ReactOS系统中平衡二叉树，在一个空间中寻找与给定地址范围重合或部分重合的（已分配）区间

在一个空间中寻找与给定地址范围重合或部分重合的（已分配）区间

PMEMORY_AREA NTAPI MmLocateMemoryAreaByRegion(
PMADDRESS_SPACE AddressSpace,
PVOID Address,
ULONG_PTR Length
);

---

MmLocateMemoryAreaByRegion

/***************************************************************************************/
//在一个空间中寻找与给定地址范围重合或部分重合的（已分配）区间
PMEMORY_AREA STDCALL MmLocateMemoryAreaByRegion(PMADDRESS_SPACE AddressSpace,
    PVOID Address, ULONG_PTR Length)
{ 
    PMEMORY_AREA Node;
    PVOID Extent = (PVOIDK(ULONG_PTR)Address + Length);//地址范围的终点
    MmVerifyMemoryAreas(AddressSpace);//检测该AVL树是否存在问题
    /*Special ease for empty tree.*/
    if (AddressSpace->MemoryAreaBoot == NULL)
        return NULL;
    /* Traverse the tree from left to right.*/
    for (Node = MmIterateFirstNode(AddressSpace->MemoryAreaRoot);
        Node!= NULL;Node = MmIterateNextNode(Node))
    {
        if (Node->StartingAddress >= Address && Node->StartingAddress < Extent)
            return Node;//部分重合，区间的起点落在给定范围之内
        if (Node->EndingAddress > Address && Node->EndingAddress < Extent)
            return Node;//部分重合，区间的终点落在给定范围之内
        if (Node->StartingAddress <= Address && Node->EndingAddress >= Extent)
            return Node;//全部重合，给定范围落在区间之内
       if(Node->StartingAddress >= Extent)
            return NULL;
} //end for
return NULL;
}

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