized)
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LeaveCriticalSection(&referenceTable->lock);
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return count;
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}
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UINT32 ReferenceTable_Release(wReferenceTable* referenceTable, void* ptr)
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{
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UINT32 count = 0;
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wReference* reference = NULL;
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if (referenceTable->synchronized)
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EnterCriticalSection(&referenceTable->lock);
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reference = ReferenceTable_FindEntry(referenceTable, ptr);
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if (reference)
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{
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count = --(reference->Count);
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if (count < 1)
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{
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if (referenceTable->ReferenceFree)
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{
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referenceTable->ReferenceFree(referenceTable->context, ptr);
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reference->Pointer = NULL;
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reference->Count = 0;
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}
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}
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}
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if (referenceTable->synchronized)
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LeaveCriticalSection(&referenceTable->lock);
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return count;
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}
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wReferenceTable* ReferenceTable_New(BOOL synchronized, void* context, REFERENCE_FREE ReferenceFree)
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{
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wReferenceTable* referenceTable;
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referenceTable = (wReferenceTable*)calloc(1, sizeof(wReferenceTable));
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if (!referenceTable)
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return NULL;
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referenceTable->context = context;
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referenceTable->ReferenceFree = ReferenceFree;
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referenceTable->size = 32;
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referenceTable->array = (wReference*)calloc(referenceTable->size, sizeof(wReference));
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if (!referenceTable->array)
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goto error_array;
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referenceTable->synchronized = synchronized;
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if (synchronized && !InitializeCriticalSectionAndSpinCount(&referenceTable->lock, 4000))
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goto error_critical_section;
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return referenceTable;
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error_critical_section:
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free(referenceTable->array);
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error_array:
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free(referenceTable);
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return NULL;
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}
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void ReferenceTable_Free(wReferenceTable* referenceTable)
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{
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if (referenceTable)
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{
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if (referenceTable->synchronized)
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DeleteCriticalSection(&referenceTable->lock);
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DeleteCriticalSection(&referenceTable->lock);
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free(referenceTable->array);
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free(referenceTable);
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}
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}
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